VENTANA MEDICAL SYSTEMS INC
S-1/A, 1996-07-03
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<PAGE>   1
 
   
      AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JULY 3, 1996
    
 
                                                       REGISTRATION NO. 333-4461
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                            ------------------------
 
   
                                AMENDMENT NO. 2
    
 
                                       TO
 
                                    FORM S-1
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
                            ------------------------
 
                         VENTANA MEDICAL SYSTEMS, INC.
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)
                            ------------------------
 
<TABLE>
<S>                             <C>                             <C>
            DELAWARE                          3841                         94-2976937
(STATE OR OTHER JURISDICTION OF   (PRIMARY STANDARD INDUSTRIAL          (I.R.S. EMPLOYER
 INCORPORATION OR ORGANIZATION)   CLASSIFICATION CODE NUMBER)        IDENTIFICATION NUMBER)
</TABLE>
 
                        3865 NORTH BUSINESS CENTER DRIVE
                             TUCSON, ARIZONA 85705
                                 (520) 887-2155
  (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE, OF
                   REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)
 
                                R. JAMES DANEHY
                     PRESIDENT AND CHIEF EXECUTIVE OFFICER
                         VENTANA MEDICAL SYSTEMS, INC.
                        3865 NORTH BUSINESS CENTER DRIVE
                             TUCSON, ARIZONA 85705
                                 (520) 887-2155
 (NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE,
                             OF AGENT FOR SERVICE)
                            ------------------------
 
                                   COPIES TO:
 
<TABLE>
<S>                                             <C>
             BARRY E. TAYLOR, ESQ.                           GARY L. SELLERS, ESQ.
         CHRISTOPHER D. MITCHELL, ESQ.                     SIMPSON THACHER & BARTLETT
            TREVOR J. CHAPLICK, ESQ.                          425 LEXINGTON AVENUE
        WILSON SONSINI GOODRICH & ROSATI                 NEW YORK, NEW YORK 10017-3954
            PROFESSIONAL CORPORATION                             (212) 455-2000
               650 PAGE MILL ROAD
        PALO ALTO, CALIFORNIA 94304-1050
                 (415) 493-9300
</TABLE>
 
                            ------------------------
 
        APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC:
As soon as practicable after the effective date of this Registration Statement.
                            ------------------------
 
     If any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, check the following box. / /
 
     If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering. / /
 
     If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. / /
 
     If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box. / /
                            ------------------------
 
     THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL
FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(A) OF
THE SECURITIES ACT OF 1933 OR UNTIL THE REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SUCH SECTION 8(A),
MAY DETERMINE.
 
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<PAGE>   2
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
                             CROSS-REFERENCE SHEET
         PURSUANT TO ITEM 501(B) OF REGULATION S-K SHOWING LOCATION IN
                     PROSPECTUS OF PART I ITEMS OF FORM S-1
 
<TABLE>
<CAPTION>
          ITEM NUMBER AND HEADING IN FORM S-1
                REGISTRATION STATEMENT                     LOCATION OF CAPTION IN PROSPECTUS
- -------------------------------------------------------  -------------------------------------
<C>   <S>                                                <C>
  1.  Forepart of the Registration Statement and
      Outside Front Cover Page of Prospectus...........  Forepart of Registration Statement;
                                                         Outside Front Cover Page; Additional
                                                         Information
  2.  Inside Front and Outside Back Cover Pages of
      Prospectus.......................................  Inside Front Cover Page; Outside Back
                                                         Cover Page
  3.  Summary Information, Risk Factors and Ratio of
      Earnings to Fixed Charges........................  Prospectus Summary; The Company; Risk
                                                         Factors
  4.  Use of Proceeds..................................  Use of Proceeds
  5.  Determination of Offering Price..................  Outside Front Cover Page;
                                                         Underwriting
  6.  Dilution.........................................  Dilution; Risk Factors
  7.  Selling Security Holders.........................  Principal and Selling Stockholders
  8.  Plan of Distribution.............................  Outside and Inside Front Cover Pages;
                                                         Underwriting; Outside Back Cover Page
  9.  Description of Securities to be Registered.......  Prospectus Summary; Dividend Policy;
                                                         Capitalization; Description of
                                                         Capital Stock; Shares Eligible for
                                                         Future Sale
 10.  Interests of Named Experts and Counsel...........  Legal Matters
 11.  Information with Respect to the Registrant.......  Outside and Inside Front Cover Pages;
                                                         Prospectus Summary; Risk Factors; Use
                                                         of Proceeds; Dividend Policy;
                                                         Capitalization; Dilution; Selected
                                                         Consolidated Financial and Operating
                                                         Data; Management's Discussion and
                                                         Analysis of Financial Condition and
                                                         Results of Operations; Business;
                                                         Management; Certain Transactions;
                                                         Principal Stockholders; Description
                                                         of Capital Stock; Shares Eligible for
                                                         Future Sale; Financial Statements;
                                                         Outside Back Cover Page
 12.  Disclosure of Commission Position on
      Indemnification for Securities Act Liabilities...  Not Applicable
</TABLE>
<PAGE>   3
 
     INFORMATION CONTAINED HEREIN IS SUBJECT TO COMPLETION OR AMENDMENT. A
     REGISTRATION STATEMENT RELATING TO THESE SECURITIES HAS BEEN FILED WITH THE
     SECURITIES AND EXCHANGE COMMISSION. THESE SECURITIES MAY NOT BE SOLD NOR
     MAY OFFERS TO BUY BE ACCEPTED PRIOR TO THE TIME THE REGISTRATION STATEMENT
     BECOMES EFFECTIVE. THIS PROSPECTUS SHALL NOT CONSTITUTE AN OFFER TO SELL OR
     THE SOLICITATION OF AN OFFER TO BUY NOR SHALL THERE BE ANY SALE OF THESE
     SECURITIES IN ANY STATE IN WHICH SUCH OFFER, SOLICITATION OR SALE WOULD BE
     UNLAWFUL PRIOR TO REGISTRATION OR QUALIFICATION UNDER THE SECURITIES LAWS
     OF ANY SUCH STATE.
 
   
                   SUBJECT TO COMPLETION, DATED JULY 3, 1996
    
 
                                3,000,000 SHARES
 
                                      LOGO
                         VENTANA MEDICAL SYSTEMS, INC.
 
                                  COMMON STOCK
                         ------------------------------
 
     Of the 3,000,000 shares (the "Shares") of common stock, par value $.001 per
share (the "Common Stock"), offered hereby (the "Offering"), 2,200,000 Shares
are being sold by Ventana Medical Systems, Inc. ("Ventana" or the "Company") and
800,000 Shares are being sold by certain stockholders of the Company (the
"Selling Stockholders"). See "Principal and Selling Stockholders." The Company
will not receive any of the proceeds from the sale of Shares by the Selling
Stockholders. Prior to the Offering, there has been no public market for the
Common Stock of the Company, and no assurance can be given that an active
trading market for the Common Stock will develop after the Offering. It is
currently estimated that the initial public offering price will be between
$14.00 and $16.00 per share. See "Underwriting" for a discussion of the factors
to be considered in determining the initial public offering price.
                         ------------------------------
 
        THE COMMON STOCK OFFERED HEREBY INVOLVES A HIGH DEGREE OF RISK.
   
                    SEE "RISK FACTORS" BEGINNING ON PAGE 6.
    
                         ------------------------------
 
THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES
     AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS
        THE COMMISSION OR ANY STATE SECURITIES COMMISSION PASSED UPON
           THE ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY
                REPRESENTATION TO THE CONTRARY IS A CRIMINAL
                   OFFENSE.
 
<TABLE>
<S>                                 <C>              <C>              <C>              <C>
- -------------------------------------------------------------------------------------------------------
- -------------------------------------------------------------------------------------------------------
                                                       UNDERWRITING                      PROCEEDS TO
                                        PRICE TO      DISCOUNTS AND     PROCEEDS TO        SELLING
                                         PUBLIC       COMMISSIONS(1)     COMPANY(2)      STOCKHOLDERS
- -------------------------------------------------------------------------------------------------------
Per Share..........................        $                $                $                $
- -------------------------------------------------------------------------------------------------------
Total(3)...........................        $                $                $                $
- -------------------------------------------------------------------------------------------------------
- -------------------------------------------------------------------------------------------------------
</TABLE>
 
(1) The Company and the Selling Stockholders have agreed to indemnify the
    Underwriters against certain liabilities, including liabilities arising
    under the Securities Act of 1933, as amended. See "Underwriting."
 
(2) Before deducting expenses of the Offering payable by the Company, estimated
    at $925,000.
 
(3) Certain of the Selling Stockholders have granted the Underwriters a 30-day
    option to purchase up to an additional 450,000 shares of Common Stock on the
    same terms as the Common Stock offered hereby solely to cover
    over-allotments, if any (the "Over-Allotment Option"). If the Over-Allotment
    Option is exercised in full, the total Price to Public, Underwriting
    Discounts and Commissions and Proceeds to Selling Stockholders will be
    $          , $          and $          , respectively. See "Underwriting"
    and "Principal and Selling Stockholders."
                         ------------------------------
 
The Shares are being offered by the several Underwriters, subject to prior sale,
when, as and if delivered and accepted by them, subject to certain conditions,
including the approval of certain legal matters by counsel for the Underwriters.
The Underwriters reserve the right to withdraw, cancel or modify such offer and
to reject orders in whole or in part. It is expected that delivery of the Shares
will be made against payment therefor on or about                , 1996, at the
offices of Bear, Stearns & Co. Inc., 245 Park Avenue, New York, New York 10167.
                         ------------------------------
 
BEAR, STEARNS & CO. INC.                                 DILLON, READ & CO. INC.
 
                                           , 1996
<PAGE>   4
 
IN CONNECTION WITH THIS OFFERING, THE UNDERWRITERS MAY OVER-ALLOT OR EFFECT
TRANSACTIONS WHICH STABILIZE OR MAINTAIN THE MARKET PRICE OF THE COMMON STOCK OF
THE COMPANY AT A LEVEL ABOVE THAT WHICH MIGHT OTHERWISE PREVAIL IN THE OPEN
MARKET. SUCH TRANSACTIONS MAY BE EFFECTED ON THE NASDAQ NATIONAL MARKET OR
OTHERWISE. SUCH STABILIZING, IF COMMENCED, MAY BE DISCONTINUED AT ANY TIME.
<PAGE>   5
 
                               PROSPECTUS SUMMARY
 
   
     The following summary is qualified in its entirety by the more detailed
information, including "Risk Factors" and the Consolidated Financial Statements
and Notes thereto appearing elsewhere in this Prospectus. Unless otherwise
indicated, all information in this Prospectus (i) assumes no exercise of the
Underwriters' Over-Allotment Option, (ii) reflects a 1-for-2.7059046 reverse
split of the Common Stock to be effected prior to the closing of this Offering,
(iii) reflects the conversion of all outstanding shares of Convertible
Redeemable Preferred Stock ("Preferred Stock") into Common Stock and
cancellation of accrued dividends upon such conversion, and (iv) assumes the
exercise of warrants to purchase 81,530 shares of Common Stock of the Company
upon the closing of this Offering, which warrants will terminate if not so
exercised. See "Description of Capital Stock" and "Underwriting." The Shares of
Common Stock offered hereby are subject to a high degree of risk. See "Risk
Factors." This Prospectus contains forward-looking statements that involve risks
and uncertainties. The Company's actual results may differ materially from the
results discussed in the forward-looking statements. Factors that might cause
such differences include, but are not limited to, those discussed in "Risk
Factors."
    
                                  THE COMPANY
   
     Ventana develops, manufactures and markets proprietary instrument/reagent
systems that automate immunohistochemistry ("IHC") and in situ hybridization
("ISH") tests for the analysis of cells and tissues on microscope slides. These
tests are important tools used in diagnosing and selecting treatment for cancer.
With a worldwide installed base of 581 instruments as of March 31, 1996, the
Company believes that it is the worldwide leader in the automated IHC testing
market. The Company estimates that its installed base of instruments is
approximately five times as large as the combined installed base of all of the
Company's current competitors. Ventana has placed instruments with 35 of the 42
cancer centers identified as principal cancer research centers by the National
Cancer Institute including the Mayo Clinic, the Dana Farber Cancer Institute,
The Johns Hopkins University and the M.D. Anderson Cancer Center. Each Ventana
proprietary system placed typically provides a recurring revenue stream as
customers consume reagents and supplies sold by the Company with each test
conducted.
    
   
     Ventana's "patient priority" systems (the Ventana ES and gen II) perform
multiple tests rapidly on a single patient biopsy thereby providing a matrix of
diagnostic data to the pathologist. In February 1996, Ventana acquired BioTek
Solutions, Inc. ("BioTek") for several strategic reasons. The Company believes
the combination of Ventana's "patient priority" systems and BioTek's TechMate
"batch processing" systems, which process high volumes of tests on multiple
patient biopsies, will enable the Company to serve the full range of health care
institutions that perform IHC tests. Ventana increased its installed base of
instruments from 294 to 581 as a result of the acquisition, thereby increasing
the corresponding aggregate recurring reagent revenue stream and enabling the
Company to become the worldwide leader in automated IHC testing. Ventana
believes significant synergies and margin improvements can be realized from the
integration of BioTek into Ventana's business model in which important
value-added activities are performed internally, in contrast to BioTek's
reliance on third parties.
    
   
     Cancer is the second leading cause of death in the United States accounting
for 25% of deaths. Currently, approximately 10 million people in the United
States have a history of invasive cancer. It is estimated that approximately 1.4
million new cases of invasive cancer will be diagnosed each year. The vast
majority of IHC testing associated with cancer diagnosis and treatment in the
United States is conducted in an aggregate of approximately 2,200 clinical
institutions and reference and research laboratories which the Company estimates
creates the opportunity for the placement of as many as 2,500 automated IHC
testing instruments. The Company believes that less than 25% of such
institutions and laboratories currently conduct IHC testing on an automated
basis. The international market for instrument placements is estimated by the
Company to be approximately 1.2 times the size of the United States market, with
Europe accounting for the majority of the international market potential.
    
   
     As compared to manual IHC testing, Ventana's automated systems provide
improved reliability, reproducibility and consistency of test results. The
systems' economic advantages include reduced cost per test, faster turnaround
time, increased test throughput and a reduced dependence on skilled laboratory
technicians. The Company believes it will play a critical, expanding role in
cancer science as researchers will use Ventana systems to accelerate the
identification and development of new tests and that the Company's installed
base of instruments will speed the commercialization and clinical implementation
of such new tests.
    
   
     The main element of the Company's strategy to strengthen its leadership
position in automated IHC testing is to maximize instrument placements in order
to create a barrier that competitors, which compete on the basis of product and
price, will need to overcome. To meet this objective, the Company plans to
introduce two lower priced instruments, one for potential patient priority
customers (the Ventana NexES) and one for potential batch processing customers
(the TechMate 250). The Company believes that these lower priced instruments
will enable it to increase its emphasis on instrument placements through reagent
programs ("RPs"). In an RP, the Company provides the customer with the use of an
instrument with no capital investment which creates an opportunity for the
Company to generate reagent revenue. The Company believes that it can accelerate
the rate of expansion of its installed base of instruments by using RPs because
the required capital investment associated with a purchase, a significant sales
    
hurdle, will be eliminated.
 
                                        3
<PAGE>   6
 
   
                                  THE OFFERING
    
 
   
<TABLE>
<S>                                         <C>
Common Stock offered:
  By the Company..........................  2,200,000 shares
  By the Selling Stockholders.............  800,000 shares
          Total...........................  3,000,000 shares
Common Stock to be outstanding after the
  Offering................................  10,990,091 shares(1)
Use of proceeds...........................  For repayment of approximately $16.2 million of
                                            indebtedness, capital expenditures, working
                                            capital and general corporate purposes.
Proposed Nasdaq National Market Symbol....  VMSI
</TABLE>
    
 
- ---------------
 
   
(1) Includes 8,708,561 outstanding shares of Common Stock, 81,530 shares of
    Common Stock issuable upon the exercise of outstanding warrants which would
    otherwise expire upon the closing of this Offering and the 2,200,000 Shares
    of Common Stock offered by the Company hereby. Excludes 887,740 shares of
    Common Stock issuable upon exercise of warrants that may remain outstanding
    after the completion of this Offering and 840,399 shares of Common Stock
    issuable upon the exercise of options outstanding under the Company's stock
    option plans.
    
 
                                        4
<PAGE>   7
 
           SUMMARY CONSOLIDATED FINANCIAL INFORMATION AND OPERATING DATA
                   (DOLLARS IN THOUSANDS, EXCEPT PER SHARE DATA)
 
   
<TABLE>
<CAPTION>
                                                                     ACTUAL                               PRO FORMA(1)
                                                ------------------------------------------------   ---------------------------
                                                                                 THREE MONTHS                     THREE MONTHS
                                                  YEAR ENDED DECEMBER 31,      ENDED MARCH 31,      YEAR ENDED       ENDED
                                                ---------------------------   ------------------   DECEMBER 31,    MARCH 31,
                                                 1993      1994      1995      1995       1996         1995           1996
                                                -------   -------   -------   -------   --------   ------------   ------------
<S>                                             <C>       <C>       <C>       <C>       <C>        <C>            <C>
STATEMENT OF OPERATIONS DATA:
Sales:
  Instruments.................................  $ 1,162   $ 2,588   $ 4,644   $ 1,007   $  1,594     $  8,396       $  1,733
  Reagents and other..........................    1,519     3,339     5,969     1,195      2,552       11,079          3,495
                                                -------   -------   -------   -------    -------      -------        -------
    Total net sales...........................    2,681     5,927    10,613     2,202      4,146       19,475          5,228
Cost of goods sold............................    1,722     2,531     4,282       936      1,432        9,096          1,924
                                                -------   -------   -------   -------    -------      -------        -------
Gross profit..................................      959     3,396     6,331     1,266      2,714       10,379          3,304
Operating expenses:
  Research and development....................    2,100     1,926     2,239       556        613        4,407            771
  Selling, general and administrative.........    4,067     6,899     7,435     1,594      2,374       10,968          2,799
  Nonrecurring expenses.......................       --        --        --        --      9,983        9,983             --
  Amortization of intangibles.................       --        --        --        --         46          557            139
                                                -------   -------   -------   -------    -------      -------        -------
Loss from operations..........................   (5,208)   (5,429)   (3,343)     (884)   (10,302)     (15,536)          (405)
Interest income (expense).....................      229        59        74        50         (5)          74             (5)
                                                -------   -------   -------   -------    -------      -------        -------
Net loss......................................  $(4,979)  $(5,370)  $(3,269)  $  (834)  $(10,307)    $(15,462)      $   (410)
                                                =======   =======   =======   =======    =======      =======        =======
Net loss per share, as adjusted(2)............                      $ (0.36)  $ (0.09)  $  (1.12)    $  (1.55)      $  (0.04)
                                                                    =======   =======    =======      =======        =======
Shares used in computing net loss per share,
  as adjusted(2)..............................                        8,973     8,838      9,204        9,975         10,206
                                                                    =======   =======    =======      =======        =======
</TABLE>
    
 
   
<TABLE>
<CAPTION>
                                                                                                  MARCH 31, 1996
                                                                                            --------------------------
                                                                                            ACTUAL      AS ADJUSTED(3)
                                                                                            -------     --------------
<S>                                                                                         <C>         <C>
BALANCE SHEET DATA:
Cash and cash equivalents.................................................................  $ 3,436        $ 18,413
Long-term debt............................................................................   15,035              --
Working capital...........................................................................      419          15,396
Total assets..............................................................................   21,742          36,719
Accumulated deficit(4)....................................................................  (32,436)        (32,436)
Total stockholders' equity (deficit)(4)...................................................   (1,560)         28,452
</TABLE>
    
 
SELECTED OPERATING DATA:
 
    The following table sets forth the Company's pro forma annual instrument
placements and instrument installed base for the periods indicated as if the
acquisition of BioTek had taken place on January 1, 1992:
 
   
<TABLE>
<CAPTION>
                                                                                                                 THREE
                                                                                                                 MONTHS
                                                                                YEAR ENDED DECEMBER 31,          ENDED
                                                                              ----------------------------     MARCH 31,
                                                                              1992    1993    1994    1995        1996
                                                                              ----    ----    ----    ----    ------------
<S>                                                                           <C>     <C>     <C>     <C>     <C>
INSTRUMENT PLACEMENTS (UNITS):
Patient priority (Ventana).................................................    17      56      74     113           33
Batch processing (BioTek)..................................................     4      37     106     128           12
                                                                               --      --
                                                                                              ---     ---          ---
  Total annual placements..................................................    21      93     180     241           45
                                                                               ==      ==     ===     ===          ===
    Total instrument installed base........................................    22     115     295     536          581
                                                                               ==      ==     ===     ===          ===
    RPs in installed base..................................................     6      25      44      66           72
                                                                               ==      ==     ===     ===          ===
</TABLE>
    
 
- ---------------
 
   
(1) Adjusted to reflect the acquisition of BioTek as if it had occurred on
    January 1, 1995. BioTek was acquired on February 26, 1996.
    
 
   
(2) See Note 1 to the Consolidated Financial Statements and Note 8 to the
    Unaudited Pro Forma Condensed Consolidated Financial Statements for
    information concerning the computation of net loss per share.
    
 
   
(3) Adjusted to give effect to the sale of the Shares of Common Stock offered by
    the Company hereby and the application of the net proceeds thereof (at an
    assumed initial public offering price of $15.00 per share). See "Use of
    Proceeds," "Capitalization" and "Dividend Policy."
    
 
   
(4) Gives effect to the cancellation of accrued Preferred Stock dividends upon
    the assumed conversion of the Preferred Stock into Common Stock. Actual
    amounts reflect the assumed conversion of the Preferred Stock but not the
    exercise of warrants which would otherwise expire upon the closing of this
    Offering.
    
 
                                        5
<PAGE>   8
 
                                    RISK FACTORS
 
   
     In addition to the other information in this Prospectus, the following risk
factors should be considered carefully in evaluating the Company and its
business before purchasing the Shares of Common Stock offered hereby. This
Prospectus contains forward-looking statements which involve risks and
uncertainties. The Company's actual results may differ materially from the
results discussed in the forward-looking statements. Factors that might cause
such differences include, but are not limited to, those discussed in Risk
Factors.
    
 
   
CONTINUING LOSSES; UNCERTAINTY OF FUTURE PROFITABILITY
    
 
   
     The Company has incurred cumulative losses of $32.4 million from its
inception in 1985 through March 31, 1996. In February 1996, the Company acquired
BioTek, which had sustained cumulative losses of $18.2 million since its
inception in October 1990. The Company intends to make increased investments in
both product development and sales and marketing and expects to incur operating
losses through at least the first half of 1997. The Company's ability to achieve
profitability is dependent on a variety of factors including the extent to which
its instrument and reagent systems continue to achieve market acceptance, the
Company's ability to sell reagents to its customers, the Company's ability to
compete successfully, the Company's ability to develop, introduce, market and
distribute existing and new diagnostic systems, the Company's ability to expand
manufacturing capacity as required, the successful integration of BioTek's
operations and the receipt of required regulatory approvals for products
developed by the Company. There can be no assurance that the Company will be
successful in these efforts. Moreover, if profitability is achieved, the level
of profitability cannot be accurately predicted and there can be no assurance
that any such profitability will be sustained. See "Management's Discussion and
Analysis of Financial Condition and Results of Operations" and "Business."
    
 
   
FUTURE FLUCTUATIONS IN OPERATING RESULTS
    
 
   
     The Company derives revenues from the sale of reagents and instruments. The
initial placement of an instrument is subject to a longer, less consistent sales
cycle than the sale of reagents, which begin and are typically recurring once an
instrument is placed. Consequently, the Company's future operating results are
likely to fluctuate substantially from period to period because instrument sales
are likely to remain an important part of revenues in the near future. The
degree of fluctuation will depend on the timing, level and mix of instruments
placed through direct sales and instruments placed through RPs. The Company
anticipates that the percentage of instruments placed through RPs, in particular
RP placements without formal reagent purchase commitments, will increase in the
future which is likely to result in a decrease in instrument sales both in
absolute dollars and as a percentage of total revenues. In addition, average
daily reagent use by customers may fluctuate from period to period, which may
contribute to future fluctuations in revenues. In particular, customers who have
received instruments under RP arrangements that do not provide for specified
reagent purchase commitments are not contractually obligated to purchase
reagents from the Company, and there can be no assurance as to the timing or
volume of reagent purchases by such customers. Furthermore, customers that have
entered into contractual RP agreements may also attempt to cancel all or a
portion of their reagent purchase commitments. Accordingly, there can be no
assurance as to the level of revenues that will be generated by customers
procuring instruments through RP arrangements, particularly from those customers
who obtain instruments without reagent purchase commitments. In the event that
RP customers do not purchase anticipated quantities of reagents, the Company
will have incurred substantial costs in supplying instruments to RP customers
without receipt of an adequate reagent revenue stream and the Company's
business, financial condition and results of operations would be materially and
adversely affected. Sales of instruments may fluctuate from period to period
because sales to the Company's international distributors typically provide such
distributors with several months of instrument inventory, which the distributors
will subsequently seek to place with end users. The Company's instrument
installed base includes instruments shipped to DAKO A/S ("DAKO") and recognized
as sales, over 85% of which the Company believes DAKO has placed with end-users.
Results of operations for the remainder of 1996 are also expected to be affected
by costs associated with the integration of BioTek's operations. These include
costs associated with centralizing reagent manufacturing, expanding reagent
product offerings for batch processing instruments and eliminating operational
redundancies. Other factors that may result in fluctuations in operating results
include the timing of new product announcements and the introduction of new
products and new technologies by the Company
    
 
                                        6
<PAGE>   9
 
   
and its competitors, market acceptance of the Company's current or new products,
developments with respect to regulatory matters, availability and cost of raw
materials from its suppliers, competitive pricing pressures, increased research
and development expenses, and increased marketing and sales expenses associated
with the implementation of the Company's market expansion strategies for its
instrument and reagent products. Future instrument and reagent sales could also
be adversely affected by the configuration of the Company's patient priority
systems, which require the use of the Company's detection chemistries,
particularly if and to the extent that competitors are successful in developing
and introducing new IHC instruments or if competitors offer reagent supply
arrangements having pricing or other terms more favorable than those offered by
the Company. In connection with future introductions of new products, the
Company may be required to incur reserves or charges for inventory obsolescence
in connection with unsold inventory of older generations of products. To date,
however, the Company has not incurred material charges or expenses associated
with inventory obsolescence in connection with new product introductions. In
addition, a significant portion of the Company's expense levels are based on its
expectation of a higher level of revenues in the future and are relatively fixed
in nature. Therefore, if revenue levels are below expectations, operating
results in a given period are likely to be adversely affected. See "Management's
Discussion and Analysis of Financial Condition and Results of Operations."
    
 
   
RATE OF MARKET ACCEPTANCE AND TECHNOLOGICAL CHANGE
    
 
   
     Use of automated systems to perform diagnostic tests is relatively new.
Historically, the diagnostic tests performed by the Company's systems have been
performed manually by laboratory personnel. The rate of market acceptance of the
Company's products will be largely dependent on the Company's ability to
persuade the medical community of the benefits of automated diagnostic testing
using the Company's products. Market acceptance and sales of the Company's
products may also be affected by the price and quality of the Company's
products. The Company's products could also be rendered obsolete or
noncompetitive by virtue of technological innovations in the fields of cellular
or molecular diagnostics. Failure of the Company's products to achieve market
acceptance would have a material adverse effect on the Company's business,
financial condition and results of operations. See "Business."
    
 
   
RISKS ASSOCIATED WITH DEVELOPMENT AND INTRODUCTION OF NEW PRODUCTS
    
 
   
     The Company's future growth and profitability will be dependent, in large
part, on its ability to develop, introduce and market new instruments and
reagents used in the diagnosis and treatment of cancer and additional disease
states. In particular, the Company must successfully and timely introduce the
NexES and TechMate 250. These instruments are smaller capacity, lower priced
instruments than the Company's current instruments and are necessary to expand
the market opportunity at smaller hospitals and reference laboratories in the
United States and Europe. The Company depends in part on the success of medical
research in developing new antibodies, nucleic acid probes and clinical
diagnostic procedures that can be adapted for use in the Company's systems. In
addition, the Company will need to obtain licenses on satisfactory terms to
certain of these technologies, as to which there is no assurance. Certain of the
Company's products are currently under development, initial testing or
preclinical or clinical evaluation by the Company. Other products are scheduled
for future development. Products under development or scheduled for future
development may prove to be unreliable from a diagnostic standpoint, may be
difficult to manufacture in an efficient manner, may fail to receive necessary
regulatory clearances, may not achieve market acceptance or may encounter other
unanticipated difficulties. The failure of the Company to develop, introduce and
market new products on a timely basis or at all could have a material adverse
effect on the Company's business, financial condition and results of operations.
See "Business -- Research and Development."
    
 
COMPETITION
 
   
     Competition in the diagnostic industry is intense and is expected to
increase. Competition in the diagnostic industry is based on, among other
things, product quality, performance, price and the breadth of a company's
product offerings. The Company's systems compete both with products manufactured
by competitors and with traditional manual diagnostic procedures. The Company's
competitors may succeed in developing products that are more reliable or
effective or less costly than those developed by the Company and may be more
successful than the Company in manufacturing and marketing their products. There
are other
    
 
                                        7
<PAGE>   10
 
   
companies engaged in research and development of diagnostic devices or reagents,
and, notwithstanding the Company's product development efforts, the introduction
of such devices or alternative methods for diagnostic testing could hinder the
Company's ability to compete effectively and could have a material adverse
effect on the Company's business, financial condition and results of operations.
    
 
   
     In the instrument market, several companies offer instruments that perform
IHC tests and can be used with any supplier's reagents, which may be attractive
to certain customers. In addition, any future growth in the market for automated
IHC instruments may result in additional market entrants and increased
competition, including more aggressive price competition. Many of the companies
selling or developing diagnostic devices and instruments and many potential
entrants in the automated IHC market have financial, manufacturing, marketing
and distribution resources significantly greater than those of Ventana. In
addition, many of these current and potential competitors have long-term
supplier relationships with Ventana's existing and potential customers. These
competitors may be able to leverage existing customer relationships to enhance
their ability to place new IHC instruments. Competition in the market for
automated IHC instruments, including the advent of new market entrants and
increasing price competition, could have a material adverse effect on the
Company's business, financial condition and results of operations.
    
 
   
     In the market for reagents, the Company encounters competition from
suppliers of primary antibodies and detection chemistries, which are the two
principal types of reagents used in IHC tests. The Company's patient priority
instruments require the use of the Company's detection chemistries but can be
used with primary antibodies supplied by third parties, and the Company's batch
processing instruments can be used with both detection chemistries and primary
antibodies supplied by third parties. Accordingly, the Company encounters
significant competition in the sale of reagents for use on those of its
instruments that can be used with reagents supplied by third parties. Lower
prices for reagents used in manual IHC tests could also limit the growth of
automation. Certain of the Company's current and potential competitors in the
reagent market have financial, manufacturing, marketing and distribution
resources greater than those of the Company. Competition in the market for
reagents could also increase as a result of new market entrants providing more
favorable reagent supply arrangements than the Company, including lower reagent
prices. In particular, new entrants in the instrument market may seek to enhance
their competitive position through reduced reagent
pricing or more favorable supply arrangements; the Company's current instrument
customers may find it attractive to purchase primary antibodies for patient
priority instruments and primary antibodies and detection chemistries for batch
processing instruments from such competitors. Increased competition in the
reagent market could have a material adverse effect on the Company's business,
financial condition and results of operations. See "Business -- Competition."
    
 
MANUFACTURING RISKS
 
   
     The Company has only manufactured patient priority instruments and reagents
for commercial sale since late 1991, and manufacturing of the Company's batch
processing instruments is performed by third parties. As the Company continues
to increase production of such instruments and reagents and develops and
introduces new products, it may from time to time experience difficulties in
manufacturing. BioTek currently manufactures reagents in its Santa Barbara,
California facility and Ventana manufactures reagents in its Tucson, Arizona
facilities. The Company expects to complete, in September 1996, the
consolidation of reagent manufacturing in its Tucson facilities. Difficulties or
delays in integrating reagent manufacturing could result in the inability to
achieve anticipated cost reductions and could have a material adverse effect on
the Company's business, financial condition and results of operations. Ventana
must increase production volumes of instruments and reagents in a cost-effective
manner in order to be profitable. To increase production levels, the Company
will need to scale-up its manufacturing facilities, increase its automated
manufacturing capabilities and continue to comply with the current good
manufacturing practices ("GMPs") prescribed by the United States Food and Drug
Administration ("FDA") and other standards prescribed by various federal, state
and local regulatory agencies in the United States and other countries,
including the International Standards Organization ("ISO") 9000 Series
certifications. There can be no assurance that manufacturing and quality
problems will not arise as the Company increases its manufacturing operations or
that such scale-up can be achieved in a timely manner or at a commercially
reasonable cost. Manufacturing or quality
    
 
                                        8
<PAGE>   11
 
   
problems or difficulties or delays in manufacturing scale-up could have a
material adverse effect on the Company's business, financial condition and
results of operations. See "Business -- Manufacturing."
    
 
   
DEPENDENCE UPON KEY SUPPLIERS
    
 
   
     The Company's reagent products are formulated from both chemical and
biological materials utilizing proprietary Ventana technology as well as
standard processing techniques. Certain components and raw materials, primarily
antibodies, used in the manufacturing of the Company's reagent products are
currently provided by single-source vendors. There can be no assurance that the
materials or reagents needed by the Company will be available in commercial
quantities or at acceptable prices. Any supply interruption or yield problems
encountered in the use of materials from these vendors could have a material
adverse effect on the Company's ability to manufacture its products until a new
source of supply is obtained. The use of alternative or additional suppliers
could be time consuming and expensive. In addition, a number of the components
used to manufacture the ES and gen II instruments are fabricated on a custom
basis to the Company's specifications and are currently available from a limited
number of sources. Consequently, in the event the supply of materials or
components from any of these vendors were delayed or interrupted for any reason
or in the event of quality or reliability problems with such components or
suppliers, the Company's ability to supply such instruments could be impaired,
which could have a material adverse effect on the Company's business, financial
condition and results of operations. See "Business -- Manufacturing."
    
 
   
DEPENDENCE UPON THIRD-PARTY MANUFACTURERS FOR BATCH PROCESSING INSTRUMENTS
    
 
   
     The Company relies on two outside parties to manufacture its batch
processing instruments. Kollsman Manufacturing Company, Inc. ("Kollsman")
currently manufactures the TechMate 500 instrument and the Company has entered
into an agreement with Kollsman for the manufacture of such instrument. The
Company has entered into a contract manufacturing agreement with LJL BioSystems,
Inc. ("LJL") for the manufacture of the TechMate 250 instrument. There can be no
assurance that these manufacturers will be able to meet the Company's product
needs in a satisfactory, cost effective or timely manner. The Company's reliance
on third-party manufacturers involves a number of additional risks, including
the absence of guaranteed capacity, and reduced control over delivery schedules,
quality assurance and costs. The amount and timing of resources to be devoted to
these activities by such manufacturers are not within the control of the
Company, and there can be no assurance that manufacturing problems will not
occur in the future. Any such manufacturing or supply problems could have a
material adverse effect on the Company's business, financial condition and
results of operations. See "Business -- Manufacturing."
    
 
   
RISKS ASSOCIATED WITH UNITED STATES DISTRIBUTION RELATIONSHIP
    
 
   
     The Company's batch processing instruments and reagents are sold under
distribution agreements entered into by BioTek. In the United States, batch
processing instruments and reagents are sold through Curtin Matheson Scientific,
Inc., a subsidiary of Fischer Scientific, Inc. ("CMS"), under an exclusive
agreement that expires in April 1998. United States sales through CMS are
subject to several operating conditions and risks. In particular, it has
historically been necessary for BioTek to support, and the Company anticipates
that it will need to continue to support, the efforts of CMS with direct field
sales and support personnel. As a result, the Company generates lower gross
margins on sales through CMS than it would generate were it to sell directly to
end-users and incurs higher selling expenses than typically associated with
third-party distribution arrangements. As a result of these factors and due to
the presence of the Company's direct sales force in the United States, the
Company does not intend to renew the agreement with CMS upon its expiration in
April 1998. The Company has had discussions regarding possible modifications to
or early termination of the relationship with CMS. However, these discussions
are not currently ongoing. To the extent that CMS does not adequately promote
and market batch processing instruments and reagents or manage customer
relationships or in the event that difficulties arise in the relationship
between the Company and CMS, the Company's sales of batch processing instruments
and reagents in the United States could be adversely affected and the Company
could also experience disruptions in the supply of batch processing instruments
and reagents to customers in the United States. These developments could have a
material adverse effect on the Company's business, financial condition and
results of operations.
    
 
                                        9
<PAGE>   12
 
   
RISKS ASSOCIATED WITH EUROPEAN DISTRIBUTION RELATIONSHIP
    
 
   
     In Europe, batch processing instruments are sold through DAKO which also
pays BioTek a fixed dollar royalty for each instrument in service in exchange
for the right to sell its own reagents for use with such systems. The agreement
with DAKO provides DAKO with exclusive distribution rights for batch processing
instruments in Europe and other territories, subject to certain performance
requirements. The agreement expires in December 1999. Accordingly, the Company
is likely to be dependent upon DAKO for international sales of batch processing
instruments through this date.
    
 
     In connection with BioTek's agreement with DAKO, DAKO made two loans
secured by a pledge of substantially all of BioTek's assets. DAKO also made
prepayments on future instrument sales and reagent royalties to BioTek. These
loans and prepayments were used to fund TechMate 250 instrument development and
working capital requirements. The aggregate balance of the secured loans and
prepayments was $1.6 million and $0.9 million, respectively, at March 31, 1996.
Of the secured loans, $0.3 million bears interest at 5% per annum and the
remaining $1.3 million does not bear interest. The prepayments do not bear
interest. The secured loans and prepayments are recorded as advances from
distributor in the Company's Consolidated Financial Statements. The amounts
payable under these loans are repaid through discounts on DAKO instrument
purchases from BioTek. Upon termination of the distribution agreement or in the
event of a default by BioTek under the distribution agreement (including a
failure to satisfy development milestones with respect to the TechMate 250
instrument), the secured loans will convert to fixed term loans that will be due
and payable in 12 equal quarterly installments commencing upon such event.
 
   
     Since the acquisition of BioTek, Ventana and DAKO have been engaged in
discussions regarding various provisions of the distribution agreement. DAKO has
asserted that BioTek has not fulfilled its obligations with respect to
development and commercial introduction of the TechMate 250 instrument. DAKO's
remedies under the agreement include (i) requiring repayment of the secured
loans in 12 equal quarterly installments commencing upon a default by BioTek and
(ii) an irrevocable license to manufacture TechMate instruments for resale
internationally and a related reduction in the fixed dollar royalty rate paid by
DAKO to BioTek for each instrument included in the royalty base. The
negotiations with DAKO could result in an attempt by DAKO to exercise
contractual remedies available to it under the distribution agreement and terms
of the secured loans, an interruption in the distribution of the Company's batch
processing instruments outside the United States or litigation between the
parties with respect to the agreement, which would involve significant costs as
well as diversion of management time. Any of the foregoing could have a material
adverse effect on the Company's business, financial condition and results of
operations. There can be no assurance that the Company would prevail in any
litigation involving the agreement.
    
 
   
     There can be no assurance as to the future course or outcome of the
Company's negotiations with DAKO or as to the Company's future relationship with
DAKO. If DAKO were successful in obtaining a manufacturing license for TechMate
instruments, the Company could experience a loss of instrument and royalty
revenue which could have a material adverse effect on the Company's business,
financial condition and results of operations. In addition, termination of the
agreement with DAKO could materially adversely affect the Company's business,
financial condition and results of operations.
    
 
   
RISKS ASSOCIATED WITH PAST AND FUTURE ACQUISITIONS
    
 
   
     In February 1996 the Company acquired BioTek. Although the Company has no
pending agreements or commitments, the Company may make additional acquisitions
of complementary businesses, products or technologies in the future.
Acquisitions of companies, divisions of companies, or products entail numerous
risks, including (i) the potential inability to successfully integrate acquired
operations and products or to realize anticipated synergies, economies of scale
or other value, (ii) diversion of management's attention, and (iii) loss of key
employees of acquired operations. No assurance can be given that the Company
will not incur problems in integrating the BioTek operations or any future
acquisitions and there can be no assurance that the acquisition of BioTek or any
other future acquisition will result in the Company becoming profitable or, if
the Company achieves profitability, that such acquisition will increase the
Company's profitability. Furthermore, there can be no assurance that the Company
will realize value from any such acquisition which equals or exceeds the
consideration paid. Any such problems could have a material adverse effect on
the Company's
    
 
                                       10
<PAGE>   13
 
business, financial condition and results of operations. In addition, future
acquisitions by the Company may result in dilutive issuances of equity
securities, the incurrence of additional debt, large one-time write-offs and the
creation of goodwill or other intangible assets that could result in
amortization expense. These factors could have a material adverse effect on the
Company's business, financial condition and results of operations. See
"Management's Discussion and Analysis of Financial Condition and Results of
Operations" and "Business."
 
   
RISKS RELATING TO PATENTS AND PROPRIETARY RIGHTS
    
 
   
     The Company's success depends, in part, on its ability to obtain patents,
maintain trade secret protection and operate without infringing the proprietary
rights of others. There can be no assurance that the Company's patent
applications will result in patents being issued or that any issued patents will
provide protection against competitive technologies or will be held valid if
challenged. Others may independently develop products similar to those of the
Company or design around or otherwise circumvent patents issued to the Company.
In the event that any relevant claims of third-party patents are upheld as valid
and enforceable, the Company could be prevented from practicing the subject
matter claimed in such patents, or would be required to obtain licenses from the
patent owners of each of such patents or to redesign its products or processes
to avoid infringement. There can be no assurance that such licenses would be
available or, if available, would be on terms acceptable to the Company or that
the Company would be successful in any attempt to redesign its products or
processes to avoid infringement. If the Company does not obtain necessary
licenses, it could be subject to litigation and encounter delays in product
introductions while it attempts to design around such patents. Alternatively,
the development, manufacture or sale of such products could be prevented.
Litigation would result in significant cost to the Company as well as diversion
of management time. Adverse determinations in any such proceedings could have a
material adverse effect on the Company's business, financial condition and
results of operations. See "Business -- Patents and Proprietary Rights."
    
 
     Ventana also relies upon trade secret protection for its confidential and
proprietary information. There can be no assurance that others will not
independently develop substantially equivalent proprietary information or
techniques, gain access to Ventana's trade secrets or disclose such technology,
or that Ventana can effectively protect its trade secrets. Litigation to protect
Ventana's trade secrets would result in significant cost to the Company as well
as diversion of management time. Adverse determinations in any such proceedings
or unauthorized disclosure of Ventana trade secrets could have a material
adverse effect on Ventana's business, financial condition and results of
operations.
 
     BioTek is a party to litigation initiated by BioGenex Laboratories, Inc.
("BioGenex") relating to certain alleged past infringements of patent rights of
BioGenex. The Company believes that the resolution of this matter will not have
a material adverse effect on the Company's business, financial condition and
results of operations. For additional detail regarding this litigation, see
"Business -- Legal Proceedings."
 
   
UNCERTAINTY OF FUTURE FUNDING OF CAPITAL REQUIREMENTS
    
 
   
     The Company anticipates that its existing capital resources, including the
net proceeds of this Offering and interest earned thereon, will be adequate to
satisfy its capital requirements through at least the next 18 to 24 months. The
Company's future capital requirements will depend on many factors, including the
extent to which the Company's products gain market acceptance, the mix of
instruments placed through direct sales or through RPs, progress of the
Company's product development programs, competing technological and market
developments, expansion of the Company's sales and marketing activities, the
cost of manufacturing scale-up activities, possible acquisitions of
complementary businesses, products or technologies, the extent and duration of
operating losses and timing of regulatory approvals. The Company may require
additional capital resources and there is no assurance such capital will be
available to the extent required, on terms acceptable to the Company or at all.
Any such future capital requirements could result in the issuance of equity
securities which would be dilutive to existing stockholders. See "Management's
Discussion and Analysis of Financial Condition and Results of Operations."
    
 
                                       11
<PAGE>   14
 
   
DEPENDENCE ON KEY PERSONNEL
    
 
   
     The Company is dependent upon the retention of principal members of its
management, scientific, technical, marketing and sales staff and the recruitment
of additional personnel. The Company does not maintain "key person" life
insurance on any of its personnel. The Company competes with other companies,
academic institutions, government entities and other organizations for qualified
personnel in the areas of the Company's activities. The inability to hire or
retain qualified personnel could have a material adverse effect on the Company's
business, financial condition and results of operations. See "Management."
    
 
   
UNCERTAINTIES RELATED TO GOVERNMENT FUNDING
    
 
   
     A portion of the Company's products are sold to universities, research
laboratories, private foundations and other institutions where funding is
dependent upon grants from government agencies, such as the National Institutes
of Health. Research funding by the government, however, may be significantly
reduced under several budget proposals being discussed by the United States
Congress or for other reasons. Any such reduction may materially affect the
ability of the Company's research customers to purchase the Company's products.
    
 
   
FDA AND OTHER GOVERNMENT REGULATION
    
 
   
     The manufacturing, marketing and sale of the Company's products are subject
to extensive and rigorous government regulation in the United States and in
other countries. In the United States and certain other countries, the process
of obtaining and maintaining required regulatory approvals is lengthy, expensive
and uncertain. In the United States, the FDA regulates, as medical devices,
clinical diagnostic tests and reagents, as well as instruments used in the
diagnosis of adverse conditions. The Federal Food, Drug, and Cosmetic Act
governs the design, testing, manufacture, safety, efficacy, labeling, storage,
record keeping, approval, advertising and promotion of the Company's products.
There are two principal FDA regulatory review paths for medical devices: the
510(k) pre-market notification ("510(k)") process and the pre-market approval
("PMA") process. The PMA process typically requires the submission of more
extensive clinical data and is costlier and more time-consuming to complete than
the 510(k) process. For a detailed description of this regulatory framework, see
"Business -- Government Regulation."
    
 
     The FDA regulates, as medical devices, instruments, diagnostic tests and
reagents that are traditionally manufactured and commercially marketed as
finished test kits or equipment. Some clinical laboratories, however, choose to
purchase individual reagents intended for specific analyses and develop and
prepare their own finished diagnostic tests. Although neither the individual
reagents nor the finished tests prepared from them by the clinical laboratories
have traditionally been regulated by the FDA, the FDA has recently proposed a
rule that, if adopted, would regulate the reagents sold to clinical laboratories
as medical devices. The proposed rule would also restrict sales of these
reagents to clinical laboratories certified under the Clinical Laboratory
Improvement Amendments of 1988 ("CLIA") as high complexity testing laboratories.
The Company intends to market some diagnostic products as finished test kits or
equipment and others as individual reagents; consequently, some or all of these
products may be regulated as medical devices.
 
     Medical devices generally require FDA approval or clearance prior to being
marketed in the United States. The process of obtaining FDA clearances or
approvals necessary to market medical devices can be time-consuming, expensive
and uncertain, and there can be no assurance that any clearance or approval
sought by the Company will be granted or that FDA review will not involve delays
adversely affecting the marketing and sale of the Company's products. Further,
clearances or approvals may place substantial restrictions on the indications
for which the product may be marketed or to whom it may be marketed.
Additionally, there can be no assurance that the FDA will not require additional
data, require that the Company conduct further clinical studies or obtain a PMA
causing the Company to incur further cost and delay.
 
     The Company's instruments, with respect to automated IHC testing functions,
have been categorized by the FDA as automated cell staining devices and have
been exempted from the 510(k) notification process. To date, ISH tests have not
received FDA approval and, therefore, use of the gen II for ISH tests will be
restricted to research applications. New instrument products that the Company
may introduce could require
 
                                       12
<PAGE>   15
 
future 510(k) notifications. Certain antibodies that the Company may wish to
market with labeling indicating that they can be used in the diagnosis of
particular diseases may require PMA approval. In addition, the FDA has proposed
that some of the antibody products that Ventana may wish to market be subjected
to a pre-filing certification process. Certain of the Company's products are
currently sold for research use and are labeled as such.
 
     Failure to comply with applicable regulatory requirements can, among other
consequences, result in fines, injunctions, civil penalties, suspensions or loss
of regulatory approvals, recalls or seizures of products, operating restrictions
and criminal prosecutions. In particular, the FDA enforces regulations
prohibiting the marketing of products for nonindicated uses. In addition,
governmental regulations may be established that could prevent or delay
regulatory approval of the Company's products. Delays in or failure to receive
approval of products the Company plans to introduce, loss of or additional
restrictions or limitations relating to previously received approvals, other
regulatory action against the Company or changes in the applicable regulatory
climate could individually or in the aggregate have a material adverse effect on
the Company's business, financial condition and results of operations.
 
   
     The Company is also required to register as a medical device manufacturer
with the FDA and is inspected on a routine basis by the FDA for compliance with
the FDA GMP regulations. The Company's clinical laboratory customers are subject
to CLIA, which is intended to ensure the quality and reliability of medical
testing.
    
 
   
     In addition to these regulations, the Company is subject to numerous
federal, state and local laws and regulations relating to such matters as safe
working conditions and environmental matters. There can be no assurance that
such laws or regulations will not in the future have a material adverse effect
on the Company's business, financial condition and results of operations. See
"-- Environmental Matters" and "Business -- Government Regulation."
    
 
   
RISKS RELATING TO AVAILABILITY OF THIRD-PARTY REIMBURSEMENT AND POTENTIAL
ADVERSE EFFECTS OF HEALTH CARE REFORM
    
 
   
     The Company's ability to achieve revenue growth and profitability may
depend on the ability of the Company's customers to obtain adequate levels of
third-party reimbursement for use of certain diagnostic tests in the United
States, Europe and other countries. Currently, availability of third-party
reimbursement is limited and uncertain for some IHC tests.
    
 
     In the United States, the Company's products are purchased primarily by
medical institutions and laboratories which bill various third-party payors,
such as Medicare, Medicaid, other government programs and private insurance
plans, for the health care services provided to their patients. Third-party
payors may deny reimbursement to the Company's customers if they determine that
a prescribed device or diagnostic test has not received appropriate FDA or other
governmental regulatory clearances or approvals, is not used in accordance with
cost-effective treatment methods as determined by the payor, or is experimental,
unnecessary or inappropriate. The success of the Company's products may depend
on the extent to which appropriate reimbursement levels for the costs of such
products and related treatment are obtained by the Company's customers from
government authorities, private health insurers and other organizations, such as
health maintenance organizations ("HMOs"). Third-party payors are increasingly
challenging the prices charged for medical products and services. The trend
towards managed health care in the United States and the concurrent growth of
organizations such as HMOs could significantly influence the purchase of health
care services and products. In addition, the federal government and certain
members of Congress have proposed, and various state governments have adopted or
are considering, programs to reform the health care system. These proposals are
focused, in large part, on controlling the escalation of health care
expenditures. The cost containment measures that health care payors are
instituting and the impact of any health care reform could have a material
adverse effect on the levels of reimbursement the Company's customers receive
from third-party payors and the Company's ability to market and sell its
products and consequently could have a material adverse effect on the Company's
business, financial condition and results of operations. See "Business --
Third-Party Reimbursement."
 
                                       13
<PAGE>   16
 
   
PRODUCT LIABILITY AND RECALLS; PRODUCT LIABILITY INSURANCE
    
 
   
     The marketing and sale of the Company's diagnostic instruments and reagents
entails risk of product liability claims. The Company has product liability
insurance coverage with a per occurrence maximum of $2.0 million and an
aggregate annual maximum of $5.0 million. There can be no assurance that this
level of insurance coverage will be adequate or that insurance coverage will
continue to be available on acceptable terms or at all. A product liability
claim or recall could have a material adverse effect on the Company's business,
reputation, financial condition and results of operations.
    
 
   
ENVIRONMENTAL MATTERS
    
 
   
     Certain of the Company's manufacturing processes, primarily processes
involved in manufacturing certain of the Company's reagent products, require the
use of potentially hazardous and carcinogenic chemicals. The Company is required
to comply with applicable federal, state and local laws regarding the use,
storage and disposal of such materials. The Company currently uses third-party
disposal services to remove and dispose of the hazardous materials used in its
processes. The Company could in the future encounter claims from individuals,
governmental authorities or other persons or entities in connection with
exposure to or disposal or handling of such hazardous materials or violations of
environmental laws by the Company or its contractors and could also be required
to incur additional expenditures for hazardous materials management or
environmental compliance. Costs associated with environmental claims, violations
of environmental laws or regulations, hazardous materials management and
compliance with environmental laws could have a material adverse effect on the
business, financial condition and results of operations of the Company. See
"Business -- Government Regulation."
    
 
   
BROAD DISCRETION OF MANAGEMENT TO ALLOCATE OFFERING PROCEEDS
    
 
   
     The Company intends to use $16.2 million of the estimated net proceeds from
the Offering to repay certain indebtedness. The Company anticipates that the
remaining estimated net proceeds of this Offering will be used for capital
expenditures, working capital and general corporate purposes. The amounts
identified for such uses under "Use of Proceeds" are estimates and the amounts
actually expended for each such purpose and the timing of such expenditures may
vary depending upon numerous factors. The Company's management will have broad
discretion in determining the amount and timing of expenditures, particularly
with respect to that portion of the net proceeds available for use for working
capital and general corporate purposes. See "Use of Proceeds."
    
 
   
CONTROL BY EXISTING STOCKHOLDERS; ANTI-TAKEOVER PROVISIONS
    
 
   
     After this Offering, the Company's officers, directors and principal
stockholders will beneficially own approximately 55% of the Company's
outstanding Common Stock. These stockholders will be able to elect all members
of the Company's Board of Directors and will have the ability to control
corporate actions requiring stockholder approval. Such concentration of
ownership may have the effect of delaying or preventing a change in control of
the Company. In addition, the Board of Directors has the authority, without
action by the stockholders, to fix the rights and preferences of, and issue
shares of, one or more series of preferred stock, which may have the effect of
delaying or preventing a change in control of the Company, and to issue
additional Common Stock which would be dilutive to existing stockholders. In
addition, provisions in the Company's Certificate of Incorporation and Bylaws
(i) prohibit the stockholders from acting by written consent without a meeting
or calling a special meeting of stockholders, (ii) require advance notice of
business proposed to be brought before an annual or special meeting of
stockholders and (iii) provide for a classified board of directors. The
amendment or modification of these provisions will require the affirmative vote
of the holders of 66 2/3% of the outstanding shares of Common Stock. See
"Principal and Selling Stockholders," "Management" and "Description of Capital
Stock."
    
 
   
ABSENCE OF PRIOR PUBLIC MARKET; POSSIBLE VOLATILITY OF STOCK PRICE
    
 
   
     Prior to this Offering, there has been no public market for the Company's
Common Stock. There can be no assurance that an active trading market for the
Common Stock will develop or, if developed, will be
    
 
                                       14
<PAGE>   17
 
sustained. The public offering price will be established by negotiations between
the Company and the Representatives of the Underwriters and may bear no
relationship to the price at which the Company's Common Stock trades after the
Offering. See "Underwriting" for a discussion of the factors to be considered in
determining the initial public offering price. In addition, the market price of
the Company's Common Stock, similar to the securities of other medical device
and life sciences companies, is likely to be highly volatile. Factors such as
fluctuations in the Company's operating results, announcements of technological
innovations or new products by the Company or its competitors, FDA and other
government regulation, developments with respect to patents or proprietary
rights, public concern as to the safety of products developed by the Company or
others, changes in financial analysts' estimates or recommendations regarding
the Company and general market conditions may have a material adverse effect on
the market price of the Company's Common Stock. The Company's results of
operations may, in future periods, fall below the expectations of public market
analysts and investors and, in such event, the market price of the Company's
Common Stock could be materially adversely affected.
 
   
SHARES ELIGIBLE FOR FUTURE SALE
    
 
   
     Sales of Common Stock (including shares issued upon the exercise of
outstanding options) in the public market after this Offering could impair the
Company's ability to raise capital through an offering of securities and could
materially adversely affect the market price of the Common Stock. Such sales
also might make it more difficult for the Company to sell equity securities or
equity-related securities in the future at a time and price that the Company
deems appropriate or at all. Upon consummation of this Offering, the Company
will have 10,990,091 shares of Common Stock outstanding, of which the 3,000,000
Shares offered hereby will be freely tradable (unless held by affiliates of the
Company) and the remaining 7,990,091 shares will be restricted securities within
the meaning of the Securities Act of 1933, as amended (the "Securities Act").
Approximately 39,703 of such shares will be available for immediate public
resale on the date of this Offering. An additional 2,023 shares of Common Stock
will be saleable at 90 days after the Offering. An additional 8,786 shares of
Common Stock will be saleable between 90 and 180 days after this Offering. The
Company's directors, executive officers and certain stockholders, who in the
aggregate hold 7,468,559 shares of Common Stock of the Company outstanding
immediately prior to the completion of this Offering, have entered into or are
subject to lock-up agreements under which they have agreed not to sell, directly
or indirectly, any shares owned by them for a period of 180 days after the date
of this Prospectus without the prior written consent of Bear, Stearns & Co. Inc.
Holders of outstanding options to purchase Common Stock have entered into or are
subject to similar agreements. Upon expiration of the 180-day lock-up
agreements, approximately 7,817,760 shares of Common Stock (including
approximately 349,201 shares subject to outstanding vested options) will become
eligible for immediate public resale, subject in some cases to vesting
provisions and volume limitations pursuant to Rule 144. The remaining
approximately 313,957 shares held by existing stockholders will become eligible
for public resale at various times over a period of less than two years
following the completion of this Offering, subject in some cases to vesting
provisions and volume limitations. 7,286,334 of the shares outstanding
immediately following the completion of this Offering will be entitled to
registration rights with respect to such shares upon termination of lock-up
agreements. The number of shares sold in the public market could increase if
registration rights are exercised. See "Description of Capital
Stock -- Registration Rights" and "Shares Eligible for Future Sale."
    
 
   
DILUTION
    
 
   
     The initial public offering price is substantially higher than the net
tangible book value per share of Common Stock. Investors purchasing shares of
Common Stock in this Offering will therefore incur immediate and substantial
dilution. See "Dilution."
    
 
   
ABSENCE OF DIVIDENDS
    
 
   
     The Company has not declared or paid any cash dividends since its inception
and does not anticipate paying any dividends in the foreseeable future. In
addition, the Company's bank credit agreement currently prohibits the Company
from paying cash dividends. See "Dividend Policy."
    
 
                                       15
<PAGE>   18
 
                                  THE COMPANY
 
     Ventana was incorporated in California in June 1985 and was reincorporated
in Delaware in December 1993. As used in this Prospectus, the terms "Ventana"
and the "Company" refer to Ventana Medical Systems, Inc. and its subsidiaries,
Ventana Medical Systems, S.A., Ventana Medical Systems GmbH and BioTek
Solutions, Inc. unless the context otherwise requires. The Company's principal
executive offices are located at 3865 North Business Center Drive, Tucson,
Arizona 85705. Its telephone number is (520) 887-2155.
 
   
     Ventana(TM), the Ventana logo(TM), ES(TM), gen II, TechMate(TM), Liquid
Coverslip(TM) and CheMate(TM) are trademarks of the Company. Trademarks of
others are also referred to in this Prospectus.
    
 
                                USE OF PROCEEDS
 
     The net proceeds to the Company from the sale of the Shares of Common Stock
offered hereby are estimated to be approximately $30.0 million assuming an
initial public offering price of $15.00 per share and after deducting the
estimated underwriting discounts and commissions and expenses of the Offering.
 
   
     The Company intends to use $16.2 million of the estimated net proceeds from
the Offering to repay (i) $14.2 million of debt incurred in connection with the
acquisition of BioTek and financing of related working capital requirements (the
"Acquisition Debt") and (ii) a $2.0 million bank term loan (the "Term Loan").
The Acquisition Debt bears interest at 7% per annum and matures in February
1998; however, accrued interest will be forgiven if the principal is repaid
prior to December 31, 1996. The Acquisition Debt is due and payable 30 days
after the completion of this Offering. The Term Loan bears interest at a rate of
2% over the bank's prime rate, is secured by a pledge of the Company's assets
and matures in March 1999. The Company expects to use approximately $1.8 million
of the net proceeds during the next 12 months for capital expenditures for
manufacturing and computer equipment. The Company anticipates that the estimated
remaining net proceeds of $12.0 million will be used for working capital and
general corporate purposes. Although the Company may use a portion of the net
proceeds for the acquisition of complementary businesses, products or
technologies, the Company currently has no agreements or commitments in this
regard. Pending such uses, the Company intends to invest the net proceeds of the
Offering in short-term, interest-bearing, investment-grade securities.
    
 
     The Company will not receive any proceeds from the sale of Shares by the
Selling Stockholders.
 
                                DIVIDEND POLICY
 
     The Company has not declared or paid any dividends since its inception and
does not intend to pay any dividends in the foreseeable future. In addition, the
Company's bank credit agreement currently prohibits the Company from paying cash
dividends.
 
                                       16
<PAGE>   19
 
                                    DILUTION
 
   
     The net tangible book value of the Company at March 31, 1996 was $(10.4)
million or $(1.29) per share after giving effect to the conversion of the
Preferred Stock into Common Stock and the issuance of 81,530 shares of Common
Stock upon the assumed exercise of outstanding warrants which would otherwise
expire upon the closing of this Offering. The net tangible book value per share
represents the Company's total tangible assets less total liabilities, divided
by the number of shares of Common Stock outstanding (assuming conversion of the
Preferred Stock). Dilution per share represents the difference between the
amount per share paid by investors in this Offering and the net tangible book
value per share after the Offering. After giving effect to (i) the sale of
Shares in this Offering at an assumed initial public offering price of $15.00
per share and (ii) the issuance of 81,530 shares of Common Stock upon the
assumed exercise of outstanding warrants which would otherwise expire upon the
closing of this Offering, the estimated net proceeds to the Company would be
approximately $30.0 million and the net tangible book value of the Company at
March 31, 1996 would be $19.6 million or $1.76 per share. This represents an
immediate increase in net tangible book value of $3.05 per share to existing
stockholders and an immediate dilution in net tangible book value of $13.24 per
share to new investors purchasing Shares at the assumed initial public offering
price. The following table illustrates this per share dilution:
    
 
   
<TABLE>
<S>                                                                          <C>        <C>
Assumed initial public offering price per share..........................               $15.00
  Net tangible book value per share before the Offering..................    $(1.29)
  Increase per share attributable to new investors.......................      3.05
                                                                             ------
Net tangible book value per share after the Offering.....................                 1.76
                                                                                        ------
Immediate dilution per share to new investors............................               $13.24
                                                                                        ======
</TABLE>
    
 
     The following table summarizes, as of March 31, 1996, the difference
between the existing stockholders and new investors purchasing Shares in this
Offering with respect to the number of Shares of Common Stock purchased, the
total consideration paid and the average price per share paid (assuming an
initial public offering price of $15.00 per share):
 
   
<TABLE>
<CAPTION>
                                        SHARES PURCHASED          TOTAL CONSIDERATION
                                     ----------------------     -----------------------     AVERAGE PRICE
                                       NUMBER       PERCENT       AMOUNT        PERCENT       PER SHARE
                                     ----------     -------     -----------     -------     -------------
<S>                                  <C>            <C>         <C>             <C>         <C>
Existing stockholders..............   8,113,424        79%      $31,016,000        48%         $  3.82
New investors......................   2,200,000        21%       33,000,000        52%           15.00
                                        -------       ---           -------       ---
          Total....................  10,313,424       100%      $64,016,000       100%         $  6.21
                                        =======       ===           =======       ===
</TABLE>
    
 
   
     The computations in the above table (i) are determined before deducting the
underwriting discounts and commissions and estimated expenses of the Offering
payable by the Company, (ii) assume no exercise of outstanding stock options or
warrants, other than the issuance of 81,530 shares of Common Stock upon the
assumed exercise of outstanding warrants which would otherwise expire upon the
closing of this Offering and (iii) do not give effect to stock issuance activity
subsequent to March 31, 1996, which consists of 646,664 shares issued upon the
exercise of stock purchase rights and 30,003 shares issued upon the exercise of
options and warrants through May 15, 1996. At May 15, 1996, there were options
outstanding to purchase 840,399 shares of Common Stock at a weighted average
exercise price of $2.48 per share. In addition, warrants to purchase 887,740
shares of Common Stock at an exercise price of $5.82 per share may remain
outstanding upon the completion of this Offering. To the extent outstanding
options and warrants are exercised, there will be further dilution to new
investors. See "Management -- Incentive Stock Plans," "Description of Capital
Stock" and Notes 7 and 10 to the Consolidated Financial Statements.
    
 
                                       17
<PAGE>   20
 
                                 CAPITALIZATION
 
     The following table sets forth the capitalization of the Company as of
March 31, 1996, after giving effect to the conversion of the Preferred Stock
into Common Stock upon the closing of the Offering, the restatement of the
Company's Certificate of Incorporation to provide for authorized capital stock
consisting of 50,000,000 shares of Common Stock and 5,000,000 shares of
undesignated preferred stock, and adjusted for the receipt of the estimated net
proceeds from the sale of Common Stock offered hereby and the application
thereof:
 
   
<TABLE>
<CAPTION>
                                                                             MARCH 31, 1996
                                                                        ------------------------
                                                                                         AS
                                                                         ACTUAL      ADJUSTED(1)
                                                                        --------     -----------
                                                                             (IN THOUSANDS)
<S>                                                                     <C>          <C>
Long-term debt(2).....................................................  $ 15,035      $      --
Stockholders' equity:
  Preferred Stock: $.001 par value, 5,000,000 shares authorized; none
     outstanding......................................................        --             --
  Common Stock: $.001 par value, 50,000,000 shares authorized;
     8,031,894 shares issued and outstanding and; 10,313,424 shares
     issued and outstanding, as adjusted-amount paid in(3)(4)(5)......    31,016         61,028
Accumulated deficit(6)................................................   (32,436)       (32,436)
Cumulative foreign currency translation adjustment....................      (140)          (140)
                                                                        --------       --------
  Total stockholders' equity (deficit)(4)(5)..........................    (1,560)        28,452
                                                                        --------       --------
          Total capitalization........................................  $ 13,475      $  28,452
                                                                        ========       ========
</TABLE>
    
 
- ---------------
 
   
(1) As adjusted shares outstanding includes the issuance of 81,530 shares of
    Common Stock upon the assumed exercise of outstanding warrants which would
    otherwise expire upon the closing of this Offering. As adjusted shares
    outstanding excludes 840,399 shares issuable upon exercise of stock options
    outstanding under the Company's 1988 Incentive Stock Option Plan as of May
    15, 1996 and warrants to purchase 887,740 shares of Common Stock which may
    remain outstanding upon completion of this Offering. As adjusted shares
    outstanding does not give effect to stock issuance activity after March 31,
    1996, which consists of 646,664 shares issued upon exercise of stock
    purchase rights and 30,003 shares issued upon the exercise of options and
    warrants through May 15, 1996. See "Management -- Incentive Stock Plans,"
    "Description of Capital Stock" and Notes 7 and 10 to the Consolidated
    Financial Statements.
    
 
   
(2) As of March 31, 1996, the Company had outstanding borrowings of $1.0 million
    under the bank credit agreement. Subsequent to March 31, 1996, the Company
    borrowed an additional $1.0 million, all of which was converted into a $2.0
    million term loan. The Company also raised $0.5 million through the private
    placement of subordinated notes subsequent to March 31, 1996 in connection
    with the acquisition of BioTek. The Company intends to repay $16.2 million
    of such debt with the proceeds of this Offering. See "Use of Proceeds."
    
 
(3) Assumes net proceeds of $30.0 million from this Offering based on an assumed
    initial public offering price of $15.00 per share.
 
(4) See Notes 6 and 7 to the Consolidated Financial Statements.
 
(5) Actual amounts reflect the assumed conversion of the Preferred Stock but not
    the exercise of warrants which would otherwise expire upon the closing of
    this Offering.
 
(6) Gives effect to cancellation of accrued Preferred Stock dividends upon the
    assumed conversion of the Preferred Stock into Common Stock.
 
                                       18
<PAGE>   21
 
    SELECTED CONSOLIDATED ACTUAL AND PRO FORMA FINANCIAL AND OPERATING DATA
 
   
     The selected consolidated statement of operations data set forth below for
the years ended December 31, 1995, 1994 and 1993, except for the components of
net sales, are derived from the Company's audited Consolidated Financial
Statements included elsewhere in this Prospectus. The selected consolidated
statement of operations data set forth below for the years ended December 31,
1992 and 1991, except for the components of net sales, are derived from audited
financial statements of the Company not included in this Prospectus. The
selected actual consolidated statement of operations data for the three months
ended March 31, 1996 and 1995, the components of net sales for all periods
presented, and the balance sheet data at March 31, 1996 are derived from
unaudited financial statements of the Company, which, in the opinion of
management, include all adjustments, consisting only of normal recurring
adjustments, necessary for a fair presentation of the financial position and
results of operations for the unaudited periods. The selected pro forma
statement of operations data are derived from the Unaudited Pro Forma Condensed
Consolidated Financial Statements included elsewhere in this Prospectus. The
unaudited interim information and pro forma information for the periods
presented are not necessarily indicative of the results which may be realized in
the future. The selected actual and pro forma consolidated financial and
operating data set forth below should be read in conjunction with "Management's
Discussion and Analysis of Financial Condition and Results of Operations" and
the Consolidated Financial Statements and Notes thereto included elsewhere in
this Prospectus. The Company has not paid any cash dividends since its
inception.
    
 
   
<TABLE>
<CAPTION>
                                                                ACTUAL                                        PRO FORMA(1)
                                 --------------------------------------------------------------------  --------------------------
                                                                                      THREE MONTHS     
                                                                                         ENDED                       THREE MONTHS
                                             YEAR ENDED DECEMBER 31,                   MARCH 31,        YEAR ENDED      ENDED
                                 -----------------------------------------------   ------------------  DECEMBER 31,   MARCH 31,
   STATEMENT OF OPERATIONS:       1991      1992      1993      1994      1995      1995       1996        1995          1996
                                 -------   -------   -------   -------   -------   -------   --------  ------------  ------------
                                                              (IN THOUSANDS, EXCEPT PER SHARE DATA)
<S>                              <C>       <C>       <C>       <C>       <C>       <C>       <C>       <C>           <C>
Sales:
  Instruments..................  $    50   $   717   $ 1,162   $ 2,588   $ 4,644   $ 1,007   $  1,594    $  8,396       $1,733
  Reagents and other...........       28       452     1,519     3,339     5,969     1,195      2,552      11,079        3,495
                                 --------  --------  --------  --------  --------  --------  --------    --------     --------
    Total net sales............       78     1,169     2,681     5,927    10,613     2,202      4,146      19,475        5,228
Cost of goods sold.............       49       832     1,722     2,531     4,282       936      1,432       9,096        1,924
                                 --------  --------  --------  --------  --------  --------   -------    --------     --------
Gross profit...................       29       337       959     3,396     6,331     1,266      2,714      10,379        3,304
Operating expenses:
  Research and development.....    1,352     1,194     2,100     1,926     2,239       556        613       4,407          771
  Selling, general and
    administrative.............      892     2,465     4,067     6,899     7,435     1,594      2,374      10,968        2,799
  Nonrecurring expenses........       --        --        --        --        --        --      9,983       9,983           --
  Amortization of
    intangibles................       --        --        --        --        --        --         46         557          139
                                 --------  --------  --------  --------  --------  --------   -------    --------      -------
Loss from operations...........   (2,215)   (3,322)   (5,208)   (5,429)   (3,343)     (884)   (10,302)    (15,536)        (405)
Interest income (expense)......       23        48       229        59        74        50         (5)         74           (5)
                                 --------  --------  --------  --------  --------  -------  ---------    --------      -------
Net loss.......................  $(2,192)  $(3,274)  $(4,979)  $(5,370)  $(3,269)  $  (834)  $(10,307)   $(15,462)      $ (410)
                                 ======== ========= ========= ========= ========= ========= =========    ========      =======
Per share data(2):
  Net loss per share, as
    adjusted...................                                          $ (0.36)  $ (0.09)  $  (1.12)   $  (1.55)      $(0.04)
                                                                         ========= ========= =========   ========      =======
  Shares used in computing net
    loss per share, as
    adjusted...................                                            8,973     8,838      9,204       9,975       10,206
                                                                         ========= ========= =========   ========      =======
</TABLE>
    
 
   
<TABLE>
<CAPTION>
                                                                                                             MARCH 31, 1996
                                                                                                        ------------------------
                                                                                                         ACTUAL   AS ADJUSTED(3)
                                                                                                        --------  --------------
                                                                                                             (IN THOUSANDS)
<S>                                                                                                     <C>       <C>
BALANCE SHEET DATA:
Cash and cash equivalents...........................................................................    $ 3,436      $ 18,413
Long-term debt......................................................................................     15,035            --
Working capital.....................................................................................        419        15,396
Total assets........................................................................................     21,742        36,719
Accumulated deficit(4)..............................................................................    (32,436 )     (32,436)
Total stockholders' equity(deficit)(4)..............................................................     (1,560 )      28,452
</TABLE>
    
 
- ---------------
   
(1) Adjusted to reflect the acquisition of BioTek as if it had occurred on
    January 1, 1995. BioTek was acquired February 26, 1996.
    
 
(2) See Note 1 to Consolidated Financial Statements and Note 8 to the Unaudited
    Pro Forma Condensed Consolidated Financial Statements for information
    concerning the computation of net loss per share.
 
   
(3) Adjusted to give effect to the receipt of the net proceeds from the sale of
    the Shares of Common Stock offered by the Company hereby and the application
    thereof at an assumed initial public offering price of $15.00 per share. See
    "Use of Proceeds," and "Capitalization" and "Dividend Policy."
    
 
   
(4) Gives effect to the cancellation of accrued Preferred Stock dividends upon
    the assumed conversion of the Preferred Stock into Common Stock. Actual
    amounts reflect the assumed conversion of the Preferred Stock but not the
    exercise of warrants which would otherwise expire upon the closing of this
    Offering.
    
 
                                       19
<PAGE>   22
 
SELECTED OPERATING DATA:
 
   
     The following table sets forth the Company's annual pro forma instrument
placements and instrument installed base for the periods indicated as if the
acquisition of BioTek had occurred on January 1, 1992:
    
 
   
<TABLE>
<CAPTION>
                                                                                        THREE MONTHS
                                                                                         ENDED MARCH
                                                        YEAR ENDED DECEMBER 31,              31,
                                                    -------------------------------     -------------
                                                    1992     1993     1994     1995     1995     1996
                                                    ----     ----     ----     ----     ----     ----
<S>                                                 <C>      <C>      <C>      <C>      <C>      <C>
INSTRUMENT PLACEMENTS (UNITS)(1):
Patient priority..................................   17       56       74      113       28       33
Batch processing..................................    4       37      106      128       35       12
                                                     --
                                                             ---      ---      ---      ---      ---
     Total current placements.....................   21       93      180      241       63       45
                                                     ==      ===      ===      ===      ===      ===
RPs in current placements.........................    6       19       19       22        8        6
                                                     ==      ===      ===      ===      ===      ===
INSTRUMENT INSTALLED BASE (UNITS)(1):
Patient priority..................................   18       74      148      261      176      294
Batch processing..................................    4       41      147      275      182      287
                                                     --
                                                             ---      ---      ---      ---      ---
     Total instrument installed base..............   22      115      295      536      358      581
                                                     ==      ===      ===      ===      ===      ===
RPs in installed base.............................    6       25       44       66       52       72
                                                     ==      ===      ===      ===      ===      ===
</TABLE>
    
 
- ---------------
 
   
(1) Instrument placements refers to the number of instruments placed by the
    Company (either through a direct sale, rental, or RP) during a particular
    fiscal period (e.g., a fiscal quarter or year). Instrument installed base
    refers to the cumulative number of instruments shipped to customers as of
    the end of a particular fiscal period. Instrument installed base includes
    batch processing instruments shipped to DAKO and recognized as sales, over
    85% of which the Company believes DAKO has placed with end-users.
    
 
                                       20
<PAGE>   23
 
                      MANAGEMENT'S DISCUSSION AND ANALYSIS
                OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
 
     The following discussion of the financial condition and historical and pro
forma results of operations of the Company should be read in conjunction with
the Financial Statements and related Notes thereto included elsewhere in this
Prospectus. This Prospectus contains forward-looking statements which involve
risks and uncertainties. The Company's actual results may differ materially from
those anticipated by the forward-looking statements as a result of certain
factors, including those set forth in Risk Factors and elsewhere in this
Prospectus.
 
OVERVIEW
 
   
     Ventana develops, manufactures and markets proprietary instrument/reagent
systems that automate IHC and ISH tests for the analysis of cells and tissues on
microscope slides. Each Ventana proprietary system placed typically provides a
recurring revenue stream as customers consume reagents and supplies sold by the
Company with each test conducted. Reagents consist of two components: a primary
antibody and a detection chemistry which is used to visualize the primary
antibody. Therefore, the principal economic drivers for the Company are the
number, type and method of placement of instruments placed and the amount of
reagents and consumables used by the customer. The Company's strategy is to
maximize the number of instruments placed with customers and thereby increase
its ongoing, higher margin reagent revenue stream. The Company expects that
reagents will comprise a greater proportion of total revenues in the future as
its installed base of instruments increases, as new instrument placements
represent a smaller percentage of the Company's existing installed base of
instruments and as RP placements increase as a percentage of total instrument
placements.
    
 
   
     In February 1996, Ventana acquired BioTek for aggregate consideration of
$18.8 million, consisting of cash, promissory notes and the assumption of
liabilities. BioTek, founded in 1990, markets and sells automated diagnostic
systems that perform reliable, high volume batch processing of a single IHC test
on multiple patient biopsies. Ventana acquired BioTek for several strategic
reasons including its installed instrument base and complementary product line.
Historically, BioTek generated lower gross and operating margins than Ventana
due to its employment of a different business strategy which primarily involved
the use of third parties for key activities. BioTek's instruments were produced
by third-party manufacturers which prevented BioTek from capturing manufacturing
margin. BioTek's instruments have an open configuration, enabling the customer
to use reagents purchased from BioTek or others which impacted both the price
and volume of reagents purchased by customers from BioTek. In contrast,
Ventana's instruments have a closed configuration requiring the customer to use
Ventana's prepackaged detection chemistries. BioTek also realized lower gross
margins on reagents than Ventana due to its utilization of intermediate
materials in the manufacturing process which resulted in the capture of fewer
value-added steps. BioTek used CMS and DAKO as third-party distributors in the
United States and international markets, respectively, and supported its United
States sales efforts with field sales and technical support personnel. As a
result, BioTek experienced both lower gross margins than if it had sold its
products directly and a higher level of selling expense than typically incurred
in conjunction with third-party distribution arrangements.
    
 
   
     Ventana's goal is to integrate the operations of BioTek into the Ventana
business model, in which manufacturing, sales and marketing activities are
performed by Company employees. In May 1996, the Company completed the
integration of the BioTek and Ventana direct field sales and technical
personnel. The Company does not intend to renew the United States distribution
agreement with CMS which expires in April 1998. The Company is engaged in
discussions with DAKO regarding various aspects of the distribution arrangement.
The international distribution agreement with DAKO expires in December 1999. The
Company expects to complete the consolidation of BioTek's reagent manufacturing
into Ventana's Tucson facilities in September 1996. Following this
consolidation, the Company intends to convert BioTek's reagent manufacturing to
the process used by Ventana in which basic raw materials are used and important
value-added steps are performed internally. The Company believes that in the
near term it will be more cost effective to continue sourcing batch processing
instruments from third-party manufacturers. The Company has entered into a
manufacturing agreement with Kollsman for the TechMate 500 instrument and has
entered into a manufac-
    
 
                                       21
<PAGE>   24
 
   
turing agreement with LJL for production of the Company's next generation batch
processing instrument, the TechMate 250.
    
 
   
     From its inception in 1985 through its first commercial sale in late 1991,
Ventana's activities consisted primarily of research and development of its
instrument and reagent systems. During this period, Ventana incurred aggregate
net losses of $5.2 million. During the period from January 1, 1992 through March
31, 1996, the Company incurred additional net losses of $27.2 million including
$10.0 million related to the expensing of in-process research and development
and restructuring costs associated with the acquisition of BioTek, resulting in
cumulative losses of $32.4 million as of March 31, 1996. Similarly, BioTek
incurred over $18.2 million in losses from operations from its inception in
October 1990 until its acquisition by the Company in February 1996. The Company
expects that it will continue to incur losses through at least the first half of
1997 primarily as a result of expenses associated with the integration of
BioTek's operations and expenses associated with the expansion of manufacturing,
sales and marketing activities. There can be no assurance that the Company will
achieve profitability or that profitability, if achieved, will be sustained on
an annual or quarterly basis, or at all.
    
 
   
     The Company places instruments through direct sales, including nonrecourse
leases, instrument rentals and the Company's reagent programs ("RPs"). In an RP,
the Company provides the customer with the use of an instrument with no capital
investment which creates an opportunity for the Company to generate reagent
revenue. The terms and conditions of RP instrument placements can vary from
formal agreements specifying minimum volumes and unit pricing for reagent
purchases to short-term, informal arrangements where customers purchase reagents
on a month-to-month basis. For RP placements, the Company incurs the cost of
manufacturing or procuring instruments and recognizes revenues only as customers
purchase reagents rather than at the time of instrument placement. The
manufacturing cost of instruments placed through RPs is charged to cost of goods
sold by depreciating standard costs over a period of three or four years. As a
result, gross profit for instruments placed through RPs is recognized over a
three or four year period rather than at the time of placement, as is the case
in direct sales. Revenue associated with instruments placed through RPs is based
on a volume pricing matrix which is designed to enable the Company to recover
the sales value of the instrument through an increased price on the reagents
purchased by the user. The Company typically recovers the cash costs associated
with the placement of instruments through RPs in less than two years, although
the Company's ability to recover such costs may be affected by the volume and
pricing of reagents purchased by customers. Due to the working capital
requirements associated with RPs, the Company has historically sought to limit
the amount of instruments placed through RPs to approximately 30% of instrument
placements. However, the Company anticipates that the percentage of instruments
placed through RPs, in particular RP placements without formal reagent purchase
commitments, will increase with the introduction of the NexES and TechMate 250
and as the Company obtains the additional working capital required to support
additional RP placements. This is likely in the future to result in a decrease
in instrument sales both in absolute dollars and as a percentage of total
revenues. Instruments provided to customers under RPs without formal reagent
purchase commitments are only considered placements if and when certain reagent
purchase criteria are met by the customer. The Company typically only provides
an instrument under an RP without a formal reagent purchase commitment if the
Company believes that the customer performs a minimum number of IHC tests
annually. As of March 31, 1996, the Company had placed 72 instruments through
RPs.
    
 
   
     The Company's future results of operations may fluctuate significantly from
period to period due to a variety of factors. The initial placement of an
instrument is subject to a longer, less consistent sales cycle than the sale of
reagents which begin and typically are recurring once an instrument is placed.
The Company's operating results in the future are likely to fluctuate
substantially from period to period because instrument sales are likely to
remain an important part of revenues in the near future. The degree of
fluctuation will depend on the timing, level and mix of instruments placed
through direct sales and instruments placed through RPs. In addition, average
daily reagent use by customers may fluctuate from period to period, which may
contribute to future fluctuations in revenues. Sales of instruments may also
fluctuate from period to period because sales to the Company's international
distributors typically provide such distributors with several months of
instrument inventory, which the distributors will subsequently seek to place
with end-users. The Company's instrument installed base includes instruments
shipped to DAKO and recognized as sales, over
    
 
                                       22
<PAGE>   25
 
   
85% of which the Company believes DAKO has placed with end users. Results of
operations for the remainder of 1996 are also expected to be affected by costs
associated with the integration of BioTek's operations. These include costs
associated with centralizing reagent manufacturing, expanding reagent product
offerings for batch processing instruments and eliminating operational
redundancies. Other factors that may result in fluctuations in operating results
include the timing of new product announcements and the introduction of new
products and new technologies by the Company and its competitors, market
acceptance of the Company's current or new products, developments with respect
to regulatory matters, availability and cost of raw materials purchased from
suppliers, competitive pricing pressures, increased sales and marketing expenses
associated with the implementation of the Company's market expansion strategies
for its instruments and reagent products, and increased research and development
expenditures. Future instrument and reagent sales could also be adversely
affected by the configuration of the Company's patient priority systems, which
require the use of the Company's detection chemistries, particularly if and to
the extent that competitors are successful in developing and introducing new IHC
instruments or if competitors offer reagent supply arrangements having pricing
or other terms more favorable than those offered by the Company. In connection
with future introductions of new products, the Company may be required to incur
charges for inventory obsolescence in connection with unsold inventory of older
generations of products. To date, however, the Company has not incurred material
charges or expenses associated with inventory obsolescence in connection with
new product introductions. In addition, a significant portion of the Company's
expense levels is based on its expectation of a higher level of revenues in the
future and is relatively fixed in nature. Therefore, if revenue levels are below
expectations, operating results in a given period are likely to be adversely
affected.
    
 
   
     Total revenues grew from $2.7 million in 1993 to $10.6 million in 1995, a
compound annual growth rate of 98%. Instrument sales grew from $1.2 million in
1993 to $4.6 million in 1995, a compound annual growth rate of 96%. Reagent
sales grew from $1.5 million in 1993 to $6.0 million in 1995, a compound annual
growth rate of 100%. The growth in revenues is primarily attributable to the
growth in (i) instrument placements and (ii) the instrument installed base and
the associated corresponding increase in the aggregate recurring reagent revenue
stream. The Company's installed base of instruments increased from 74 at
December 31, 1993 to 261 at December 31, 1995. Instrument placements have
increased in every year, from 56 in 1993 to 113 in 1995. The Company's installed
base of instruments was significantly enhanced by the BioTek acquisition in the
first quarter of 1996.
    
 
   
     Gross margin increased from 36% in 1993 to 60% in 1995 as both instrument
and reagent gross margins increased. Gross margin increased primarily due to a
higher level of revenues available to cover fixed costs, economies of scale and
efficiencies in purchasing and manufacturing activities. Research and
development and selling, general and administrative expenses in the period were
maintained at levels that anticipated a higher level of revenues in the future,
which resulted in operating losses in each year between 1993 and 1995.
    
 
                                       23
<PAGE>   26
 
RESULTS OF OPERATIONS
 
  THREE MONTHS ENDED MARCH 31, 1996 AND 1995
 
     Ventana acquired BioTek on February 26, 1996. Consequently, approximately
one month of BioTek operations are included in the results of operations for the
three months ended March 31, 1996.
 
     Net Sales
 
     Presented below is a summary of revenue, instrument placements and
instrument installed base for the three months ended March 31, 1996 and 1995.
 
<TABLE>
<CAPTION>
                                                           THREE MONTHS ENDED MARCH 31,
                                                  -----------------------------------------------
                                                          1995
                                                  ---------------------
                                                    $
                                                  ------                            1996
    REVENUE SUMMARY:                                                        ---------------------
                                                             % OF SALES       $        % OF SALES
                                                             ----------     ------     ----------
                                                              (DOLLARS IN THOUSANDS)
    <S>                                           <C>        <C>            <C>        <C>
      Instruments...............................  $1,007         46%        $1,594         38%
      Reagents and other........................   1,195         54%         2,552         62%
                                                  ------        ----        ------        ----
              Total revenue.....................  $2,202        100%        $4,146        100%
                                                  ======        ====        ======        ====
</TABLE>
 
   
<TABLE>
<CAPTION>
                                                                            THREE MONTHS
                                                                          ENDED MARCH 31,
                                                                          ----------------
    INSTRUMENT PLACEMENTS (UNITS):                                        1995
                                                                          ----
                                                                                      1996
                                                                                      ----
    <S>                                                                   <C>         <C>
    Patient priority...................................................    28          33
    Batch processing...................................................    --           7
                                                                                      -- -
                                                                          ---
              Total current placements.................................    28          40
                                                                          ===         ===
    RPs in current placements..........................................     8           6
</TABLE>
    
 
   
<TABLE>
<CAPTION>
                                                                             MARCH 31,
                                                                         ------------------
                    INSTRUMENT INSTALLED BASE (UNITS):                   1995        1996
                                                                         ----       -------
    <S>                                                                  <C>        <C>
    Patient priority...................................................  176          294
    Batch processing...................................................   --          287
                                                                         ---          ---
              Total instrument installed base..........................  176          581
                                                                         ===          ===
    RPs in installed base..............................................   52           72
</TABLE>
    
 
   
     Net sales for the three months ended March 31, 1996 increased 88% to $4.1
million from $2.2 million in the three months ended March 31, 1995. The increase
in net sales was attributable to a 58% increase in instrument sales and a 114%
increase in reagent sales. Instrument sales increased due to increased
instrument placements and higher selling prices associated with gen II
placements. Reagent sales increased due to sales of reagents to new customers,
as well as to increases in reagent sales to existing customers. United States
patient priority reagent consumption by customers with instruments in place
before October 1, 1994 increased an average of 19% from the first quarter of
1995 to the first quarter of 1996. Sales in the three months ended March 31,
1996 included $0.6 million in sales of batch processing instruments and related
reagents following the BioTek acquisition on February 26, 1996.
    
 
     Gross Margin
 
     Gross profit for the three months ended March 31, 1996 increased to $2.7
million from $1.3 million in the three months ended March 31, 1995. Gross margin
for the three months ended March 31, 1996 increased to 65% from 58% in the three
months ended March 31, 1995. Overall gross margins increased primarily due to a
shift in revenue mix toward higher margin reagent products. Gross margins on
instrument sales increased due to increased sales of gen II instruments,
improvements in manufacturing efficiencies and increased absorption of
manufacturing overhead. Gross margins on reagent sales increased due to
economies of scale associated with increased volumes and improvements in
manufacturing efficiencies.
 
                                       24
<PAGE>   27
 
     Research and Development
 
     Research and development expense was approximately equal in the three
months ended March 31, 1996 and 1995, but declined to 15% of net sales in the
period ended March 31, 1996 from 25% of net sales in the period ended March 31,
1995. Research and development expense for the three months ended March 31, 1996
related primarily to the development of new reagents and instruments, including
the NexES. Research and development expense for the period ended March 31, 1995
related primarily to gen II instrument development and reagent development.
 
     Selling, General and Administrative ("SG&A")
 
     Presented below is a summary of SG&A expense for the three months ended
March 31, 1996 and 1995.
 
   
<TABLE>
<CAPTION>
                                                           THREE MONTHS ENDED MARCH 31,
                                                  -----------------------------------------------
                                                          1995                      1996
                                                  ---------------------     ---------------------
                                                    $        % OF SALES       $        % OF SALES
                                                  ------     ----------     ------     ----------
                                                              (DOLLARS IN THOUSANDS)
    <S>                                           <C>        <C>            <C>        <C>
    Sales and marketing.........................  $1,212         55%        $1,796         43%
    Administration..............................     382         17%           578         14%
                                                  ------     ----------     ------     ----------
              Total SG&A........................  $1,594         72%        $2,374         57%
                                                  ======     ========       ======     ========
</TABLE>
    
 
   
     SG&A expense in the three months ended March 31, 1996 increased to $2.4
million from $1.6 million in the three months ended March 31, 1995, but declined
to 57% of net sales in the period ended March 31, 1996 from 72% of net sales in
the period ended March 31, 1995. The fluctuation in SG&A expense from period to
period reflects the growth of Ventana's internal sales and marketing
organization to facilitate its market expansion strategy and a corresponding
increase in infrastructure expenses to support a larger business base. The
growth in sales and marketing expense is the result of the Company's decision to
service the market through its own sales and marketing staff and expenses needed
to support sales growth. Increases in administrative expense are associated with
the Company's regulatory strategy and costs associated with supporting an
expanding business base.
    
 
     In-Process Research and Development Expense
 
   
     In accordance with Statement of Financial Accounting Standards No. 2
"Accounting for Research and Development Costs" ("FAS 2"), the Company charged
to expense at the date of the acquisition of BioTek, $7.9 million relating to
the portion of the purchase price allocated to those in-process research and
development projects where technological feasibility had not yet been
established and for which there are no alternative future uses.
    
 
  YEARS ENDED DECEMBER 31, 1995, 1994 AND 1993
 
     Net Sales
 
     Presented below is a summary of revenue, instrument placements and
instrument installed base for the three years ended December 31, 1995, 1994 and
1993.
 
<TABLE>
<CAPTION>
                                                          YEAR ENDED DECEMBER 31,
                                      ----------------------------------------------------------------
                                             1993                  1994                   1995
                                      -------------------   -------------------   --------------------
                                        $      % OF SALES     $      % OF SALES      $      % OF SALES
                                      ------   ----------   ------   ----------   -------   ----------
                                                           (DOLLARS IN THOUSANDS)
    <S>                               <C>      <C>          <C>      <C>          <C>       <C>
    REVENUE SUMMARY:
    Instruments.....................  $1,162       43%      $2,588       44%      $ 4,644       44%
    Reagents and other..............   1,519       57%       3,339       56%        5,969       56%
                                      ------      ----      ------      ----         ----
              Total revenue.........  $2,681      100%      $5,927      100%      $10,613      100%
                                      ======      ====      ======      ====         ====
</TABLE>
 
                                       25
<PAGE>   28
 
   
<TABLE>
<CAPTION>
                                                                           YEAR ENDED DECEMBER
                                                                                   31,
                                                                          ----------------------
                     INSTRUMENT PLACEMENTS (UNITS):                       1993     1994     1995
                                                                          ----     ----     ----
<S>                                                                       <C>      <C>      <C>
Current placements......................................................   56       74      113
RPs in current placements...............................................   19       19       22
</TABLE>
    
 
   
<TABLE>
<CAPTION>
                                                                               DECEMBER 31,
                                                                          ----------------------
                   INSTRUMENT INSTALLED BASE (UNITS):                     1993     1994     1995
                                                                          ----     ----     ----
<S>                                                                       <C>      <C>      <C>
Instrument installed base...............................................   74      148      261
RPs in installed base...................................................   25       44       66
</TABLE>
    
 
   
     Net sales for the year ended December 31, 1995 increased by 79% to $10.6
million from $5.9 million for the year ended December 31, 1994. Net sales for
the year ended December 31, 1994 increased by 121% to $5.9 million from $2.7
million for the year ended December 31, 1993. The increases in net sales were
attributable to increases in instrument sales as well as increases in reagent
sales. Instrument sales increased over the prior year by 79% in 1995 and 123% in
1994, respectively. Reagent sales increased over the prior year by 79% in 1995
and 120% in 1994, respectively. Instrument sales increased during these periods
primarily due to increased placements. Instrument sales in 1995 were positively
impacted by the higher selling prices associated with gen II instrument
placements. Instrument sales in 1995 and 1994 were impacted by the placement of
a significant number of instruments through RPs, which resulted in lower
instrument revenues than if the placements had been made on a direct sale basis.
Reagent sales grew primarily because of the growth in the installed base of
instruments, as well as increased sales to existing customers. Despite the
growth in the Company's installed base of instruments from 1993 to 1995, reagent
sales as a percentage of net sales did not increase significantly. This was due
primarily to (i) the high percentage of new instrument placements in each year
relative to the existing installed base of instruments, (ii) the recognition of
revenues on direct instrument sales at the time of sale and (iii) the receipt of
reagent revenue for only that portion of the year during which an instrument was
in place.
    
 
     Gross Margin
 
     Gross profit for the year ended December 31, 1995 increased to $6.3 million
from $3.4 million in the year ended December 31, 1994 and $1.0 million in the
year ended December 31, 1993. Gross margin increased to 60% in 1995 from 57% in
1994 and 36% in 1993. The improvement in gross margin resulted primarily from a
higher volume of revenues available to cover the Company's fixed costs,
economies of scale and efficiencies in manufacturing operations. Gross margins
on instruments increased in 1994 as compared to 1993 primarily due to reductions
in instrument manufacturing costs. Instrument gross margins in 1995 were
approximately equivalent to 1994. Reagent gross margins decreased in 1994 as
compared to 1993 due primarily to primary antibody promotional programs
initiated during 1994 and partially offset by improvements in manufacturing
efficiencies during 1994. Reagent gross margins in 1995 increased compared to
1994 and exceeded the margins achieved in 1993 because the Company (i)
discontinued its primary antibody promotional programs, (ii) realized lower
material prices from higher purchasing volumes and (iii) achieved improvements
in manufacturing efficiencies.
 
     Research and Development
 
     Research and development expense in the year ended December 31, 1995
increased to $2.2 million from $1.9 million in the year ended December 31, 1994
and $2.1 million in the year ended December 31, 1993. Research and development
expense primarily reflects gen II and NexES development and development of
additional primary antibodies.
 
     Selling, General and Administrative
 
     Presented below is a summary of the various components of SG&A expense and
their respective percentages of net sales during the years ended December 31,
1995, 1994 and 1993.
 
                                       26
<PAGE>   29
 
<TABLE>
<CAPTION>
                                                           YEAR ENDED DECEMBER 31,
                                   -----------------------------------------------------------------------
                                           1993                    1994                      1995
                                   ---------------------   ---------------------     ---------------------
                                     $        % OF SALES     $        % OF SALES       $        % OF SALES
                                   ------     ----------   ------     ----------     ------     ----------
                                                           (DOLLARS IN THOUSANDS)
<S>                                <C>        <C>          <C>        <C>            <C>        <C>
Sales and marketing..............  $2,748        103%      $4,843         81%        $5,674         53%
Administration...................   1,319         49%       2,056         35%         1,761         17%
                                   ------     ----------   ------     ----------     ------       -----
          Total SG&A.............  $4,067        152%      $6,899        116%        $7,435         70%
                                   ======     ========     ======     ========       ======     ========
</TABLE>
 
     SG&A expense in the year ended December 31, 1995 increased to $7.4 million
from $6.9 million in the year ended December 31, 1994 and $4.1 million in the
year ended December 31, 1993. The fluctuation in SG&A expense from period to
period reflects the growth of Ventana's internal sales and marketing
organization to facilitate its market expansion strategy and a corresponding
increase in infrastructure expenses to support a larger business base. The
growth in sales and marketing expense is the result of the decision by the
Company to service the market through its own sales and marketing staff and
costs needed to support sales growth during these periods. The increase in
administrative expense is associated with the Company's regulatory strategy and
costs associated with supporting an expanding business base.
 
INCOME TAXES
 
     Ventana and BioTek have neither provided for nor paid any federal income
taxes since their respective inceptions because neither company generated
taxable income in any fiscal year. At December 31, 1995, Ventana had net
operating loss carryforwards for federal and state purposes of approximately
$12.0 million. These federal and state carryforwards will begin to expire in
2000 and 1996 respectively, if not previously utilized. The Company also has
research and development tax credit carryforwards of approximately $0.7 million
which will begin to expire in 2005, if not previously utilized. Utilization of
Ventana's net operating loss carryforwards will be subject to limitations due to
the "change in ownership" provisions of the Internal Revenue Code of 1986, as
amended (the "Code") as a result of the Company's prior issuances of equity
securities. These carryforwards, therefore, may expire prior to being fully
utilized. Future financings may cause additional changes in ownership and
further limitations on the use of federal net operating loss carryforwards. Due
to the losses incurred by Ventana since inception, deferred tax assets of
approximately $8.6 million at December 31, 1995, related to these carryforwards,
credits and temporary differences, have been fully reserved in accordance with
Statement of Financial Accounting Standards No. 109, "Accounting for Income
Taxes" ("FAS 109").
 
     At December 31, 1995, BioTek had net operating loss carryforwards for
federal and state purposes of approximately $10.8 million. These federal and
state carryforwards will begin to expire in 2008, if not previously utilized.
Utilization of BioTek's net operating loss carryforwards will be subject to
limitations due to the change in ownership provisions of the Code as a result of
the acquisition by Ventana. Therefore, these carryforwards may expire prior to
being fully utilized. Due to the losses incurred by BioTek since inception,
deferred tax assets of $5.7 million at December 31, 1995, related to these
carryforwards, have been reserved in accordance with FAS 109.
 
ACCOUNTING FOR STOCK-BASED COMPENSATION
 
     In October 1995, Statement of Financial Accounting Standards No. 123,
"Accounting for Stock-Based Compensation" ("FAS 123"), was issued. FAS 123 is
effective for the Company's 1996 financial statements. The Company intends to
continue to account for employee stock options in accordance with APB Opinion
No. 25 and will include the pro forma disclosures required by FAS 123 beginning
in 1996.
 
UNAUDITED PRO FORMA CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS
 
   
     The Company acquired BioTek for $18.8 million on February 26, 1996. The pro
forma results of operations reflect the Company's operations as if it had
acquired BioTek on January 1, 1995 and are adjusted
    
 
                                       27
<PAGE>   30
 
   
to reflect the sale of 2,200,000 shares of Common Stock by the Company in this
Offering and the application of the net proceeds therefrom. The acquisition has
been accounted for as a purchase. The composition of the consideration paid for
BioTek and the allocation of the purchase price is presented below:
    
 
   
<TABLE>
<CAPTION>
                                                                             (IN THOUSANDS)
    <S>                                                                      <C>
    The purchase price for BioTek consisted of:
      Cash consideration...................................................     $  2,500
      Stock issued to BioTek noteholders...................................        3,007
      Exchange Notes issued................................................        8,978
      Note payable -- escrow for contingencies.............................          234
      Net historical liabilities assumed...................................        4,044
                                                                                   -----
              Total purchase price.........................................     $ 18,763
                                                                                   =====
    The purchase price was allocated as follows:
      Tangible net assets..................................................     $  2,288
      In-process research & development....................................        7,900
      Goodwill and other intangibles.......................................        1,675
      Developed technology.................................................        2,800
      Customer base........................................................        4,100
                                                                                   -----
              Total purchase price.........................................     $ 18,763
                                                                                   =====
</TABLE>
    
 
   
     In accordance with FAS 2, the Company charged to expense at the date of the
acquisition $7.9 million relating to the portion of the purchase price allocated
to those in-process research and development projects where technological
feasibility had not yet been established and where there are no alternative
future uses.
    
 
   
     Upon the closing of the acquisition, BioTek's revenue recognition policy
was changed to adopt the Company's policy of recording certain sales upon
shipment of instruments and reagents to end-users. The pro forma sales and
related costs of goods sold, are adjusted as if BioTek had followed this policy
beginning January 1, 1995. The combined effect of the change in accounting
policy is an increase in pro forma net sales in 1995. This is primarily due to
(i) shipments of instruments and reagents to CMS in 1994 which were subsequently
placed with end-users in 1995 and (ii) sales being recorded at prices paid by
the end-user as opposed to the net price paid by CMS. Accordingly, cost of goods
sold has been adjusted to reflect the differences in the timing of sales and the
mix of products sold, and selling expense has been increased to reflect the
distribution commission paid to CMS. The commission is equal to the product of
(i) the number of units shipped to end-users and (ii) the difference between the
price paid by the end-user to CMS and the net price paid by CMS.
    
 
   
     The pro forma financial results reflect cost savings associated with (i)
consolidation of facilities (allocated to cost of goods sold (50%), research and
development expense (10%), and selling, general, and administrative expense
(40%)) and (ii) elimination of certain redundant selling and administrative
positions. The pro forma financial results also reflect nonrecurring items
including $7.9 million of acquired in-process research and development which was
charged to expense (as discussed above) and $2.1 million of costs associated
with the acquisition and integration of BioTek. These charges were incurred in
the first quarter of 1996 and are reflected in the pro forma financial
statements as if such charges had been incurred in the year ended December 31,
1995.
    
 
   
     Comparisons of pro forma results for the first quarter of 1996 to actual
results for the first quarter of 1996 are not meaningful because Ventana's
actual results of operations for the first quarter of 1996 include approximately
one month of BioTek operations.
    
 
                                       28
<PAGE>   31
 
PRO FORMA RESULTS OF OPERATIONS
 
   
     YEARS ENDED DECEMBER 31, 1995 AND THREE MONTHS ENDED MARCH 31, 1996
    
 
     Net Sales
 
   
     Presented below is a summary of pro forma consolidated revenue, instrument
placements and instrument installed base for the year ended December 31, 1995
and the three months ended March 31, 1996.
    
 
   
<TABLE>
<CAPTION>
                                                                                THREE MONTHS
                                                            YEAR ENDED              ENDED
                                                           DECEMBER 31,           MARCH 31,
                                                         ----------------     -----------------
                                                               1995                 1996
                                                         ----------------     -----------------
                                                            $         %          $          %
                                                         -------     ----     -------      ----
                                                         (DOLLARS IN THOUSANDS)
<S>                                                      <C>         <C>      <C>          <C>
REVENUE SUMMARY:
Instruments............................................. $ 8,396      43%     $ 1,733       33%
Reagents and other......................................  11,079      57%       3,495       67%
                                                         -------      ---      ------       ---
  Total revenue......................................... $19,475     100%     $ 5,228      100%
                                                         =======      ===      ======       ===
</TABLE>
    
 
   
<TABLE>
<CAPTION>
                                                                                      THREE MONTHS
                                                                        YEAR ENDED    ENDED MARCH
                                                                       DECEMBER 31,       31,
                    INSTRUMENT PLACEMENTS (UNITS):                         1995           1996
                                                                       ------------   ------------
<S>                                                                    <C>            <C>
Patient priority......................................................      113             33
Batch processing......................................................      128             12
                                                                            ---            ---
     Total current placements.........................................      241             45
                                                                            ===            ===
RPs in current placements.............................................       22              6
</TABLE>
    
 
   
<TABLE>
<CAPTION>
                                                                       DECEMBER 31,    MARCH 31,
                                                                           1995           1996
                                                                       ------------   ------------
<S>                                                                    <C>            <C>
INSTRUMENT INSTALLED BASE (UNITS):
Patient priority......................................................      261            294
Batch processing......................................................      275            287
                                                                            ---            ---
     Total instrument installed base..................................      536            581
                                                                            ===            ===
RPs in installed base.................................................       66             72
</TABLE>
    
 
   
     Pro forma instrument placements and sales during the fourth quarter of 1995
and first quarter of 1996 were adversely affected by BioTek's inability to
procure instruments due to insufficient working capital.
    
 
   
  Gross Margin and Operating Expenses
    
 
   
     Pro forma gross margin was 63% in the quarter ended March 31, 1996 as
compared to 53% in the year ended December 31, 1995. Pro forma gross margin is
lower than Ventana's stand-alone gross margin because BioTek's margin is
adversely affected by BioTek's (i) use of contract manufacturers and third-party
distributors, (ii) lower value-added reagent manufacturing strategy and (iii)
lower reagent volumes and pricing due to the open configuration of BioTek's
instruments. Pro forma research and development expenditures for 1995 also
reflect BioTek's development of the TechMate 250 instrument and an ISH oven.
During the first quarter of 1996, BioTek reduced research and development and
SG&A expenditures due to working capital constraints.
    
 
                                       29
<PAGE>   32
 
   
QUARTERLY PRO FORMA CONSOLIDATED RESULTS OF OPERATIONS
    
 
     The following table contains summary unaudited quarterly pro forma
consolidated statements of operations data for the five quarters ended March 31,
1996. Management has prepared the quarterly pro forma consolidated statements of
operations data on the same basis as the Unaudited Pro Forma Condensed
Consolidated Statements of Operations contained in this Prospectus. The
Company's results of operations have varied and may continue to fluctuate
significantly from quarter to quarter. Results of operations in any period
should not be considered indicative of the results to be expected for any future
period.
 
                     SUMMARY UNAUDITED QUARTERLY PRO FORMA
   
                     CONDENSED CONSOLIDATED FINANCIAL DATA
    
                 (DOLLARS IN THOUSANDS, EXCEPT PER SHARE DATA)
 
   
<TABLE>
<CAPTION>
                                                                                            THREE
                                                                  1995                     MONTHS
                                                  -------------------------------------     ENDED
                                                   FIRST    SECOND     THIRD    FOURTH    MARCH 31,
                                                  QUARTER   QUARTER   QUARTER   QUARTER     1996
                                                  -------   -------   -------   -------   ---------
<S>                                               <C>       <C>       <C>       <C>       <C>
STATEMENT OF OPERATIONS DATA:
Sales:
  Instruments...................................  $ 2,040   $ 2,148   $ 2,461   $ 1,747   $   1,733
  Reagents and other............................    2,378     2,484     2,931     3,286       3,495
                                                  -------   -------   -------   -------     -------
          Total net sales.......................    4,418     4,632     5,392     5,033       5,228
Cost of goods sold..............................    2,134     2,236     2,438     2,288       1,924
                                                  -------   -------   -------   -------     -------
Gross profit....................................    2,284     2,396     2,954     2,745       3,304
Operating expenses:
  Research and development......................      721     1,815     1,002       869         771
  Selling, general and administrative...........    2,367     3,130     2,675     2,796       2,799
  Nonrecurring expenses.........................    9,983        --        --        --          --
  Amortization of intangibles...................      139       139       140       139         139
                                                  -------   -------   -------   -------     -------
Loss from operations............................  (10,926)   (2,688)     (863)   (1,059)       (405)
Interest income (expense).......................       50        37        25       (38)         (5)
                                                  -------   -------   -------   -------     -------
Net loss........................................  $(10,876) $(2,651)  $  (838)  $(1,097)  $    (410)
                                                  -------   -------   -------   -------     -------
Pro forma net loss per share....................  $ (1.11)  $ (0.27)  $ (0.08)  $ (0.11)  $   (0.04)
                                                  =======   =======   =======   =======     =======
Pro forma shares used in computing net loss
  per share.....................................    9,840     9,962    10,034    10,060      10,206
                                                  =======   =======   =======   =======     =======
</TABLE>
    
 
   
LIQUIDITY AND CAPITAL RESOURCES
    
 
   
     Since inception, the Company's expenses have significantly exceeded its net
sales, resulting in an accumulated deficit of $32.4 million at March 31, 1996.
The Company has funded its operations primarily through the private placement of
approximately $31.0 million of equity and debt securities. At March 31, 1996,
the Company's principal source of liquidity consisted of cash and cash
equivalents of $3.4 million and available borrowing capacity under the Company's
bank credit facility.
    
 
   
     Net cash flow from operating activities during the three months ended March
31, 1996 and 1995 was approximately $(1.2) million and $(0.4) million,
respectively. Net cash flow from operating activities was approximately $(2.9)
million, $(5.3) million and $(5.1) million for the years ended December 31,
1995, 1994 and 1993, respectively. Net cash flow from operating activities
during these periods primarily reflects the Company's operating losses.
    
 
     Net cash flow from investing activities was $(2.6) million and $(0.4)
million for the three months ended March 31, 1996 and 1995, respectively. The
Company expended $2.5 million in cash as part of the consideration for the
purchase of BioTek in the three months ended March 31, 1996. Net cash flow from
investing activities (excluding sales or purchases of short-term investments)
was approximately $(1.0) million, $(0.6) million and $(1.7) million for the
years ended December 31, 1995, 1994 and 1993. Net cash flow from investing
activities was primarily used for capital expenditures to increase manufacturing
capacity and to
 
                                       30
<PAGE>   33
 
   
upgrade management information systems. The Company anticipates using
approximately $1.8 million of the net proceeds of this Offering for capital
expenditures during the next 12 months. Of such amount, approximately $0.2
million is subject to outstanding commitments by the Company.
    
 
   
     Net cash flow from financing activities was $6.1 million and $2.4 million
for the three months ended March 31, 1996 and 1995, respectively. Net cash flow
from financing activities was $2.6 million, $3.0 million and $5.1 million for
the years ended December 31, 1995, 1994 and 1993, respectively. Net cash flow
from financing activities was primarily the result of private placements of
equity securities.
    
 
   
     During the quarter ended March 31, 1996, the Company raised $4.6 million
through the private placement of subordinated notes. An additional $0.5 million
was raised through the private placement of such notes subsequent to March 31,
1996. In connection with the issuance of such subordinated notes, the Company
issued warrants to purchase an aggregate of 887,740 shares of Common Stock of
the Company at an exercise price of $5.82 per share. The proceeds of these notes
were used to fund the cash portion of the BioTek acquisition consideration and
to provide working capital. These notes bear interest at 7% per annum, which
will be forgiven if the notes are repaid prior to December 31, 1996. The
subordinated notes are required to be repaid by the Company within 30 days of
the completion of this Offering.
    
 
     The Company also has a credit facility with a bank lender which consists of
a term loan facility of $2.0 million and a revolving line of credit of $2.7
million. The term loan and the revolving line of credit bear interest at the
lender's prime rate plus 2.0% per annum and mature in 1999. The revolving line
of credit permits the Company to borrow up to a specified percentage of eligible
accounts receivable. The credit facility is secured by a pledge of substantially
all of the Company's assets and is subject to certain financial covenants,
including certain financial ratios and dividend restrictions. At March 31, 1996,
the Company had borrowed $1.0 million under the revolving credit line which was
subsequently converted to a term loan. Subsequent to March 31, 1996, the Company
borrowed an additional $1.0 million under the term loan facility. The Company
plans to repay the entire $2.0 million balance of the term loan with the net
proceeds of this Offering.
 
     In 1994, the Company arranged, on a non-recourse basis, for third-party
lease financing for instrument purchases by customers. To date, this program has
generated 12 non-recourse leases and has had a small positive net cash flow
impact for the Company.
 
   
     In connection with the acquisition of BioTek, Ventana issued an aggregate
of $12.2 million in exchange notes (collectively, the "Exchange Notes") to the
holders of outstanding indebtedness of BioTek. The Exchange Notes bear interest
at the rate of 7% per annum which will be forgiven if the Exchange Notes are
repaid prior to December 31, 1996. The Exchange Notes provided each holder with
the opportunity, during a 30-day period, to convert Exchange Notes into shares
of Ventana Common Stock at a conversion price of $13.53 per share. Upon
expiration of the conversion period, an aggregate of $3.0 million in principal
amount of Exchange Notes were converted into 222,973 shares of Common Stock and
an aggregate of $9.2 million of Exchange Notes remained outstanding. These
Exchange Notes are due and payable 30 days after the completion of this Offering
and will be repaid with the net proceeds of this Offering.
    
 
     In connection with BioTek's agreement with DAKO, DAKO made two loans
secured by a pledge of substantially all of BioTek's assets. DAKO also made
prepayments on future instrument sales and reagent royalties to BioTek. These
loans and prepayments were used to fund TechMate 250 instrument development and
working capital requirements. The aggregate balance of the secured loans and
prepayments was $1.6 million and $0.9 million, respectively, at March 31, 1996.
Of the secured loans, $0.3 million bear interest at 5% per annum and the
remaining $1.3 million does not bear interest. The prepayments do not bear
interest. The secured loans and prepayments are recorded as advances from
distributor in the Company's Consolidated Financial Statements. The loans are
repaid through discounts on DAKO's purchases of instruments from BioTek. Upon
termination of the distribution agreement or in the event of a default by BioTek
under the distribution agreement, these loans will convert to fixed term loans
that will be due and payable in 12 equal quarterly installments commencing upon
such event. See "Business -- Sales, Marketing and Customer Support."
 
                                       31
<PAGE>   34
 
   
     The Company believes that the anticipated net proceeds from this Offering
together with its existing capital resources, and interest earned thereon, will
be sufficient to satisfy its working capital requirements through at least 1997.
The Company's future capital requirements will depend on many factors, including
the extent to which the Company's products gain market acceptance, the mix of
instruments placed through direct sales or RPs, progress of the Company's
product development programs, competing technological and market developments,
expansion of the Company's sales and marketing activities, the cost of
manufacturing scale-up activities, possible acquisitions of complementary
businesses, products or technologies, the extent and duration of operating
losses and timing of regulatory approvals. The Company may be required to raise
additional capital in the future through the issuance of either equity
securities or debt instruments or both. There is no assurance such capital will
be available to the extent required by or on terms acceptable to the Company or
at all.
    
 
                                       32
<PAGE>   35
 
                                    BUSINESS
 
OVERVIEW
 
   
     Ventana develops, manufactures and markets proprietary instrument/reagent
systems that automate IHC and ISH tests for the analysis of cells and tissues on
microscope slides. These tests are important tools used in diagnosing and
selecting treatment for cancer. The Company believes that it is the worldwide
leader in the automated IHC testing market, as the Company estimates that its
worldwide installed base of 581 instruments as of March 31, 1996 is
approximately five times as large as the combined installed base of all of the
Company's current competitors. Ventana has placed instruments with 31 of the 40
leading cancer centers according to U. S. News & World Report and 35 of the 42
cancer centers identified as principal cancer research centers by the National
Cancer Institute, including the Mayo Clinic, the Dana Farber Cancer Institute,
The Johns Hopkins University, the M.D. Anderson Cancer Center and the Fred
Hutchinson Cancer Center. Each Ventana proprietary system placed provides a
recurring revenue stream as customers consume reagents and supplies sold by the
Company with each test conducted. Consequently, two key elements of the
Company's strategy are to increase the number of instrument placements and to
maximize the recurring revenue stream per placement through increased sales of
reagents and supplies.
    
 
     In late 1991, Ventana began commercial shipment of its first system, the
Ventana 320 instrument and related reagents used for automated IHC tests. Since
then, Ventana has developed and introduced the Ventana ES, the successor to the
320, as well as the Ventana gen II, which is capable of performing ISH tests in
addition to IHC tests. These patient priority systems use Ventana's proprietary
horizontal slide processing technology to perform multiple tests rapidly on a
single patient biopsy. In February 1996, Ventana acquired BioTek which
introduced its first automated IHC system, the TechMate 1000, in 1992, and has
also introduced the successor TechMate 500 instrument. BioTek's batch processing
systems use proprietary vertical slide processing technology to reliably and
cost effectively process high volumes of single tests on multiple patient
biopsies. These complementary product lines enable Ventana to serve a broad
range of customers. Smaller hospitals, which generally do not handle a high
volume of cancer patients, typically use patient priority systems to meet their
automated testing needs. Reference and research laboratories which serve
numerous institutions typically use batch processing systems to process large
volumes of tests. Large hospitals with a high volume of patients and a broad
range of test requirements may use both patient priority and batch processing
systems.
 
   
     Cancer is the second leading cause of death in the United States accounting
for 25% of deaths (approximately 555,000 deaths per year). Currently,
approximately 10 million people in the United States have a history of invasive
cancer, and it is estimated that approximately 1.4 million new cases of invasive
cancer will be diagnosed each year. The vast majority of IHC testing associated
with cancer diagnosis and treatment in the United States is conducted in an
aggregate of approximately 2,200 clinical institutions and reference and
research laboratories which the Company estimates creates the opportunity for
the placement of as many as 2,500 automated IHC testing instruments. The Company
believes that less than 25% of such institutions and laboratories currently
conduct IHC testing on an automated basis. The international market for
automated IHC and ISH testing is estimated by the Company to be approximately
1.2 times the size of the United States market, with Europe accounting for the
majority of the international market potential.
    
 
     Currently most IHC testing is performed manually which often yields
inconsistency of test results. As compared to manual IHC testing, Ventana's
automated systems provide improved reliability, reproducibility and consistency
of test results. The systems' economic advantages include reduced cost per test,
faster turnaround time, increased test throughput and a reduced dependence on
skilled laboratory technicians. Additional benefits include the ability to
perform new and emerging diagnostic tests, improved visual clarity which aids
the interpretation of test results, and the ability to obtain maximum clinical
information from minimally sized biopsies. The Company believes it will play a
critical, expanding role in cancer science as researchers will use Ventana
systems to accelerate the identification and development of new tests and that
its installed base of instruments will speed the commercialization and clinical
implementation of such new tests.
 
                                       33
<PAGE>   36
 
The Company anticipates that its reagent test menu will expand due to the major
emphasis of cancer research on the identification of new prognostic IHC and ISH
indicators.
 
ACQUISITION OF BIOTEK
 
     Ventana acquired BioTek in February 1996 for total consideration of $18.8
million. The acquisition of BioTek enhanced Ventana's competitive position and
enabled the Company to become the worldwide leader in the automated IHC and ISH
testing market. Ventana's installed base of instruments increased from 294
instruments to 581 instruments as of March 31, 1996 as a result of the
acquisition. The increase in the instrument base also increased the aggregate
recurring revenue stream from reagents and supplies sold to customers. The
acquisition also enabled Ventana to add a number of prestigious cancer centers
to its list of customers. BioTek's product line complements Ventana's and
enables the Company to meet the differing needs of customers requiring patient
priority or batch processing systems, or both. The acquisition also creates the
opportunity for operational synergies including the change to higher value-added
and consolidation of reagent manufacturing, the rationalization of sales and
marketing forces and the elimination of redundant regulatory, general and
administration functions and personnel.
 
   
     Historically, BioTek generated lower gross margins than Ventana due to its
employment of a different business strategy which primarily involved the use of
third parties for key activities. BioTek's instruments were produced by
third-party manufacturers which prevented BioTek from capturing manufacturing
margin. BioTek's instruments have an open configuration, enabling the customer
to use reagents purchased from BioTek or others, which impacted both the price
and volume of reagents purchased by customers from BioTek. In contrast,
Ventana's instruments have a closed configuration requiring the customer to use
Ventana's prepackaged detection chemistries. BioTek also realized lower gross
margins on reagents than Ventana due to its utilization of intermediate
materials in the manufacturing process which resulted in the capture of fewer
value-added steps. BioTek used CMS and DAKO as third-party distributors in the
United States and international markets, respectively, and supported its United
States sales efforts with field sales and technical support personnel. As a
result, BioTek experienced both lower gross margins than if it had sold its
products directly and a higher level of selling expense than typically incurred
in conjunction with third-party distribution arrangements.
    
 
   
     Ventana's goal is to integrate the operations of BioTek into the Ventana
business model, in which manufacturing, sales and marketing activities are
performed by Company employees. In May 1996, the Company completed the
integration of the BioTek and Ventana direct field sales and technical
personnel. The Company does not intend to renew the United States distribution
agreement with CMS which expires in April 1998. The Company is engaged in
discussions with DAKO regarding various aspects of the distribution arrangement,
which expires in December 1999. The Company expects to complete the
consolidation of BioTek's reagent manufacturing into Ventana's Tucson facilities
in September 1996. Following this consolidation, the Company intends to convert
BioTek's reagent manufacturing to the process used by Ventana in which basic raw
materials are used and important value-added steps are performed internally. The
Company believes that in the near term it will be more cost effective to
continue sourcing batch processing instruments from third-party manufacturers.
The Company has entered into a manufacturing agreement with Kollsman for the
TechMate 500 instrument and has entered into an agreement with LJL for
production of the Company's next generation batch processing instrument, the
TechMate 250.
    
 
INDUSTRY BACKGROUND
 
  IMMUNOHISTOCHEMISTRY
 
   
     Cancer is the second leading cause of death in the United States accounting
for 25% of deaths (approximately 555,000 deaths per year). Currently,
approximately 10 million people in the United States have a history of invasive
cancer, and it is estimated that approximately 1.4 million new cases will be
diagnosed each year. In the United States, the lifetime risk of developing
invasive cancer is 47% for males and 38% for females. The risk of developing
cancer increases with age. Among the principal forms of cancer are leukemia,
lymphoma and cervical, breast, urinary, lung, prostate, ovarian, colon and
rectal cancer.
    
 
                                       34
<PAGE>   37
 
     Early detection is the number one factor in increasing the long term
survival of cancer patients. Health care professionals are increasing their
emphasis on and use of screening and early detection programs for cancer because
cancer treatments are generally significantly more effective and less costly the
earlier that cancer is detected. Complementing screening and early detection are
recent advances in less invasive biopsy methods that can obtain tissue samples
from progressively smaller tumors. As a result of these developments, there has
been a steady increase in the initial diagnosis of invasive cancer. However,
smaller tissue samples are often difficult to analyze with traditional
diagnostic tests, increasing the dependence of surgical pathologists on IHC for
accurate diagnosis of early stage cancer.
 
     After preliminary screening of a biopsy to determine the presence of
cancer, IHC is the principal diagnostic test method used for cancer diagnosis
and therapy selection. IHC tests use specific antibodies to identify and detect
antigens (proteins) in cells and tissues which assist pathologists in assessing
various aspects of a patient's cancer. IHC tests, or assays, have two major
components: primary antibodies and detection chemistries. The primary antibody
is the specific antibody used to bind to the antigen in question. Detection
chemistries are composed of multiple reagents including secondary antibodies,
enzyme conjugates/complexes and chromogenic enzyme substrates which allow
visualization of the primary antibody.
 
     IHC tests are performed on cells and tumor tissue to:
 
     -     determine the type of cancer
     -     determine the site of the primary tumor
     -     determine the degree of malignancy
     -     determine if the cancer has metastasized
     -     assist in the selection of the most appropriate therapy
     -     monitor patient progress
     -     develop a prognosis
 
     Correct prognosis is essential in selecting the appropriate therapy regimen
and monitoring program for individual cancer patients. IHC assays provide
significant prognostic information such as cell cycle and hormone receptor
status which, in many cases, cannot be obtained from other tests. This
information allows the pathologist to improve risk assessment on an individual
patient basis. IHC testing is therefore instrumental to controlling and reducing
health care costs and improving cancer survival rates because earlier, more
accurate diagnoses and prognoses can lead to earlier, more targeted therapy and
may reduce the risk of use of an incorrect or inappropriate treatment.
 
     Manual IHC assays require skilled technical personnel to perform as many as
60 individual processes and can require several days to complete. For the assay
to be successful, each process must be performed in the proper sequence and for
the proper length of time. In addition, the length of time and the reagents used
for each of the steps varies depending upon the primary antibody used in the
assay. The complexity of manual IHC assays leads to poor reproducibility and
inconsistency of results. Therefore, while IHC has been used routinely in
clinical diagnosis for over 10 years, the requirement of skilled technical
personnel, labor intensity (approximately 40 slides per day per technician) and
lack of standardization has limited the growth of clinical IHC.
 
     The development of new diagnostic systems composed of instruments and
reagents has resulted in the automation of tests in a number of diagnostic
market segments. The trend toward automation of diagnostic testing began in the
1960s with the automation of hematology testing by Coulter Electronics
Corporation and clinical chemistry testing by Technicon Instruments Corporation.
In the 1980s, Abbott Laboratories, Inc. ("Abbott") introduced two instruments
with proprietary prepackaged reagents to automate immunoassay tests performed on
serum or urine. Ventana's systems are fundamental enabling technologies that
overcome major obstacles, including the inherent limitations of manual
processing, which have historically prevented both the broader use and growth of
IHC.
 
                                       35
<PAGE>   38
 
  IN SITU HYBRIDIZATION
 
     ISH tests are advanced tests for infectious disease and cancer diagnosis
and other applications that generate visual signals based on probes used to
detect the presence of specific nucleic acids (DNA/RNA) contained in a cell.
Over the next decade, Ventana believes that ongoing research and development in
the field of molecular analysis will result in the continued introduction of new
IHC and ISH tests.
 
     ISH assays are technically far more challenging and labor intensive than
IHC assays. In addition to requiring a similar number of processes which must be
performed in the proper sequence and for the proper length of time, ISH assays
require multiple wash solutions, or buffers, and the temperature at which each
of the steps must be executed typically ranges from 37(++)C to 98(++)C.
Furthermore, the conditions for each of these processes is dependent upon the
specific probe being used. Due to this extreme degree of technical difficulty,
there are very few clinical laboratories capable of performing manual ISH
assays. Ventana's gen II system represents a fundamental enabling technology for
the rapid, accurate and cost effective identification of unique RNA and DNA
(probe diagnostics) and is designed to overcome the inherent limitations of
manual processing.
 
VENTANA STRATEGY
 
     The Company's objective is to strengthen its worldwide leadership position
in the automated IHC testing market and to develop and expand the automated ISH
testing market. The following represent key elements of the Company's strategy:
 
   
     Maximize Instrument Placements. The Company's objective is to strengthen
its competitive position in the automation of IHC testing by establishing a
larger installed base of instruments that current or future market entrants must
overcome. The Company estimates that its worldwide installed base of 581
instruments is approximately five times as large as the combined installed base
of instruments of all of the Company's current competitors. The Company believes
that its placement of instruments in 35 of the 42 cancer centers identified as
principal cancer research centers by the National Cancer Institute provides a
powerful reference tool for potential new customers. To facilitate instrument
placements, the Company offers customers a wide selection of instruments which
address the patient priority needs of hospital clinical laboratories and the
batch processing needs of large hospitals and reference and research
laboratories. In order to satisfy the broad spectrum of customers' operational
and financial criteria, the Company intends to continue to offer several
instrument procurement options, including RPs, and to expand the range and price
points of its instrument offerings. In an RP, the Company provides the customer
with the use of an instrument with no capital investment which creates an
opportunity for the Company to generate reagent revenue. The Company believes it
can accelerate the rate of expansion of its installed base by increasing its
emphasis on the placement of instruments through RPs because the required
capital investment associated with a purchase, a significant sales hurdle, will
be eliminated.
    
 
   
     Maximize Revenue Stream Per Placement. Each instrument placed typically
provides the Company with a recurring revenue stream through the sale of
reagents and supplies. The Company seeks to increase this revenue stream by
converting all existing manual tests performed by the customer to full
automation and by selling to the customer all reagents required for such tests.
The Company then seeks to have the customer expand its test menu through the
inclusion of all tests that are offered by Ventana as well as new tests as they
are introduced. To meet these objectives, the Company's systems have been
designed as broad enabling platforms which permit customers to easily expand
their test menu. The Company also has a comprehensive customer education program
which includes on-site technical training in instrument use, user group meetings
and Company-sponsored national teleconferences with leading medical experts who
regularly update customers on diagnostic and testing developments.
    
 
   
     Develop New and Enhanced Products. Since 1991, the Company has successfully
introduced and commercialized the Ventana ES, the Ventana gen II and the
TechMate 500, as well as 48 new reagents. The Company intends to introduce lower
priced instruments which it expects it will place through RPs in order to
provide greater financial flexibility for its customers in instrument
procurement. Ventana recently initiated broad-scale commercialization of its gen
II ISH system and has placed 15 systems in leading research sites in
    
 
                                       36
<PAGE>   39
 
the United States and Europe. The Company intends to continue to innovate in the
field of automated cellular diagnostics through the development and introduction
of new instruments, software and reagents.
 
     Expand Intellectual Property Position. The Company seeks to expand its
intellectual property position by entering into strategic alliances, acquiring
rights of first refusal on future commercial developments and licensing existing
technologies. The Company evaluates and intends to pursue the licensing of
nucleic acid probe technology for ISH applications from biopharmaceutical
companies, research institutions and others. In conjunction with gen II system
placements, the Company has and continues to enter into agreements with
customers which provide the Company with a right of first refusal to
commercialize new tests developed by such customers for use on the gen II
system. The Company believes customers are willing to enter into these
arrangements because the gen II is an enabling platform that facilitates the
development and commercialization of new ISH tests.
 
PRODUCTS
 
     The Company offers proprietary systems composed of instrumentation,
reagents and consumable products which are designed to enable clinical and
research laboratories to perform standardized IHC and ISH testing. The
proprietary nature of the Company's systems is based upon the interrelationship
among the electronics and mechanical and software control of the instrument and
the stabilization, composition, packaging and delivery of reagents. The
Company's broad line of products includes patient priority systems targeted to
hospital clinical laboratories and batch processing systems targeted to large
hospital clinical laboratories and reference and research laboratories. The
Company's patient priority systems are "closed" in that customers must purchase
detection chemistries from Ventana in order to operate the instruments. Although
the Company's existing batch processing systems are "open," providing the
customer with the ability to purchase reagents from either the Company or other
sources, users of more than 85% of the Company's United States installed batch
processing systems regularly purchase reagents from the Company. The following
are the principal benefits of automated cellular and tissue analysis using the
Company's integrated systems as compared with manual methods:
 
     -     improved reliability, reproducibility and consistency of test results
     -     reduced cost per test
     -     faster turnaround time for test results
     -     increased test throughput for the testing laboratory
     -     ability to perform new and emerging molecular tests
     -     reduced dependence on skilled laboratory technicians
     -     ability to perform special staining applications (batch processing
instruments)
     -     ability to obtain maximum clinical information from minimally-sized
biopsies
     -     ability to document processing protocols (patient priority
instruments)
     -     enhanced cellular differentiation through multiple staining on a
single slide
 
     To confirm the cost advantages of automated analysis using the Company's
instruments as compared to manual methods, the Company completed a cost study
involving 11 representative users of the Company's systems. These users
encompass a cross-section of the Company's customers and include hospitals of
varying sizes and a reference laboratory. The cost data compiled in the study
was based on the users' internal allocations of IHC test costs. The results of
the study indicate that automated IHC analysis using the Company's products
results in cost savings per test of approximately 10% as compared to manual
methods.
 
  INSTRUMENT PRODUCTS
 
     Patient Priority Instruments. Ventana currently offers two patient priority
systems, the Ventana ES and the Ventana gen II. The Ventana patient priority
systems provide a complete automated approach, requiring users to only prepare
specimens and place them on microscope slides. The patient priority systems are
barcode driven and are designed for multiple tests on a single patient biopsy
with rapid turnaround time and walk-away convenience. A barcode label affixed to
each slide positively identifies the slide and the test procedures to be
performed. Up to 40 slides can be processed at one time in the reaction chamber
of the instrument utilizing as
 
                                       37
<PAGE>   40
 
many as 25 individual reagents, providing the user with significant flexibility.
The instrument scans the barcodes on the slides and the reagent dispensers and
processes each slide with the unique steps necessary to perform each test. The
Company's proprietary software controls all aspects of the test procedures. The
steps of dispensing, incubating (i.e. temperature and time control) and washing
are performed by the instrument using a series of proprietary
chemical/mechanical methods developed by Ventana. These methods are critical to
obtaining precise, sensitive and rapid test results and make the system reliable
and easy to use. Typically, the processing of slides on the instrument requires
less than two hours.
 
     The Ventana gen II uses the same basic architecture as the Ventana ES
instrument and has additional functions enabling it to perform ISH tests. These
functions are (i) an improved heating system which allows for incubation
temperatures of up to 98(++)C, (ii) rapid incubation temperature cycling and
(iii) additional and improved wash stations which permit the use of multiple
buffers and instrument controlled changes in the concentration of buffers.
Ventana's gen II system represents a fundamental enabling technology for the
rapid, accurate and cost effective identification of unique RNA and DNA (probe
diagnostics) and is designed to overcome the inherent limitations of manual
processing.
 
     The Company is currently in the process of developing a new IHC instrument,
the NexES. The NexES, a patient priority system having IHC capabilities similar
to the Ventana ES, will be offered at a lower price per unit than the ES. Unlike
the Ventana ES, the NexES is based upon a modular design and an external
personal computer with a Windows 95 operating environment for software control.
Each module holds up to 20 slides in the reaction chamber and 25 reagents in its
reagent carousel. The modular design of the NexES and external personal computer
will permit the linkage of up to eight NexES modules together, creating the
capacity to process up to 160 slides using up to 200 reagents at one time. The
NexES will therefore offer users a significant degree of flexibility as users
can purchase from one to eight modules depending upon their test volume
requirements. Initial prototypes of the NexES are currently at the in-house
testing stage with beta site testing scheduled for early 1997. Commercial
introduction of the NexES is currently scheduled for 1997.
 
     Batch Processing Instruments. The Company's line of TechMate batch
processing instruments are designed for large volume testing using a single
antibody on multiple patient biopsies and research applications in which long
incubation times and unique detection chemistries are required. The Company's
batch processing instruments employ capillary action to perform IHC tests.
Patient biopsies are placed on capillary gap slides which maintain a space of
predetermined width between adjacent slides when loaded into TechMate systems.
Reagents are loaded into disposable reagent trays and programmable software
directs the instrument to apply the reagents in the proper sequence. The
instrument immerses the bottoms of the slides in the reagents as programmed and
the reagents are drawn up the slide and over the tissue specimen by capillary
action. After each reagent application and incubation, the instrument removes
the reagent from the specimen by placing the slides onto disposable blotting
pads.
 
     The Company's original batch instrument, the TechMate 1000, has a 300 slide
capacity. This large capacity is suited to large reference laboratories which
run a limited number of antibody tests on vast numbers of patient biopsies. The
Company has ceased production of the TechMate 1000. The successor instrument,
the TechMate 500, has a 120 slide capacity, which is applicable to both large
and moderately-sized reference laboratories and large research laboratories. The
Company has completed development of, and through LJL is initiating production
of, the TechMate 250 instrument. The TechMate 250, which has a 40 slide
capacity, is targeted primarily for the European market.
 
  REAGENT AND CONSUMABLE PRODUCTS
 
     Reagent Products
 
     Reagent products are composed of primary antibodies and detection
chemistries, each of which is required for an IHC test. Customers that have
patient priority systems must use Ventana detection chemistries on all tests;
such customers have the option of purchasing primary antibodies from Ventana or
other sources. Customers who have the Company's batch processing systems have
the option of purchasing both antibodies and detection chemistries from Ventana
or other sources. Users of more than 85% of the Company's United States
installed batch processing systems regularly purchase reagents from the Company.
 
                                       38
<PAGE>   41
 
     Primary Antibodies. Ventana sells a line of in excess of 30 primary
antibodies used to detect antigens in combination with detection chemistry kits
on the Company's instruments. Ventana markets all of the antibodies used to
perform the IHC tests that currently account for approximately 85% of total IHC
test volume.
 
     Detection Kits. Detection chemistries typically account for approximately
70% of the total expenditures for reagents required to perform IHC tests using
the Company's instruments. Ventana produces a line of detection chemistries for
use on both patient priority and batch processing systems which provide the user
with standardized reagents, thereby giving the user convenient and rapid
results. The detection chemistries have been developed by the Company using
proprietary formulations which, when combined with the Company's primary
antibodies and other reagents, optimize the results of tests performed on the
Company's instruments. These kits generate the visual signal in an IHC reaction
at the site where a primary antibody is bound to a specific antigen or molecule
in the cell or tissue. The patient priority system utilizes detection kits which
include (i) a DAB Kit which generates a brown color; (ii) an AEC Kit which
generates a deep red color; (iii) an AlkPhos Red Kit which generates a bright
red color; and (iv) an AlkPhos Blue Kit which generates a deep blue color. The
Company currently sells DAB and AlkPhos Red for use with its batch processing
instruments. The detection kits are designed to perform tests on a wide variety
of specimens, so a laboratory can, for example, perform tests on tissue
preserved in paraffin and on frozen tissue simultaneously. The Company's
detection chemistries have been formulated to provide long term stability for
reproducibility and ease of use as well as a high signal to noise ratio for
optimal sensitivity.
 
     Consumable Products
 
     Ventana offers a line of consumable ancillary products that are necessary
for processing slides on the Company's instruments. These include buffers for
optimizing the IHC reaction and counterstains for staining cell nuclei, which
are used with both patient priority and batch processing instruments. The
buffers ensure good morphology, low backgrounds and high signals. The
counterstains provide additional convenience for the customer by eliminating the
need for additional processing of the slides after staining on the instrument.
For use with patient priority instruments, Ventana also supplies a proprietary
liquid coverslip which is used to inhibit evaporation during processing in the
instrument, fixatives for maintaining the morphology of cells or tissues,
enzymes for unmasking antigens, and slide barcodes for use in identifying the
slide and its specific IHC reaction steps. For use with batch processing
instruments, the Company also provides disposable reagent trays which are used
to hold the reagents during IHC reactions, capillary gap slides and wicking pads
used for reagent removal between applications.
 
MARKETS AND CUSTOMERS
 
     There are approximately 4,200 acute care hospitals and clinics in the
United States. Of these, there are approximately 1,900 hospitals with over 200
beds which perform the vast majority of surgical and other medical procedures
related to cancer diagnosis and treatment. In addition, there are approximately
200 reference and research laboratories and approximately 100 biotechnology and
pharmaceutical companies which also perform substantial numbers of IHC and ISH
tests. The combination of these health care institutions creates a total
instrument site potential of 2,200 locations. Ventana considers this to be its
core market segment for cancer testing and focuses the bulk of its sales and
marketing efforts on these institutions.
 
   
     The Company estimates there are as many as 2,500 instrument placement
opportunities in the 2,200 potential instrument site locations in the United
States. The international market for instrument placements is estimated by the
Company to be approximately 1.2 times the size of the United States market.
Europe is estimated to account for the majority of the international market
potential, and Japan, the Pacific Rim and Latin American markets constitute the
balance of the international market opportunity.
    
 
     As of March 31, 1996, the Company had 441 instrument placements in 406 of
the 2,200 potential United States instrument sites. The Company believes that
less than 25% of such United States potential instrument sites currently conduct
IHC testing on an automated basis. The Company believes that its worldwide
installed base of 581 instruments is approximately five times as large as the
combined installed base of instruments of all of the Company's current
competitors.
 
                                       39
<PAGE>   42
 
   
     Ventana has placed instruments with 31 of the top 40 cancer centers
according to U.S. News & World Report and 35 of the 42 cancer centers identified
as principal cancer research centers by the National Cancer Institute, including
the Mayo Clinic, the Dana Farber Cancer Institute, The Johns Hopkins University,
the M.D. Anderson Cancer Center and the Fred Hutchinson Cancer Center.
    
 
   
     Presented below is a representative list of existing customers, all of
which have purchased products from the Company within the past year:
    
 
                             HOSPITALS AND CLINICS
 
Albany Medical Center Hospital (3 units)
Baylor School of Medicine
Boston University
City of Hope National Medical Center (3 units)
Cleveland Clinic (3 units)
Columbia Presbyterian
Dana Farber Cancer Institute
Fox Chase Cancer Center
Fred Hutchinson Cancer Center (2 units)
Georgetown University (2 units)
Harvard University Medical School (2 units)
The Johns Hopkins University (2 units)
 
REFERENCE AND RESEARCH LABORATORIES
 
Corning Nichols/MetPath (2 units)
Dianon (2 units)
National Cancer Institute
National Institutes of Health (5 units)
M.D. Anderson Cancer Center (2 units)
Mayo Clinic (4 units)
New York University (2 units)
Northwestern University
Ochsner Clinic
Stanford University
UCLA Medical Center
University of Chicago (4 units)
University of Michigan (4 units)
Walter Reed Army Medical Center (2 units)
Yale University
 
BIOTECHNOLOGY AND PHARMACEUTICAL
 
Amgen, Inc. (2 units)
Bristol-Myers Squibb Company
Eli Lilly and Company
Prizm Pharmaceuticals
Schering-Plough Corporation
 
   
     The Company intends to introduce lower priced instruments, including the
NexES and the TechMate 250, which it expects to place through RPs in order to
provide greater financial flexibility for its customers in equipment
procurement. The Company believes that lower priced systems and the RP
placements will have particular appeal to those hospitals which are currently
losing reimbursement revenue and incurring increased costs as a result of not
performing IHC tests internally. Additionally, smaller hospitals can benefit
from the Company's RP placements and lower priced instruments due to the absence
of an initial capital expenditure and an increased ability to compete with
larger hospitals by providing IHC testing and consultation on site.
    
 
SALES, MARKETING AND CUSTOMER SUPPORT
 
     Ventana markets and sells its instruments and reagents in North America
through a direct sales force and CMS. The Company markets and sells its
instruments and reagents in Europe through a direct sales organization
headquartered in Strasbourg, France, distribution relationships in certain
countries and a distribution arrangement with DAKO, a manufacturer and supplier
of reagents used in manual IHC testing. The distribution arrangements with CMS
in the United States and DAKO in Europe were inherited with the BioTek
acquisition and only relate to batch processing systems. The Company plans to
seek a strategic partner for the Japanese market and is in the early stages of
evaluating distributors for other geographic markets.
 
     Although BioTek used third parties for sales and distribution, BioTek
maintained a small field sales organization in the United States in order to
support the efforts of CMS. Ventana completed the integration of BioTek's field
based personnel in May 1996. Ventana's direct sales force in North America now
consists of 24 direct representatives, 4 regional managers, a national managed
care accounts manager, a national sales manager, 7 field based technical
marketing representatives and 4 field service engineers. Ventana's patient
priority systems are sold through its direct sales force. The sales force is
organized around geographic territories which have been designed to provide each
sales representative with an approximately equal number of sales opportunities.
The Company's sales representatives typically have technical backgrounds or
prior medical capital equipment sales experience. The Company's sales
representatives are incentivized to both increase instrument placements and
maximize recurring reagent sales.
 
                                       40
<PAGE>   43
 
     BioTek entered into its distribution agreement with CMS in January 1993.
Under the agreement, CMS has exclusive United States distribution rights for
TechMate instruments and related reagents. The agreement requires CMS to make
good-faith commercial efforts to purchase certain specified quantities of
instruments and to maintain a sufficient inventory of reagents to meet customer
requests. Under the terms of the agreement, CMS is guaranteed specified gross
profit margins on instruments, subject to BioTek's prior approval of sales below
prices prescribed by the agreement. Repairs, customer service and provision of
spare parts are the responsibility of BioTek. BioTek is obligated to repurchase
at cost all unsalable instruments and any slow-moving reagents. Unless earlier
amended, replaced or terminated, the agreement with CMS expires in April 1998.
 
     United States sales through CMS are subject to several operating
conditions. In particular, it has historically been necessary for BioTek to
support, and the Company anticipates that it will need to continue to support,
the efforts of CMS with direct field sales and support personnel. As a result,
the Company generates lower gross margins on sales through CMS than it would
generate were it to sell directly to end-users and incurs higher selling
expenses than typically associated with third-party distribution arrangements.
As a result of these factors and due to the presence of the Company's direct
sales force in the United States, the Company does not intend to renew the
agreement with CMS upon its expiration in April 1998. The Company has had
discussions regarding possible modifications to or early termination of the
relationship with CMS. However, these discussions are not currently ongoing.
 
     Ventana's sales force in Europe consists of eight sales and support
personnel located in France. This sales force markets and sells Ventana's
patient priority systems direct in France, Germany and the Benelux countries and
markets and sells through distribution relationships in Italy, Spain and
Scandinavia. This sales force is geographically organized and is compensated in
a manner similar to the United States sales force. Ventana expects to
significantly expand its direct sales and marketing activities in Europe in 1996
and 1997.
 
     BioTek entered into its agreement with DAKO in September 1994. DAKO is a
market leader in Europe in supplying reagents for use in manual IHC tests. DAKO
has exclusive rights to distribute TechMate instruments and related accessories
in Europe and several other territories. The agreement also permits DAKO to
supply customers with its own reagents for the instruments in return for paying
BioTek a fixed dollar royalty amount over a five-year royalty term for each
instrument installed at a customer site. As of March 31, 1996, there were 115
instruments included in the royalty base. Under the agreement, DAKO is subject
to certain minimum purchase requirements for instruments.
 
     In connection with BioTek's agreement with DAKO, DAKO made two loans
secured by a pledge of substantially all of BioTek's assets. DAKO also made
prepayments on future instrument sales and reagent royalties to BioTek. These
loans and prepayments were used to fund TechMate 250 instrument development and
working capital requirements. The aggregate balance of the secured loans and
prepayments was $1.6 million and $0.9 million, respectively, at March 31, 1996.
Of the secured loans, $0.3 million bears interest at 5% per annum and the
remaining $1.3 million does not bear interest. The prepayments do not bear
interest. The secured loans and prepayments are recorded as advances from
distributor in the Company's Consolidated Financial Statements. The amounts
payable under these loans are repaid through discounts on DAKO purchases of
instruments from BioTek. Upon termination of the distribution agreement or in
the event of a default by BioTek under the distribution agreement (including a
failure to satisfy development milestones with respect to the TechMate 250
instrument), these loans will convert to fixed term loans that will be due and
payable in 12 equal quarterly installments commencing upon such event.
 
     Since the acquisition of BioTek, Ventana and DAKO have been engaged in
discussions regarding various provisions of the distribution agreement. DAKO has
asserted that BioTek has not fulfilled its obligations with respect to the
development and commercial introduction of the TechMate 250 instrument. The
Company denies this assertion and believes that it is in substantial compliance
with its obligations under these development milestones. In particular, the
Company believes that the recent contract manufacturing agreement with LJL will
enable it to satisfy DAKO's requirements for TechMate 250 instruments.
Nevertheless, the negotiations with DAKO could result in an attempt by DAKO to
exercise contractual remedies available to it under the distribution agreement
and the terms of the secured loans, an interruption in the distribution of the
Company's batch processing instruments outside the United States or litigation
between the parties with respect to the agreement, which would involve
significant costs as well as diversion of
 
                                       41
<PAGE>   44
 
management time. Any of the foregoing could have a material adverse effect on
the Company's business, financial condition and results of operations. There can
be no assurance that the Company would prevail in any litigation involving the
agreement. DAKO's remedies under the agreement include (i) requiring repayment
of the secured loans in 12 equal quarterly installments commencing upon a
default by BioTek and (ii) an irrevocable license to manufacture TechMate
instruments for resale internationally and a related reduction in the fixed
dollar royalty rate paid by DAKO to BioTek for each instrument included in the
royalty base.
 
   
     There can be no assurance as to the future course or outcome of the
Company's negotiations with DAKO or as to the Company's future relationship with
DAKO. If DAKO were successful in obtaining a manufacturing license for TechMate
instruments, the Company could experience a loss of instrument revenue which
could have a material adverse effect on the Company's business, financial
condition and results of operations. In addition, termination of the agreement
with DAKO could materially adversely affect the Company's business, financial
condition and results of operations.
    
 
   
     Ventana's sales and marketing strategy for its systems is focused on
increasing its penetration of the hospital and laboratory market through several
instrument placement options. The Company places instruments through direct
sales including nonrecourse leases, instrument rentals and the Company's RPs. In
an RP, the Company provides the customer with the use of an instrument with no
capital investment which creates an opportunity for the Company to generate
reagent revenue. The terms and conditions of RP instrument placements can vary
from formal agreements specifying minimum volumes and unit pricing for reagent
purchases to short-term, informal arrangements where customers purchase reagents
on a month-to-month basis. Due to the working capital requirements associated
with RPs, the Company has historically sought to limit the amount of instruments
placed through RPs to approximately 30% of instrument placements. However, the
Company anticipates that the percentage of instruments placed through RPs, in
particular RP placements without formal reagent purchase commitments, will
increase with the introduction of the NexES and TechMate 250 and as the Company
obtains the additional working capital required to support additional RP
placements, which is likely in the future to result in a decrease in instrument
sales both in absolute dollars and as a percentage of total revenues. As of
March 31, 1996, the Company had placed 72 instruments through RPs.
    
 
     A key component of the Company's business strategy is to increase the sale
of reagents into its installed instrument base through a high level of customer
support. The Company's technical marketing representatives assist in training
customers in the use of the Company's systems and seek to increase customer
reagent utilization by facilitating the transfer of workload from manual
procedures. Through direct customer contact, the Company's technical marketing
representatives are able to promote sales of reagents and suggest new IHC test
applications to customers. New customers receive initial training on the systems
either in the field or at Ventana's facilities in Tucson, Arizona. The Company's
technical marketing representatives then visit the customer to provide
additional on-site training. Thereafter, Ventana actively supports customers
with periodic product bulletins and provides 24-hour customer telephone support.
Ventana actively markets its products through participation at industry trade
shows, video and audio presentations by leading pathologists and direct mail.
 
     The Company provides emergency field service for instruments during an
initial warranty period of 6 to 12 months. After the warranty period has
expired, field service is provided under service contract or on a billed time
and material basis. As of April 30, 1996 the Company had 85 instruments under
service contracts out of a total of approximately 230 instruments in the United
States that are outside the warranty period. Current annual service contract
prices typically range from $4,250 to $6,500.
 
MANUFACTURING
 
     The Company manufactures its patient priority instruments at its facilities
in Tucson, Arizona. The Company is currently in the process of expanding its
manufacturing operations in Tucson and believes that this expansion will provide
the Company with sufficient manufacturing capacity to meet its anticipated
requirements for patient priority instruments for approximately the next three
years. Components for patient priority instruments are purchased from a variety
of vendors, subject to stringent quality specifications. The components are
assembled by Ventana's highly skilled manufacturing technicians into finished
products. A
 
                                       42
<PAGE>   45
 
quality assurance group performs tests at regular intervals in the manufacturing
cycle to verify compliance with the Company's specifications and regulatory
requirements, including FDA GMP requirements.
 
     A number of the components used in the ES and gen II systems are fabricated
on a custom basis to the Company's specifications and are currently obtained
from a limited number of sources. To date, however, the Company has not
experienced any material disruptions in the supply of such components. The
Company believes that additional suppliers, if required, could be obtained and
qualified. To date, the Company has not experienced significant difficulties
with manufacturing yields and has experienced minimal manufacturing waste in the
patient priority instrument manufacturing process.
 
   
     The Company has relationships with third-party manufacturers for the
manufacture of batch processing instruments. The Company uses Kollsman for the
manufacture of TechMate 500 instruments and LJL for the manufacture of TechMate
250 instruments. The Company has entered into contract manufacturing agreements
with LJL and Kollsman.
    
 
     Reagents sold for use with the Company's patient priority instruments are
manufactured by Ventana, which purchases basic raw materials and performs
value-added manufacturing processes, such as formulation and packaging, at its
facilities. Certain components and raw materials, primarily antibodies, used in
the manufacturing of the Company's reagent products are currently provided by
single source vendors. To date, the Company has not experienced any material
disruptions in supply from these vendors and has experienced levels of
manufacturing waste in the reagent manufacturing process that it believes to be
below industry averages. Reagents sold for use with the Company's batch
processing instruments have historically been manufactured by third parties,
with only a few final steps in the manufacturing process being performed
internally.
 
     The Company expects to complete the consolidation of batch processing
reagent manufacturing into Ventana's Tucson facilities in September 1996.
Following this consolidation, Ventana intends to convert the manufacturing
process for such reagents to the process used by Ventana in which basic raw
materials are used and important value-added steps are performed internally. The
goals of this transition are to capture margin and value added currently being
lost through payments to third-party manufacturers, increase economies of scale
in both raw material purchasing and manufacturing, standardize procedures and
processes, increase control over scheduling and improve manufacturing
flexibility.
 
     The Company's reagent manufacturing process at its Tucson, Arizona facility
is currently semi-automated. The Company anticipates that as production volumes
increase it will increase the level of automation. The Company currently has
sufficient reagent manufacturing capacity to meet its anticipated needs for
approximately the next three years. The Company's long-term plans are to build a
separate reagent manufacturing facility in the Tucson area to increase its
reagent manufacturing capacity and increase the level of automation of the
manufacturing process. The Company anticipates commencing construction of this
facility in 1998.
 
     The Company's manufacturing operations are required to be conducted in
accordance with FDA GMP requirements. GMP requires the Company to maintain
documentation and process control in a prescribed manner with respect to
manufacturing, testing and quality control. In addition, the Company is subject
to FDA inspections to verify compliance with GMP requirements. The Company also
intends to implement manufacturing policies and procedures which will enable the
Company to receive ISO 9000 certification. ISO 9000 standards are global
standards for manufacturing process control and quality assurance. After
mid-1998, the Company will be required to obtain the CE mark for continued sale
of its products in the countries comprising the European Union. The CE mark is
an international symbol of quality assurance and compliance with applicable
European Union medical device directives.
 
RESEARCH AND DEVELOPMENT
 
     The Company's research and development projects are generally divided
between reagent development and instrumentation development. Reagent development
emphasizes existing instrumentation, and with the recent acquisition of BioTek,
is divided into consolidation and integration, patient priority, IHC and ISH
projects. Instrument development emphasizes the development of new instruments
and enhancements to existing instruments.
 
                                       43
<PAGE>   46
 
     Reagent Development Projects. Ventana's objective is to consolidate the
reagent manufacturing process for both patient priority and batch processing
systems in order to have common formulations to improve manufacturing
efficiencies. The Company estimates that reagent manufacturing will be
consolidated at Ventana's Tucson facilities in September 1996 and that by 1998
the Company will have fully integrated the reagent formulations and
manufacturing processes for patient priority and batch processing reagents.
Ventana's principal focus in the area of new reagent product development is the
introduction of new prognostic indicators. Ventana closely monitors third-party
development of new primary antibodies with prognostic potential. When such
prognostic markers appear, Ventana will seek to incorporate the marker into its
product line or will use its licensed fusion protein technology to develop
similar markers. Ventana is also developing a second generation estrogen
receptor ("ER") assay for use in breast cancer diagnosis. The assay incorporates
an improved primary antibody clone which significantly increases the assay's
sensitivity. The improved ER assay is currently undergoing beta testing and is
expected to be available for sale labelled for research use only in the fourth
quarter of 1996. The Company also intends to seek appropriate FDA approvals or
clearances for this product. Ventana is also improving its detection chemistry
sensitivity by developing a first generation amplification kit. This
amplification system will be compatible with all four existing patient priority
detection chemistries marketed by the Company as well as the first generation of
ISH detection chemistries currently under development. Through the use of
monoclonal antibodies that recognize each of the molecules used to label nucleic
acid probes in ISH tests, Ventana is developing a line of ISH detection
chemistries for research use. The Company's ISH detection chemistries are
scheduled for beta testing during the third quarter of 1996 with availability
for commercial sale for research use expected in 1997.
 
     Instrumentation Development Projects. In addition to completion of
development of the NexES instrument, Ventana has two major instrument
development projects underway. The first, the COSMIC, is a microscope system
which is aimed at the emerging field of telepathology and information transfer.
This system uses rastering of focused light and conventional optics to provide
high resolution digital images in real time. The images generated by the
microscope are digitized and stored or sent to remote sites. Twelve production
prototypes are currently being manufactured and beta site testing is scheduled
for 1997. Ventana is also developing a barcode label printing system for use
with its patient priority instruments, all of which are barcode driven. To
support its patient priority systems, Ventana currently maintains a stock
inventory of 125 different prepackaged barcodes. The barcode printer will enable
customers to print their own barcode labels from a stock of proprietary blank
barcodes. This will reduce the number of stock inventory barcode labels
maintained by Ventana to one and enable the customer to include pertinent
patient information on each slide for tracking purposes.
 
   
     At May 31, 1996, Ventana's research and development group consisted of 24
persons, many of whom have graduate degrees. Ventana's research and development
activities are performed primarily in-house by Ventana employees. These efforts
are supplemented by consulting services and assistance from Ventana's scientific
advisors.
    
 
     In addition to these projects, the Company inherited with the acquisition
of BioTek a development program for an ISH oven designed for use with TechMate
1000 and 500 instruments. This instrument will require substantial additional
development work and will also require the development of detection chemistries
for use with the instrument.
 
   
     During the years ended December 31, 1995, 1994 and 1993, Ventana spent $2.2
million, $1.9 million and $2.1 million, respectively, on research and
development. Pro forma spending for the year ended December 31, 1995 was $4.4
million.
    
 
PATENTS AND PROPRIETARY RIGHTS
 
   
     Ventana has pursued a strategy of patenting key technology as it relates to
both the automation and the chemistry of analyzing cells and tissues on
microscope slides. Ventana holds 11 United States patents and eight foreign
patents, including two European patents, and has filed additional United States
and foreign patent applications. Three of Ventana's United States patent
applications have been allowed. Several of Ventana's issued United States
patents relate to reagent formulations and methods, including a reagent
formulation characterized by long-term stability and a method of inhibiting
evaporation of reagents during processing. Other issued United States patents
relate to a reagent dispenser, a tissue fixative and various
    
 
                                       44
<PAGE>   47
 
   
aspects of the capillary gap technology and methods and devices for batch
processing of slides. Pending applications relate to mechanical aspects of
automated instruments for performing reactions on slides and processing methods
used in these instruments. In addition, a patent application filed by the
Company covers an evaporation inhibitor liquid that is effective for high
temperature applications. The expiration dates of the Company's issued United
States patents range from September 2005 to November 2013.
    
 
     There can be no assurance that the Company's patent applications will
result in patents being issued or that any issued patents will provide
protection against competitive technologies or will be held valid if challenged.
Others may independently develop products or processes similar to those of the
Company or design around or otherwise circumvent patents issued to the Company.
 
     Because patent applications in the United States are maintained in secrecy
until patents are issued and since publication of discoveries in scientific
literature tends to lag behind actual discoveries by several months, Ventana
cannot be certain that it was the first creator of inventions covered by its
patents or pending patent applications or that it was the first to file patent
applications for such inventions. Moreover, the Company may have to participate
in interference proceedings declared by the United States Patent and Trademark
Office to determine the priority of inventions, which could result in
substantial cost to the Company. In the event that any relevant claims of
third-party patents are upheld as valid and enforceable, the Company could be
prevented from practicing the subject matter claimed in such patents, or would
be required to obtain licenses from the patent owners of each of such patents or
to redesign its products or processes to avoid infringement. There can be no
assurance that such licenses would be available or, if available, would be
available on terms acceptable to the Company or that the Company would be
successful in any attempt to redesign its products or processes to avoid
infringement. If the Company does not obtain necessary licenses, it could be
subject to litigation and encounter delays in product introductions while it
attempts to design around such patents. Alternatively, the development,
manufacture or sale of such products could be prevented. Litigation would result
in significant cost to the Company as well as diversion of management time. The
outcome of any such litigation cannot be predicted with any assurance. Adverse
determinations in any such proceedings could have a material adverse effect on
the Company's business, financial condition and results of operations.
 
     BioTek is a party to litigation initiated by BioGenex relating to past
infringements of patent rights of BioGenex. For a discussion of these
proceedings, see "Legal Proceedings."
 
     Ventana also relies upon trade secret protection for its confidential and
proprietary information. There can be no assurance that others will not
independently develop substantially equivalent proprietary information or
techniques, gain access to Ventana's trade secrets or disclose such technology,
or that Ventana can effectively protect its trade secrets. Litigation to protect
Ventana's trade secrets would result in significant cost to the Company as well
as diversion of management time. Adverse determinations in any such proceedings
or unauthorized disclosure of Ventana trade secrets could have a material
adverse effect on Ventana's business, financial condition and results of
operations.
 
     Ventana's policy is to require its employees, consultants and significant
scientific collaborators to execute confidentiality agreements upon the
commencement of an employment or consulting relationship with Ventana. These
agreements generally provide that all confidential information developed or made
known to the individual during the course of the individual's relationship with
Ventana is to be kept confidential and not disclosed to third parties except in
specific circumstances. Agreements with employees provide that all inventions
conceived by the individual in the course of rendering services to Ventana shall
be the exclusive property of Ventana. There can be no assurance, however, that
these agreements will not be breached or that they will provide meaningful
protection or adequate remedies for unauthorized use or disclosure of Ventana's
trade secrets.
 
COMPETITION
 
   
     Competition in the diagnostic industry is intense and is expected to
increase. Competition in the diagnostic industry is based on, among other
things, product quality, performance, price and the breadth of a company's
product offerings. Ventana's instrument and reagent systems for IHC tests
compete with products offered by various manufacturers as well as with manual
diagnostic methods. In addition, flow cytometry can be used for cellular testing
and may, in certain markets, be competitive with the Company's products. The
    
 
                                       45
<PAGE>   48
 
   
Company's competitors may succeed in developing products that are more reliable
or effective or less costly than those developed by the Company and may be more
successful than the Company in manufacturing and marketing their products.
Although the Company plans to continue to work to develop new and improved
products, there are other companies engaged in research and development of
diagnostic devices or reagents, and the introduction of such devices or
alternative methods for diagnostic testing could hinder the Company's ability to
compete effectively and could have a material adverse effect on the Company's
business, financial condition and results of operations.
    
 
   
     In the instrument market, several companies, including Leica (a division of
Leitz Microscope GmbH), Shandon Scientific Limited (a division of Life Sciences
International PLC), BioGenex and DAKO (U.S.), offer instruments that perform IHC
tests and can be used with any supplier's reagents, which may be attractive to
certain customers. As of March 31, 1996, the Company had an installed base of
581 instruments which the Company estimates is more than five times the combined
installed base of instruments of all of the Company's current competitors. The
Company has included semi-automated instruments manufactured by its competitors
in arriving at its estimates of its market share. In addition, any future growth
in the market for automated IHC instruments may result in additional market
entrants and increased competition, including more aggressive price competition.
Many of the companies selling or developing diagnostic devices and instruments
and many potential entrants in the automated IHC market have financial,
manufacturing, marketing and distribution resources significantly greater than
those of Ventana. In addition, many of these current and potential competitors
have long-term supplier relationships with Ventana's existing and potential
customers. These competitors may be able to leverage existing customer
relationships to enhance their ability to place new IHC instruments. Competition
in the market for automated IHC instruments, including the advent of new market
entrants and increasing price competition, could have a material adverse effect
on the Company's business, financial condition and results of operations.
    
 
   
     In the market for reagents, the Company encounters competition from
suppliers of primary antibodies and detection chemistries. The major suppliers
of primary antibodies in the anatomical pathology market in the United States
are DAKO, BioGenex and Coulter Immunology. The principal suppliers of detection
chemistries in the United States are Vector Laboratories, BioGenex and DAKO. The
Company's patient priority instruments require the use of the Company's
detection chemistries but can be used with primary antibodies supplied by third
parties, and the Company's batch processing instruments can be used with both
detection chemistries and primary antibodies supplied by third parties.
Accordingly, the Company encounters significant competition in the sale of
reagents for use on those of its instruments that can be used with reagents
supplied by third parties. Lower prices for reagents used in manual IHC tests
could also limit the growth of automation. Certain of the Company's current and
potential competitors in the reagent market have financial, manufacturing,
marketing and distribution resources greater than those of the Company.
Competition in the market for reagents could also increase as a result of new
market entrants providing more favorable reagent supply arrangements than the
Company, including lower reagent prices. In particular, new entrants in the
instrument market may seek to enhance their competitive position through reduced
reagent pricing or more favorable supply arrangements; the Company's current
instrument customers may find it attractive to purchase primary antibodies for
patient priority instruments and primary antibodies and detection chemistries
for batch processing instruments from such competitors. Increased competition in
the reagent market could have a material adverse effect on the Company's
business, financial condition and results of operations.
    
 
   
GOVERNMENT REGULATION
    
 
     The manufacturing, marketing and sale of the Company's products are subject
to regulation by governmental authorities in the United States and other
countries. In the United States, clinical diagnostic devices are subject to
rigorous FDA regulation. The Federal Food, Drug and Cosmetic Act governs the
design, testing, manufacture, safety, efficacy, labeling, storage, record
keeping, approval, advertising and promotion of the Company's products.
Obtaining regulatory approval for new products within this regulatory framework
may take a number of years and involves the expenditure of substantial
resources. In addition, there can be no assurance that this regulatory framework
will not change or that additional regulation will not arise, which may affect
approval of or delay an application or require additional expenditures by the
Company.
 
                                       46
<PAGE>   49
 
     The FDA regulates, as medical devices, instruments, diagnostic tests and
reagents that are traditionally manufactured and commercially marketed as
finished test kits or equipment. Some clinical laboratories, however, choose to
purchase individual reagents intended for specific analytes and develop and
prepare their own finished diagnostic tests. Although neither the individual
reagents nor the finished tests prepared from them by the clinical laboratories
have traditionally been regulated by the FDA, the FDA has recently proposed a
rule that, if adopted, would regulate the reagents sold to clinical laboratories
as medical devices. The proposed rule would also restrict sales of these
reagents to clinical laboratories certified under CLIA as high complexity
testing laboratories. The Company intends to market some diagnostic products as
finished test kits or equipment and others as individual reagents; consequently,
some or all of these products will be regulated as medical devices.
 
     The Company's clinical diagnostic systems are regulated by the FDA under a
3-tier classification system -- Class I, II and III. The degree of regulation,
as well as the cost and time required to obtain regulatory approvals, generally
increases from Class I to Class III. Most diagnostic devices are regulated as
Class I or Class II devices, although certain diagnostic tests for particular
diseases may be classified as Class III devices. Prior to entering commercial
distribution, most Class I, II, or III medical devices must undergo FDA review
under one of two basic review schemes depending upon the type of device or
procedure. These review schemes are the 510(k) pre-market notification process
and the PMA process. A 510(k) notification is generally a filing submitted to
demonstrate that the device in question is "substantially equivalent" to another
legally marketed device. Approval under this procedure may be granted within 90
days, but generally takes longer, and in some cases up to a year or more. Class
I and II devices, as well as certain Class III devices for which the FDA has not
called for a PMA, are reviewed under the 510(k) process. For all other Class III
products, the manufacturer must file a PMA to show that the product is safe and
effective based on extensive clinical testing and controlled trials among
several diverse testing sites and population groups. These controlled trials may
be conducted under an Investigational Device Exemption ("IDE") cleared by the
FDA, or they may be conducted without FDA review if exempt from IDE
requirements. The PMA process typically involves significantly more clinical
testing than does the 510(k) procedure and could involve a significantly longer
FDA review period after the date of filing. In responding to a PMA application,
the FDA can either accept it for filing or reject it and require the
manufacturer to include additional information in a resubmitted application. PMA
applications that are accepted for filing may be reviewed by an FDA scientific
advisory panel, which issues either a favorable or unfavorable recommendation
regarding the device. The FDA is not bound by the panel's recommendation, but
tends to give it significant weight. By law, the PMA process is to be completed
within 180 days of acceptance of the PMA application for filing, although this
time period can be, and typically is, extended by the FDA. A PMA application can
take from one to several years to complete, and there can be no assurance that
any submitted PMA application will ultimately be approved. Further, clearance or
approval may place substantial restrictions on to whom and the indications for
which the product may be marketed or to whom it may be marketed. Additionally,
there can be no assurance that the FDA will not request additional data, or
request that the Company conduct further clinical studies.
 
   
     The Company's instruments, with respect to automated IHC testing functions,
have been categorized by the FDA as automated cell staining devices and have
been exempted from the 510(k) notification process. To date, ISH tests have not
received FDA approval and, therefore, use of the gen II for ISH tests will be
restricted to research applications. New instrument products that the Company
may develop and introduce could require 510(k) notifications and clearances or
PMA applications.
    
 
     All of the detection chemistries and most of the primary antibody products
being sold by the Company are currently classified as Class II devices. Many of
Ventana's detection chemistries have received 510(k) clearance from the FDA.
Some of the antibodies being marketed by the Company are labeled for diagnostic
use and have received 510(k) clearance from the FDA. The Company may wish to
market certain antibodies with a label indicating that they can be used in the
diagnosis of particular diseases, including cancer. These devices may be
classified as Class III devices and may therefore require a PMA.
 
     After products have been cleared for marketing by the FDA, the Company will
be subject to continuing FDA obligations. Clearances may be withdrawn or
products may be recalled if compliance with regulatory standards is not
maintained or if problems occur after the product reaches the market. The FDA
may require
 
                                       47
<PAGE>   50
 
surveillance programs to monitor the effect of products which have been
commercialized, and has the power to prevent or limit further marketing of the
product based on the results of these post-marketing programs. The FDA enforces
regulations prohibiting the marketing of products for unapproved uses. Further,
if the Company wanted to make changes on a product after FDA clearance or
approval, including changes in indications or intended use or other significant
modifications to labeling or manufacturing, additional clearances or approvals
would be required. The FDA has broad regulatory and enforcement powers including
the ability to levy fines and civil penalties, suspend or delay issuance of
approvals, seize or recall products, withdraw clearances or approvals, restrict
or enjoin the marketing of products, and impose civil and criminal penalties,
any one or more of which could have a material adverse effect upon the Company.
 
     The Company is subject to FDA GMP regulations. The Company is in the
process of implementing policies and procedures which are intended to allow the
Company to receive ISO 9000 certification. ISO 9000 standards are worldwide
standards for manufacturing process control, documentation and quality
assurance. There can be no assurance that the Company will be successful in
meeting ISO 9000 certification requirements. Under GMP regulations and ISO 9000
standards, the Company is subject to ongoing FDA and international compliance
inspections.
 
     Laboratories using the Company's diagnostic devices for clinical use in the
United States are regulated under CLIA, which is intended to ensure the quality
and reliability of medical testing. Regulations implementing CLIA establish
requirements for laboratories and laboratory personnel in the areas of
administration, participation and proficiency testing, patient test management,
quality control, personnel, quality assurance and inspection. Under these
regulations, the specific requirements that a laboratory must meet depend on the
complexity of the test being performed by the laboratory. Under CLIA
regulations, all laboratories performing moderately complex or highly complex
tests will be required to obtain either a registration certificate or
certificate of accreditation from the Health Care Financing Administration. CLIA
requirements may prevent some clinical laboratories from using certain of the
Company's diagnostic products. Therefore, there can be no assurance that CLIA
regulations and future administrative interpretations of CLIA will not have a
material adverse impact on the Company by limiting the potential market for the
Company's products.
 
     The Company sells products in certain international markets and plans to
enter additional international markets. International sales of medical devices
are subject to foreign government regulation, the requirements of which vary
substantially from country to country. These range from comprehensive device
approval requirements for some or all of the Company's medical device products
to requests for product data or certifications. FDA approval is required for the
export of Class III devices.
 
   
     In addition to the foregoing, the Company is subject to numerous federal,
state and local laws and regulations relating to such matters as safe working
conditions, laboratory and manufacturing practices, fire hazard control,
disposal of hazardous or potentially hazardous substances and other
environmental matters. To date, compliance with these laws and regulations has
not had a material effect on the Company's financial position, and the Company
has no plans for material capital expenditures relating to such matters. The
Company currently uses third party disposal services to remove and dispose of
the hazardous materials used in its processes. The Company could in the future
encounter claims from individuals, governmental authorities or other persons or
entities in connection with exposure to or disposal or handling of such
hazardous materials or violations of environmental laws by the Company or its
contractors and could also be required to incur additional expenditures for
hazardous materials management or environmental compliance. Costs associated
with environmental claims, violations of environmental laws or regulations,
hazardous materials management and compliance with environmental laws could have
a material adverse effect on the business, financial condition or results of
operations of the Company.
    
 
     Although the Company believes it will be able to comply with all applicable
regulations regarding the manufacture and sale of diagnostic products, such
regulations are always subject to change and depend heavily upon administrative
interpretations. Delays in or failure to receive clearances or approvals of
products the Company plans to introduce, or changes in the applicable regulatory
climates could have a material adverse effect upon the business, financial
condition or results of operations of the Company.
 
                                       48
<PAGE>   51
 
THIRD-PARTY REIMBURSEMENT
 
     Third-party payors, such as governmental programs and private insurance
plans, can indirectly affect the pricing or relative attractiveness of the
Company's products by regulating the maximum amount of reimbursement they will
provide to the Company's customers for diagnostic testing services. In recent
years, health care costs have risen substantially, and third-party payors have
come under increasing pressure to reduce such costs. In this regard, legislative
proposals relating to health care reform and cost containment have been
introduced at the state and federal levels. The cost-containment measures that
health care payors are instituting and the impact of any health care reform
could have a material adverse effect on the levels of reimbursement the
Company's customers receive from third-party payors and as a result on the
Company's ability to market and sell its products. Such factors could have a
material adverse effect on the Company's business, financial condition and
results of operations.
 
FACILITIES
 
     Ventana's research laboratories, instrument and reagent manufacturing
facilities and administrative offices are located in approximately 30,000 square
feet of leased space in Tucson, Arizona. The lease expires in March 2001,
subject to renewal terms. The BioTek research laboratory and reagent
manufacturing facilities are located in a 8,500 square foot facility in Santa
Barbara, California. This lease expires in September 1998; however, these
operations are expected to be consolidated into the Tucson facilities in
September 1996. The Company believes these premises can be subleased for the
remaining term of the lease.
 
EMPLOYEES
 
   
     As of May 31, 1996, Ventana employed 128 persons full time. Of these
employees, 58 were engaged in sales and marketing, 24 in research and
development, 31 in manufacturing and 15 in general and administrative functions.
None of Ventana's employees are covered by a collective bargaining agreement.
Ventana considers its relations with its employees to be satisfactory.
    
 
BACKLOG
 
     Ventana typically ships orders for instruments and reagents shortly after
receipt, and accordingly does not maintain a significant backlog.
 
LEGAL PROCEEDINGS
 
   
     In March 1995, BioGenex sued BioTek in federal court for infringement of
certain patent rights held by BioGenex relating to an antigen retrieval method
used in IHC tests. BioGenex's claims include claims of both direct, indirect and
contributory infringement. BioTek has denied infringement and has asserted
several defenses, including invalidity of the patent that is the subject of the
litigation. In April 1995, BioTek ceased offering the products that were the
subject of the alleged infringements. BioTek's total sales of these products
during the period were approximately $0.6 million. A trial is currently
scheduled for October 1, 1996. The parties have, from time to time, engaged in
settlement negotiations. There can, however, be no assurance that a pre-trial
settlement will be reached. Although there can be no assurance as to the
ultimate resolution of this matter, based on currently available information,
the Company does not believe that the resolution of this matter will have a
material adverse effect on the Company's business, financial condition or
results of operations.
    
 
     The Company has received notices of various claims from certain current and
former employees of BioTek. To date, no litigation has been instituted by any of
these individuals. However, there can be no assurance that such individuals will
not institute litigation against the Company. Based on its review of these
matters, the Company does not believe that their resolution will have a material
adverse effect on the Company's business, financial condition or results of
operations.
 
     Other than the foregoing litigation, the Company is not a party to any
material pending litigation.
 
                                       49
<PAGE>   52
 
                                   MANAGEMENT
 
DIRECTORS AND EXECUTIVE OFFICERS
 
   
     The following table sets forth certain information regarding the directors
and executive officers of the Company as of June 30, 1996:
    
 
   
<TABLE>
<CAPTION>
             NAME               AGE                   POSITION
  --------------------------    ---       ---------------------------------
  <S>                           <C>       <C>
  Jack W. Schuler(1)(III)       55        Chairman of the Board of
                                          Directors
  R. James Danehy(III)          51        President, Chief Executive
                                          Officer and Director
  Stephen A. Tillson, Ph.D.     55        Vice President, Scientific
                                          Affairs and Quality Assurance
  R. Michael Rodgers            51        Vice President, Finance, Chief
                                          Financial Officer and Secretary
  Carl W. Hull                  38        Vice President, Marketing and
                                          Business Development
  Michael K. Cusack             39        Vice President, International
  Anthony L. Hartman            45        Vice President, Research and
                                          Development
  Brian J. McGraw               35        Director of Engineering
  David P. Pauluzzi             35        National Sales Manager
  Bernard O. C. Questier        42        Vice President, European
                                          Operations
  Rex J. Bates(II)              72        Director
  Michael R. Danzi(II)          36        Director
  Edward M. Giles(1)(II)        60        Director
  Thomas M. Grogan,             50        Director
    M.D.(III)
  John Patience(2)(III)         48        Director
  C. Anthony Stellar,           66        Director
    M.D.(I)
  James M. Strickland(I)        53        Director
  James R. Weersing(1)(2)(I)    57        Director
</TABLE>
    
 
- ---------------
 
(1) Member of the Compensation Committee.
 
(2) Member of the Audit Committee.
 
   
  (I) Class I director
    
   
 (II) Class II director
    
   
(III) Class III director
    
 
     Mr. Schuler has served as a director of Ventana since April 1991 and as
Chairman of the Board of Directors since November 1995. Mr. Schuler has been
Chairman of the Board of Directors of Stericycle, Inc., a specialized medical
waste management company, since March 1990. Mr. Schuler is also a partner in
Crabtree Partners, a Chicago based venture capital firm. Prior to joining
Stericycle, Mr. Schuler held various executive positions at Abbott from December
1972 through August 1989, serving most recently as President and Chief Operating
Officer. He is currently a director of Medtronic, Inc., Somatogen, Inc. and
Chiron Corporation. Mr. Schuler received a B.S. in Mechanical Engineering from
Tufts University and an M.B.A. from Stanford University.
 
   
     Mr. Danehy has served as President and Chief Executive Officer and a
director of Ventana since September 1994. From June 1994 to September 1994, Mr.
Danehy served as a consultant to the Company. From November 1993 to June 1994,
Mr. Danehy served as an interim Chief Executive Officer and consultant for
BioStar Diagnostics, where he also served as a director from January 1994 to
March 1995. From 1972 to 1993, Mr. Danehy worked in a variety of capacities for
Abbott. From 1977 through 1989, Mr. Danehy held marketing and general management
responsibilities in Abbott's Diagnostics Division that included Product Manager
for hepatitis products, Marketing Manager for Clinical Chemistry Systems, Group
Marketing
    
 
                                       50
<PAGE>   53
 
Manager for TDx Systems, Director of Marketing for North America and General
Manager for Transfusion Diagnostics which included the AIDS test. Mr. Danehy
received a B.S. in Chemistry from St. Joseph's College and an M.B.A. from Loyola
University of Chicago.
 
   
     Dr. Tillson has served as Vice President of Scientific Affairs and Quality
Assurance since August 1995. From the time of his joining Ventana in May 1992
until July 1995, Dr. Tillson served as Director of Scientific Affairs and
Quality Assurance. From January 1990 to May 1992, Dr. Tillson served as a
principal of Ticon Company Consulting. He has 25 years experience in the
diagnostic and pharmaceutical industry. Dr. Tillson holds a Ph.D. from Purdue
University and received a B.S. from California State Polytechnic University and
an M.B.A. from St. Mary's College of California.
    
 
     Mr. Rodgers joined Ventana in February 1994 as Chief Financial Officer and
was appointed Vice President, Finance and Secretary in May 1994. From June 1992
until October 1993, Mr. Rodgers was Vice President and Chief Financial Officer
with BioMedical Waste Systems, Inc., a medical waste management firm. From
December 1988 to December 1991, Mr. Rodgers served as Executive Vice President
of Friedkin Investments, Inc., a merchant banking firm. Mr. Rodgers received a
B.S. in Business and Accounting from Menlo College and an M.B.A. from the
University of Houston. Mr. Rodgers is a Certified Public Accountant.
 
   
     Mr. Hull joined Ventana in June 1996 as Vice President, Marketing and
Business Development. From 1989 until joining Ventana, Mr. Hull held various
marketing and management positions with several divisions of Abbott. He served
most recently as Vice President and General Manager of Abbott Puerto Rico from
February 1995 to June 1996, and as Marketing Manager at Sequoia-Turner Corp., a
subsidiary of Abbott, from October 1993 to February 1995. From March 1989 to
September 1992, Mr. Hull held various marketing and management positions in
Abbott's Diagnostic Division. Mr. Hull received a B.A. in Political Science and
International Relations from The Johns Hopkins University and an M.B.A. from the
University of Chicago.
    
 
   
     Mr. Cusack joined Ventana as Vice President of Marketing in September 1994
and was promoted to Vice President, International in June, 1996. Mr. Cusack has
also served as President Directeur General of Ventana Medical Systems, S.A., a
wholly-owned subsidiary of Ventana, since September 1995. From November 1992
until joining Ventana, Mr. Cusack acted as General Manager, Europe and Mideast
for CYTYC S.A.R.L., a medical diagnostics company with operations in the United
States and abroad. Prior to CYTYC, Mr. Cusack held various marketing and
managerial positions with Abbott's Diagnostics Division. Mr. Cusack received a
B.S. from the University of Delaware and an M.B.A. from Temple University.
    
 
     Mr. Hartman has served as Vice President of Research and Development since
April 1996. Mr. Hartman joined Ventana in August 1990 as Senior Research and
Development Scientist, and he has also served as Director of Product Development
and Customer Support. Prior to joining Ventana, Mr. Hartman was a Research
Assistant Professor of Pathology at the University of Cincinnati College of
Medicine where he supervised the departmental service laboratory for IHC and
ISH. Mr. Hartman received a B.S. in General Science from the University of
Portland and an M.S. in Biophysics and Genetics from the University of Colorado.
 
     Mr. McGraw joined Ventana in September 1991 and has been the Director of
Engineering since December 1994. Prior to Mr. McGraw's promotion to Director of
Engineering, he was a Senior Engineer. From July 1987 until August 1991, Mr.
McGraw held various management and system design positions in Abbott's
Diagnostics Division. Mr. McGraw received a B.S. in Mechanical Engineering from
West Virginia University.
 
     Mr. Pauluzzi has served as National Sales Manager of Ventana since June
1995. He had previously served in various sales positions since joining Ventana
in March 1993. From January 1985 until joining Ventana, Mr. Pauluzzi worked for
Abbott's Diagnostics Division in a variety of marketing and sales and product
management positions. Mr. Pauluzzi received a B.B.A. in Public Accounting from
Loyola University of Chicago.
 
     Mr. Questier has served as Vice President of European Operations of Ventana
since February 1996. From October 1990 until joining Ventana in October 1995,
Mr. Questier held a number of management positions in
 
                                       51
<PAGE>   54
 
E.I. DuPont de Nemours, most recently as Business Manager for New Products in
Europe. Mr. Questier received a degree in Chemical Engineering from the
Technical Institute in Oostende, Belgium.
 
   
     Mr. Bates has served as a director of Ventana since April of 1996. From
August 1991 to May 1995, Mr. Bates served on the Board of Directors of Twentieth
Century Industries and was a member of its compensation committee. Prior to
Twentieth Century Industries, Mr. Bates served as the Vice-Chairman of the Board
of Directors of the State Farm Mutual Automobile Insurance Company. Mr. Bates
also served as State Farm's Chief Investment Officer. In March of 1991, Mr.
Bates retired from State Farm. Prior to Mr. Bates' employment with State Farm,
he was a partner in the investment firm of Stein, Roe & Farnham in Chicago. Mr.
Bates received a B.S. and an M.S. from the University of Chicago.
    
 
     Mr. Danzi has served as a director of Ventana since April 1996. Prior to
the acquisition of BioTek, Mr. Danzi served as the President and Chairman of
BioTek and was associated with BioTek as a director and investor since 1993. Mr.
Danzi is the founder and Managing Director of Danzi Capital Group, a securities
firm. Mr. Danzi received a B.S. in Materials Science and Engineering from
Cornell University, is a graduate of the United States Naval Nuclear Power
School graduate level engineering program and received an M.B.A. from Harvard
University.
 
     Mr. Giles has served as director of Ventana since September 1992. Mr. Giles
has served as Chairman and President of The Vertical Group, Inc., a venture
capital investment firm, since January 1989. Mr. Giles was previously President
of F. Eberstadt & Co., Inc., a securities firm, and Vice Chairman of Peter B.
Cannell & Co., Inc., an investment management firm. He is currently a director
of McWhorter Technologies, Inc. Mr. Giles received a B.S.E.E. in Chemical
Engineering from Princeton University and an M.S. in Industrial Management from
the Massachusetts Institute of Technology.
 
     Dr. Grogan is a founder, a director and Chairman Emeritus of Ventana. He
has served as a director since the founding of the Company in June 1985 and as
Chairman of the Board of Ventana from June 1985 to November 1995. He is
currently a professor of pathology at the University of Arizona, College of
Medicine, where he has taught since 1979. He received a B.A. in Biology from the
University of Virginia and an M.D. from George Washington School of Medicine.
Dr. Grogan completed a post-doctorate fellowship at Stanford University.
 
     Mr. Patience has served as a director of Ventana since July 1989. Mr.
Patience was a co-founder and served as a General Partner of Marquette Venture
Partners, a venture capital investment firm, from January 1988 until March 1995.
Since April 1995, Mr. Patience has been a partner in Crabtree Partners, a
Chicago-based venture capital firm. Mr. Patience was previously a partner in the
consulting firm of McKinsey & Co., specializing in health care. He is currently
a director of TRO Learning, Inc. Mr. Patience received a B.A. in Liberal Arts
and an L.L.B. from the University of Sydney, Australia, and an M.B.A. from the
University of Pennsylvania Wharton School of Business.
 
     Dr. Stellar has served as a director of Ventana since April 1996. Since
1964, he has been in private practice as a surgeon in Laguna Hills, California.
Dr. Stellar is certified by the American Board of Surgery and the Board of
Thoracic Surgery and is a Fellow of the American College of Surgeons and the
College of Chest Physicians. Dr. Stellar received a B.S. and an M.D. from
Stanford University.
 
     Mr. Strickland has served as a director of Ventana since December 1987. Mr.
Strickland is a founder and has been the General Partner of Coronado Venture
Management L.P., a venture capital investment firm, since October 1986. Mr.
Strickland was previously Vice President of Burr Brown Corporation, a
semiconductor manufacturer. Mr. Strickland received a B.S. and an M.S. in
Electrical Engineering from the University of New Mexico and an M.S. in
Industrial Administration from the Carnegie Institute of Technology.
 
     Mr. Weersing has served as a director of Ventana since October 1994. Since
1984, Mr. Weersing has been a Managing Director of MBW Venture Partners, a
venture capital investment firm. Mr. Weersing has also served as President of
JRW Technology, Inc., a consulting firm. Mr. Weersing served as a director of
Circadian, Inc., an asthma dosage management company, from December 1993 until
January 1996. Circadian filed a petition under Chapter 7 of the federal
bankruptcy laws in January 1996. Mr. Weersing received an B.S.M.E. and an MBA
from Stanford University.
 
                                       52
<PAGE>   55
 
BOARD OF DIRECTORS
 
   
     The Company's Bylaws authorize and the Company currently has a board of 10
directors. All directors hold office until the next annual meeting of
stockholders or until their successors have been elected. The Company's
certificate of incorporation and Bylaws, however, provide that upon the
effective date of this Offering, the Board of Directors will be divided into
three classes. Each class will consist of three or four directors. The terms of
office of class I, class II and class III directors will expire at the Company's
1997, 1998 and 1999 annual meetings of stockholders, respectively. At each
annual meeting of stockholders at which the term of office of a particular class
of directors first expires, the persons elected to the board positions
represented by such class of directors will be elected to serve from the time of
election until the third annual meeting following election. Any additional
directorships resulting from an increase in the number of directors will be
distributed among the three classes of directors so that, as nearly as possible,
each class will consist of one-third of the directors. This classification of
the Board of Directors may have the effect of delaying or preventing changes in
control or management of the Company. Officers serve at the discretion of the
Board of Directors. There are no family relationships among any of the directors
or executive officers of the Company. The Company does not pay cash compensation
to directors for serving in that capacity, although the Company does reimburse
directors for expenses incurred in attending Board of Directors meetings. The
Board of Directors has, among other committees, a Compensation Committee that
makes recommendations concerning salaries and incentive compensation for
employees of and consultants to the Company and an Audit Committee that reviews
the results and scope of the audit and other services provided by the Company's
independent auditors. From and after the closing date of the acquisition of
BioTek and until the repayment of the principal amount of the Exchange Notes by
Ventana in exchange for notes held by holders of BioTek, Ventana is obligated to
nominate at its annual meetings of stockholders two representatives of BioTek
(the "BioTek Representatives") for election to Ventana's Board of Directors. The
BioTek Representatives who are currently serving on the Board of Directors
pursuant to this right are Michael R. Danzi and C. Anthony Stellar, M.D.
    
 
                                       53
<PAGE>   56
 
EXECUTIVE COMPENSATION
 
     The following table sets forth certain information regarding the
compensation of the Company's Chief Executive Officer and each of the other four
most highly compensated executive officers calculated on an annual basis (salary
and bonus) for services rendered in all capacities to the Company during the
year ended December 31, 1995 (collectively, the "Named Executive Officers").
 
                           SUMMARY COMPENSATION TABLE
 
   
<TABLE>
<CAPTION>
                                                                   LONG-TERM COMPENSATION
                                                                   -----------------------
                                                                           AWARDS
                                                                   -----------------------
                                          ANNUAL COMPENSATION      RESTRICTED   SECURITIES      ALL OTHER
                                          --------------------       STOCK      UNDERLYING       ANNUAL
  NAME AND PRINCIPAL POSITION     YEAR    SALARY($)    BONUS($)    AWARDS($)     OPTIONS     COMPENSATION($)
- -------------------------------  ------   --------     -------     ----------   ----------   ---------------
<S>                              <C>      <C>          <C>         <C>          <C>          <C>
R. James Danehy................   1995    $200,000          --          --             --             --
  President and Chief Executive
  Officer
Bernard O. C. Questier.........   1995     150,000(1)        0(2)       --         36,956        $63,800(3)
  Vice President, European
  Operations
David P. Pauluzzi..............   1995      84,855      48,207(4)       --         23,098             --
  National Sales Manager
Michael K. Cusack..............   1995     100,054          --          --             --             --
  Vice President, International
R. Michael Rodgers.............   1995      97,030          --          --         15,152             --
  Vice President, Finance and
  Chief Financial Officer and
  Secretary
</TABLE>
    
 
- ---------------
 
(1) Mr. Questier joined the Company in October of 1995. During 1995, he was paid
    $12,500 per month. His salary is fixed to the French Franc to protect
    against currency fluctuations should the United States Dollar depreciate
    relative to the French Franc; however, if the United States Dollar
    appreciates relative to the French Franc, Mr. Questier's salary shall remain
    unchanged.
 
(2) Although Mr. Questier received no bonus for 1995, he was guaranteed a
    one-time nonrecurring $7,500 bonus in 1996 for signing his employment
    contract in October of 1995 and meeting certain other conditions.
 
(3) Consists of relocation expenses of $55,000 associated with Mr. Questier's
    move from Germany to France, which have been accrued but not yet fully paid,
    and an $8,800 annual automobile allowance.
 
(4) Consists entirely of commissions earned through employment as the Company's
    Northern Regional Sales Manager prior to his promotion to National Sales
    Manager in June of 1995.
 
                                       54
<PAGE>   57
 
STOCK OPTION INFORMATION
 
   
     The following table contains information concerning the stock option grants
made to each of the Named Executive Officers for the year ended December 31,
1995.
    
 
                           OPTION GRANTS IN LAST YEAR
 
   
<TABLE>
<CAPTION>
                                                                                            POTENTIAL
                                                                                           REALIZABLE
                                              INDIVIDUAL GRANTS                         VALUE AT ASSUMED
                            ------------------------------------------------------       ANNUAL RATES OF
                            NUMBER OF      % OF TOTAL                                      STOCK PRICE
                            SECURITIES      OPTIONS       EXERCISE                      APPRECIATION FOR
                            UNDERLYING     GRANTED TO      OR BASE                       OPTION TERM(4)
                             OPTIONS       EMPLOYEES        PRICE       EXPIRATION     -------------------
           NAME             GRANTED(1)     IN 1995(2)     ($/SH)(3)        DATE         5%($)      10%($)
- --------------------------  ----------     ----------     ---------     ----------     -------     -------
<S>                         <C>            <C>            <C>           <C>            <C>         <C>
R. James Danehy...........         --            --            --               --          --          --
Bernard O. C. Questier....     36,957         11.39%        $0.84          10/4/05     $19,523     $49,476
David P. Pauluzzi.........     23,098          7.12          0.84           4/4/05-     12,202      30,922
                                                                           6/30/05
Michael K. Cusack.........         --            --            --               --          --          --
R. Michael Rodgers........     15,153          4.67          0.84           4/4/05       8,005      20,286
</TABLE>
    
 
- ---------------
 
(1) Options were granted under the Company's 1988 Stock Option Plan. These
    generally vest over four years from the date of grant.
 
   
(2) Based on an aggregate of 324,505 options granted by the Company in the year
    ended December 31, 1995 under the Company's 1988 Stock Option Plan to all
    employees of and consultants to the Company, including the Named Executive
    Officers.
    
 
(3) The exercise price per share of each option was equal to the fair market
    value of the Common Stock on the date of grant as determined by the
    Company's Board of Directors.
 
(4) The 5% and 10% assumed annual rates of compounded stock price appreciation
    are mandated by rules of the Securities and Exchange Commission. There can
    be no assurance provided to any executive officer or any other holder of the
    Company's securities that the actual stock price appreciation over the
    10-year option term will be at the assumed 5% and 10% levels or at any other
    defined level. Unless the market price of the Common Stock appreciates over
    the option term, no value will be realized from the option grants made to
    the executive officers.
 
AGGREGATED OPTION EXERCISES IN LAST YEAR AND YEAR-END OPTION VALUES
 
     The following table sets forth, for each of the Named Executive Officers,
the shares acquired and the value realized on exercises of stock options during
the year ended December 31, 1995 and the year-end number and value of
exercisable and unexercisable options.
 
<TABLE>
<CAPTION>
                                                            NUMBER OF SECURITIES
                                                                 UNDERLYING                 VALUE OF UNEXERCISED
                                                            UNEXERCISED OPTIONS             IN-THE-MONEY OPTIONS
                           SHARES                           AT DECEMBER 31, 1995            AT DECEMBER 31, 1995
                         ACQUIRED ON       VALUE        ----------------------------    ----------------------------
         NAME            EXERCISE(#)    REALIZED($)     EXERCISABLE    UNEXERCISABLE    EXERCISABLE    UNEXERCISABLE
- -----------------------  -----------    ------------    -----------    -------------    -----------    -------------
<S>                      <C>            <C>             <C>            <C>              <C>            <C>
R. James Danehy........         --             --           4,968         209,419         $ 3,898        $ 164,333
Bernard O.C.
  Questier.............         --             --              --          36,956              --           29,000
David P. Pauluzzi......      1,899         $1,461             661          25,157             495           19,620
Michael K. Cusack......         --             --           8,623          20,942           6,767           16,433
R. Michael Rodgers.....      9,239          6,500           4,157          31,320           3,150           23,040
</TABLE>
 
- ---------------
 
(1) The value of "in-the-money" stock options represents the positive spread
    between the exercise price of stock options, which ranges from $0.60 per
    share to $0.95 per share, and the fair market value for the Company's Common
    Stock of $1.62 per share as of December 31, 1995, as determined by the
    Company's Board of Directors.
 
                                       55
<PAGE>   58
 
EMPLOYMENT AGREEMENTS
 
     The Company has an employment agreement with Bernard O.C. Questier, its
Vice President of European Operations. The agreement provides for annual
compensation of $150,000, which is fixed to the French Franc to protect against
currency fluctuations should the United States Dollar depreciate relative to the
French Franc; however, if the United States Dollar appreciates relative to the
French Franc, Mr. Questier's salary shall remain unchanged. The agreement also
provides for, in the event of Mr. Questier's termination, continued compensation
through the quarter in which notice of termination is given plus one additional
full quarter. The agreement does not provide for any specified term of
employment. The Company currently has no employment contracts or agreements with
any of the other Named Executive Officers or with any other person.
 
COMPENSATION COMMITTEE INTERLOCKS AND INSIDER PARTICIPATION
 
   
     The Compensation Committee of the Board of Directors consists of Jack W.
Schuler, James R. Weersing and Edward M. Giles. The Compensation Committee makes
recommendations to the Board of Directors concerning salaries and incentive
compensation for employees of and consultants to the Company, except that the
Compensation Committee has full power and authority to grant stock options to
the Company's executive officers under the Company's 1996 Stock Option Plan. Mr.
Danehy served as a member of the Compensation Committee until April 1996.
    
 
STOCK PLANS
 
   
     1996 Stock Option Plan. The Company's 1996 Stock Option Plan (the "1996
Stock Plan") was adopted by the Board of Directors in April 1996. A total of
1,000,000 shares of Common Stock are reserved for issuance under the 1996 Stock
Plan. As of May 15, 1996, no options to purchase shares of Common Stock have
been granted pursuant to the 1996 Stock Plan. In the event of a change in
control of the Company, including a merger of the Company with or into another
corporation or the sale of substantially all of the assets of the Company, then
all shares subject to options granted under the 1996 Stock Plan will become
fully vested and exercisable unless such options are assumed by the successor or
acquiring company. The 1996 Stock Plan will terminate in April 2006, unless
earlier terminated in accordance with the terms of the 1996 Stock Plan.
    
 
   
     1996 Director Option Plan. In June 1996, the Company adopted a 1996
Director Option Plan (the "Director Plan") and reserved a total of 250,000
shares of Common Stock for issuance thereunder. Commencing with the Company's
1997 annual meeting of stockholders, each nonemployee director will be granted a
nonstatutory option to purchase an amount of shares of Common Stock of the
Company equal to 5,000 shares multiplied by a fraction, the numerator of which
shall be $15.00 and the denominator of which shall be the fair market value of
one share of the Company's Common Stock on the date of grant. The exercise price
of options granted under the Director Plan will be equal to the fair market
value of one share of the Company's Common Stock on the date of grant. Each
option granted under the Director Plan will vest on a cumulative monthly basis
over a one-year period and will have a 10-year term. In the event of a change in
control of the Company, including a merger of the Company with or into another
corporation or the sale of substantially all of the assets of the Company, then
all shares subject to options granted under the Director Plan will become fully
vested and exercisable unless such options are assumed by the successor or
acquiring company. The Director Plan will terminate in June 2001, unless earlier
terminated in accordance with the terms of the Director Plan.
    
 
     1988 Stock Option Plan. The Company's 1988 Stock Option Plan (the "1988
Stock Plan") was adopted by the Board of Directors in March 1988 and approved by
the stockholders in February 1989. A total of 1,339,663 shares of Common Stock
are reserved for issuance under the 1988 Stock Plan. As of May 15, 1996, 298,453
shares of Common Stock had been issued upon exercise of stock options, options
to purchase an aggregate of 840,357 shares were outstanding at a weighted
average exercise price of $2.48 per share, and 200,842 shares remained available
for future issuance under the 1988 Stock Plan.
 
   
     1991 Employee Stock Purchase Plan.  The Company's 1991 Employee Stock
Purchase Plan (the "1991 Purchase Plan") was adopted by the Board of Directors
in 1991 and approved by the stockholders in 1991. Shares of Preferred Stock
convertible into an aggregate of 92,391 shares of Common Stock had been
authorized for issuance under the 1991 Purchase Plan as of March 31, 1996 of
which 82,403 shares have been
    
 
                                       56
<PAGE>   59
 
   
issued as of such date. In June 1996, shares of Preferred Stock convertible into
an additional 12,627 shares of Common Stock were reserved for issuance under the
1991 Purchase Plan to enable the Company to complete the issuance of shares of
Preferred Stock in the purchase period that ended on June 30, 1996. The 1991
Purchase Plan, which is intended to qualify under Section 423 of the Code, is
administered by the Board of Directors of the Company or by a committee
appointed by the Board of Directors. The 1991 Purchase Plan terminated on June
30, 1996 at the conclusion of the current purchase period.
    
 
   
     1996 Employee Stock Purchase Plan. The Company's 1996 Employee Stock
Purchase Plan (the "1996 Purchase Plan") was adopted by the Board of Directors
in April 1996. A total of 200,000 shares of Common Stock are reserved for
issuance under the 1996 Purchase Plan. Under the 1996 Purchase Plan, the Company
withholds a specified percentage of each salary payment to participating
employees over certain offering periods. Any employee who is currently employed
for at least 20 hours per week and more than five months in a calendar year by
the Company or any majority owned subsidiary designated by the Board of
Directors from time to time, and who does not own 5% or more of the total
combined voting power or value of all classes of the capital stock of the
Company or of any subsidiary of the Company, is eligible to participate in the
1996 Purchase Plan. Unless the Board of Directors determines otherwise, each
offering period will run for 24 months and will be divided into four consecutive
periods of approximately six months. The first offering period and first
purchase period will commence on or about the date of this Prospectus. New
offering periods will commence every six months. The price at which stock is
purchased under the 1996 Purchase Plan is equal to 85% of the fair market value
of the Common Stock on the first day of the applicable offering period or the
last day of the applicable purchase period, whichever is lower.
    
 
SECTION 401(K) PLAN
 
     In September 1993, the Company adopted a Retirement Savings and Investment
Plan that is intended to qualify under Section 401(k) of the Code (the "401(k)
Plan") covering the Company's full-time employees located in the United States.
Pursuant to the 401(k) Plan, employees may elect to reduce their current
compensation by up to the statutorily prescribed annual limit ($9,500 in 1996)
and have the amount of such reduction contributed to the 401(k) Plan. The 401(k)
Plan permits, but does not require, additional matching contributions to the
401(k) Plan by the Company on behalf of all participants in the 401(k) Plan. To
date, the Company has not made any contributions to the 401(k) Plan.
 
LIMITATIONS ON DIRECTORS' LIABILITIES AND INDEMNIFICATION
 
     The Company has adopted provisions in its Restated Certificate of
Incorporation that eliminate the personal liability of its directors for
monetary damages arising from breach of their fiduciary duties in certain
circumstances to the fullest extent permitted by law, and authorize the Company
to indemnify its directors and officers to the fullest extent permitted by law.
Such limitation of liability does not apply to liabilities arising under the
federal securities laws and does not affect the availability of equitable
remedies such as injunctive relief or rescission.
 
     The Company's Bylaws provide that the Company will indemnify its directors
and officers to the fullest extent permitted by Delaware law, including
circumstances in which indemnification is otherwise discretionary under Delaware
law. The Company has entered into indemnification agreements providing for the
foregoing with its directors and executive officers. The indemnification
agreements may require the Company, among other things, to indemnify such
officers and directors against certain liabilities that may arise by reason of
their status or service as officers or directors (other than liabilities arising
from willful misconduct of a culpable nature) and to advance their expenses
incurred as a result of any proceeding against them as to which they could be
indemnified.
 
     At present, there is no pending litigation or proceeding involving a
director or officer of the Company where indemnification is required or
permitted, nor is the Company aware of any threatened litigation or proceeding
that may result in a claim for such indemnification.
 
                                       57
<PAGE>   60
 
                              CERTAIN TRANSACTIONS
 
     Since January 1, 1993, the Company has sold shares of Series D Preferred
Stock convertible into shares of Common Stock in private financings. In
connection with such sales, the Company has also issued warrants to acquire
shares of Series D Preferred Stock at an exercise price of $5.82 which are
convertible into shares of Common Stock. The purchasers of the Series D
Preferred Stock included the following 5% stockholders, directors and entities
affiliated with directors.
 
   
<TABLE>
<CAPTION>
                                                                                SHARES OF
                                                                                SERIES D
                                                      SHARES OF SERIES D     PREFERRED STOCK
                            NAME                      PREFERRED STOCK(1)   UNDERLYING WARRANTS
        --------------------------------------------  ------------------   -------------------
        <S>                                           <C>                  <C>
        DIRECTORS AND ENTITIES AFFILIATED WITH
          DIRECTORS
        Entities affiliated with Coronado Venture
          Fund
          (James M. Strickland).....................         103,136                 860
        Edward M. Giles IRA.........................           1,211                  61
        MBW Venture Partners, L.P. (James R.
          Weersing).................................          90,466               4,524
        Jack W. Schuler.............................          12,200                 611
        Entities affiliated with The Vertical Group
          (Edward M. Giles).........................          10,624                 533
        Rex J. Bates................................           5,090                 255
        OTHER 5% STOCKHOLDERS
        State Farm Mutual Automobile Insurance
          Company...................................         171,890               8,595
        Entities affiliated with Marquette Venture
          Partners..................................         475,123               6,568
</TABLE>
    
 
- ---------------
 
   
(1) Each share of Preferred Stock will convert into 0.37 shares of Common Stock
    upon the closing of this Offering.
    
 
   
     In April and May 1996, the Company sold an aggregate of 646,664 shares of
Common Stock to Jack Schuler, the Company's Chairman, John Patience, a director
of the Company, and venture capital funds affiliated with Marquette Venture
Partners ("Marquette"), a principal stockholder of the Company, at a purchase
price of $1.62 per share. Messrs. Schuler and Patience paid the purchase price
for their shares 10% in cash and 90% through a full recourse promissory note
secured by the underlying shares of Common Stock. The promissory notes bear
interest of 6% per annum and are due and payable in full on February 26, 1998.
Marquette paid the purchase price for their shares in cash. These stock
purchases were approved by the Company's Board of Directors in principle in
January 1996 and the specific terms of the stock purchases were approved by the
Board of Directors on February 23, 1996. The purchase price of $1.62 per share
was determined by the Board of Directors of the Company in January 1996 and
equals the fair market value of Company's Common Stock as of such date, as
determined by the board. Messrs. Schuler and Patience were provided with the
opportunity to purchase these shares in connection with (i) their efforts and
assistance in completing the BioTek acquisition and assisting management with
the integration of the companies, (ii) Mr. Schuler's decision to serve as
Chairman of the Board of Directors and (iii) Mr. Schuler's and Mr. Patience's
devotion of a significant portion of their work time to the Company's business.
These shares are subject to a right of repurchase at cost in favor of the
Company, which repurchase right will lapse as the shares become vested. The
shares will become vested as follows: (i) an aggregate of 193,948 shares
(including 97,011 shares purchased by Mr. Schuler, 66,754 shares purchased by
Mr. Patience and 30,183 shares purchased by Marquette) will become vested upon
the completion of this Offering, (ii) 172,463 shares purchased by Mr. Schuler
will vest in 48 equal monthly installments commencing February 26, 1996 provided
that Mr. Schuler continues to serve as Chairman of the Board of Directors, and
(iii) 129,348 shares purchased by Mr. Patience and 150,905 shares purchased by
Mr. Schuler will vest in 24 equal monthly installments provided that such
individuals devote one-half of their work time to the Company's business on a
cumulative basis over such vesting period.
    
 
                                       58
<PAGE>   61
 
   
     In 1994 the Company hired R. James Danehy to serve as President, Chief
Executive Officer and a director of the Company. In connection therewith, the
Company issued Mr. Danehy a stock option (the "Option") covering 295,650 shares
of Common Stock at an exercise price of $0.84 per share. In addition, the
Company provided Mr. Danehy the opportunity to purchase up to $200,000 of Series
D Preferred Stock at $5.82 per share. As an incentive to purchase such shares,
the Company also provided Mr. Danehy the opportunity to purchase approximately
0.37 additional shares of Common Stock at $0.84 per share for each two shares of
Series D Preferred Stock purchased. Mr. Danehy acquired 34,378 shares of Series
D Preferred Stock and 17,189 shares of Common Stock pursuant to this right in
January 1996. In order to facilitate the transfer of shares to Mr. Danehy's
individual retirement account ("IRA"), the Company in November 1995 cancelled
81,263 shares subject to the Option which had vested and allowed Mr. Danehy to
purchase 81,263 shares of Common Stock at a purchase price of $0.84 per share
through his self-directed IRA. In January 1996 the Company granted Mr. Danehy
options to acquire 28,975 shares of Common Stock at $1.63 per share.
    
 
   
     In February 1996 the Company acquired BioTek for aggregate consideration of
$18.8 million including the issuance of approximately $12.0 million in Exchange
Notes in exchange for notes held by the holders of BioTek. In addition, $0.2
million in Exchange Notes were held back from the amounts payable at the closing
of the acquisition and placed in escrow to indemnify Ventana from losses
incurred in connection with certain matters related to the acquisition. Until
the Exchange Notes have been repaid, the Company is obligated to nominate at its
annual meeting of stockholders two BioTek Representatives for election to
Ventana's Board of Directors. The BioTek Representatives currently serving on
the Ventana Board are Michael R. Danzi and C. Anthony Stellar, M.D. In
connection with the acquisition, Mr. Danzi and Dr. Stellar exchanged BioTek
notes for Exchange Notes in aggregate principal amounts of $352,496 and
$1,196,511, respectively.
    
 
   
     The Exchange Notes provide each holder, during a 30-day period, the
opportunity to convert Exchange Notes into shares of Ventana Common Stock at a
conversion price of $13.53 per share. Holders of Exchange Notes who did not make
an election to convert all or any portion of such holders' Exchange Notes were
deemed to have automatically converted one-half of the principal amount of such
holders' Exchange Notes. No interest was deemed to accrue on the balance of
Exchange Notes which were converted. Upon expiration of the conversion period,
an aggregate of $3.0 million in principal amount of Exchange Notes were
converted into 222,973 shares of Common Stock and an aggregate of $9.2 million
of Exchange Notes remained outstanding.
    
 
   
     In connection with the acquisition in February 1996, the Company issued
(the "BioTek Financing") $4.6 million of convertible subordinated debt (the
"Notes") together with warrants to purchase 800,356 shares of Series D Preferred
Stock at an exercise price of $5.82 per share (the "Warrants") to certain
current stockholders of the Company. The proceeds from the issuance of the Notes
were used to fund all of the cash portion of the consideration paid by Ventana
to acquire BioTek plus related working capital requirements. In May 1996, the
Company provided all holders of Preferred Stock who did not participate in the
BioTek Financing the opportunity to purchase identical securities as were issued
in the BioTek Financing and pursuant to the election by such holders, $0.5
million in principal amount of Notes and Warrants to acquire 87,384 shares of
Series D Preferred Stock were issued. The Notes were convertible into Common
Stock at a conversion price of $13.53 per share for a period of 30 days from
issuance. No holders elected to convert their Notes into Common Stock. The
following table sets forth the aggregate principal amount of the Ventana
    
 
                                       59
<PAGE>   62
 
Notes and the number of shares of Series D Preferred Stock to be issued upon
exercise of the Warrants held by executive officers, directors and 5%
stockholders:
 
   
<TABLE>
<CAPTION>
                                                                                     SHARES
                                                                       LOAN        UNDERLYING
                                                                     PRINCIPAL      WARRANTS
                                                                     ---------     ----------
    <S>                                                              <C>           <C>
    MBW Venture Partners, L.P......................................  $ 938,424       162,059
    State Farm Mutual Automobile Insurance Company.................    630,555       108,893
    Jack W. Schuler................................................    688,601       118,917
    Entities affiliated with Edward M. Giles.......................    653,944       112,933
    John Patience..................................................    559,884        96,689
    Rex J. Bates...................................................     64,698        11,173
    James R. Weersing..............................................     24,884         4,298
    James M. Strickland............................................      5,000           860
    Thomas M. Grogan, M.D.(1) .....................................      2,667           459
</TABLE>
    
 
- ---------------
(1) Represents shares beneficially owned by C. Ovens, Inc.
 
                                       60
<PAGE>   63
 
                       PRINCIPAL AND SELLING STOCKHOLDERS
 
     The following table sets forth information known to the Company with
respect to the beneficial ownership of its Common Stock as of May 15, 1996
(assuming the exercise of all outstanding warrants and the conversion of all
outstanding shares of Preferred Stock into Common Stock), and as adjusted to
reflect the sale of Common Stock offered by the Company and by each of the
Selling Stockholders hereby, for (i) each Selling Stockholder, (ii) each person
who is known by the Company to own beneficially more than 5% of the Company's
Common Stock, (iii) each of the Company's directors, (iv) each Named Executive
Officer, and (v) all directors and executive officers as a group.
 
   
<TABLE>
<CAPTION>
                                               SHARES BENEFICIALLY                SHARES BENEFICIALLY
                                                  OWNED PRIOR TO      NUMBER OF     OWNED AFTER THE
                                                  OFFERING(1)(2)       SHARES         OFFERING(3)
                                               --------------------     BEING     -------------------
                     NAME                        NUMBER     PERCENT    OFFERED     NUMBER     PERCENT
- ---------------------------------------------- ----------   -------   ---------   ---------   -------
<S>                                            <C>          <C>       <C>         <C>         <C>
EXECUTIVE OFFICERS, DIRECTORS OR 5%
  STOCKHOLDERS
Entities affiliated with Marquette Venture
Partners(4)
  520 Lake Cook Rd., Suite 450
  Deerfield, IL 60015.........................  1,918,650     21.8%     449,668   1,468,982     13.4%
MBW Venture Partners, L.P.(5)
  James R. Weersing
  365 South Street
  Morristown, NJ 07960........................  1,442,351     16.1           --   1,442,351     12.9
State Farm Mutual Automobile Insurance
  Company(6)
  One State Farm Plaza
  Bloomington, IL 61701.......................    887,173     10.0           --     887,173      8.0
Jack W. Schuler(7)
  1419 Lake Cook Road, Suite 415
  Deerfield, IL 60015.........................    965,963     10.8           --     965,963      8.7
R. James Danehy(8)............................    209,890      2.4           --     209,890      1.9
R. Michael Rodgers(9).........................     22,291        *           --      22,291        *
Michael K. Cusack(10).........................     14,053        *           --      14,053        *
David P. Pauluzzi(11).........................     10,927        *           --      10,927        *
Bernard O.C. Questier.........................          0        *           --           0        *
Rex J. Bates(12)..............................     31,301        *           --      31,301        *
Michael R. Danzi(13)..........................      9,566        *           --       9,566        *
Edward M. Giles(14)...........................    291,548      3.3           --     291,548      2.6
Thomas M. Grogan, M.D.(15)....................    169,820      1.9           --     169,820      1.5
John Patience(16).............................    292,789      3.3           --     292,789      2.6
C. Anthony Stellar, M.D.(17)..................     19,959        *           --      19,959        *
James M. Strickland(7)(18)....................    402,547      4.6           --     402,547      3.7
James R. Weersing(5)(19)......................  1,452,858     16.2           --   1,452,858     13.0
All directors and executive officers as
  a group (17 persons)........................  3,944,545     41.7           --   3,944,545     33.8
</TABLE>
    
 
                                       61
<PAGE>   64
 
   
<TABLE>
<CAPTION>
                                               SHARES BENEFICIALLY                SHARES BENEFICIALLY
                                                  OWNED PRIOR TO      NUMBER OF     OWNED AFTER THE
                                                  OFFERING(1)(2)       SHARES         OFFERING(3)
                                               --------------------     BEING     -------------------
                     NAME                        NUMBER     PERCENT    OFFERED     NUMBER     PERCENT
- ---------------------------------------------- ----------   -------   ---------   ---------   -------
<S>                                            <C>          <C>       <C>         <C>         <C>
OTHER SELLING STOCKHOLDERS
The CIT Group/Venture Capital, Inc.(20).......    438,320      4.9%     103,243     335,077      3.0%
Interwest Partners IV, L.P. ..................    370,900      4.2       87,363     283,537      2.6
Victoria Bannister(21)........................    286,863      3.3       10,881     275,982      2.5
W. Ross Humphreys(22).........................    148,218      1.7       73,558      74,660        *
J. David Lowell(23)...........................     64,191        *       28,428      35,763        *
David Nunnery.................................     46,993        *          943      46,050        *
Jan Karel Smeets..............................     31,271        *       15,635      15,636        *
Douglas F. Sweet..............................     30,465        *          725      29,740        *
Thomas B. Healey..............................     20,882        *       10,441      10,441        *
Dorothy L. O'Neal Revocable Trust(24).........     19,903        *        8,814      11,089        *
Wm. Kent Wonders(25)..........................     12,839        *        1,895      10,944        *
Charles J. Casebeer(26).......................      9,765        *          263       9,502        *
Jessica Youle(27).............................      9,630        *        4,264       5,366        *
Mary Cawley(28)...............................      6,653        *        3,326       3,327        *
Entities affiliated with the Thomas H. and
  Rosemary S. Tisch Trust.....................      2,349        *          553       1,796        *
</TABLE>
    
 
- ---------------
 
  * Less than 1%.
 
 (1) Except as indicated in the footnotes to this table and pursuant to
     applicable community property laws, the persons named in the table have
     sole voting and investment power with respect to all shares of Common
     Stock.
 
   
 (2) Applicable percentage of ownership is based on 8,790,091 shares of Common
     Stock outstanding as of May 15, 1996 together with shares issuable pursuant
     to applicable options and warrants of such stockholder which may be
     exercised within 60 days after May 15, 1996. Shares of Common Stock subject
     to options and warrants currently exercisable or exercisable within 60 days
     after May 15, 1996 are deemed outstanding for computing the percentage
     ownership of the person holding such options and warrants, but are not
     deemed outstanding for computing the percentage of any other person.
     Assumes the issuance of 81,530 shares of Common Stock upon the assumed
     exercise of outstanding warrants which would otherwise expire upon the
     closing of this Offering.
    
 
   
 (3) Assumes no exercise of the Underwriters' Over-Allotment Option. See
     "Underwriting." Applicable percentage ownership is based upon 10,990,091
     shares of Common Stock outstanding as of May 15, 1996 together with shares
     issuable pursuant to applicable options and warrants for each stockholder
     currently exercisable or exercisable within 60 days after May 15, 1996.
    
 
   
     In the event that the Over-Allotment Option is exercised, entities
     affiliated with Marquette Venture Partners, The CIT Group/Venture Capital,
     Inc., Interwest Partners IV, L.P., Victoria Bannister, David Nunnery,
     Douglas F. Sweet, Charles J. Casebeer and entities affiliated with the
     Thomas H. and Rosemary S. Tisch Trust will sell to the Underwriters a
     percentage of the shares subject to the Over-Allotment Option approximately
     equal to the percentage of the Shares being offered by such Selling
     Stockholder (and set forth in the table above) bears to the total number of
     Shares being offered by all such Selling Stockholders (and set forth in the
     table above).
    
 
 (4) Includes 1,464,153 shares beneficially owned by Marquette Venture Partners,
     L.P.; 441,871 shares beneficially owned by Marquette Venture Partners II,
     L.P.; and 12,626 shares beneficially owned by MVP II Affiliate Fund, L.P.
 
   
 (5) Includes 162,059 shares issuable upon the exercise of warrants held by MBW
     Venture Partners, L.P. Mr. Weersing, a director of the Company, is Managing
     Director of MBW Venture Partners Limited. Mr. Weersing disclaims beneficial
     ownership of the shares beneficially owned by MBW Venture Partners, L.P.
     except to the extent of his proportional partnership interest therein.
    
 
                                       62
<PAGE>   65
 
 (6) Includes 108,893 shares issuable upon the exercise of warrants held by
     State Farm Mutual Automobile Insurance Company.
 
 (7) Includes 118,917 shares issuable upon the exercise of warrants held by Mr.
     Schuler; 73,512 shares beneficially owned by Mr. Schuler, as custodian for
     Tanya Eva Schuler; 73,513 shares beneficially owned by Mr. Schuler, as
     custodian for Tess Heidi Schuler; and 73,512 shares beneficially owned by
     Mr. Schuler, as custodian for Tino Hans Schuler.
 
 (8) Includes 77,059 shares issuable upon the exercise of options exercisable
     within 60 days of May 15, 1996 held by Mr. Danehy.
 
 (9) Includes 13,050 shares issuable upon the exercise of options exercisable
     within 60 days of May 15, 1996 held by Mr. Rodgers.
 
(10) Includes 12,935 shares issuable upon the exercise of options exercisable
     within 60 days of May 15, 1996 held by Mr. Cusack.
 
(11) Includes 8,056 shares issuable upon the exercise of options exercisable
     within 60 days of May 15, 1996 held by Mr. Pauluzzi.
 
(12) Includes 11,173 shares issuable upon the exercise of warrants held by Mr.
     Bates.
 
(13) Includes 1,087 shares beneficially owned by Barbara A. Danzi.
 
   
(14) Includes 122,886 shares beneficially owned by Vertical Fund, L.P. (of which
     85,945 shares are issuable upon the exercise of warrants held by Vertical
     Fund, L.P.); 36,941 shares beneficially owned by Vertical Medical Partners,
     L.P.; and 108,292 shares beneficially owned by Vertical Partners, L.P. (of
     which 21,831 shares are issuable upon the exercise of warrants held by
     Vertical Partners, L.P.). Also includes 23,429 shares beneficially owned by
     Edward M. Giles IRA (of which 5,157 shares are issuable upon the exercise
     of warrants held by Edward M. Giles IRA). Mr. Giles, a director of the
     Company, is Chairman and President of The Vertical Group, Inc. Mr. Giles
     disclaims beneficial ownership of the shares beneficially owned by such
     entities affiliated with The Vertical Group, Inc. except to the extent of
     his proportionate partnership interest therein.
    
 
(15) Includes 3,696 shares beneficially owned by Andrew Grogan; 7,710 shares
     beneficially owned by C. Ovens, Inc. (of which 459 shares are issuable upon
     the exercise of warrants held by C. Ovens, Inc.); and 38,306 shares
     issuable upon exercise of options exercisable within 60 days of May 15,
     1996 held by Dr. Grogan.
 
(16) Includes 96,689 shares issuable upon the exercise of warrants held by Mr.
     Patience.
 
(17) Includes 740 shares beneficially owned by Diane Stellar, and 740 shares
     beneficially owned by Andrew Stellar.
 
(18) Includes 860 shares issuable upon the exercise of warrants held by Mr.
     Strickland. Also includes 120,670 shares beneficially owned by Coronado
     Venture Fund; 163,059 shares beneficially owned by Coronado Venture Fund
     II, L.P.; 103,996 shares beneficially owned by Coronado Venture Fund III,
     L.P.; and 13,962 shares beneficially owned by Coronado Venture Co-Investor
     Limited Partnership. Mr. Strickland, a director of the Company, is a
     general partner of Coronado Venture Management. Mr. Strickland disclaims
     beneficial ownership of the shares beneficially owned by such entities
     except to the extent of his proportionate partnership interest therein.
 
   
(19) Includes 6,209 shares beneficially owned by James R. Weersing and Mary H.
     Weersing, Trustees of the Weersing Family Trust U/D/T dated April 24, 1991.
     Also includes 4,298 shares issuable upon the exercise of warrants held by
     Mr. Weersing.
    
 
(20) Includes 77,351 shares issuable upon exercise of warrants held by the CIT
     Group/Venture Capital, Inc.
 
(21) Includes 15,303 shares issuable upon the exercise of warrants held by Ms.
     Bannister.
 
(22) Includes 1,101 shares issuable upon the exercise of warrants held by Mr.
     Humphreys.
 
(23) Includes 7,334 shares issuable upon the exercise of warrants held by Mr.
     Lowell.
 
   
(24) Includes 2,274 shares issuable upon the exercise of warrants held by the
     Dorothy L. O'Neal Revocable Trust.
    
 
   
(25) Includes 1,467 shares issuable upon the exercise of warrants held by Mr.
     Wonders.
    
 
   
(26) Includes 1,116 shares issuable upon the exercise of warrants held by Mr.
     Casebeer.
    
 
   
(27) Includes 1,101 shares issuable upon the exercise of warrants held by Ms.
     Youle.
    
 
   
(28) Includes 370 shares beneficially owned by Ms. Cawley as custodian for
     Andrew C. Cawley, and 370 shares beneficially owned by Ms. Cawley as
    
     custodian for Graham D. Cawley.
 
                                       63
<PAGE>   66
 
                          DESCRIPTION OF CAPITAL STOCK
 
     The authorized capital stock of the Company will consist of 50,000,000
shares of Common Stock and 5,000,000 shares of preferred stock after giving
effect to the restatement of the Company's Certificate of Incorporation upon the
closing of this Offering. Prior to this Offering, there has been no public
market for the Company's Common Stock. The following summary of certain
provisions of the Common Stock and preferred stock does not purport to be
complete and is subject to, and qualified in its entirety by, the provisions of
the Company's Restated Certificate of Incorporation which is included as an
exhibit to the Registration Statement of which this Prospectus is a part and by
the provisions of applicable law.
 
COMMON STOCK
 
   
     As of May 15, 1996, there were 10,990,091 shares of Common Stock
outstanding which were held of record by 359 stockholders, as adjusted to
reflect the conversion of all outstanding shares of Preferred Stock upon the
closing of this Offering and the issuance of 81,530 shares of Common Stock upon
the exercise of outstanding warrants on the closing of this Offering.
    
 
     The holders of Common Stock are entitled to one vote per share on all
matters to be voted upon by the stockholders. Subject to preferences that may be
applicable to any outstanding preferred stock, the holders of Common Stock are
entitled to receive ratably such dividends, if any, as may be declared from time
to time by the board of directors out of funds legally available for that
purpose. See "Dividend Policy." In the event of a liquidation, dissolution or
winding up of the Company, the holders of Common Stock are entitled to share
ratably in all assets remaining after the payment of liabilities, subject to
prior distribution rights of preferred stock, if any, then outstanding. The
Common Stock has no preemptive or conversion rights or other subscription
rights. There are no redemption or sinking fund provisions applicable to the
Common Stock. All outstanding shares of Common Stock are fully paid and
nonassessable, and the Shares of Common Stock to be issued upon the closing of
this Offering will be fully paid and non-assessable.
 
     Provisions in the Company's Certificate of Incorporation and Bylaws (i)
prohibit the stockholders from acting by written consent without a meeting or
calling a special meeting of stockholders and (ii) require advance notice of
business proposed to be brought before an annual or special meeting of
stockholders. The amendment or modification of these provisions will require the
affirmative vote of the holders of 66 2/3% of the outstanding shares of Common
Stock.
 
PREFERRED STOCK
 
     Effective upon the closing of this Offering, the Company will be authorized
to issue 5,000,000 shares of undesignated preferred stock, none of which will be
outstanding upon the closing of this Offering. The Board of Directors will have
the authority, without further action by the stockholders, to issue the
undesignated preferred stock in one or more series, to fix the rights,
preferences, privileges and restrictions granted to or imposed upon any wholly
unissued shares of undesignated preferred stock and to fix the number of shares
constituting any series and the designation of such series. The issuance of
preferred stock may have the effect of delaying, deferring or preventing a
change in control of the Company without further action by the stockholders, may
discourage bids for the Company's Common Stock at a premium over the market
price of the Common Stock and may adversely affect the market price of and the
voting and other rights of the holders of Common Stock. At present, the Company
has no plans to issue any of the preferred stock.
 
WARRANTS
 
   
     After the completion of this Offering, the Company will have outstanding
warrants to purchase 887,740 shares of Common Stock at an exercise price of
$5.82 per share. These warrants are currently exercisable, will terminate in
February 2001 and may be exercised on a net basis.
    
 
CERTAIN PROVISIONS OF DELAWARE LAW
 
     Ventana is a Delaware corporation and subject to Section 203 of the
Delaware General Corporation Law, an anti-takeover law. In general, Section 203
prohibits a publicly held Delaware corporation from engaging in a "business
combination" with an "interested stockholder" for a period of three years
following the date the person became an interested stockholder, unless (with
certain exceptions) the "business combination" or the
 
                                       64
<PAGE>   67
 
transaction in which the person became an interested stockholder is approved in
a prescribed manner. Generally, a "business combination" includes a merger,
asset or stock sale, or other transaction resulting in a financial benefit to
the stockholder. Generally, an "interested stockholder" is a person who,
together with affiliates and associates, owns (or within three years prior, did
own) 15% or more of a corporation's voting stock. The existence of this
provision would be expected to have an anti-takeover effect with respect to
transactions not approved in advance by the Board of Directors, including
discouraging attempts that might result in a premium over the market price for
the shares of Common Stock held by stockholders.
 
TRANSFER AGENT AND REGISTRAR
 
     The transfer agent and registrar for the Common Stock is Norwest Bank
Minnesota, N.A. Its telephone number is (800) 468-9716.
 
                        SHARES ELIGIBLE FOR FUTURE SALE
 
   
     Prior to this Offering, there has been no market for the Common Stock of
the Company. Future sales of substantial amounts of Common Stock in the public
market could adversely affect market prices prevailing from time to time. Sales
of substantial amounts of Common Stock of the Company in the public market after
the restrictions lapse could adversely affect the prevailing market price and
the ability of the Company to raise equity capital in the future.
    
 
   
     Upon the completion of this Offering, the Company will have 10,990,091
shares of Common Stock outstanding, assuming no exercise of options after May
15, 1996 and no exercise of outstanding warrants other than warrants to purchase
81,530 shares of Common Stock that will terminate if not exercised upon the
completion of this Offering. Of these 10,990,091 shares, the 3,000,000 shares
sold in this Offering will be freely tradable without restriction under the
Securities Act, unless held by "affiliates" of the Company, as that term is
defined in Rule 144 under the Securities Act. The remaining 7,990,091 shares of
Common Stock held by existing stockholders were issued and sold by the Company
in reliance on exemptions from the registration requirements of the Securities
Act. These shares may be sold in the public market only if registered, or
pursuant to an exemption from registration such as Rule 144, 144(k) or 701 under
the Securities Act. The Company's directors, executive officers, certain
stockholders and all option holders, who in the aggregate hold 7,468,559 shares
of Common Stock, have entered into lock-up agreements under which they have
agreed not to offer, sell, contract to sell, grant any option to purchase or
otherwise dispose of, or agree to dispose of, directly or indirectly, any shares
of Common Stock, options or warrants to acquire shares of Common Stock or
securities exchangeable for or convertible into Common Stock owned by them for a
period of 180 days after the date of this Prospectus, without the prior written
consent of Bear, Stearns & Co. Inc. The Company has entered into a similar
agreement, except that the Company may grant options and issue stock under its
current stock option and stock purchase plans and pursuant to other currently
outstanding options.
    
 
   
     Approximately 39,703 shares of Common Stock will be available for immediate
public resale on the date of this Offering. An additional 2,023 shares of Common
Stock will be saleable at 90 days after the Offering. An additional 8,786 shares
of Common Stock will be saleable between 90 and 180 days after this Offering.
Upon expiration of the lock-up agreements, approximately 7,817,760 shares of
Common Stock (including approximately 349,201 shares subject to outstanding
vested options) will become eligible for immediate public resale, subject in
some cases to vesting provisions and volume limitations pursuant to Rule 144.
The remaining approximately 313,957 shares held by existing stockholders will
become eligible for public resale at various times over a period of less than
two years following the completion of this Offering, subject in some cases to
vesting provisions and volume limitations. 7,286,334 of the shares outstanding
immediately following the completion of this Offering will be entitled to
registration rights with respect to such shares upon the release of lock-up
agreements. The number of shares sold in the public market could increase if
such rights are exercised.
    
 
     As of May 15, 1996, 840,357 shares were subject to outstanding options. All
of these shares are subject to the lock-up agreements described above. As soon
as practicable after the date of this Prospectus, the Company intends to file a
Registration Statement on Form S-8 covering shares issuable under the Company's
 
                                       65
<PAGE>   68
 
1988 Stock Plan (including shares subject to then outstanding options under such
plans), the Company's 1996 Stock Plan and 1996 Employee Stock Purchase Plan,
thus permitting the resale of such shares in the public market without
restriction under the Securities Act after expiration of the applicable lock-up
agreements.
 
     In general, under Rule 144 as currently in effect, a person (or persons
whose shares are aggregated) who has beneficially owned shares for at least two
years (including the holding period of any prior owner, except an affiliate) is
entitled to sell in "broker's transactions" or to market makers, within any
three-month period commencing 90 days after the date of this Prospectus, a
number of shares that does not exceed the greater of (i) one percent of the
number of shares of Common Stock then outstanding (approximately 110,000 shares
immediately after this Offering) or (ii) the average weekly trading volume of
the Common Stock during the four calendar weeks preceding the required filing of
a Form 144 with respect to such sale. Sales under Rule 144 are generally subject
to certain manner of sale provisions and notice requirements and to the
availability of current public information about the Company. Under Rule 144(k),
a person who is not deemed to have been an affiliate of the Company at any time
during the 90 days preceding a sale, and who has beneficially owned the shares
proposed to be sold for at least three years, is entitled to sell such shares
without having to comply with the manner of sale, public information, volume
limitation or notice provisions of Rule 144. Under Rule 701 under the Securities
Act, persons who purchase shares upon exercise of options granted prior to the
effective date of this Offering are entitled to sell such shares 90 days after
the effective date of this Offering in reliance on Rule 144, without having to
comply with the holding period requirements of Rule 144 and, in the case of
non-affiliates, without having to comply with the public information, volume
limitation or notice provisions of Rule 144.
 
     The Securities and Exchange Commission has recently proposed reducing the
initial Rule 144 holding period to one year and the Rule 144(k) holding period
to two years. There can be no assurance as to when or whether such rule changes
will be enacted. If enacted, such modifications will have a material effect on
the times when shares of the Company's Common Stock become eligible for resale.
 
REGISTRATION RIGHTS OF CERTAIN HOLDERS
 
   
     The holders of 7,286,334 shares of Common Stock (including shares issuable
upon exercise of warrants) (the "Registrable Securities") or their transferees
are entitled to certain rights with respect to the registration of such shares
under the Securities Act of 1933, as amended (the "Securities Act"). These
rights are provided under the terms of an agreement between the Company and the
holders of Registrable Securities. Subject to certain limitations in the
agreement, if the holders of at least 25% of the Registrable Securities request,
the Company must on two occasions after six months from the effective date of
this Offering, use its best efforts to register the Registrable Securities for
public resale. If the Company registers any of its Common Stock either for its
own account or for the account of other security holders, the holders of
Registrable Securities are entitled to include their shares of Common Stock in
the registration, subject to the ability of the underwriters to limit the number
of shares included in the Offering. The holders of Registrable Securities may
also require the Company (but not more than once during any 12-month period) to
register all or a portion of their Registrable Securities on Form S-3 when use
of such form becomes available to the Company, provided, among other
limitations, that the proposed aggregate selling price is at least $1.0 million.
All registration expenses must be borne by the Company and all selling expenses
relating to Registrable Securities must be borne by the holders of the
securities being registered.
    
 
                                       66
<PAGE>   69
 
                                  UNDERWRITING
 
     The underwriters named below (the "Underwriters"), for whom Bear, Stearns &
Co. Inc. and Dillon, Read & Co. Inc. are acting as representatives (the
"Representatives"), have severally agreed, subject to the terms and conditions
set forth in the Underwriting Agreement, to purchase from the Company and the
Selling Stockholders, the number of Shares of Common Stock set forth opposite
their names below:
 
<TABLE>
<CAPTION>
                                                                             NUMBER
                                   UNDERWRITER                              OF SHARES
        ------------------------------------------------------------------  ---------
        <S>                                                                 <C>
        Bear, Stearns & Co. Inc...........................................
        Dillon, Read & Co. Inc............................................
                                                                            ---------
                  Total...................................................  3,000,000
                                                                             ========
</TABLE>
 
     Subject to the terms and conditions of the Underwriting Agreement, the
Underwriters have agreed to purchase all of the Shares of Common Stock being
sold pursuant to the Underwriting Agreement if any are purchased (excluding
Shares covered by the Over-Allotment Option).
 
     The Representatives have advised the Company that the Underwriters propose
to offer the Common Stock to the public initially at the public offering price
set forth on the cover page of this Prospectus and to selected dealers (who may
include Underwriters) at such price less a concession of not more than
$          per share. Additionally, the Underwriters may allow, and such dealers
may reallow, a concession of not more than $          per share to certain other
dealers. After the initial public offering, the public offering price and other
selling terms may be changed by the Underwriters.
 
     Certain of the Selling Stockholders have granted to the Underwriters an
option to purchase up to 450,000 additional Shares of Common Stock at the
initial public offering price, less the underwriting discount, set forth on the
cover page of this Prospectus, solely to cover over-allotments, if any. This
option may be exercised in whole or in part at any time within 30 days from the
date of this Prospectus. To the extent that the Underwriters exercise this
option, each of the Underwriters will have a firm commitment to purchase
approximately the same percentage thereof which the number of Shares of Common
Stock to be purchased by it shown in the above table bears to the total number
of Shares of Common Stock offered hereby.
 
     The Offering of the Shares is made for delivery, when, as and if accepted
by the Underwriters and subject to prior sale and to withdrawal, cancellation or
modification of the Offering without notice. The Underwriters reserve the right
to reject an order for the purchase of Shares in whole or in part.
 
     The Company and the Selling Stockholders have agreed to indemnify the
Underwriters against certain liabilities, including liabilities under the
Securities Act and to contribute to payments the Underwriters may be required to
make in respect thereof.
 
     The officers, directors and certain stockholders of the Company, who in the
aggregate own 7,551,250 shares of Common Stock, have agreed that they will not,
without the prior written consent of Bear, Stearns & Co. Inc., offer, sell, or
otherwise dispose of any shares of Common Stock, options or warrants to acquire
shares of Common Stock or securities exchangeable for or convertible into shares
of Common Stock owned by them during the 180 day period following the date of
this Prospectus. The Company has agreed that it will not, without the prior
written consent of Bear, Stearns & Co. Inc., offer, sell or otherwise dispose of
any shares of Common Stock, options or warrants to acquire shares of Common
Stock or securities exchangeable for or convertible into shares of Common Stock
during the 180 days following the date of this Prospectus, except that the
Company may issue shares of Common Stock and options to purchase Common Stock
under its 1996 Stock Plan and its 1996 Employee Stock Purchase Plan.
 
     Prior to the Offering, there has been no public market for the Common
Stock. The initial public offering price for the Common Stock will be determined
by negotiation among the Company and the Representatives. Among the factors to
be considered in determining the initial public offering price are prevailing
market and economic conditions, revenues and earnings of the Company, market
valuations of other companies engaged in the health care industry, estimates of
the business potential and prospects of the Company, the present state
 
                                       67
<PAGE>   70
 
of the Company's operations, the Company's management and other factors deemed
relevant. The estimated initial public offering price range set forth on the
cover of this preliminary prospectus is subject to change as a result of market
conditions and other factors. The negotiated initial public offering price may
bear no relationship to the price at which Common Stock trades after the
Offering.
 
     The Underwriters do not intend to confirm sales to accounts over which they
exercise discretionary authority.
 
   
     In February 1996, Bear, Stearns & Co. Inc. rendered a fairness opinion to
the Company in connection with the acquisition of BioTek for which Bear, Stearns
& Co. Inc. received a fee of $200,000, consisting of $50,000 in cash and 69,767
shares of Series D Preferred Stock which will convert into 25,784 shares of
Common Stock upon the completion of this offering. Bear, Stearns & Co. Inc. is
not selling any of its shares of Common Stock in the Offering. In addition, two
officers of Bear, Stearns & Co. Inc. and one officer of Dillon, Read & Co. Inc.
collectively own an aggregate of 29,753 shares of Common Stock.
    
 
                                 LEGAL MATTERS
 
   
     The validity of the Common Stock offered hereby will be passed upon for the
Company by Wilson Sonsini Goodrich & Rosati, Professional Corporation, Palo
Alto, California. As of the date of this Prospectus, certain members of Wilson
Sonsini Goodrich & Rosati, Professional Corporation and investment partnerships
of which such persons are partners beneficially own 6,160 shares of the
Company's Common Stock. Christopher D. Mitchell, Assistant Secretary of the
Company, is a member of Wilson Sonsini Goodrich & Rosati, Professional
Corporation. Certain legal matters in connection with this Offering will be
passed upon for the Underwriters by Simpson Thacher & Bartlett (a partnership
which includes professional corporations), New York, New York.
    
 
                                    EXPERTS
 
     The consolidated financial statements of Ventana Medical Systems, Inc. at
December 31, 1994 and 1995 and for each of the three years in the period ended
December 31, 1995 and the financial statements of BioTek Solutions, Inc. at June
30, 1995 and December 31, 1995 and for the year ended June 30, 1995 and the six
months ended December 31, 1995, appearing in this Prospectus and Registration
Statement have been audited by Ernst & Young LLP, independent auditors, as set
forth in their respective reports thereon appearing elsewhere herein and in the
Registration Statement, and are included in reliance upon such reports given
upon the authority of such firm as experts in accounting and auditing.
 
     The financial statements of BioTek Solutions, Inc. as of June 30, 1993 and
1994 and for the two years in the period ended June 30, 1994 included in this
Prospectus and Registration Statement have been audited by Arthur Andersen LLP,
independent public accountants, as indicated in their reports with respect
thereto, and are included herein in reliance upon the authority of such firm as
experts in accounting and auditing.
 
                             ADDITIONAL INFORMATION
 
   
     The Company has filed with the Securities and Exchange Commission (the
"Commission"), Washington, D.C. 20549, a Registration Statement on Form S-1
under the Securities Act with respect to the Shares of Common Stock offered
hereby. This Prospectus does not contain all the information set forth in the
Registration Statement and the exhibits and schedules thereto. For further
information with respect to the Company and such Common Stock, reference is made
to the Registration Statement and to the exhibits and schedules filed therewith.
Statements contained in this Prospectus as to the contents of any contract or
document to which reference is made are not necessarily complete and in each
instance reference is made to the copy of such contract or other document filed
as an exhibit to the Registration Statement, each such statement being qualified
in all respects by such reference. A copy of the Registration Statement may be
inspected without charge at the Commission's principal offices, and copies of
all or any part of the Registration Statement may be obtained from such office
upon the payment of the fees prescribed by the Commission. In addition, copies
of the Registration Statement may be obtained from the Commission's Internet
address at http://www.sec.gov.
    
 
     The Company intends to furnish its stockholders with annual reports
containing consolidated financial statements audited by its independent auditors
and with quarterly reports containing unaudited financial information for each
of the first three quarters of each fiscal year.
 
                                       68
<PAGE>   71
 
                         INDEX TO FINANCIAL STATEMENTS
 
   
<TABLE>
<CAPTION>
                                                                                        PAGE
                                                                                        ----
<S>                                                                                     <C>
VENTANA MEDICAL SYSTEMS, INC.
Unaudited Pro Forma Condensed Consolidated Financial Statements
  Introduction to Unaudited Pro Forma Condensed Consolidated Financial Statements.....   F-2
  Unaudited Pro Forma Condensed Consolidated Balance Sheet as of March 31, 1996.......   F-3
  Unaudited Pro Forma Condensed Consolidated Statements of Operations for the Year
     Ended December 31, 1995..........................................................   F-4
  Unaudited Pro Forma Condensed Consolidated Statements of Operations for the Three
     Months Ended March 31, 1996......................................................   F-5
  Notes to Unaudited Pro Forma Condensed Consolidated Financial Statements............   F-6
VENTANA MEDICAL SYSTEMS, INC.
Report of Ernst & Young LLP, Independent Auditors.....................................   F-8
Audited Consolidated Financial Statements
  Consolidated Balance Sheets as of December 31, 1994 and 1995 and March 31, 1996
     (unaudited)......................................................................   F-9
  Consolidated Statements of Operations for the years ended December 31, 1993, 1994
     and 1995 and three months ended March 31, 1995 and 1996 (unaudited)..............  F-10
  Consolidated Statements of Convertible Redeemable Preferred Stock and Stockholders'
     Equity (Deficit) for the years ended December 31, 1993, 1994 and 1995 and three
     months ended March 31, 1996 (unaudited)..........................................  F-11
  Consolidated Statements of Cash Flows for the years ended December 31, 1993, 1994
     and 1995 and three months ended March 31, 1995 and 1996 (unaudited)..............  F-12
  Notes to Consolidated Financial Statements..........................................  F-13
BIOTEK SOLUTIONS, INC.
Report of Ernst & Young LLP, Independent Auditors.....................................  F-23
Audited Financial Statements
  Balance Sheets as of June 30, 1995 and December 31, 1995............................  F-24
  Statements of Operations for the year ended June 30, 1995 and six months ended
     December 31, 1995................................................................  F-25
  Statements of Changes in Stockholders' Deficit for the year ended June 30, 1995 and
     six months ended December 31, 1995...............................................  F-26
  Statements of Cash Flows for the year ended June 30, 1995 and six months December
     31, 1995.........................................................................  F-27
  Notes to Financial Statements.......................................................  F-28
BIOTEK SOLUTIONS, INC.
Report of Arthur Andersen LLP, Independent Public Accountants.........................  F-34
Audited Financial Statements
  Balance Sheets as of June 30, 1993 and 1994.........................................  F-35
  Statements of Operations for the years ended June 30, 1993 and 1994.................  F-36
  Statements of Changes in Shareholders' Deficit for the years ended June 30, 1993 and
     1994.............................................................................  F-37
  Statements of Cash Flows for the years ended June 30, 1993 and 1994.................  F-38
  Notes to Financial Statements.......................................................  F-39
</TABLE>
    
 
                                       F-1
<PAGE>   72
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
                 INTRODUCTION TO UNAUDITED PRO FORMA CONDENSED
                       CONSOLIDATED FINANCIAL STATEMENTS
 
   
     The accompanying unaudited pro forma condensed consolidated balance sheet
as of March 31, 1996 includes the February 26, 1996 acquisition of BioTek
Solutions, Inc. (BioTek). The accompanying unaudited pro forma condensed
consolidated statements of operations for the year ended December 31, 1995 and
for the three months ended March 31, 1996 have been prepared as if the
acquisition of BioTek had been consummated as of January 1, 1995. The pro forma
balance sheet amounts are further adjusted to reflect the sale of the Shares of
Common Stock offered hereby and the utilization of the net proceeds of this
Offering as described under "Use of Proceeds."
    
 
     The pro forma information is based on the historical financial statements
of Ventana and BioTek giving effect to the transaction under the purchase method
of accounting and the assumptions and adjustments described in the accompanying
Notes to Unaudited Pro Forma Condensed Consolidated Financial Statements.
 
     The pro forma information is not indicative of actual results that would
have been achieved had the acquisition actually been completed as of the dates
indicated. The pro forma condensed consolidated financial statements should be
read in conjunction with "Management's Discussion and Analysis of Financial
Conditions and Results of Operations" and the respective historical financial
statements of Ventana Medical Systems, Inc. and BioTek Solutions, Inc. and the
related notes thereto included elsewhere in this Prospectus.
 
                                       F-2
<PAGE>   73
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
            UNAUDITED PRO FORMA CONDENSED CONSOLIDATED BALANCE SHEET
                              AS OF MARCH 31,1996
                                 (IN THOUSANDS)
 
                                     ASSETS
 
   
<TABLE>
<CAPTION>
                                                                         PRO FORMA         PRO FORMA
                                                         HISTORICAL     ADJUSTMENTS       AS ADJUSTED
                                                         ----------     -----------       -----------
<S>                                                      <C>            <C>               <C>
Current assets:
  Cash and cash equivalents............................   $   3,436      $  14,977(a)      $  18,413
  Accounts receivable..................................       2,834                            2,834
  Inventories..........................................       2,383                            2,383
  Other................................................          33                               33
                                                           --------                         --------
Total current assets...................................       8,686                           23,663
Property, plant and equipment, net.....................       2,949                            2,949
Intangibles, net.......................................      10,107                           10,107
                                                           --------        -------          --------
          Total assets.................................   $  21,742      $  14,977         $  36,719
                                                           ========        =======          ========
                         LIABILITIES, CONVERTIBLE REDEEMABLE PREFERRED STOCK
                                 AND STOCKHOLDERS' EQUITY (DEFICIT)
Current liabilities:
  Accounts payable.....................................   $   1,216                        $   1,216
  Other current liabilities............................       7,051                            7,051
                                                           --------                         --------
Total current liabilities..............................       8,267                            8,267
                                                           --------                         --------
Long term debt.........................................      15,035      $ (15,035)(a)            --
Convertible redeemable preferred stock.................      36,135        (36,135)(b)            --
Stockholders' equity (deficit):........................                                           --
  Common stock -- amount paid in.......................       3,337         57,691            61,028
  Accumulated deficit..................................     (40,892)         8,456(b)        (32,436)
  Cumulative foreign currency transactions
     adjustment........................................        (140)                            (140)
                                                           --------        -------          --------
          Total stockholders' equity (deficit).........     (37,695)        66,147            28,452
                                                           --------        -------          --------
          Total liabilities, convertible redeemable
            preferred stock and stockholders' equity
            (deficit)..................................   $  21,742      $  14,977         $  36,719
                                                           ========        =======          ========
</TABLE>
    
 
                            See accompanying notes.
 
                                       F-3
<PAGE>   74
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
       UNAUDITED PRO FORMA CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS
 
                      FOR THE YEAR ENDED DECEMBER 31, 1995
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
 
   
<TABLE>
<CAPTION>
                                          VENTANA          BIOTEK          PRO FORMA             PRO FORMA
                                         HISTORICAL     HISTORICAL(1)     ADJUSTMENTS           AS ADJUSTED
                                         ----------     -------------     -----------           -----------
<S>                                      <C>            <C>               <C>                   <C>
Net sales..............................   $ 10,613         $ 6,920          $ 1,942(2)           $  19,475
Cost of goods sold.....................      4,282           4,294              520(2)(3)            9,096
                                           -------         -------           ------                -------
Gross profit...........................      6,331           2,626            1,422                 10,379
Operating expenses:
  Research and development.............      2,239           2,198              (30)(3)              4,407
  Selling, general and
     administrative....................      7,435           3,497               36(2)(3)(4)        10,968
  Nonrecurring expenses................         --              --            9,983                  9,983
  Amortization of intangibles..........         --              --              557(6)                 557
                                           -------         -------           ------                -------
Loss from operations...................     (3,343)         (3,069)          (9,124)               (15,536)
Interest (expense) income..............         74          (2,224)           2,224(7)                  74
                                           -------         -------           ------                -------
Net loss...............................   $ (3,269)        $(5,293)         $(6,900)             $ (15,462)
                                           =======         =======           ======                =======
Pro forma net loss per share, as
  adjusted.............................   $  (0.36)                                              $   (1.55)
                                           =======                                                 =======
Pro forma weighted average shares
  outstanding, as adjusted.............      8,973                                                   9,975(8)
                                           =======                                                 =======
</TABLE>
    
 
                            See accompanying notes.
 
                                       F-4
<PAGE>   75
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
       UNAUDITED PRO FORMA CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS
 
                   FOR THE THREE MONTHS ENDED MARCH 31, 1996
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
 
   
<TABLE>
<CAPTION>
                                         VENTANA          BIOTEK          PRO FORMA             PRO FORMA
                                        HISTORICAL     HISTORICAL(1)     ADJUSTMENTS           AS ADJUSTED
                                        ----------     -------------     -----------           -----------
<S>                                     <C>            <C>               <C>                   <C>
Net sales.............................   $   4,146        $ 1,097          $   (15)(2)           $ 5,228
Cost of goods sold....................       1,432            593             (101)(2)(3)          1,924
                                          --------        -------          -------                ------
Gross profit..........................       2,714            504               86                 3,304
Operating expenses:
  Research and development............         613            163               (5)(3)               771
  Selling, general and
     administrative...................       2,374            368               57(2)(3)(4)        2,799
  Nonrecurring expenses...............       9,983            413          (10,396)(5)                --
  Amortization of intangibles.........          46             --               93(6)                139
                                          --------        -------          -------                ------
Loss from operations..................     (10,302)          (440)          10,337                  (405)
Interest (expense) income.............          (5)          (944)             944(7)                 (5)
                                          --------        -------          -------                ------
Net loss..............................   $ (10,307)       $(1,384)         $11,281               $  (410)
                                          ========        =======          =======                ======
Pro forma net loss per share, as
  adjusted............................   $   (1.12)                                              $ (0.04)
                                          ========                                                ======
Pro forma weighted average shares
  outstanding, as adjusted............       9,204                                                10,206(8)
                                          ========                                                ======
</TABLE>
    
 
                            See accompanying notes.
 
                                       F-5
<PAGE>   76
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
                     NOTES TO UNAUDITED PRO FORMA CONDENSED
                       CONSOLIDATED FINANCIAL STATEMENTS
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
 
   
     The Company acquired BioTek for $18.8 million on February 26, 1996. The pro
forma results of operations reflect the Company's operations as if it had
acquired BioTek on January 1, 1995 and are adjusted to reflect the sale of
2,200,000 shares of Common Stock by the Company in this Offering and the
application of the net proceeds therefrom. The acquisition has been accounted
for as a purchase. The composition of the consideration paid for BioTek and the
allocation of the purchase price is presented below:
    
 
   
<TABLE>
        <S>                                                              <C>
        The purchase price for BioTek consisted of:
        Cash consideration.............................................     $  2,500
        Stock issued to BioTek noteholders.............................        3,007
        Exchange Notes issued..........................................        8,978
        Note payable - escrow for contingencies........................          234
        Net historical liabilities acquired............................        4,044
                                                                         --------------
                  Total purchase price.................................     $ 18,763
                                                                         ===========
        The purchase price was allocated as follows:
          Tangible net assets..........................................     $  2,288
          In-process research and development..........................        7,900
          Goodwill and other intangibles...............................        1,675
          Developed technology.........................................        2,800
          Customer base................................................        4,100
                                                                         --------------
                                                                            $ 18,763
                                                                         ===========
</TABLE>
    
 
   
     In accordance with FAS 2, the Company charged to expense at the date of the
acquisition $7.9 million relating to the portion of the purchase price allocated
to those in-process research and development projects where technological
feasibility had not yet been established and where there are no alternative
future uses.
    
 
   
     Intangible assets consist primarily of goodwill, customer base and
developed technology. Such assets are amortized over estimated useful lives of
15 years for developed technology and goodwill, and 20 years for customer base.
    
 
BALANCE SHEET ADJUSTMENTS
 
(a)  Adjustment reflects net proceeds from the Offering to the Company after
     repayment of outstanding Exchange Notes and bank debt.
 
(b)  Adjustment reflects the automatic conversion of the Company's Preferred
     Stock into Common Stock upon completion of an initial public offering. The
     related accumulated unpaid dividends of approximately $8.5 million will be
     canceled upon such conversion.
 
STATEMENT OF OPERATIONS ADJUSTMENTS
 
(1) BioTek's historical fiscal year ended on June 30. BioTek's historical
    results of operations have been adjusted to a calendar year basis to conform
    with the reporting period of Ventana.
 
   
(2) Adjustments reflect a change in revenue recognition policy to adopt the
    Company's policy of recording certain sales upon shipment of instruments and
    reagents to end-users. As such, the pro forma sales and related costs of
    goods sold reflect the accounting policy of recognizing revenue, for United
    States sales only, upon the ultimate sale of products to the end-users as if
    such policy had been in effect as of January 1, 1995. The combined effect of
    the change in accounting policy is an increase in pro forma net sales in
    1995. This is primarily due to (i) shipments of instruments and reagents to
    CMS in 1994 which were subsequently placed with end-users in 1995 and (ii)
    recording sales based on prices paid by the end-user as opposed to the net
    price paid by CMS. Accordingly, cost of goods sold has been adjusted to
    reflect
    
 
                                       F-6
<PAGE>   77
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
                     NOTES TO UNAUDITED PRO FORMA CONDENSED
                 CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
 
    the differences in the timing of sales and the mix of products sold, and
    selling expense has been increased to reflect the distribution commission
    paid to CMS. The commission is equal to the product of (i) the number of
    units shipped to end-users and (ii) the difference between the price paid by
    the end-user to CMS and the net price paid by CMS to the Company.
 
(3) Adjustments reflect expense reductions associated with the consolidation of
    manufacturing facilities into Ventana's facilities in Tucson, Arizona.
    Effective September 1996, the Santa Barbara facility will no longer be used.
    The resulting cost reductions from the facilities consolidation are
    allocated among cost of goods sold (50%), research and development expense
    (10%), and selling, general, and administrative expense (40%).
 
(4) Reductions in selling, general, and administrative expense reflect (i) an
    increase in distribution expense associated with the change in revenue
    recognition policy discussed in footnote (2) above, (ii) the consolidation
    of the sales and marketing organizations of Ventana and BioTek, and (iii)
    the elimination of certain redundant administrative positions.
 
    A summary of the net savings recognized in the pro forma selling, general
    and administrative expense follows:
 
<TABLE>
<CAPTION>
                                                                               THREE MONTHS
                                                              YEAR ENDED           ENDED
                                                             DECEMBER 31,        MARCH 31,
                                                           -----------------   -------------
                                                            1994      1995     1995    1996
                                                           -------   -------   -----   -----
    <S>                                                    <C>       <C>       <C>     <C>
    Distribution expense.................................  $ 1,004   $ 1,038   $ 286   $ 166
    Sales and marketing..................................   (1,331)      (92)    (75)     44
    General and administrative...........................   (1,266)     (910)   (217)   (153)
                                                           -------   -------   -----   -----
                                                           $(1,593)  $    36   $  (6)  $  57
                                                           =======   =======   =====   =====
</TABLE>
 
   
(5) Adjustments for nonrecurring expenses reflect $7.9 million for acquired
    in-process research and development which was charged to expense in
    accordance with FAS 2, $2.1 million associated with the acquisition and
    integration of BioTek, and $0.4 million in fees incurred related to the
    BioTek acquisition. These charges were incurred in the first quarter of 1996
    and are reflected as if such charges had been incurred in the year ended
    December 31, 1995.
    
 
(6) Adjustment for amortization of intangibles arising from the BioTek
    acquisition.
 
(7) Adjustment to eliminate interest expense on BioTek's debt as a result of the
    merger and the retirement of debt with the net proceeds from the Offering.
 
(8) The calculation of pro forma weighted average number of shares outstanding
    is as follows:
 
   
<TABLE>
<CAPTION>
                                                                                  THREE MONTHS
                                                                  YEAR ENDED         ENDED
                                                                 DECEMBER 31,      MARCH 31,
                                                                     1995             1996
                                                                 ------------     ------------
    <S>                                                          <C>              <C>
    Weighted average shares outstanding........................        957            1,120
    Assumed conversion of Series A, C, and D preferred
      shares...................................................      6,580            6,648
    Assumed exercise of warrants to purchase Series D preferred
      shares...................................................         50               50
    Stock, options and warrants issued within one year of
      initial filing...........................................      1,386            1,386
    Shares of common stock issued in connection with the
      initial public offering to be used to retire acquisition
      debt.....................................................      1,002            1,002
                                                                    ------        ------------
    Weighted average shares outstanding, as adjusted...........      9,975           10,206
                                                                 ==========       ==========
</TABLE>
    
 
                                       F-7
<PAGE>   78
 
               REPORT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS
 
Board of Directors
Ventana Medical Systems, Inc.
 
     We have audited the accompanying consolidated balance sheets of Ventana
Medical Systems, Inc., as of December 31, 1994 and 1995, and the related
consolidated statements of operations, convertible redeemable preferred stock
and stockholders' equity (deficit), and cash flows for each of the three years
in the period ended December 31, 1995. These financial statements are the
responsibility of the Company's management. Our responsibility is to express an
opinion on these financial statements based on our audits.
 
     We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.
 
     In our opinion, the consolidated financial statements referred to above
present fairly, in all material respects, the consolidated financial position of
Ventana Medical Systems, Inc., as of December 31, 1994 and 1995, and the
consolidated results of their operations and their cash flows for the three
years in the period ended December 31, 1995 in conformity with generally
accepted accounting principles.
 
Tucson, Arizona
   
February 28, 1996, except for Note 11,
    
as to which the date is             , 1996
 
                 ---------------------------------------------
 
   
     The foregoing report is in the form that will be signed upon completion of
the recapitalization described in Note 11 to the Consolidated Financial
Statements.
    
 
Tucson, Arizona
   
July 1, 1996
    
 
                                       F-8
<PAGE>   79
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
                          CONSOLIDATED BALANCE SHEETS
 
                       (IN THOUSANDS, EXCEPT SHARE DATA)
 
                                     ASSETS
 
   
<TABLE>
<CAPTION>
                                                  DECEMBER 31,                            PRO FORMA
                                              ---------------------                     STOCKHOLDERS'
                                                1994         1995                      EQUITY (DEFICIT)
                                              --------     --------                     MARCH 31, 1996
                                                                         MARCH 31,     ----------------
                                                                           1996
                                                                        -----------    (UNAUDITED)
                                                                        (UNAUDITED)
<S>                                           <C>          <C>          <C>            <C>
Current assets:
  Cash and cash equivalents.................. $  2,511     $  1,103      $   3,436
  Accounts receivable........................    1,451        1,925          2,834
  Inventories (Note 2).......................      893        1,767          2,383
  Other......................................       38           24             33
                                              --------     --------     -----------
Total current assets.........................    4,893        4,819          8,686
Property and equipment, net (Note 3).........    2,169        2,258          2,949
Intangibles, net (Note 11)...................      217          301         10,107
                                              --------     --------     -----------
Total assets................................. $  7,279     $  7,378      $  21,742
                                              ========     ========      =========
               LIABILITIES, CONVERTIBLE REDEEMABLE PREFERRED STOCK,
                        AND STOCKHOLDERS' EQUITY (DEFICIT)
Current liabilities:
  Accounts payable........................... $    639     $  1,061      $   1,216
  Other current liabilities (Note 4).........      534          993          7,051
                                              --------     --------     -----------
Total current liabilities....................    1,173        2,054          8,267
Long-term debt...............................       --           --         15,035
Commitments (Notes 6, 9 and 11)
Convertible redeemable preferred stock at
  aggregate mandatory redemption value (Notes
  6 and 10):.................................   30,237       35,180         36,135         $     --
Stockholders' equity (deficit) (Notes
  7, 10 and 11):
  Preferred stock -- $.001 par value; no
     shares authorized, issued or outstanding
     (5,000,000 shares authorized, no shares
     issued or outstanding at March 31,
     1996 -- pro forma)......................       --           --             --               --
  Common stock -- $.001 par value; 30,000,000
     shares authorized, 875,005, 1,020,164,
     and 1,344,269 shares issued and
     outstanding at December 31, 1994 and
     1995 and
     March 31, 1996, respectively (50,000,000
     shares authorized, 8,031,894 shares
     issued and outstanding -- pro
     forma) -- amount paid in................      190          244          3,337           31,016
  Accumulated deficit........................  (24,275)     (29,980)       (40,892)         (32,436)
  Cumulative foreign currency translation
     adjustment..............................      (46)        (120)          (140)            (140)
                                              --------     --------     -----------    ----------------
Total stockholders' equity (deficit).........  (24,131)     (29,856)       (37,695)        $ (1,560)
                                                                                       ============
                                              --------     --------     -----------
Total liabilities, convertible redeemable
  preferred stock, and stockholders' equity
  (deficit).................................. $  7,279     $  7,378      $  21,742
                                              ========     ========      =========
</TABLE>
    
 
                            See accompanying notes.
 
                                       F-9
<PAGE>   80
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
                     CONSOLIDATED STATEMENTS OF OPERATIONS
 
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
 
   
<TABLE>
<CAPTION>
                                                       YEARS ENDED               THREE MONTHS ENDED
                                                      DECEMBER 31,                    MARCH 31,
                                            ---------------------------------   ---------------------
                                              1993        1994        1995        1995        1996
                                            ---------   ---------   ---------   ---------   ---------
                                                                                     (UNAUDITED)
<S>                                         <C>         <C>         <C>         <C>         <C>
Net sales.................................  $   2,681   $   5,927   $  10,613   $   2,202   $   4,146
Cost of goods sold........................      1,722       2,531       4,282         936       1,432
                                            ---------   ---------   ---------   ---------   ---------
                                                  959       3,396       6,331       1,266       2,714
Operating expenses:
  Research and development................      2,100       1,926       2,239         556         613
  Selling, general and administrative.....      4,067       6,899       7,435       1,594       2,374
  Nonrecurring expenses...................         --          --          --          --       9,983
  Amortization of intangibles.............         --          --          --          --          46
                                            ---------   ---------   ---------   ---------   ---------
Loss from operations......................     (5,208)     (5,429)     (3,343)       (884)    (10,302)
Interest income (expense).................        229          59          74          50          (5)
                                            ---------   ---------   ---------   ---------   ---------
Net loss..................................  $  (4,979)  $  (5,370)  $  (3,269)  $    (834)  $ (10,307)
                                             ========    ========    ========    ========    ========
Net loss per share, as adjusted...........                          $   (0.36)  $   (0.09)  $   (1.12)
                                                                     ========    ========    ========
Shares used in computing net loss per
  share, as adjusted......................                              8,973       8,838       9,204
                                                                     ========    ========    ========
</TABLE>
    
 
                            See accompanying notes.
 
                                      F-10
<PAGE>   81
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
       CONSOLIDATED STATEMENTS OF CONVERTIBLE REDEEMABLE PREFERRED STOCK
                       AND STOCKHOLDERS' EQUITY (DEFICIT)
 
                       (IN THOUSANDS, EXCEPT SHARE DATA)
 
   
<TABLE>
<CAPTION>
                                                                                    STOCKHOLDERS' EQUITY (DEFICIT)
                                                                     ------------------------------------------------------------
                                                                                                           CUMULATIVE
                                 CONVERTIBLE REDEEMABLE                                                      FOREIGN
                                     PREFERRED STOCK                     COMMON STOCK                       CURRENCY
                       -------------------------------------------   --------------------   ACCUMULATED    TRANSLATION
                       SERIES A    SERIES C    SERIES D     TOTAL     SHARES      AMOUNT      DEFICIT      ADJUSTMENT     TOTAL
                       ---------   ---------   ---------   -------   ---------   --------   ------------   -----------   --------
<S>                    <C>         <C>         <C>         <C>       <C>         <C>        <C>            <C>           <C>
Balance at January 1,
  1993...............    $ 536      $ 8,731     $ 9,034    $18,301     820,294   $    165     $(10,147)       $  --      $ (9,982)
  Sale of Series D
    preferred stock..       --           --       5,117      5,117          --         --           --           --            --
  Accretion of
    preferred stock
    redemption
    requirement......       --          656       1,140      1,796          --         --       (1,796)          --        (1,796)
  Sale of common
    stock............       --           --          --         --      88,800         33           --           --            33
  Repurchase of
    stock............       --           (2)         --         (2)       (924)        (1)          --           --            (1)
Net loss.............       --           --          --         --          --         --       (4,979)          --        (4,979)
                       ---------   ---------   ---------   -------   ---------   --------   ------------   -----------   --------
Balance at December
  31, 1993...........      536        9,385      15,291     25,212     908,170        197      (16,922)          --       (16,725)
  Sale of Series D
    preferred stock..       --           --       3,042      3,042          --         --           --           --            --
  Accretion of
    preferred stock
    redemption
    requirement......       --          656       1,327      1,983          --         --       (1,983)          --        (1,983)
  Sale of common
    stock............       --           --          --         --      29,199          8           --           --             8
  Repurchase of
    common stock.....       --           --          --         --     (62,364)       (15)          --           --           (15)
  Translation
    adjustment.......       --           --          --         --          --         --           --          (46)          (46)
  Net loss...........       --           --          --         --          --         --       (5,370)          --        (5,370)
                       ---------   ---------   ---------   -------   ---------   --------   ------------   -----------   --------
Balance at December
  31, 1994...........      536       10,041      19,660     30,237     875,005        190      (24,275)         (46)      (24,131)
  Sale of Series D
    preferred stock..       --           --       2,507      2,507          --         --           --           --            --
  Accretion of
    preferred stock
    redemption
    requirement......       --          655       1,781      2,436          --         --       (2,436)          --        (2,436)
  Sale of common
    stock............       --           --          --         --     160,210         67           --           --            67
  Repurchase of
    common stock.....       --           --          --         --     (15,051)       (13)          --           --           (13)
  Translation
    adjustment.......       --           --          --         --          --         --           --          (74)          (74)
  Net loss...........       --           --          --         --          --         --       (3,269)          --        (3,269)
                       ---------   ---------   ---------   -------   ---------   --------   ------------   -----------   --------
Balance at December
  31, 1995...........      536       10,696      23,948     35,180   1,020,164        244      (29,980)        (120)      (29,856)
  Sale of Series D
    preferred stock
    (unaudited)......       --           --         350        350          --         --           --           --            --
  Accretion of
    preferred stock
    redemption
    requirement
    (unaudited)......       --          163         442        605          --         --         (605)          --          (605)
  Conversion of debt
    into common stock
    (unaudited)......       --           --          --         --     222,973      3,007           --           --         3,007
  Sale of common
    stock
    (unaudited)......       --           --          --         --     101,132         86           --           --            86
  Translation
    adjustment
    (unaudited)......       --           --          --         --          --         --           --          (20)          (20)
  Net loss
    (unaudited)......       --           --          --         --          --         --      (10,307)          --       (10,307)
                       ---------   ---------   ---------   -------   ---------   --------   ------------   -----------   --------
Balance at March 31,
  1996 (unaudited)...    $ 536      $10,859     $24,740    $36,135   1,344,269   $  3,337     $(40,892)       $(140)     $(37,695)
                       ========    ========    ========    ========  =========   =========  ============   ==========    =========
</TABLE>
    
 
                            See accompanying notes.
 
                                      F-11
<PAGE>   82
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
                     CONSOLIDATED STATEMENTS OF CASH FLOWS
 
                                 (IN THOUSANDS)
 
   
<TABLE>
<CAPTION>
                                                     YEARS ENDED               THREE MONTHS ENDED
                                                    DECEMBER 31,                    MARCH 31,
                                           -------------------------------     -------------------
                                            1993        1994        1995        1995        1996
                                           -------     -------     -------     ------     --------
                                                                                   (UNAUDITED)
<S>                                        <C>         <C>         <C>         <C>        <C>
OPERATING ACTIVITIES:
Net loss.................................  $(4,979)    $(5,370)    $(3,269)    $ (834)    $(10,307)
Adjustments to reconcile net loss to net
  cash used in operating activities:
  Purchased in-process research and
     development.........................       --          --          --         --        7,900
  Depreciation and amortization..........      334         477         911        211          298
Changes in operating assets and
  liabilities:
  Accounts receivable....................     (244)       (941)       (474)       165         (287)
  Inventories............................     (258)        (24)       (874)       (64)        (488)
  Other assets...........................     (126)         37        (114)       (39)          (9)
  Accounts payable.......................       69         321         422         48         (341)
  Other current liabilities..............      110         224         459        132        2,024
                                           -------     -------     -------     ------     --------
Net cash used in operating activities....   (5,094)     (5,276)     (2,939)      (381)      (1,210)
INVESTING ACTIVITIES:
Purchase of property and equipment,
  net....................................   (1,700)       (604)       (956)      (399)         (69)
Acquisition of BioTek Solutions, Inc.....       --          --          --         --       (2,500)
Sales (purchases) of short-term
  investments available for sale.........   (4,063)      4,063          --         --           --
                                           -------     -------     -------     ------     --------
Net cash (used in) provided by investing
  activities.............................   (5,763)      3,459        (956)      (399)      (2,569)
FINANCING ACTIVITIES:
Repayments of notes payable..............      (42)        (36)         --         --           --
Issuance of debt (including amounts from
  related parties) and stock.............    5,147       3,035       2,561      2,415        6,092
                                           -------     -------     -------     ------     --------
Net cash provided by financing
  activities.............................    5,105       2,999       2,561      2,415        6,092
Effect of exchange rate changes on
  cash...................................       --         (46)        (74)        --           20
                                           -------     -------     -------     ------     --------
Net (decrease) increase in cash and cash
  equivalents............................   (5,752)      1,136      (1,408)     1,635        2,333
Cash and cash equivalents, beginning of
  period.................................    7,127       1,375       2,511      2,511        1,103
                                           -------     -------     -------     ------     --------
Cash and cash equivalents, end of
  period.................................  $ 1,375     $ 2,511     $ 1,103     $4,146     $  3,436
                                           =======     =======     =======     ======     ========
</TABLE>
    
 
                            See accompanying notes.
 
                                      F-12
<PAGE>   83
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
 
                               DECEMBER 31, 1995
    (INFORMATION FOR THE PERIODS ENDED MARCH 31, 1995 AND 1996 IS UNAUDITED)
 
 1.  ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES
 
   
     Organization:  Ventana Medical Systems, Inc. (the "Company") develops,
manufactures, and markets proprietary instruments and reagents that automate
diagnostic procedures used for molecular analysis of cells. Subsequent to year
end, the Company acquired all of the outstanding common stock of Biotek
Solutions, Inc. ("Biotek"). See Note 11 for discussion of the Company's
acquisition of Biotek. At present, the Company's principal markets are North
America and Europe.
    
 
     Principles of Consolidation:  The consolidated financial statements include
the accounts of the Company's wholly-owned foreign subsidiaries, Ventana Medical
Systems, S.A. and Ventana Medical Systems GmbH. All significant intercompany
accounts have been eliminated.
 
     Interim Consolidated Financial Information:  The consolidated financial
statements at March 31, 1996 and for the three months ended March 31, 1995 and
1996 are unaudited, but include all adjustments (consisting only of normal
recurring adjustments) that management considers necessary for a fair
presentation of the financial information set forth therein, in accordance with
generally accepted accounting principles. The results for the three months ended
March 31, 1996 are not necessarily indicative of the results for the entire
year.
 
     Reclassifications:  The consolidated financial statements for 1993 and 1994
have been reclassified to conform with the 1995 presentation.
 
     Cash and Cash Equivalents:  Cash equivalents include investments (primarily
money market accounts and overnight reverse repurchase agreements) with
maturities of three months or less from the date of purchase.
 
     On December 31, 1994, the Company purchased $2.1 million of U.S. Government
Securities from Bank One, Arizona (the "Bank") under an agreement to resell such
securities. The Company did not take possession of the securities which were
instead held in the Company's safekeeping account at the Bank. The amortized
cost of this investment approximates the market value.
 
     Inventories:  Inventories, principally chemical and biological reagents and
instrument parts and finished instruments, are stated at the lower of cost
(first-in first-out) or market.
 
     Property and Equipment:  Property and equipment are stated at cost.
Depreciation is computed using the straight-line method over estimated useful
lives of three to ten years. Amortization of leasehold improvements is
calculated using a straight-line method over the term of the lease. Maintenance
and repairs are charged to operations as incurred.
 
   
     Diagnostic instruments include automated instruments used by customers
under cancelable reagent plans ("RPs"), which generally are cancelable upon 90
days written notice. These agreements also require the customer to purchase a
specified amount of reagents for tests from the Company over the term of the
agreement. The manufacturing cost of the related instruments is amortized over a
period of 36 to 48 months and charged to cost of goods sold. Diagnostic
instruments also include instruments placed with customers for evaluation or
demonstration as part of the Company's sales process.
    
 
   
     Intangibles:  Intangible assets consist primarily of goodwill, customer
base, and developed technology acquired in the BioTek acquisition (see Note 11).
Such assets are amortized over estimated useful lives of 15 years for developed
technology and goodwill, and 20 years for customer base. Impairment is
recognized in operating results if a permanent decline in value occurs. The
Company will measure possible impairment of its intangible assets periodically
by comparing the cash flows generated by those assets to their carrying values.
The Company will periodically evaluate the useful lives assigned to the various
categories of intangible assets
    
 
                                      F-13
<PAGE>   84
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                               DECEMBER 31, 1995
    (INFORMATION FOR THE PERIODS ENDED MARCH 31, 1995 AND 1996 IS UNAUDITED)
 
   
considering such factors as (i) demand, obsolescence, competition, market share,
and other economic factors; (ii) legal and regulatory provisions; and (iii) the
periods expected to be benefited.
    
 
   
     Revenue Recognition:  Sales of instruments and reagents are generally
recognized upon shipment. Sales through domestic distributors are recognized
upon shipment of products by the distributors to end users. Revenues from
reagents sold under RPs and similar leasing arrangements are recognized when
reagents are shipped.
    
 
     Concentration of Credit Risk:  The Company sells its instruments and
reagent products primarily to hospitals, medical clinics, reference
laboratories, and universities. Credit losses have been minimal to date. The
Company invests its excess cash primarily in U.S. government securities and has
an established policy relating to diversification and maturities that is
designed to maintain safety and liquidity. The Company has not experienced any
material losses on its cash equivalents or short-term investments.
 
   
     Nonrecurring Expenses:  Nonrecurring expenses consist of the estimated
costs of integrating Biotek's operations into Ventana's and the cost of research
and development in process acquired from Biotek (see Note 11).
    
 
   
     Foreign Currency Translation:  Foreign currency financial statements of the
Company's foreign subsidiaries are converted into United States dollars by
translating balance sheet accounts at the current exchange rate at year end and
statement of operations accounts at the average exchange rate for the year, with
resulting translation adjustments reported as a separate component of
stockholders' equity (deficit).
    
 
     Income Taxes:  The Company accounts for income taxes using the liability
method. Deferred tax assets and liabilities are determined based on differences
between financial reporting and tax bases of assets and liabilities and are
measured using enacted tax rates and laws expected to be in effect when the
differences are expected to reverse. Valuation allowances are established when
necessary to reduce the carrying amount of deferred tax assets to their net
realizable value.
 
     Use of Estimates:  The preparation of financial statements in accordance
with generally accepted accounting principles requires management to make
estimates and assumptions that affect the reported amounts of assets and
liabilities and disclosure of contingent assets and liabilities at the date of
the financial statements and the reported amounts of revenues and expenses
during the reporting period. Actual results could differ from those estimates.
 
     Fair Value of Financial Instruments:  The Company's cash, accounts
receivable, and convertible redeemable preferred stock represent financial
instruments as defined by Statement of Financial Accounting Standards No. 107,
Disclosures About Fair Value of Financial Instruments. The carrying value of
these financial instruments is a reasonable approximation of fair value.
 
     Stock-Based Compensation:  The Company accounts for its stock compensation
arrangements under the provisions of APB No. 25, Accounting for Stock Issued to
Employees, and intends to continue to do so.
 
   
     Loss Per Common Share:  Loss per common share is computed using the
weighted average number of shares of common stock outstanding, except as noted
below. Common equivalent shares from stock options and warrants are excluded
from the computation as their effect is antidilutive, except that, pursuant to
the Securities and Exchange Commission Staff Accounting Bulletins and Staff
policy, common and preferred shares, options, and warrants issued during the
period commencing 12 months prior to the initial filing of the proposed initial
public offering at prices below the anticipated public offering price are
presumed to have been in contemplation of the public offering and have been
included in the calculation as if they were outstanding for all periods
presented, determined using the treasury stock method and the anticipated price
from the initial public offering.
    
 
                                      F-14
<PAGE>   85
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                               DECEMBER 31, 1995
    (INFORMATION FOR THE PERIODS ENDED MARCH 31, 1995 AND 1996 IS UNAUDITED)
 
     Net loss per common share was as follows:
 
   
<TABLE>
<CAPTION>
                                                       YEARS ENDED               THREE MONTHS ENDED
                                                      DECEMBER 31,                    MARCH 31,
                                            ---------------------------------   ---------------------
                                              1993        1994        1995        1995        1996
                                            ---------   ---------   ---------   ---------   ---------
                                                                 (IN THOUSANDS)
<S>                                         <C>         <C>         <C>         <C>         <C>
Net loss..................................  $  (4,979)  $  (5,370)  $  (3,269)  $    (834)  $ (10,307)
Less accretion of preferred stock
  redemption requirement..................     (1,796)     (1,983)     (2,436)       (579)       (605)
                                            ---------   ---------   ----------  ----------
Net loss applicable to common stock.......  $  (6,775)  $  (7,353)  $  (5,705)  $  (1,413)  $ (10,912)
                                            =========   =========   ==========  ==========
Net loss per common share.................  $   (3.02)  $   (3.19)  $   (2.43)  $   (0.62)  $   (4.36)
                                            =========   =========   ==========  ==========
Weighted average shares outstanding.......      2,243       2,303       2,343       2,289       2,505
                                            =========   =========   ==========  ==========
</TABLE>
    
 
     The as adjusted calculation of net loss per share presented in the
consolidated statements of operations has been computed as described above, but
also gives effect to the conversion of all outstanding shares of convertible
redeemable preferred stock into common stock upon closing of the Company's
initial public offering (determined using the if-converted method) and the
assumed exercise of warrants to purchase Series D preferred stock which would
otherwise expire upon completion of the Offering.
 
 2.  INVENTORIES
 
     Inventories consist of the following:
 
   
<TABLE>
<CAPTION>
                                                              DECEMBER 31,
                                                             ---------------     MARCH 31,
                                                             1994      1995        1996
                                                             ----     ------     ---------
                                                                    (IN THOUSANDS)
    <S>                                                      <C>      <C>        <C>
    Raw materials and work-in-process......................  $752     $1,265      $ 1,330
    Finished goods.........................................   141        502        1,053
                                                             ----     ------       ------
                                                             $893     $1,767      $ 2,383
                                                             ====     ======       ======
</TABLE>
    
 
 3.  PROPERTY AND EQUIPMENT
 
     Property and equipment consist of the following:
 
   
<TABLE>
<CAPTION>
                                                              DECEMBER 31,
                                                            -----------------     MARCH 31,
                                                             1994       1995        1996
                                                            ------     ------     ---------
                                                                    (IN THOUSANDS)
    <S>                                                     <C>        <C>        <C>
         Diagnostic instruments...........................  $1,544     $2,008      $ 2,180
         Machinery and equipment..........................   1,356      1,501        2,366
         Computers and related equipment..................     187        284          275
         Furniture and fixtures...........................     116        272          273
         Leasehold improvements...........................      39        133          133
                                                            ------     ------       ------
                                                             3,242      4,198        5,227
    Less accumulated depreciation and amortization........   1,073      1,940        2,278
                                                            ------     ------       ------
                                                            $2,169     $2,258      $ 2,949
                                                            ======     ======       ======
</TABLE>
    
 
                                      F-15
<PAGE>   86
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                               DECEMBER 31, 1995
    (INFORMATION FOR THE PERIODS ENDED MARCH 31, 1995 AND 1996 IS UNAUDITED)
 
 4.  OTHER CURRENT LIABILITIES
 
     Other current liabilities consist of the following:
 
   
<TABLE>
<CAPTION>
                                                           DECEMBER 31,
                                                           -------------     MARCH 31,
                                                           1994     1995       1996
                                                           ----     ----     ---------
                                                                 (IN THOUSANDS)
        <S>                                                <C>      <C>      <C>
        Accrued payroll and payroll taxes................  $205     $289      $   630
        Accrued commissions..............................   150      198           38
        Deferred revenue.................................    46      127        1,955
        Advances from distributor........................    --       --        1,733
        Accrued integration costs........................    --       --          750
        Accrued legal fees and settlement costs..........    --       --          600
        Sales tax payable................................    --      167          312
        Other accrued expenses...........................   133      212        1,033
                                                           ----     ----       ------
                                                           $534     $993      $ 7,051
                                                           ====     ====       ======
</TABLE>
    
 
 5. LINE OF CREDIT
 
   
     During 1995, the Company had $2.75 million available under a line of credit
arrangement with a bank. Borrowings under the line are collateralized by the
Company's receivables and intellectual property. The line contains certain
financial covenants with which the Company must comply. No borrowings were
outstanding under the line at December 31, 1995. Subsequent to year end, this
arrangement was amended (see Note 11).
    
 
 6. CONVERTIBLE REDEEMABLE PREFERRED STOCK
 
     Each share of Series A, C and D preferred stock is convertible, at the
option of the holder, into approximately 0.37 share of common stock (subject to
adjustments for events of dilution). Shares are automatically converted upon a
public offering of common stock meeting specified criteria, which principally
are a minimum amount of proceeds and price per share levels. Each share of
preferred stock has the same voting rights as common stock and is entitled to
the same number of votes as shares of common stock into which it is convertible.
Subsequent to payment of all accumulated dividends, any dividend declared or
paid would be pro rata and for preferred shares, would be based upon the number
of shares of common stock into which such preferred shares are convertible.
 
     The holders of at least 50% of the outstanding preferred stock may request
the Company to redeem 1/8 of the outstanding preferred stock each quarter
beginning June 30, 1997. The redemption price of Series A preferred stock is
$0.715 per share. The redemption prices for Series C and D preferred stock are
$0.90 per share and $2.15 per share, respectively, plus accumulated unpaid
dividends. If funds are not available for such redemptions, the shares must be
redeemed as soon as funds are legally available.
 
                                      F-16
<PAGE>   87
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                               DECEMBER 31, 1995
    (INFORMATION FOR THE PERIODS ENDED MARCH 31, 1995 AND 1996 IS UNAUDITED)
 
     The following is a summary of mandatory redemption value, accumulated
unpaid dividends and authorized, issued, and outstanding shares:
 
   
<TABLE>
<CAPTION>
                                                       DECEMBER 31,
                                        -------------------------------------------      MARCH 31,
                                           1993            1994            1995            1996
                                        -----------     -----------     -----------     -----------
                                                     (IN THOUSANDS, EXCEPT SHARE DATA)
<S>                                     <C>             <C>             <C>             <C>
Series A (non-cumulative):
  Mandatory redemption................  $       536     $       536     $       536     $       536
  Authorized, issued and outstanding
     shares...........................      750,000         750,000         750,000         750,000
Series C (9% cumulative):
  Mandatory redemption, including
     accumulated dividends............  $     9,385     $    10,041     $    10,696     $    10,859
  Accumulated dividends...............  $     2,109     $     2,765     $     3,420     $     3,583
  Authorized shares...................    8,300,000       8,300,000       8,300,000       8,300,000
  Issued and outstanding shares.......    8,083,039       8,084,543       8,084,543       8,084,543
Series D (9% cumulative):
  Mandatory redemption, including
     accumulated dividends............  $    15,291     $    19,660     $    23,948     $    24,740
  Accumulated dividends...............  $     1,338     $     2,650     $     4,431     $     4,873
  Authorized shares...................    6,750,000      10,250,000      10,250,000      10,250,000
  Issued and outstanding shares.......    6,489,954       7,911,836       9,098,741       9,261,531
Totals
  Mandatory redemption, including
     accumulated dividends............  $    25,212     $    30,237     $    35,180     $    36,135
  Accumulated dividends...............  $     3,447     $     5,415     $     7,851     $     8,456
  Authorized shares...................   15,800,000      19,300,000      19,300,000      19,300,000
  Issued and outstanding shares.......   15,322,993      16,746,379      17,933,284      18,096,074
</TABLE>
    
 
     In the event of the conversion of convertible redeemable preferred stock
into common stock as a result of a public offering, all accumulated unpaid
dividends on the preferred stock are canceled.
 
     In the event of a liquidation or merger, the preferred stockholders would
receive $0.65 per share of Series A preferred stock, $0.90 per share plus any
accumulated unpaid dividends for Series C preferred stock, and $2.15 per share
plus any accumulated unpaid dividends for Series D preferred stock prior to any
distribution to the common stockholders. If the assets of the Company are
insufficient to permit the payment of the full amount of the liquidation
preference to the preferred stockholders, the assets of the Company would be
distributed to the preferred stockholders in proportion to the total number of
preferred shares then outstanding.
 
     The articles of incorporation and the preferred stock agreements require
the Company to meet certain provisions related to transaction and debt
restrictions, stock dilution, redemption payments and administrative
restrictions. If such requirements are not met, the holders of at least 50% of
the outstanding preferred stock may request an increase in the number of
directors of the Company's Board of Directors as would constitute a minimum
majority and the holders of preferred stock, voting separately as a single
class, may elect individuals to fill such newly created directorships. All
preferences, covenants, and other provisions terminate upon an initial public
offering.
 
                                      F-17
<PAGE>   88
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                               DECEMBER 31, 1995
    (INFORMATION FOR THE PERIODS ENDED MARCH 31, 1995 AND 1996 IS UNAUDITED)
 
   
     Through the Company's 1991 Employee Qualified Stock Purchase Plan (the
"1991 Purchase Plan"), employees of the Company are able to purchase Series D
preferred stock through accumulated payroll deductions for $2.15 per share. A
total of 250,000 shares of Series D preferred stock have been reserved for
issuance under this plan. Shares of 222,987 were issued and outstanding at
December 31, 1995, which are convertible into 82,403 shares of common stock.
    
 
   
     Warrants for the purchase of 228,914 shares of Series D preferred stock are
outstanding at December 31, 1995, with exercise prices of $2.15 per share. Such
warrants will expire upon an initial public offering, to the extent not
previously exercised.
    
 
 7. COMMON STOCK
 
     1988 Stock Option Plan: Under the Company's 1988 Stock Option Plan (the
"Plan"), incentive and non-qualified stock options for the purchase of up to
1,339,663 shares of common stock are reserved for grant to employees and
directors. Options must be granted at not less than 100% of fair market value
(as determined by the Board of Directors) at the date of grant. Options
generally vest over a four year period and expire five to ten years after the
date of grant. However, the Board of Directors, at its discretion, may decide
the period over which options become exercisable and their expiration dates.
 
     A summary of stock option activity is as follows:
 
   
<TABLE>
<CAPTION>
                                                              OUTSTANDING STOCK OPTIONS
                                                            -----------------------------
                                                            NUMBER OF        EXERCISE
                                                             OPTIONS      PRICE PER SHARE
                                                            ---------     ---------------
        <S>                                                 <C>           <C>
        Balance at January 1, 1993........................    312,092      $0.18 -- $0.60
          Granted.........................................     44,717       0.60 --  0.95
          Exercised.......................................    (54,987)      0.18 --  0.24
          Canceled........................................    (28,836)      0.24 --  0.60
                                                            ---------           ---------
        Balance at December 31, 1993......................    272,986       0.18 --  0.95
          Granted.........................................    564,836       0.84 --  0.95
          Exercised.......................................    (28,090)      0.24 --  0.95
          Canceled........................................   (196,955)      0.18 --  0.95
                                                            ---------           ---------
        Balance at December 31, 1994......................    612,777       0.24 --  0.95
          Granted.........................................    324,505                0.84
          Exercised.......................................   (160,210)      0.24 --  0.95
          Canceled........................................   (126,618)      0.24 --  0.95
                                                            ---------           ---------
        Balance at December 31, 1995......................    650,454       0.24 --  0.95
          Granted.........................................     69,256                1.62
          Exercised.......................................     (7,616)      0.24 --  0.95
          Canceled........................................     (9,429)      0.60 --  0.84
                                                            ---------           ---------
        Balance at March 31, 1996.........................    702,665      $0.24 -- $1.62
                                                            =========           =========
</TABLE>
    
 
     Options to purchase 133,716 shares of common stock were immediately
exercisable at December 31, 1995.
 
                                      F-18
<PAGE>   89
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                               DECEMBER 31, 1995
    (INFORMATION FOR THE PERIODS ENDED MARCH 31, 1995 AND 1996 IS UNAUDITED)
 
 8. INCOME TAXES
 
     The Company's deferred tax assets consist of the following:
 
<TABLE>
<CAPTION>
                                                                      DECEMBER 31,
                                                                   -------------------
                                                                    1994        1995
                                                                   -------     -------
                                                                     (IN THOUSANDS)
        <S>                                                        <C>         <C>
        Non-current:
          Net operating loss carryforwards.......................  $ 4,345     $ 5,004
          Capitalized research and development...................    2,256       2,471
          General business credit carryforwards..................      617         767
          Other..................................................       67         186
        Current:
          Miscellaneous..........................................       19         154
                                                                    ------      ------
        Total deferred tax assets................................    7,304       8,582
        Valuation allowance......................................   (7,304)     (8,582)
                                                                    ------      ------
        Net deferred tax assets..................................  $    --     $    --
                                                                    ======      ======
</TABLE>
 
     The valuation allowance for deferred tax assets was increased by
$5,500,000, $1,843,000, and $1,319,000 in the years ended December 31, 1993,
1994, and 1995, respectively to fully offset deferred tax balances.
 
     Temporary differences between the net operating losses for financial
reporting and income tax purposes primarily relate to the deferral of research
and development expenses for tax purposes.
 
     At December 31, 1995, the Company has net operating loss carryforwards for
federal and state purposes of approximately $12.0 million. These federal and
state carryforwards will begin to expire in 2000 and 1996, respectively, if not
previously utilized. The Company also has research and development tax credit
carryforwards of approximately $700,000 which will begin to expire in 2005, if
not previously utilized. Utilization of the Company's net operating loss
carryforwards will be subject to limitations due to the "change in ownership"
provisions of the Internal Revenue Code of 1996, as amended, as a result of the
Company's prior issuances of equity securities. These carryforwards, therefore,
may expire prior to being fully utilized. Future financings may cause additional
changes in ownership and further limitations on the use of federal net operating
loss carryforwards.
 
 9. OPERATING LEASES
 
     The Company conducts its corporate operations from leased facilities. In
addition to monthly rental payments, the Company is responsible for certain
monthly operating and maintenance expenses of such facilities. The lease expires
in 2001. The future minimum rental payments under this and other operating lease
arrangements are as follows (in thousands):
 
<TABLE>
                <S>                                                     <C>
                1996..................................................  $185
                1997..................................................   151
                1998..................................................   137
                1999..................................................   245
                2000..................................................   289
                Thereafter............................................    72
</TABLE>
 
     Rent expense totaled $125,000, $157,000 and $188,000 for the years ended
December 31, 1993, 1994 and 1995, respectively.
 
                                      F-19
<PAGE>   90
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                               DECEMBER 31, 1995
    (INFORMATION FOR THE PERIODS ENDED MARCH 31, 1995 AND 1996 IS UNAUDITED)
 
   
10. FOREIGN OPERATIONS, GEOGRAPHIC, AND SEGMENT DATA
    
 
   
     The Company operates predominantly in one segment, the medical diagnostic
devices industry. Inventory transfers to foreign subsidiaries are made at
standard cost. The following summary includes both net sales to unaffiliated
customers and transfers between geographic areas. The North America operations
include corporate activity that benefits the Company as a whole. The North
America geographic area represents primarily the United States. The European
geographic area represents primarily France and Germany.
    
 
   
<TABLE>
<CAPTION>
                                                                    YEAR ENDED DECEMBER 31,
                                                                -------------------------------
                                                                 1993        1994        1995
                                                                -------     -------     -------
<S>                                                             <C>         <C>         <C>
Net Sales:
  North America unaffiliated customers........................  $ 2,681     $ 5,627     $ 9,657
  Europe unaffiliated customers...............................       --         300         956
  Consolidated subsidiaries...................................       --         903         521
                                                                -------     -------     -------
                                                                  2,681       6,830      11,134
  Eliminations................................................       --        (903)       (521)
                                                                -------     -------     -------
                                                                $ 2,681     $ 5,927     $10,613
                                                                =======     =======     =======
Net Loss:
  North America...............................................  $(4,979)    $(3,974)    $(2,654)
  Europe......................................................       --      (1,164)       (363)
                                                                -------     -------     -------
                                                                 (4,979)     (5,138)     (3,017)
  Eliminations................................................       --        (232)       (252)
                                                                -------     -------     -------
                                                                $(4,979)    $(5,370)    $(3,269)
                                                                =======     =======     =======
Identifiable Assets:
  North America...............................................  $ 9,151     $ 8,506     $ 8,823
  Europe......................................................       --         952       1,099
                                                                -------     -------     -------
                                                                  9,151       9,458       9,922
  Eliminations................................................       --      (2,179)     (2,544)
                                                                -------     -------     -------
                                                                $ 9,151     $ 7,279     $ 7,378
                                                                =======     =======     =======
</TABLE>
    
 
   
11. SUBSEQUENT EVENTS
    
 
     In April 1996, the Company's Board of Directors authorized the Company to
file a Registration Statement with the Securities and Exchange Commission to
sell shares of its common stock in an underwritten public offering. The
Company's Board of Directors also approved a reduction in the number of
authorized shares of undesignated preferred stock to 5,000,000 and an increase
in the number of authorized shares of common stock to 50,000,000. Unaudited pro
forma stockholders' equity, as adjusted for the assumed conversion of the
Preferred Stock and concurrent cancellation of undeclared dividends of
$8,456,000, is set forth on the accompanying consolidated balance sheet.
 
     In conjunction with the proposed Offering, the Board of Directors
authorized a 1-for-2.7059046 reverse split of its common stock to be effected
prior to the closing of the offering. The accompanying consolidated financial
statements have been adjusted retroactively to reflect the reverse split of the
common stock. The conversion ratios of the respective series of convertible
preferred stock were automatically adjusted to reflect the reverse split.
 
                                      F-20
<PAGE>   91
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                               DECEMBER 31, 1995
    (INFORMATION FOR THE PERIODS ENDED MARCH 31, 1995 AND 1996 IS UNAUDITED)
 
   
     If the Offering is consummated under terms presently anticipated, all of
the currently outstanding preferred stock will automatically convert into
6,687,625 shares of common stock, and 81,530 shares of common stock will be
issued due to warrant exercises. Unaudited pro forma stockholders' equity as
adjusted for the assumed conversion (but not for the exercise of outstanding
warrants) is set forth in the accompanying balance sheet.
    
 
     The Company acquired BioTek for $18.8 million on February 26, 1996. The
acquisition has been accounted for as a purchase.
 
     The purchase price for BioTek consisted of:
 
<TABLE>
<CAPTION>
                                                                 (IN THOUSANDS)
                <S>                                              <C>
                Cash consideration.............................     $  2,500
                Stock issued to BioTek noteholders.............        3,007
                Exchange Notes issued..........................        8,978
                Note payable -- escrow for contingencies.......          234
                Net historical liabilities assumed.............        4,044
                                                                     -------
                                                                    $ 18,763
                                                                     =======
</TABLE>
 
     The purchase price was allocated as follows:
 
   
<TABLE>
<CAPTION>
                                                                 (IN THOUSANDS)
                <S>                                              <C>
                Tangible net assets............................     $  2,288
                In-process research and development............        7,900
                Goodwill and other intangibles.................        1,675
                Developed technology...........................        2,800
                Customer base..................................        4,100
                                                                      ------
                Total purchase price...........................     $ 18,763
                                                                      ======
</TABLE>
    
 
   
     The Company charged to expense at the date of the acquisition $7.9 million
relating to the portion of the purchase price allocated to those in-process
research and development projects where technological feasibility had not yet
been established and where there are no alternative future uses.
    
 
     The Exchange Notes were convertible into the Company's common stock for 30
days subsequent to the acquisition. As of March 25, 1996 approximately
$3,007,000 of the Exchange Notes were converted into the Company's common stock.
The Exchange Notes are payable at the earlier of 30 days after an initial public
offering of the Company's common stock of at least $20 million or February 1998.
The Exchange Notes bear interest at 7% payable on December 31, 1996 and 1997.
The December 31, 1996 interest payment may be made in cash or common stock, at
the Company's option. If the Notes are redeemed prior to December 31, 1996, no
interest is payable.
 
     On March 15, 1996, the Company amended its borrowing agreement with its
bank. The Company obtained a lending commitment for $2.0 million under a term
loan with interest at the bank's prime rate plus 2.0%. The Company will make
monthly interest payments on amounts borrowed through March 1997, at which time
any amount borrowed plus accrued interest must be repaid in 24 equal monthly
installments. The Company's line of credit was extended through March 1997.
 
   
     Between February 26, 1996 and May 14, 1996, the Company issued
approximately $5.1 million of convertible subordinated notes together with
warrants to purchase an 2,378,898 shares of Preferred Stock of the Company at an
exercise price of $2.15 per share. The proceeds of these notes were used to fund
the cash
    
 
                                      F-21
<PAGE>   92
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)
 
                               DECEMBER 31, 1995
    (INFORMATION FOR THE PERIODS ENDED MARCH 31, 1995 AND 1996 IS UNAUDITED)
 
portion of the BioTek acquisition consideration and to provide working capital.
These notes bear interest at 7% per annum, which will be forgiven if the notes
are repaid prior to December 31, 1996. The subordinated notes are required to be
repaid by the Company within 30 days of the completion of this Offering.
 
   
     On February 26, 1996, the Company sold 646,664 shares of common stock to
two directors of the Company and a related partnership at a price of $1.62 per
share for their efforts and assistance in completing the BioTek acquisition and
assisting management with its integration of the companies. These shares are
subject to buyback by the Company at the issuance price for various periods.
These buyback provisions lapse upon successful completion of an initial public
offering or sale of the Company for a price of at least $10.82 per share.
    
 
   
     In April 1996, the Company established the 1996 Stock Option Plan (the
"1996 Stock Plan") and reserved 1,000,000 shares of common stock for issuance.
No options to purchase shares of common stock have been granted.
    
 
   
     In April 1996, the Board of Directors authorized the 1996 Employee Stock
Purchase Plan (the "1996 Purchase Plan"). A total of 200,000 shares of common
stock are reserved for issuance under the 1996 Purchase Plan. No shares have
been issued under the 1996 Purchase Plan. The 1996 Purchase Plan permits
eligible employees to purchase common stock through payroll deductions, subject
to certain limitations. The price at which stock is purchased under the 1996
Purchase Plan is equal to 85% of the fair market value of the common stock on
the first day of the applicable offering period or the last day of the
applicable offering period, whichever is lower.
    
 
   
     In June 1996, the Company adopted a 1996 Director Option Plan (the
"Director Plan") and reserved a total of 250,000 shares of common stock for
issuance thereunder. Commencing with the Company's 1997 annual meeting of
stockholders, each nonemployee director will be granted a nonstatutory option to
purchase an amount of shares of common stock of the Company equal to 5,000
shares multiplied by a fraction, the numerator of which shall be $15.00 and the
denominator of which shall be the fair market value of one share of the
Company's common stock on the date of grant. The exercise price of options
granted under the Director Plan will be equal to the fair market value of one
share of the Company's common stock on the date of grant. Each option granted
under the Director Plan will vest on a cumulative monthly basis over a one-year
period and will have a 10-year term. The Director Plan will terminate in June
2001, unless earlier terminated.
    
 
                                      F-22
<PAGE>   93
 
               REPORT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS
 
Board of Directors
BioTek Solutions, Inc.
 
     We have audited the accompanying balance sheets of BioTek Solutions, Inc.,
as of June 30, 1995 and December 31, 1995, and the related statements of
operations, changes in stockholders' equity (deficit), and cash flows for the
year ended June 30, 1995 and the six-months ended December 31, 1995. These
financial statements are the responsibility of the Company's management. Our
responsibility is to express an opinion on these financial statements based on
our audits.
 
     We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.
 
     In our opinion, the financial statements referred to above present fairly,
in all material respects, the financial position of BioTek Solutions, Inc. as of
June 30, 1995 and December 31, 1995, and the results of its operations and its
cash flows for the year ended June 30, 1995 and the six-months ended December
31, 1995, in conformity with generally accepted accounting principles.
 
   
                                          ERNST & YOUNG LLP
    
 
Tucson, Arizona
February 2, 1996, except for Note 12,
as to which the date is February 20, 1996
 
                                      F-23
<PAGE>   94
 
                             BIOTEK SOLUTIONS, INC.
 
                                 BALANCE SHEETS
                       (IN THOUSANDS, EXCEPT SHARE DATA)
 
                                ASSETS (Note 8)
 
<TABLE>
<CAPTION>
                                                                       JUNE 30,      DECEMBER
                                                                         1995        31, 1995
                                                                       --------     -----------
<S>                                                                    <C>          <C>
Current assets:
  Cash...............................................................  $    275      $      31
  Accounts receivable, net of allowance of $50 at June 30, 1995 and
     $78 at December 31, 1995........................................       425            523
  Inventories (Note 4)...............................................       152            168
  Prepaid expenses...................................................       115            607
                                                                       --------       --------
          Total current assets.......................................       967          1,329
Property and equipment, net (Note 5).................................       940            795
Other assets (Note 6)................................................       581            470
                                                                       --------       --------
                                                                       $  2,488      $   2,594
                                                                       ========       ========
LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT)
Current liabilities:
  Accounts payable...................................................  $  1,443      $   1,128
  Accrued expenses (Note 7)..........................................     3,700          5,228
  Current portion of long-term debt (Note 8).........................     1,106          8,685
                                                                       --------       --------
          Total current liabilities..................................     6,249         15,041
Long-term debt, less current portion (Note 8)........................     8,971          2,080
Commitments and contingencies (Note 11)
Stockholders' equity (deficit):
  Common stock, no par value:
     Authorized -- 10,000,000 shares
     Outstanding -- 8,593,915 and 9,024,195 shares at June 30, 1995
      and December 31, 1995, respectively............................     3,047          3,051
  Accumulated deficit................................................   (15,764)       (17,563)
  Treasury stock.....................................................       (15)           (15)
                                                                       --------       --------
          Total stockholders' equity (deficit).......................   (12,732)       (14,527)
                                                                       --------       --------
                                                                       $  2,488      $   2,594
                                                                       ========       ========
</TABLE>
 
                            See accompanying notes.
 
                                      F-24
<PAGE>   95
 
                             BIOTEK SOLUTIONS, INC.
 
                            STATEMENTS OF OPERATIONS
                                 (IN THOUSANDS)
 
<TABLE>
<CAPTION>
                                                                                      SIX-MONTHS
                                                                      YEAR ENDED        ENDED
                                                                       JUNE 30,      DECEMBER 31,
                                                                         1995            1995
                                                                      ----------     ------------
<S>                                                                   <C>            <C>
Revenues............................................................   $  6,043        $  3,640
Cost of sales.......................................................      3,714           2,233
                                                                        -------         -------
                                                                          2,329           1,407
Cost and expenses:
  Research and development..........................................      1,734             751
  Selling, general and administrative expenses......................      3,666           1,327
                                                                        -------         -------
Loss from operations................................................     (3,071)           (671)
Interest expense....................................................      1,730             979
Amortization and other..............................................        298             149
                                                                        -------         -------
Net loss............................................................   $ (5,099)       $ (1,799)
                                                                        =======         =======
</TABLE>
 
                            See accompanying notes.
 
                                      F-25
<PAGE>   96
 
                             BIOTEK SOLUTIONS, INC.
 
            STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (DEFICIT)
 
                       (IN THOUSANDS, EXCEPT SHARE DATA)
 
<TABLE>
<CAPTION>
                                             COMMON STOCK
                                        ----------------------
                                          SHARES                   ACCUMULATED     TREASURY
                                        OUTSTANDING     AMOUNT       DEFICIT        STOCK        TOTAL
                                        -----------     ------     -----------     --------     --------
<S>                                     <C>             <C>        <C>             <C>          <C>
Balance, July 1, 1994.................   7,478,985      $2,335      $  (9,920)       $ --       $ (7,585)
  Net loss............................          --          --         (5,099)         --         (5,099)
  Issuance of common stock with
     debt.............................   1,082,964         694             --          --            694
  Repurchase of founder's shares with
     note.............................    (950,000)         --           (745)        (15)          (760)
  Shares issued as compensation for
     financings.......................     574,770           6             --          --              6
  Exercise of warrants................     407,196          12             --          --             12
                                         ---------      ------       --------        ----       --------
Balance, June 30, 1995................   8,593,915       3,047        (15,764)        (15)       (12,732)
  Net loss............................          --          --         (1,799)         --         (1,799)
  Exercise of warrants................     430,280           4             --          --              4
                                         ---------      ------       --------        ----       --------
Balance, December 31, 1995............   9,024,195      $3,051      $ (17,563)       $(15)      $(14,527)
                                         =========      ======       ========        ====       ========
</TABLE>
 
                            See accompanying notes.
 
                                      F-26
<PAGE>   97
 
                             BIOTEK SOLUTIONS, INC.
 
                            STATEMENTS OF CASH FLOWS
                                 (IN THOUSANDS)
 
<TABLE>
<CAPTION>
                                                                                      SIX-MONTHS
                                                                      YEAR ENDED        ENDED
                                                                       JUNE 30,      DECEMBER 31,
                                                                         1995            1995
                                                                      ----------     ------------
<S>                                                                   <C>            <C>
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss............................................................   $ (5,099)       $ (1,799)
Adjustments to reconcile net loss to net cash used in operating
  activities:
  Depreciation and amortization.....................................      1,501             776
Changes in operating assets and liabilities:
  Accounts receivable...............................................       (306)            (98)
  Inventories.......................................................        379             (16)
  Other assets......................................................       (152)            (15)
  Accounts payable..................................................       (233)           (834)
  Other liabilities.................................................        571             781
                                                                      ----------     ------------
Net cash used in operating activities...............................     (3,339)         (1,205)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of property and equipment.................................        (84)             --
                                                                      ----------     ------------
Net cash used in investing activities...............................        (84)             --
CASH FLOWS FROM FINANCING ACTIVITIES
Issuance of common stock............................................         18               4
Issuance of notes payable, net of loan origination fees.............      3,418             957
                                                                      ----------     ------------
Net cash provided by financing activities...........................      3,436             961
                                                                      ----------     ------------
Net increase (decrease) in cash.....................................         13            (244)
Cash, beginning of period...........................................        262             275
                                                                      ----------     ------------
Cash, end of period.................................................   $    275        $     31
                                                                       ========      ==========
SUPPLEMENTAL CASH FLOW INFORMATION
Cash paid for interest..............................................   $    351        $     69
                                                                       ========      ==========
</TABLE>
 
                            See accompanying notes.
 
                                      F-27
<PAGE>   98
 
                             BIOTEK SOLUTIONS, INC.
 
                         NOTES TO FINANCIAL STATEMENTS
 
                               DECEMBER 31, 1995
 
 1. BACKGROUND
 
     BioTek Solutions, Inc. (the Company) develops, manufactures, markets and
supports proprietary computerized instruments that automate biopsy tests for the
diagnosis of cancer, viruses and other conditions and diseases. These
instruments use the Company's chemical reagents and utilize monoclonal
antibodies, DNA probes and other sophisticated analytical techniques. This
system effectively replaces the labor-intensive, manually-performed sequences of
immunohistochemistry analysis of the biopsy, and allows the user to perform up
to five test routines simultaneously with increased accuracy and significant
cost reduction. The Company also provides extensive after-sale support and
maintenance.
 
 2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
 
   
     Revenue: Revenue generally is recognized upon shipment of products. Revenue
from service contracts is recognized ratably over the lives of the contracts.
Export sales, which were made primarily to Denmark, totaled $1,478,000 and
$2,492,000 for the 6 months ended December 31, 1995 and the year ended June 30,
1995.
    
 
     Credit Risk: Virtually all of the Company's sales are made through two
distributors. The Company has not experienced bad debts from these distributors
in the past. The domestic distribution agreement expires in April 1998, and the
international distribution agreement expires in December 1999, if not renewed by
the parties.
 
     A portion of the cash flows from these distribution agreements have been
pledged to repay the advances from one of the distributors and to reimburse
contract manufacturers for start-up expenses (see Note 7).
 
     Inventories: Inventories are stated at the lower of cost (first-in,
first-out method) or market.
 
     Property and Equipment: Property and equipment are stated at cost. The
Company capitalizes expenditures that materially increase asset lives and
charges ordinary repairs and maintenance to operations as incurred. Depreciation
and amortization are provided using the straight-line method over the estimated
useful lives of the assets, which are generally three to five years.
 
     Income Taxes: The Company accounts for income taxes using the liability
method. Deferred tax assets and liabilities are determined based on differences
between financial reporting and tax bases of assets and liabilities and are
measured using enacted tax rates and laws expected to be in effect when the
differences are expected to reverse. Valuation allowances are established when
necessary to reduce the carrying amount of deferred tax assets to their net
realizable value.
 
     Stock-Based Compensation: The Company accounts for its stock compensation
arrangements under the provisions of APB 25, Accounting for Stock Issued to
Employees, and intends to continue to do so.
 
     Use of Estimates: The preparation of financial statements in accordance
with generally accepted accounting principles requires management to make
estimates and assumptions that affect the reported amounts of assets and
liabilities and disclosure of contingent assets and liabilities at the date of
the financial statements and the reported amounts of revenues and expenses
during the reporting period. Actual results could differ from those estimates.
 
 3. FAIR VALUE OF FINANCIAL INSTRUMENTS
 
     The Company's cash, accounts receivable, and long-term debt represent
financial instruments as defined by Statement of Financial Accounting Standards
No. 107, Disclosures About Fair Value of Financial Instruments. The carrying
value of these financial instruments is a reasonable approximation of fair
value.
 
                                      F-28
<PAGE>   99
 
                             BIOTEK SOLUTIONS, INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
 4. INVENTORIES
 
     Inventories consist of the following:
 
<TABLE>
<CAPTION>
                                                                 JUNE 30,     DECEMBER 31,
                                                                   1995           1995
                                                                 --------     ------------
                                                                      (IN THOUSANDS)
        <S>                                                      <C>          <C>
        Raw materials and work-in-process......................    $100           $102
        Finished goods.........................................      52             66
                                                                   ----           ----
                                                                   $152           $168
                                                                   ====           ====
</TABLE>
 
 5. PROPERTY AND EQUIPMENT
 
     Property and equipment consist of the following:
 
<TABLE>
<CAPTION>
                                                                JUNE 30,      DECEMBER 31,
                                                                  1995            1995
                                                                ---------     -------------
                                                                      (IN THOUSANDS)
        <S>                                                     <C>           <C>
        Machinery and equipment...............................   $ 1,311         $ 1,312
        Furniture and fixtures................................        31              31
        Leasehold improvements................................       135             135
        Other.................................................        22              18
                                                                  ------          ------
                                                                   1,499           1,496
        Less accumulated depreciation and amortization........       559             701
                                                                  ------          ------
                                                                 $   940         $   795
                                                                  ======          ======
</TABLE>
 
 6. OTHER ASSETS
 
     Other assets consist of the following:
 
<TABLE>
<CAPTION>
                                                                JUNE 30,      DECEMBER 31,
                                                                  1995            1995
                                                                ---------     -------------
                                                                      (IN THOUSANDS)
        <S>                                                     <C>           <C>
        Patents, net..........................................    $ 148           $ 167
        Loan origination fees, net............................      417             282
        Deposits and other....................................       16              21
                                                                   ----            ----
                                                                  $ 581           $ 470
                                                                   ====            ====
</TABLE>
 
     Patents are net of amortization of $14,000 and $19,000 at June 30, 1995 and
December 31, 1995, respectively. Loan origination fees are net of amortization
of $512,000 and $647,000 at June 30, 1995 and December 31, 1995, respectively.
 
     Loan origination fees were paid to a broker/dealer controlled by a member
of the Company's Board of Directors in connection with private placement
offerings. These fees include a commission of 10% of the funds raised from
investors not identified by the Company and 5% for investors identified by the
Company, as well as five-year warrants to buy common stock equal to 10% of
common stock issued for investors not identified by the Company and 6% for
investors identified by the Company. These fees are included in other assets in
the accompanying balance sheets and are being amortized over the terms of the
related notes payable.
 
                                      F-29
<PAGE>   100
 
                             BIOTEK SOLUTIONS, INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
 7. ACCRUED EXPENSES
 
     Accrued expenses consist of the following:
 
<TABLE>
<CAPTION>
                                                                JUNE 30,      DECEMBER 31,
                                                                  1995            1995
                                                                ---------     -------------
                                                                      (IN THOUSANDS)
        <S>                                                     <C>           <C>
        Advances from distributor.............................   $ 1,402         $ 2,239
        Legal fees and settlements............................       868           1,124
        Accrued interest......................................       380             676
        Deferred revenue......................................       341             455
        Reimbursement of start-up expenses to contract
          manufacturers.......................................       230             242
        Due to officers.......................................       210             227
        Other.................................................       269             265
                                                                  ------          ------
                                                                 $ 3,700         $ 5,228
                                                                  ======          ======
</TABLE>
 
 8.  LONG-TERM DEBT
 
     Long-term debt, consists of the following:
 
<TABLE>
<CAPTION>
                                                                JUNE 30,      DECEMBER 31,
                                                                  1995            1995
                                                                ---------     -------------
                                                                      (IN THOUSANDS)
        <S>                                                     <C>           <C>
        Notes payable issued through private placements:
          7.5% due July 31, 1995, extended (see below)........   $ 1,500         $ 1,500
          7.5% due December 31, 1996..........................     1,146           1,087
          7.5% due March 31, 1996.............................       500             500
          7.5% due June 30, 1996..............................       600             600
          8.25% due September 30, 1996........................     5,869           5,869
          Zero coupon, due September 30, 1997.................     1,113           1,334
        Other.................................................       881             877
                                                                  ------          ------
                                                                  11,609          11,767
        Less:
          Original issue discount.............................     1,532           1,002
          Current portion.....................................     1,106           8,685
                                                                  ------          ------
                                                                 $ 8,971         $ 2,080
                                                                  ======          ======
</TABLE>
 
     Substantially all of the Company's financing has consisted of financing
units. Each unit consists of a note payable with a fixed interest rate and a
specified number of shares of the Company's common stock. The value of the
common stock has been recorded as imputed interest on the notes payable, and is
being amortized as additional interest expense over the life of the notes. This
discount increases the interest rates on the notes from stated rates of between
7.5% and 8.25% to effective rates of between 7.8% and 31.6%.
 
     Annual maturities of the Company's long-term debt are $8,685,000 in 1996
and $2,080,000 in 1997.
 
     During the fiscal year ended June 30, 1995, investors holding notes with a
face value of $966,000 and accrued interest of $180,000 due December 31, 1994
exchanged these notes for new notes with a face value of $1,146,000 due December
31, 1996 with interest payable quarterly at 7.5%.
 
     In accordance with the terms of the offering document, the Company extended
the maturity of the notes originally due July 31, 1995 until October 31, 1995.
Under the terms of the offering document, holders of
 
                                      F-30
<PAGE>   101
 
                             BIOTEK SOLUTIONS, INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
these notes must proceed against the Company as a group (defined as holders of
at least 50% of the total principal balance) to declare the notes in default.
The Company has obtained waivers from holders of greater than 50% of the
outstanding principal balance, deferring any action against the Company until
March 31, 1996.
 
     Notes with a face value of $1,113,000 and $1,334,000 at June 30, 1995 and
December 31, 1995 are convertible into the Company's common stock at a
conversion rate of one share of stock per $1.00 of note principal.
 
     All notes call for quarterly payments of interest. The notes may be called
prior to maturity at the option of the Company. The Company may extend the
maturity of the notes by three months upon notice. The notes are automatically
due in full upon liquidation of the Company, sale of the Company, default or an
initial public offering in excess of $5,000,000. The notes are collateralized by
substantially all of the Company's assets.
 
     In connection with the business combination transaction (see Note 12),
Ventana Medical Systems, Inc. ("Ventana") replaced substantially all of the
above notes with Ventana exchange notes ("Exchange Notes"). The Exchange Notes
are payable at the earlier of 30 days after a successful public offering of
Ventana stock or February 1998. The Exchange Notes bear interest at 7%, payable
December 31, 1996 and 1997. The interest due December 31, 1996 is payable either
in cash or Ventana common stock, at Ventana's option. If the notes are redeemed
prior to December 31, 1996, no interest is payable. The Exchange Notes are
convertible into Ventana common stock at a price of $5.00 per share for 30 days
subsequent to the closing of the transaction.
 
 9. STOCKHOLDERS' EQUITY (DEFICIT)
 
     In January 1994, the Board of Directors adopted the Amended and Restated
1991 Stock Incentive Plan (the Plan). The Plan provides for the granting of
options to purchase common stock that are either intended to qualify as
incentive common stock options or nonqualified options. All officers, directors,
employees, consultants, advisers, independent contractors and agents are
eligible to receive options under the Plan, except that only employees may
receive incentive common stock options. The maximum number of common shares
available for issuance under the Plan is 1,250,000.
 
     The exercise price of incentive common stock options granted under the Plan
must be at least equal to the fair market value of the shares on the date of
grant (110% of fair market value in the case of participants who own shares
possessing more than 10% of the combined voting power of the Company) and may
not have a term in excess of ten years from the date of grant (five years in the
case of participants who own shares possessing more than 10% of the combined
voting power of the Company). A summary of changes in the common shares under
option follows:
 
<TABLE>
<CAPTION>
                                                              SHARES            PRICE
                                                           UNDER OPTION         RANGE
                                                           ------------     -------------
        <S>                                                <C>              <C>
        Balance, July 1, 1994............................     818,000       $.45 -- $3.00
          Granted........................................       8,000                2.50
          Canceled.......................................    (119,419)       .45 --  2.50
                                                           ------------     -------------
        Balance, June 30, 1995...........................     706,581        .45 --  3.00
          Granted........................................          --                  --
          Canceled.......................................          --                  --
                                                           ------------     -------------
        Balance, December 31, 1995.......................     706,581       $.45 -- $3.00
                                                           ==========        ============
</TABLE>
 
     In January 1996, the Company's Board of Directors terminated the Plan
pursuant to the Plan document. Upon termination, all options became fully
vested. All options not exercised within 30 days of the termination are
canceled.
 
                                      F-31
<PAGE>   102
 
                             BIOTEK SOLUTIONS, INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
     Warrants for the purchase of 1,248,917 shares of common stock with exercise
prices between $.01-$3.33 were outstanding at December 31, 1995. All warrants
will be canceled upon closing of the Ventana acquisition (see Note 12).
 
10. INCOME TAXES
 
     The Company's deferred tax assets consist of the following:
 
<TABLE>
<CAPTION>
                                                   JUNE 30, 1995         DECEMBER 31, 1995
                                                -------------------     -------------------
                                                             NON-                    NON-
                                                CURRENT     CURRENT     CURRENT     CURRENT
                                                -------     -------     -------     -------
                                                              (IN THOUSANDS)
        <S>                                     <C>         <C>         <C>         <C>
        Net operating loss carryforwards......   $  --      $ 3,954      $  --      $ 4,331
        Capitalized research and
          development.........................      --        1,025         --        1,133
        Research and development credits......      --           76         --          113
        Basis of fixed assets.................      --           82         --          110
        Reserves and allowances not currently
          deductible..........................     355           --        332           --
                                                 -----      -------      -----      -------
                                                   355        5,137        332        5,687
        Valuation allowance...................    (355)      (5,137)      (332)      (5,687)
                                                 -----      -------      -----      -------
        Net deferred tax assets...............   $  --      $    --      $  --      $    --
                                                 =====      =======      =====      =======
</TABLE>
 
     Temporary differences between the federal net operating losses for
financial reporting and income tax purposes primarily relate to the deferral of
research and development expenses for tax purposes.
 
     At June 30, 1995 and December 31, 1995, the Company had net operating loss
carryforwards for federal and state purposes of $9,884,000 and $10,828,000,
respectively. These federal and state carryforwards will begin to expire in
2008, if not previously utilized. Utilization of the Company's net operating
loss carryforwards will be subject to limitations due to the change in ownership
provisions of the Internal Revenue Code as a result of the acquisition by
Ventana (see Note 12). These carryforwards, therefore, may expire prior to being
fully utilized.
 
11. COMMITMENTS AND CONTINGENCIES
 
     The Company leases its operating facility under an operating lease. The
Company has the following future minimum annual lease payments as of December
31, 1995:
 
<TABLE>
<CAPTION>
                                                         (IN THOUSANDS)
                                                         --------------
                        <S>                              <C>
                        1996...........................       $147
                        1997...........................        113
                        1998...........................         66
                                                              ----
                                                              $326
                                                              ====
</TABLE>
 
     Total rent expense related to these facility leases was approximately
$195,000 for the year ended June 30, 1995 and $110,000 for the six-months ended
December 31, 1995.
 
     A competitor has filed suit against the Company alleging infringement of
certain patent rights. The Company is involved in various other litigation
arising in the normal course of business. Management, in conjunction with
outside counsel, periodically reviews such matters and makes any accruals deemed
necessary. Management is of the opinion that the disposition of these claims
will not have a material effect on the Company's financial statements.
 
                                      F-32
<PAGE>   103
 
                             BIOTEK SOLUTIONS, INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
12. SUBSEQUENT EVENT
 
     On February 20, 1996, the Company's stockholders approved the acquisition
of all of the Company's outstanding common stock by Ventana for consideration of
$18,763,000. The purchase price includes cash, issuance of Exchange Notes, and
the assumption of liabilities. The Company does not anticipate any funds will
remain for common stockholders once the Company's liabilities are settled. The
Company will become a wholly owned subsidiary of Ventana, which will provide the
financial resources for the Company to meet its operating needs.
 
     The Company incurred $1,395,000 in costs subsequent to year end related to
the transaction, including the issuance of notes payable of $888,000 and the
payment of cash of $328,000 paid to officers and directors of the Company.
 
     Subsequent to December 31, 1995, the Company renegotiated certain
obligations with its vendors. Accounts payable, accrued expenses, and long-term
debt with carrying values totaling $1,923,000 in the accompanying balance sheet
were settled for $1,120,000. The resulting gain of $803,000 is not included in
the accompanying statement of operations.
 
                                      F-33
<PAGE>   104
 
                    REPORT OF INDEPENDENT PUBLIC ACCOUNTANTS
 
To the Board of Directors of
BioTek Solutions, Inc.
 
     We have audited the accompanying balance sheets of BIOTEK SOLUTIONS, INC.(a
California corporation) as of June 30, 1993 and 1994 and the related statements
of operations, shareholders' deficit and cash flows for the years then ended
June 30, 1993 and 1994. These financial statements are the responsibility of the
Company's management. Our responsibility is to express an opinion on these
financial statements based on our audits.
 
     We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.
 
     In our opinion, the financial statements referred to above present fairly,
in all material respects, the financial position of BioTek Solutions, Inc. as of
June 30, 1993 and 1994, and the results of its operations and its cash flows for
the years then ended in conformity with generally accepted accounting
principles.
 
                                          ARTHUR ANDERSEN LLP
 
Los Angeles, California
February 2, 1996
(except with respect to
the information in Note 8
as to which the date is
February 20, 1996)
 
                                      F-34
<PAGE>   105
 
                             BIOTEK SOLUTIONS, INC.
 
                                 BALANCE SHEETS
                          AS OF JUNE 30, 1993 AND 1994
 
                                     ASSETS
 
<TABLE>
<CAPTION>
                                                                         1993           1994
                                                                      ----------     ----------
<S>                                                                   <C>            <C>
Current Assets:
  Cash..............................................................  $  100,519     $  261,611
  Accounts receivable, net of allowance of $41,650 and $44,984 at
     June 30, 1993 and 1994, respectively...........................     246,115        421,269
  Inventories.......................................................     332,038        530,926
  Prepaid expenses..................................................          --         26,466
                                                                      ----------     ----------
          Total current assets......................................     678,672      1,240,272
                                                                      ----------     ----------
Property, Equipment and Leasehold Improvements:
  Equipment.........................................................     370,700      1,071,004
  Furniture and fixtures............................................      10,293         31,095
  Leasehold improvements............................................      30,754        130,841
  Vehicles..........................................................       5,000          5,000
  Computer hardware and software....................................      55,776        184,988
                                                                      ----------     ----------
                                                                         472,523      1,422,928
  Less -- Accumulated depreciation and amortization.................      55,076        279,139
                                                                      ----------     ----------
                                                                         417,447      1,143,789
                                                                      ----------     ----------
Other Assets:
  Patents, net of amortization of $1,929 and $6,543 at June 30, 1993
     and 1994, respectively.........................................      59,957         90,319
  Private placement origination fee, net of amortization of $51,816
     and $168,897 at June 30, 1993 and 1994, respectively...........     206,684        464,816
  Deposits..........................................................         670         18,577
                                                                      ----------     ----------
                                                                         267,311        573,712
                                                                      ----------     ----------
                                                                      $1,363,430     $2,957,773
                                                                      ==========     ==========
LIABILITIES AND STOCKHOLDERS' DEFICIT
Current Liabilities:
  Accounts payable..................................................  $  677,456     $1,862,903
  Accrued liabilities...............................................     729,375        695,726
  Other.............................................................     136,280        359,139
  Restructuring reserve.............................................          --        611,441
  Current portion of notes payable..................................          --        979,000
  Reimbursement of start-up expenses to contract manufacturer.......          --        662,000
                                                                      ----------     ----------
          Total current liabilities.................................   1,543,111      5,170,209
                                                                      ----------     ----------
Notes Payable, net of current portion and original issue discount...   3,144,099      5,372,823
                                                                      ----------     ----------
Commitments and Contingencies (Note 4)
Stockholders' Deficit:
  Common stock, no par value
     Authorized -- 10,000,000 shares issued and outstanding
     5,940,800 and 7,478,985 in 1993 and 1994 respectively..........     743,646      2,335,031
  Accumulated deficit...............................................  (4,067,426)    (9,920,290)
                                                                      ----------     ----------
                                                                      (3,323,780)    (7,585,259)
                                                                      ----------     ----------
                                                                      $1,363,430     $2,957,773
                                                                      ==========     ==========
</TABLE>
 
   The accompanying notes are an integral part of these financial statements.
 
                                      F-35
<PAGE>   106
 
                             BIOTEK SOLUTIONS, INC.
 
                            STATEMENTS OF OPERATIONS
                   FOR THE YEARS ENDED JUNE 30, 1993 AND 1994
 
<TABLE>
<CAPTION>
                                                                         1993          1994
                                                                      -----------   -----------
<S>                                                                   <C>           <C>
Revenues............................................................  $ 1,549,655   $ 6,159,843
                                                                      -----------   -----------
Cost and expenses:
  Cost of revenues..................................................    1,410,693     4,103,279
  Research and development..........................................    1,370,376       861,310
  Selling, general and administrative expenses......................    1,764,228     5,222,464
  Restructuring expense.............................................           --       877,004
                                                                      -----------   -----------
                                                                        4,545,297    11,064,057
                                                                      -----------   -----------
     Loss from operations...........................................   (2,995,642)   (4,904,214)
                                                                      -----------   -----------
Interest expense (income), net:
  Interest expense..................................................      255,406       953,691
  Interest income...................................................       (7,722)       (5,841)
                                                                      -----------   -----------
                                                                          247,684       947,850
                                                                      -----------   -----------
     Loss before provision for state income taxes...................   (3,243,326)   (5,852,064)
Provision for state income taxes....................................        1,000           800
                                                                      -----------   -----------
Net loss............................................................  $(3,244,326)  $(5,852,864)
                                                                      ===========   ===========
</TABLE>
 
   The accompanying notes are an integral part of these financial statements.
 
                                      F-36
<PAGE>   107
 
                             BIOTEK SOLUTIONS, INC.
 
                      STATEMENTS OF STOCKHOLDERS' DEFICIT
                   FOR THE YEARS ENDED JUNE 30, 1993 AND 1994
 
<TABLE>
<CAPTION>
                                                               COMMON STOCK
                                                        --------------------------
                                                          SHARES                       ACCUMULATED
                                                        OUTSTANDING       AMOUNT         DEFICIT
                                                        -----------     ----------     -----------
<S>                                                     <C>             <C>            <C>
Balance, June 30, 1992................................   3,945,000      $   54,568     $  (823,100)
  Issuance of Common Stock in connection with private
     placement........................................     229,800           2,298              --
  Issuance of Common Stock in settlement of lawsuits
     in connection with bridge loan...................      50,000             500              --
  Issuance of Common Stock in connection with the
     first private placement with a related party.....     900,000           9,000              --
  Issuance of Common Stock in connection with the
     second private placement with a related party....     250,000         207,500              --
  Issuance of Common Stock in settlement of lawsuit
     with former board member.........................     266,000         220,780              --
  Issuance of Common Stock in connection with the
     third private placement with a related party.....     300,000         249,000              --
Net loss..............................................          --                      (3,244,326)
                                                         ---------      -----------    ------------
Balance, June 30, 1993................................   5,940,800         743,646      (4,067,426)
  Issuance of common stock upon the exercise of
     warrants.........................................       5,000           2,250              --
  Issuance of common stock in connection with the
     fourth, fifth and sixth private placements with a
     related party....................................   1,533,185       1,589,135              --
Net loss..............................................          --              --      (5,852,864)
                                                         ---------      -----------    ------------
Balance, June 30, 1994................................   7,478,985      $2,335,031     $(9,920,290)
                                                         =========      ===========    ============
</TABLE>
 
   The accompanying notes are an integral part of these financial statements.
 
                                      F-37
<PAGE>   108
 
                             BIOTEK SOLUTIONS, INC.
 
                            STATEMENTS OF CASH FLOWS
                   FOR THE YEARS ENDED JUNE 30, 1993 AND 1994
 
<TABLE>
<CAPTION>
                                                                       1993            1994
                                                                    -----------     -----------
<S>                                                                 <C>             <C>
CASH FLOWS FROM OPERATING ACTIVITIES:
  Net loss........................................................  $(3,244,326)    $(5,852,864)
  Adjustments to reconcile net loss to net cash used in operating
     activities:
     Depreciation.................................................       51,626         228,677
     Interest and amortization of loan fees.......................       94,993         552,912
     Issuance of Common Stock for settlement of lawsuits..........      221,280              --
     Restructuring reserve........................................           --         611,441
     Reimbursement of start-up expenses to contract
      manufacturer................................................           --         662,000
  (Increase) decrease in:
     Accounts receivable..........................................     (245,115)       (175,154)
     Inventories..................................................     (332,038)       (198,888)
     Prepaid expenses.............................................        6,520         (26,466)
     Deposits.....................................................      (48,989)        (17,907)
     Patents......................................................        2,660         (34,976)
  Increase (decrease) in:
     Accounts payable.............................................      659,940       1,185,447
     Accrued liabilities..........................................      706,427         (33,649)
     Other liabilities............................................       91,280         222,859
                                                                    -----------     -----------
          Net cash used in operating activities...................   (2,035,742)     (2,876,568)
                                                                    -----------     -----------
CASH FLOWS FROM INVESTING ACTIVITIES:
  Purchase of property, equipment and leasehold improvements......     (376,149)       (950,405)
                                                                    -----------     -----------
CASH FLOWS FROM FINANCING ACTIVITIES:
  Issuance of Common Stock........................................           --           2,670
  Issuance of notes payable.......................................    2,626,000       4,360,608
  Loan fees paid in association with issuance of notes payable....     (258,500)       (375,213)
                                                                    -----------     -----------
          Net cash provided by financing activities...............    2,367,500       3,988,065
                                                                    -----------     -----------
NET INCREASE (DECREASE) IN CASH...................................      (44,391)        161,092
Cash, beginning of period.........................................      144,910         100,519
                                                                    -----------     -----------
Cash, end of period...............................................  $   100,519     $   261,611
                                                                    ===========     ===========
Supplemental disclosures of cash flow information:
  Cash paid during the year for:
     Interest.....................................................  $    50,000     $   272,211
                                                                    ===========     ===========
     Taxes........................................................  $     1,000     $     1,600
                                                                    ===========     ===========
</TABLE>
 
   The accompanying notes are an integral part of these financial statements.
 
                                      F-38
<PAGE>   109
 
                             BIOTEK SOLUTIONS, INC.
 
                         NOTES TO FINANCIAL STATEMENTS
 
                                 JUNE 30, 1994
 
1.  SIGNIFICANT RISKS
 
BUSINESS AND BASIS OF PRESENTATION
 
     BioTek Solutions, Inc. ("the Company") develops, manufactures, markets and
supports proprietary computerized instruments that automate biopsy tests for the
diagnosis of cancer, viruses and other conditions and diseases. These
instruments use the Company's optimized chemical reagents and monoclonal
antibodies. This system effectively replaces the labor-intensive,
manually-performed sequences of the biopsy and surgical specimen preparation and
allows the user to precisely and simultaneously perform up to five test routines
with increased accuracy and significant cost reduction. The Company also
provides extensive after-sale support and maintenance.
 
     The Company was formed in October 1990 and was a development stage company
through June 30, 1992. The Company began selling products in the first quarter
of fiscal 1993 and began volume sales in March 1993. The Company incurred net
losses of $3,244,326 and $5,852,864 for the years ended June 30, 1993 and 1994,
respectively. Continuing losses have adversely affected the liquidity of the
Company. As of June 30, 1994, the Company had a working capital deficit of
$3,929,937.
 
     The Company has relied upon private sales of equity and debt securities to
obtain necessary working capital to support its activities. On February 20,
1996, the Company's stockholders approved the acquisition of the Company by
Ventana Medical Systems, Inc. (Ventana)(see Note 8).
 
RESTRUCTURING CHARGES
 
     During fiscal 1994, the Company recorded a $877,004 charge to income for
the repositioning of the Company's operations. The repositioning was
necessitated by plans of a new management team. The charge includes costs
associated with reductions in work force, removal of former president and
termination of various leases. The Company believes that the repositioning and
resulting expense reductions will allow it to operate in a more efficient manner
in the future.
 
2.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
 
REVENUE RECOGNITION
 
     Revenue is recognized upon shipment of product. Revenue for the years ended
June 30, 1993 and 1994 were comprised of the following:
 
<TABLE>
<CAPTION>
                                                                 1993           1994
                                                              ----------     ----------
        <S>                                                   <C>            <C>
        Instruments.........................................  $  938,896     $3,519,723
        Chemistries, disposables, service and other.........     610,759      2,640,120
                                                              ----------     ----------
                                                              $1,549,655     $6,159,843
                                                              ==========     ==========
</TABLE>
 
     In January 1993, the Company signed an exclusive distribution agreement
with Curtin Matheson Scientific, Inc. (CMS). This gave CMS the exclusive rights
to sell instruments and consumables in the United States. Total sales to CMS for
the years ended June 30, 1993 and 1994 were $1,213,000 and $5,445,394,
respectively.
 
CREDIT RISK
 
     Virtually all of the Company's sales are made through two distributors. The
Company has not experienced bad debts from these distributors in the past. The
distribution agreement with CMS expires in
 
                                      F-39
<PAGE>   110
 
                             BIOTEK SOLUTIONS, INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
April 1998, and the international distribution agreement expires in December
1999, if not renewed by the parties.
 
USE OF ESTIMATES
 
     The preparation of financial statements in accordance with generally
accepted accounting principles requires management to make estimates and
assumptions that affect the reported amounts of assets and liabilities and
disclosure of contingent assets and liabilities at the date of the financial
statements and the reported amounts of revenues and expenses during the
reporting period. Actual results could differ from those estimates.
 
INVENTORY
 
     Inventory consists of automated instruments, chemical reagents, and
replacement parts for the automated instruments (see Note 4). As of June 30,
1993 and 1994, inventory consisted of:
 
<TABLE>
<CAPTION>
                                                                   1993         1994
                                                                 --------     --------
        <S>                                                      <C>          <C>
        Raw materials..........................................  $219,633     $ 36,078
        Work in process........................................    71,729      114,328
        Finished goods.........................................    40,676      380,520
                                                                 --------     --------
                                                                 $332,038     $530,926
                                                                 ========     ========
</TABLE>
 
     Inventory is stated at the lower of cost (first-in, first-out) or market.
 
DEPRECIATION AND AMORTIZATION
 
     Depreciation and amortization is provided through the use of the
straight-line method over the estimated useful lives of the assets as follows:
 
<TABLE>
<CAPTION>
                              ASSET TYPE                        USEFUL LIFE
                ---------------------------------------  -------------------------
                <S>                                      <C>
                Equipment..............................  5 years
                Furniture & Fixtures...................  5 years
                Leasehold Improvements.................  Lesser of the asset life
                                                         or the life of the
                                                         respective lease
                Vehicles...............................  5 years
                Computer Hardware......................  5 years
                Computer Software......................  3 years
</TABLE>
 
     The Company capitalizes expenditures that materially increase asset lives
and charges ordinary repairs and maintenance to operations as incurred. When
assets are sold or otherwise disposed of, the cost and related accumulated
depreciation and amortization are removed from the accounts and any gain or loss
is included in results of operations.
 
CAPITALIZED PATENT COSTS
 
     The Company capitalizes costs of obtaining patent rights for certain
products. Amortization of capitalized patent cost is provided on a straight-line
basis over 17 years.
 
                                      F-40
<PAGE>   111
 
                             BIOTEK SOLUTIONS, INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
INCOME TAXES
 
     No provision was made for federal income tax purposes since the Company has
recorded a net operating loss from inception. The primary difference between
book and tax loss is the capitalization of research and development costs for
tax purposes. At June 30, 1994, the Company had net operating losses for federal
and state purposes of $6,754,000. These federal and state carryforwards will
begin to expire in 2006, if not previously utilized. Utilization of the
Company's net operating losses will be subject to limitations due to the change
in ownership provisions of the Internal Revenue Code as a result of the
acquisition by Ventana (see Note 8). These carryforwards, therefore, may expire
prior to being fully utilized.
 
3.  CAPITAL TRANSACTIONS
 
     On September 20, 1993, the shareholders approved an increase in the number
of authorized shares of common stock from 6,500,000 to 10,000,000.
 
     In November 1990, the Company issued 1,000,000 shares of Common Stock to
each of its three founders in exchange for $45,118. In addition, two of the
founders transferred all their rights, title and interest in certain technology
and equipment which was valued at zero.
 
     In July 1992, the Company issued 25,000 shares to each of two investors and
a $24,000 note due December 31, 1992 with no interest. The note and shares were
issued as part of a settlement agreement and mutual release among the investors,
the Company and an officer of the Company.
 
     Between January 1992 and September 1992, the Company sold $979,000 in
aggregate principal amount of units in a private placement to various investors.
Each unit consisted of 30,000 shares of Common Stock and a senior secured note
in the principal amount of $25,000 with interest accruing at 7.5 percent until
maturity on July 31, 1995. Danzi Capital Group (DANZI) served as private
placement agent for the offering (see Note 6). The Common Stock was valued at
$.01 per share.
 
     In September 1992, the Company sold $1,500,000 in aggregate principal
amount of units in a private placement to various investors. Each unit consisted
of 15,000 shares of Common Stock and a senior unsecured note in the principal
amount of $25,000 with interest accruing at 7.5 percent until maturity on July
31, 1995. Danzi served as private placement agent for the offering (see Note 6).
The Common stock was valued at $.01 per share.
 
     In March 1993, the Company issued 266,000 shares to two former board
members. These shares were issued as part of settlement agreements and a mutual
release among the former board members and the Company.
 
     In April 1993, the Company sold $500,000 in aggregate principal amount of
units in a private placement to various investors. Each unit consisted of 12,500
shares of Common Stock and a senior unsecured note in the principal amount of
$25,000 with interest accruing at 7.5 percent until maturity on March 31, 1996.
Danzi served as private placement agent for the offering (see Note 6). The
Common stock was valued at $.83 per share.
 
     In May 1993, the Company sold $600,000 in aggregate principal amount of
units in a private placement to various investors. Each unit consisted of 12,500
shares of Common Stock and a senior unsecured note in the principal amount of
$25,000 with interest accruing at 7.5 percent until maturity on June 30, 1996.
Danzi served as private placement agent for the offering (see Note 6). The
Common Stock was valued at $.83 per share.
 
     Between July 1993 to October 1993, the Company sold $2,250,000 in aggregate
principal amount of units in a private placement to various investors. Each unit
consisted of 10,000 shares of Common Stock and a senior unsecured note in the
principal amount of $25,000 with interest accruing at 8.25 percent until
maturity
 
                                      F-41
<PAGE>   112
 
                             BIOTEK SOLUTIONS, INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
on September 30, 1996. Danzi served as private placement agent for the offering
(see Note 6). The Common Stock was valued at $.83 per share.
 
     Between March 1994 to June 1994, the Company sold $2,110,608 in aggregate
principal amount of units in a private placement to various investors. Each unit
consisted of 7,500 shares of Common Stock and a senior unsecured note in the
principal amount of $25,000 with interest accruing at 8.25 percent until
maturity on September 30, 1996. Danzi served as private placement agent for the
offering (see Note 6). The Common Stock was valued at $1.33 per share.
 
     The value of the common stock has been recorded as imputed interest on the
notes payable, and is being amortized as additional interest expense over the
life of the notes. This discount increases the interest rates on the notes from
stated rates of between 7.5 percent and 8.25 percent to effective rates of
between 7.8 percent and 31.6 percent.
 
4.  COMMITMENTS AND CONTINGENCIES
 
ROYALTIES
 
     In May 1993, the Company entered into a royalty agreement with a slide
manufacturer that obligates the Company to pay a percentage of the sales of
certain items to the manufacturer based on terms defined in the royalty
agreement with a guaranteed minimum of $50,000 per year for 4 years beginning in
fiscal 1994. There was royalty expense of $50,000 for the year ended June 30,
1994 and no royalty expense for the year ended June 30, 1993.
 
LEASES
 
     The Company leased its office facility during 1992 under an operating lease
on a month to month basis. The Company also has four sales offices that are
rented on a month to month basis. Total rental expense related to these facility
leases was approximately $106,000 and $140,175 for the years ended June 30, 1993
and 1994, respectively. The future minimum annual lease payments under a new 5
year office lease agreement signed subsequent to year end is as follows:
 
<TABLE>
<CAPTION>
     YEAR ENDED JUNE 30,
- ------------------------------
<S>                             <C>
      1995....................  $112,794
      1996....................   112,794
      1997....................   112,794
      1998....................   112,794
                                $451,176
</TABLE>
 
DISTRIBUTOR LICENSING AGREEMENT
 
     In January 1993, the Company entered into a 5 year exclusive distribution
agreement with CMS, a major distributor of medical products, to purchase and
promote the Company's products. As of June 30, 1994, CMS had purchased 104
TechMate(TM) systems. CMS is required to purchase a total of 300 units by April
1995 in order to retain its exclusive distribution rights. CMS has not met this
obligation; however no action has been taken.
 
STOCK PURCHASE AGREEMENT
 
     On February 14, 1992, the Company entered into a buy/sell agreement (the
"Buy-Sell Agreement") with the three founders of the Company. Under the
agreement, if a founder should be terminated for cause or voluntarily resign
without written approval of the board, then the other founders and the Company
shall have the option, but not the obligation, at any time and from time to time
to purchase all or any portion of the
 
                                      F-42
<PAGE>   113
 
                             BIOTEK SOLUTIONS, INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
shares owned by such founder. If the termination is determined to be without
cause, then such founder shall have the right to require the Company to purchase
all or a portion of the shares owned by-the-founder subject to certain
limitations as defined in the agreement. The purchase price will be at fair
market value determined on a semi-annual basis by the founders. If the fair
market value is not adjusted the last agreed upon rate will prevail. The last
established fair market value as set by the founders was $0.80 per share.
 
LITIGATION
 
     As of July 6, 1994, the former president of the Company was terminated. As
a result of an arbitration ruling in July 1995, the Company has issued the
former president a note for $760,000 bearing interest at 7.5 percent per year
for the repurchase of his 950,000 shares.
 
     In March 1995, a competitor filed suit against the Company alleging
infringement of certain patent rights. The Company is involved in various other
actions arising in the normal course of business. Management, in conjunction
with outside counsel, periodically reviews such matters and makes any accruals
deemed necessary. Management is of the opinion that the disposition of these
claims will not have a material effect on the Company's financial position or
results of operations.
 
5.  NOTES PAYABLE
 
     Notes payable, all issued in connection with private placements (see Notes
3 and 6), consisted of the following as of June 30, 1994:
 
<TABLE>
        <S>                                                                <C>
          Secured Notes payable, collateralized by the assets of the
             Company, interest at 7.5 percent payable quarterly, due
             December 31, 1994, subsequently extended to December 31,
             1996........................................................  $  979,000
          Secured Notes payable, collateralized by the assets of the
             Company, interest at 7.5 percent payable quarterly, due July
             31, 1995, subsequently extended to October 31, 1996.........   1,500,000
          Unsecured Notes payable, interest at 7.5 percent payable
             quarterly, due March 31, 1996...............................     500,000
          Unsecured Notes payable, interest at 7.5 percent payable
             quarterly, due June 30, 1996................................     600,000
          Unsecured Notes payable, interest at 8.25 percent payable
             quarterly, due September 30, 1996...........................   4,360,608
                                                                           ----------
                                                                            7,939,608
                                                                           ----------
        Less:
          Original issue discount........................................   1,587,785
          Current portion................................................     979,000
                                                                           ----------
                                                                           $5,372,823
                                                                           ==========
</TABLE>
 
     In connection with the sale of the Company to Ventana (see Note 8), the
outstanding notes were exchanged for Ventana notes which are interest free if
paid by December 31, 1996 and ultimately due with interest at 7 percent on
December 31, 1997. The entire amount is due 30 days after completion of an
initial public offering.
 
6.  RELATED PARTIES
 
     The Company has completed several private placement offerings in which
Danzi was the placement agent. In connection with these offerings Danzi was paid
a commission of 10 percent of the funds raised from
 
                                      F-43
<PAGE>   114
 
                             BIOTEK SOLUTIONS, INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
investors not identified by the Company and 5 percent for investors identified
by the Company, payable upon the closing of the transactions. As additional
consideration, the Company granted Danzi five-year warrants to buy Common Stock
equal to 10 percent of Common Stock issued to investors not identified by the
Company and 6 percent for identified obtained by the Company. Total fees paid
and warrants issued to Danzi during the years ended June 30, 1993 and 1994 were
$258,500, and 140,300 warrants in 1993 and $427,000 and 126,171 warrants in
1994. The fees paid to Danzi have been capitalized and are being amortized over
the life of the related notes payable.
 
     The warrants issued to Danzi are summarized as follows:
 
<TABLE>
<CAPTION>
                        EXPIRATION DATE                      EXERCISE PRICE     UNDERLYING SHARES
    -------------------------------------------------------  --------------     -----------------
    <S>                                                      <C>                <C>
    Between October 1997 and May 1998......................      $ 1.00              140,300
    Between July 1998 and June 1999........................      $ 1.00              126,171
                                                                                     -------
                                                                                     266,471
                                                                                     =======
</TABLE>
 
7.  STOCK OPTIONS
 
     In November 1991, the Company adopted the Biotek Solutions, Inc. 1991 Stock
Incentive Plan (the "Plan"). In January 1994, the Board of Directors adopted the
Amended and Restated 1991 Stock Incentive Plan, subject to shareholder approval.
The Plan provides for the granting of options to purchase Common Stock that are
either intended to qualify as incentive Common Stock options or non-qualified
options. All officers, directors, employees, consultants, advisers, independent
contractors and agents are eligible to receive options under the Plan, except
that employees may only receive incentive Common Stock options. The maximum
number of shares available for issuance under the Plan is 1,250,000.
 
     The exercise price of incentive Common Stock options granted under the Plan
must be at least equal to the fair market value of the shares on the date of
grant (110 percent of fair market value in the case of participants who own
shares possessing more than 10 percent of the combined voting power of the
Company) and may not have a term in excess of 10 years from the date of grant
(five years in the case of participants who are more than 10 percent Common
Stockholders).
 
     A summary of changes in the shares under option follows:
 
<TABLE>
<CAPTION>
                                                                   SHARES     PRICE RANGE
                                                                  --------    -----------
    <S>                                                           <C>         <C>
    Balance, June 30, 1992......................................   430,750    $        0.45
      Granted...................................................   303,000    0.45-- 0.83
      Canceled..................................................        --       --
                                                                   -------    -----------
    Balance, June 30, 1993......................................   733,750    0.45-- 0.83
      Granted...................................................   176,750    0.83-- 3.00
      Canceled..................................................    92,500    0.83-- 2.50
                                                                   -------    -----------
    Balance, June 30, 1994......................................   818,000    $0.45--$3.00
                                                                   =======    ===========
</TABLE>
 
     At June 30, 1993 expiration dates for options outstanding ranged from
fiscal 2002 to 2003. No amounts have been reflected in the Company's statements
of operations with respect to these stock options.
 
     In January 1996, the Company's Board of Directors terminated the plan,
pursuant to the plan document. Upon termination, all options became fully
vested. All options not exercised within 30 days of the termination are
canceled.
 
                                      F-44
<PAGE>   115
 
                             BIOTEK SOLUTIONS, INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
8.  SUBSEQUENT EVENTS
 
     On February 20, 1996, the Company's stockholders approved the acquisition
of the Company by Ventana. Under the terms of the acquisition agreement, Ventana
will pay $4.5 million in cash and notes and assume $12.5 million of the
Company's liabilities. Substantially all of the proceeds to the Company will be
used to retire existing liabilities. The Company does not anticipate any funds
will remain for common stockholders once the Company's liabilities are settled.
 
     Subsequent to December 31, 1995, the Company renegotiated certain
obligations with its vendors. Accounts payable, accrued expenses, and long-term
debt with carrying values totaling $1,923,000 in the accompanying balance sheet
were settled for $1,120,000. The resulting gain of $803,000 is not included in
the accompanying statements of operations.
 
                                      F-45
<PAGE>   116
 
- ------------------------------------------------------
- ------------------------------------------------------
 
    NO DEALER, SALESMAN OR OTHER PERSON HAS BEEN AUTHORIZED TO GIVE ANY
INFORMATION OR TO MAKE ANY REPRESENTATION NOT CONTAINED IN THIS PROSPECTUS, AND,
IF GIVEN OR MADE, SUCH INFORMATION OR REPRESENTATION MUST NOT BE RELIED UPON AS
HAVING BEEN AUTHORIZED BY THE COMPANY, ANY SELLING STOCKHOLDER, ANY UNDERWRITER
OR ANY OTHER PERSON. THIS PROSPECTUS DOES NOT CONSTITUTE AN OFFER TO SELL, OR A
SOLICITATION OF AN OFFER TO BUY, ANY SECURITIES OTHER THAN THE SECURITIES TO
WHICH IT RELATES OR AN OFFER TO SELL, OR A SOLICITATION OF AN OFFER TO BUY, TO
ANY PERSON IN ANY JURISDICTION IN WHICH SUCH AN OFFER OR SOLICITATION IS NOT
AUTHORIZED, OR IN WHICH THE PERSON MAKING SUCH OFFER OR SOLICITATION IS NOT
QUALIFIED TO DO SO, OR TO ANY PERSON TO WHOM IT IS UNLAWFUL TO MAKE SUCH OFFER
OR SOLICITATION. NEITHER THE DELIVERY OF THIS PROSPECTUS NOR ANY SALE MADE
HEREUNDER SHALL, UNDER ANY CIRCUMSTANCES, CREATE ANY IMPLICATION THAT THERE HAS
BEEN NO CHANGE IN THE AFFAIRS OF THE COMPANY SINCE THE DATE HEREOF OR THAT THE
INFORMATION CONTAINED HEREIN IS CORRECT AS OF ANY TIME SUBSEQUENT TO THE DATE
HEREOF.
 
                               ------------------
 
                               TABLE OF CONTENTS
 
   
<TABLE>
<CAPTION>
                                           PAGE
                                           ----
<S>                                        <C>
Prospectus Summary......................      3
Risk Factors............................      6
The Company.............................     16
Use of Proceeds.........................     16
Dividend Policy.........................     16
Dilution................................     17
Capitalization..........................     18
Selected Consolidated Actual and Pro
  Forma Financial and Operating Data....     19
Management's Discussion and Analysis of
  Financial Condition and Results of
  Operations............................     21
Business................................     33
Management..............................     50
Certain Transactions....................     58
Principal and Selling Stockholders......     61
Description of Capital Stock............     64
Shares Eligible for Future Sale.........     65
Underwriting............................     67
Legal Matters...........................     68
Experts.................................     68
Additional Information..................     68
Index to Financial Statements...........    F-1
</TABLE>
    
 
                               ------------------
 
    UNTIL          , 1996 (25 DAYS AFTER THE DATE OF THIS PROSPECTUS) ALL
DEALERS EFFECTING TRANSACTIONS IN THE REGISTERED SECURITIES, WHETHER OR NOT
PARTICIPATING IN THIS DISTRIBUTION, MAY BE REQUIRED TO DELIVER A PROSPECTUS.
THIS IS IN ADDITION TO THE OBLIGATION OF DEALERS TO DELIVER A PROSPECTUS WHEN
ACTING AS UNDERWRITERS AND WITH RESPECT TO THEIR UNSOLD ALLOTMENTS OR
SUBSCRIPTIONS.
- ------------------------------------------------------
- ------------------------------------------------------
- ------------------------------------------------------
- ------------------------------------------------------
 
   
                                3,000,000 SHARES
    
 
                                      LOGO
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
                                  COMMON STOCK
                            -----------------------
 
                                   PROSPECTUS
                            -----------------------
                            BEAR, STEARNS & CO. INC.
 
                            DILLON, READ & CO. INC.
 
                                               , 1996
 
- ------------------------------------------------------
- ------------------------------------------------------
<PAGE>   117
 
                         VENTANA MEDICAL SYSTEMS, INC.
 
                           APPENDIX -- GRAPHIC IMAGES
 
INSIDE FRONT COVER
 
(1) [Image: The Ventana ES System, an automated diagnostic instrument used to
    perform standardized IHC testing in clinical and research laboratories.]
 
(2) [Image: The Ventana gen II, an automated diagnostic used to perform ISH (in
    situ hybridization) testing in clinical and research laboratories.]
 
BACK INSIDE COVER
 
(3) [The BioTek TechMate 500 System, a semi-automated diagnostic instrument used
    to perform standardized IHC testing in clinical and research laboratories.]
<PAGE>   118
 
                                    PART II
 
                     INFORMATION NOT REQUIRED IN PROSPECTUS
 
ITEM 13. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION
 
     The following table sets forth the costs and expenses, other than
underwriting discounts and commissions, payable by the Registrant in connection
with the sale of Common Stock being registered. All amounts are estimates except
the SEC registration fee and the NASD filing fee.
 
<TABLE>
        <S>                                                                 <C>
        SEC registration fee..............................................  $ 19,035
        NASD filing fee...................................................     6,020
        Nasdaq National Market listing fee................................    40,000
        Printing and engraving costs......................................   150,000
        Legal fees and expenses...........................................   300,000
        Accounting fees and expenses......................................   200,000
        Blue Sky fees and expenses........................................    20,000
        Transfer Agent and Registrar fees.................................     5,000
        Directors and officers insurance coverage premiums................   150,000
        Miscellaneous expenses............................................    34,945
                                                                            --------
                  Total...................................................  $925,000
                                                                            ========
</TABLE>
 
   
ITEM 14. INDEMNIFICATION OF DIRECTORS AND OFFICERS
    
 
     Article 10 of the Registrant's Certificate of Incorporation provides for
the indemnification of directors to the fullest extent permissible under
Delaware law.
 
     Article VI of the Registrant's Bylaws provides for the indemnification of
officers, directors, employees and agents of the corporation if such person
acted in good faith and in a manner reasonably believed to be in and not opposed
to the best interest of the corporation, and, with respect to any criminal
action or proceeding the indemnified party had no reason to believe his conduct
was unlawful.
 
     Section 145 of the Delaware General Corporation Law permits a corporation
to include in its charter documents, and in agreements between the corporation
and its directors and officers, provisions expanding the scope of
indemnification beyond that specifically provided by the current law.
 
     The Registrant will enter into indemnification agreements with its
directors and executive officers, and intends to enter into indemnification
agreements with any new directors and executive officers in the future.
 
ITEM 15. RECENT SALES OF UNREGISTERED SECURITIES
 
     Since January 1, 1993, the Registrant has issued and sold (without payment
of any selling commission to any person) the following unregistered securities
(all of which are presented without giving effect to the reverse stock split to
be effected prior to the closing of the Offering):
 
          (1) From inception of the Company, the Registrant issued and sold
     807,585 shares of Common Stock to employees, directors and consultants at
     prices ranging from $.09 to $.35, upon exercise of incentive stock options
     under the Registrant's 1988 Stock Option Plan, or as stock purchases in
     connection with their employment with or services to the Company.
 
          (2) From inception of the Company, the Registrant issued and sold
     222,989 shares of preferred stock to employees at prices ranging from $.90
     to $2.15 per share pursuant to the 1991 Employee Stock Purchase Plan in
     connection with their employment with the Company.
 
                                      II-1
<PAGE>   119
 
          (3) From March 25, 1993 to January 23, 1995, Registrant issued
     4,747,119 shares of Series D Preferred Stock at a price of $2.15 per share
     and 124,270 warrants for the purchase of Series D Preferred Stock with an
     exercise price of $2.15 per share to a total of 38 investors.
 
          (4) In October 1994, Registrant issued to R. James Danehy, President,
     Chief Executive Officer and a director of the Company a stock option
     covering 800,000 shares of Common Stock at an exercise price of $0.31 per
     share. 219,891 shares subject to such option which had vested were
     cancelled by the Company in November 1995, and the Company allowed Mr.
     Danehy to purchase 219,891 shares of Common Stock at a purchase price of
     $0.31 per share through his self-directed IRA.
 
          (5) In August 1994 the Company provided to Mr. Danehy the opportunity
     to purchase $200,000 of Series D Preferred Stock at $2.15 per share and an
     additional share of Common Stock at $0.84 per share for each two shares of
     Series D Preferred Stock purchased. Pursuant to his right, Mr. Danehy
     purchased 93,023 shares of Series D Preferred Stock and 46,512 shares of
     Common Stock at $0.31 per share in January 1996.
 
          (6) In February 1996, the Company issued approximately $12 million in
     Exchange Notes in exchange for notes held by 199 holders of BioTek notes as
     consideration for the acquisition of BioTek Solutions, Inc. Such Exchange
     Notes were convertible into Common Stock at a conversion price of $5.00 per
     share. Between February 26, 1996 and May 14, 1996 the Company issued
     approximately $5.1 million of convertible subordinated debt together with
     warrants to purchase 2,378,898 shares of Series D Preferred Stock at an
     exercise price of $2.15 per share to 68 investors (i.e., certain current
     stockholders and officers and directors of the Company).
 
          (7) In January 1996, the Company issued 69,767 shares of Series D
     Preferred Stock to Bear, Stearns & Co. Inc. as partial consideration for
     services rendered in connection with the acquisition of BioTek.
 
     The sales of the above securities were deemed to be exempt from
registration under the Securities Act in reliance on Section 4(2) of the
Securities Act, or Regulation D promulgated thereunder, or Rule 701 promulgated
under Section 3(b) of the Securities Act, as transactions by an issuer not
involving a public offering or transactions pursuant to compensatory benefit
plans and contracts relating to compensation as provided under such Rule 701.
The recipients of securities in each such transaction represented their
intention to acquire the securities for investment only and not with a view to
or for sale in connection with any distribution thereof and appropriate legends
were affixed to the share certificates and warrants issued in such transactions.
All recipients had adequate access, through their relationships with the
Company, to information about the Registrant.
 
ITEM 16. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES
 
     (a) EXHIBITS
 
   
<TABLE>
<CAPTION>
        EXHIBIT
        NUMBER                                      DESCRIPTION
      -----------    -------------------------------------------------------------------------
      <S>            <C>
       1.1           Form of Underwriting Agreement.
       3.1(i)(a)*    Restated Certificate of Incorporation, as amended.
       3.1(i)(b)     Form of Restated Certificate of Incorporation to be filed after the
                     closing of the offering made under this Registration Statement.
       3.1(ii)(a)*   Bylaws.
       3.1(ii)(b)    Form of Bylaws to be effective on or about the closing of the Offering
                     made under this Registration Statement.
       4.1           Specimen Common Stock Certificate.
       5.1*          Opinion of Wilson Sonsini Goodrich & Rosati, Professional Corporation.
      10.1(a)+*      DAKO Distribution Agreement dated September 27, 1994.
      10.1(b)+*      First Amendment to DAKO Distribution Agreement dated March 24, 1995.
      10.1(c)+*      Further amendments to First Amendment to DAKO Distribution Agreement
                     dated March 24, 1995.
      10.2(a)        Kollsman Secured Promissory Note dated December 4, 1994.
</TABLE>
    
 
                                      II-2
<PAGE>   120
 
   
<TABLE>
<CAPTION>
        EXHIBIT
        NUMBER                                      DESCRIPTION
      -----------    -------------------------------------------------------------------------
      <S>            <C>
      10.2(b)        Development Secured Promissory Note dated March 24, 1995.
      10.3+*         Curtin Matheson Scientific, Inc. Distribution Agreement dated January 18,
                     1993.
      10.4(a)*       Restricted Stock Purchase Agreement with Jack W. Schuler dated April 19,
                     1996 -- Tranche 1.
      10.4(b)*       Restricted Stock Purchase Agreement with Jack W. Schuler dated April 19,
                     1996 -- Tranche 2.
      10.4(c)*       Restricted Stock Purchase Agreement with Jack W. Schuler dated April 19,
                     1996 -- Tranche 3.
      10.5(a)*       Restricted Stock Purchase Agreement with John Patience dated April 19,
                     1996 -- Tranche 1.
      10.5(b)*       Restricted Stock Purchase Agreement with John Patience dated April 19,
                     1996 -- Tranche 2.
      10.6           Form of Indemnification Agreement for directors and officers.
      10.7(a)*       1988 Stock Option Plan and forms of agreements thereunder.
      10.7(b)*       1996 Stock Option Plan and forms of agreements thereunder.
      10.8(a)*       1991 Employee Stock Purchase Plan.
      10.8(b)*       1996 Employee Stock Purchase Plan.
      10.8(c)        1996 Directors Option Plan.
      10.9*          Questier Employment Agreement dated October 20, 1995.
      10.10*         Restated Investors Rights Agreement dated February 20, 1996.
      10.11*         Sublease of Premises between the Registrant and Jerry R. Jones &
                     Associates, Inc., dated February 29, 1996, with attached Master Lease,
                     dated October 26, 1988.
      10.12*         Master Lease Purchase Agreement between the Registrant and Copelco
                     Leasing Corporation dated April 13, 1994.
      10.13(a)*      Agreement and Plan of Reorganization dated January 19, 1996.
      10.13(b)*      Agreement and Plan of Merger dated February 26, 1996.
      10.13(c)*      Escrow Agreement dated February 26, 1996.
      10.14(a)*      Form of Stock Purchase Warrant to Purchase shares of Series D Preferred
                     Stock.
      10.14(b)*      Form of Preferred Stock Purchase Warrant.
      10.14(c)*      MBW and Marquette Warrants dated August 21, 1992.
      10.14(d)*      Schuler Warrant dated September 30, 1992.
      10.15(a)*      Form of Convertible Unsecured Promissory Note.
      10.15(b)*      Form of Convertible Unsecured Promissory Note.
      10.17+*        Novocastra Laboratories Ltd. Distribution Agreement dated August 19,
                     1992.
      10.18+*        LJL BioSystems, Inc. Techmate 250 Production Agreement dated May 1, 1996.
      10.19(a)       Silicon Valley Bank Loan and Security Agreement dated February 20, 1995.
      10.19(b)       Amendment to Silicon Valley Bank Loan and Security Agreement dated
                     March 28, 1996.
      11.1           Statement regarding computation of Per Share Earnings.
      21.1*          Subsidiaries of the Registrant.
      23.1           Consent of Ernst & Young LLP, Independent Auditors (see page II-7).
      23.2           Consent of Ernst & Young LLP, Independent Auditors (see page II-8).
      23.3           Consent of Arthur Andersen LLP, Independent Public Accountants (see page
                     II-9).
      23.4*          Consent of Counsel (included in Exhibit 5.1).
      24.1*          Power of Attorney (see page II-5).
      27.1*          Financial Data Schedule.
</TABLE>
    
 
- ---------------
 
   
* Previously Filed.
    
 
 + Confidential Treatment Requested.
 
                                      II-3
<PAGE>   121
 
     (b) FINANCIAL STATEMENT SCHEDULES
 
     No schedules have been filed herein because the information required to be
set forth therein is not applicable or is shown in the financial statements or
notes thereto.
 
ITEM 17. UNDERTAKINGS
 
     The undersigned Registrant hereby undertakes to provide to the Underwriters
at the closing specified in the Underwriting Agreement certificates in such
denominations and registered in such names as required by the Underwriters to
permit prompt delivery to each purchaser.
 
     Insofar as indemnification for liabilities arising under the Securities Act
of 1933 may be permitted to directors, officers and controlling persons of the
Registrant pursuant to the foregoing provisions or otherwise, the Registrant has
been advised that in the opinion of the Securities and Exchange Commission such
indemnification is against public policy as expressed in the Securities Act and
is, therefore, unenforceable. In the event that a claim for indemnification
against such liabilities (other than the payment by the Registrant of expenses
incurred or paid by a director, officer or controlling person of the Registrant
in the successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Securities Act and will be governed by the final
adjudication of such issue.
 
     The undersigned registrant hereby undertakes that:
 
     (1) For purposes of determining any liability under the Securities Act of
1933, the information omitted from the form of prospectus filed as part of this
Registration Statement in reliance upon Rule 430A and contained in a form of
prospectus filed by the Registrant pursuant to Rule 424(b)(1) or (4) or 497(h)
under the Securities Act shall be deemed to be part of this Registration
Statement as of the time it was declared effective.
 
     (2) For the purpose of determining any liability under the Securities Act
of 1933, each post-effective amendment that contains a form of prospectus shall
be deemed to be a new registration statement relating to the securities offered
therein, and the offering of such securities at that time shall be deemed to be
the initial bona fide offering thereof.
 
                                      II-4
<PAGE>   122
 
                                   SIGNATURES
 
   
     Pursuant to the requirements of the Securities Act of 1933, as amended, the
Registrant has duly caused this Amendment to Registration Statement to be signed
on its behalf by the undersigned, thereunto duly authorized, in the City of
Tucson, State of Arizona, on the 2nd day of July, 1996.
    
 
                                          VENTANA MEDICAL SYSTEMS, INC.
 
                                          By:      /s/  R. JAMES DANEHY
 
                                            ------------------------------------
                                                 R. James Danehy, President
                                                and Chief Executive Officer
 
     Pursuant to the requirements of the Securities Act of 1933, as amended,
this Amendment to Registration Statement has been signed by the following
persons in the capacities and on the dates indicated:
 
   
<TABLE>
<CAPTION>
                   SIGNATURE                                  TITLE                    DATE
- -----------------------------------------------  -------------------------------  --------------
<S>                                              <C>                              <C>
             /s/  R. JAMES DANEHY                  President, Chief Executive      July 2, 1996
- -----------------------------------------------  Officer and Director (Principal
               (R. James Danehy)                       Executive Officer)
            /s/  R. MICHAEL RODGERS*                Vice President and Chief       July 2, 1996
- -----------------------------------------------   Financial Officer (Principal
             (R. Michael Rodgers)                   Financial and Accounting
                                                            Officer)
               /s/  REX J. BATES*                           Director               July 2, 1996
- -----------------------------------------------
                (Rex J. Bates)
             /s/  MICHAEL R. DANZI*                         Director               July 2, 1996
- -----------------------------------------------
              (Michael R. Danzi)
             /s/  EDWARD M. GILES*                          Director               July 2, 1996
- -----------------------------------------------
               (Edward M. Giles)
          /s/  THOMAS M. GROGAN, M.D.*                      Director               July 2, 1996
- -----------------------------------------------
           (Thomas M. Grogan, M.D.)
             /s/   JOHN PATIENCE*                           Director               July 2, 1996
- -----------------------------------------------
                (John Patience)
</TABLE>
    
 
                                      II-5
<PAGE>   123
 
   
<TABLE>
<CAPTION>
                   SIGNATURE                                  TITLE                    DATE
- -----------------------------------------------  -------------------------------  --------------
<S>                                              <C>                              <C>
             /s/  JACK W. SCHULER*                          Director               July 2, 1996
- -----------------------------------------------
               (Jack W. Schuler)
         /s/  C. ANTHONY STELLAR, M.D.*                     Director               July 2, 1996
- -----------------------------------------------
          (C. Anthony Stellar, M.D.)
           /s/  JAMES M. STRICKLAND*                        Director               July 2, 1996
- -----------------------------------------------
             (James M. Strickland)
            /s/  JAMES R. WEERSING*                         Director               July 2, 1996
- -----------------------------------------------
              (James R. Weersing)
        *By:       /s/  R. JAMES DANEHY
- -----------------------------------------------
                (R. James Danehy)
                (Attorney in-fact)
</TABLE>
    
 
                                      II-6
<PAGE>   124
 
                                                                    EXHIBIT 23.1
 
               CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS
 
   
We consent to the reference to our firm under the caption "Experts" and to the
use of our report dated February 28, 1996, except for Note 11, as to which the
date is           1996, of Ventana Medical Systems, Inc. in Amendment No. 2 to
the Registration Statement (Form S-1 No. 333-4461) and related Prospectus of
Ventana Medical Systems, Inc., for the registration of 3,450,000 shares its
common stock.
    
 
Tucson, Arizona
- --------------------------------------------------------------------------------
 
   
     The foregoing consent is in the form that will be signed upon the
completion of the restatement of capital accounts described in Note 11 to the
consolidated financial statements.
    
 
                                          ERNST & YOUNG LLP
 
Tucson, Arizona
   
July 1, 1996
    
 
                                      II-7
<PAGE>   125
 
                                                                    EXHIBIT 23.2
 
               CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS
 
   
     We consent to the reference to our firm under the caption "Experts" and to
the use of our report dated February 2, 1996, except for Note 10, as to which
the date is February 20, 1996, of BioTek Solutions, Inc. in Amendment No. 2 to
the Registration Statement (Form S-1 No. 333-4461) and related Prospectus of
Ventana Medical Systems, Inc. for the registration of 3,450,000 shares of its
common stock.
    
 
                                          ERNST & YOUNG LLP
 
Tucson, Arizona
   
July 1, 1996
    
 
                                      II-8
<PAGE>   126
 
                                                                    EXHIBIT 23.3
 
                   CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS
 
As independent public accountants, we hereby consent to the use of our report
dated February 2, 1996 (except with respect to the information in Note 8 as to
which the date is February 20, 1996) with respect to the financial statements of
BioTek Solutions, Inc. (and to all references to our Firm included in or made a
part of this Registration Statement (Form S-1).
 
                                            /s/ ARTHUR ANDERSEN LLP
                                              Arthur Andersen LLP
 
Los Angeles, California
   
July 1, 1996
    
 
                                      II-9
<PAGE>   127
 
                               INDEX TO EXHIBITS
 
<TABLE>
<CAPTION>
         EXHIBIT
         NUMBER                                     DESCRIPTION
      -------------   ------------------------------------------------------------------------
      <S>             <C>
       1.1            Form of Underwriting Agreement.
</TABLE>
 
   
<TABLE>
      <S>             <C>
       3.1(i)(a)*     Restated Certificate of Incorporation, as amended.
       3.1(i)(b)      Form of Restated Certificate of Incorporation to be filed after the
                      closing of the offering made under this Registration Statement.
       3.1(ii)(a)*    Bylaws.
       3.1(ii)(b)     Form of Bylaws to be effective on or about the closing of the Offering
                      made under this Registration Statement.
       4.1            Specimen Common Stock Certificate.
       5.1*           Opinion of Wilson Sonsini Goodrich & Rosati, Professional Corporation.
      10.1(a)+*       DAKO Distribution Agreement dated September 27, 1994.
      10.1(b)+*       First Amendment to DAKO Distribution Agreement dated March 24, 1995.
      10.1(c)+*       Further amendments to First Amendment to DAKO Distribution Agreement
                      dated March 24, 1995.
      10.2(a)         Kollsman Secured Promissory Note dated December 4, 1994.
      10.2(b)         Development Secured Promissory Note dated March 24, 1995.
      10.3+*          Curtin Matheson Scientific, Inc. Distribution Agreement dated January
                      18, 1993.
      10.4(a)*        Restricted Stock Purchase Agreement with Jack W. Schuler dated April 19,
                      1996 -- Tranche 1.
      10.4(b)*        Restricted Stock Purchase Agreement with Jack W. Schuler dated April 19,
                      1996 -- Tranche 2.
      10.4(c)*        Restricted Stock Purchase Agreement with Jack W. Schuler dated April 19,
                      1996 -- Tranche 3.
      10.5(a)*        Restricted Stock Purchase Agreement with John Patience dated April 19,
                      1996 -- Tranche 1.
      10.5(b)*        Restricted Stock Purchase Agreement with John Patience dated April 19,
                      1996 -- Tranche 2.
      10.6            Form of Indemnification Agreement for directors and officers.
      10.7(a)*        1988 Stock Option Plan and forms of agreements thereunder.
      10.7(b)*        1996 Stock Option Plan and forms of agreements thereunder.
      10.8(a)*        1991 Employee Stock Purchase Plan.
      10.8(b)*        1996 Employee Stock Purchase Plan.
      10.8(c)         1996 Directors Option Plan.
      10.9*           Questier Employment Agreement dated October 20, 1995.
      10.10*          Restated Investors Rights Agreement dated February 20, 1996.
      10.11*          Sublease of Premises between the Registrant and Jerry R. Jones &
                      Associates, Inc., dated February 29, 1996, with attached Master Lease,
                      dated October 26, 1988.
      10.12*          Master Lease Purchase Agreement between the Registrant and Copelco
                      Leasing Corporation dated April 13, 1994.
      10.13(a)*       Agreement and Plan of Reorganization dated January 19, 1996.
      10.13(b)*       Agreement and Plan of Merger dated February 26, 1996.
      10.13(c)*       Escrow Agreement dated February 26, 1996.
      10.14(a)*       Form of Stock Purchase Warrant to Purchase shares of Series D Preferred
                      Stock.
      10.14(b)*       Form of Preferred Stock Purchase Warrant.
      10.14(c)*       MBW and Marquette Warrants dated August 21, 1992.
</TABLE>
    
<PAGE>   128
 
   
<TABLE>
<CAPTION>
         EXHIBIT
         NUMBER                                     DESCRIPTION
      -------------   ------------------------------------------------------------------------
      <S>             <C>
      10.14(d)*       Schuler Warrant dated September 30, 1992.
      10.15(a)*       Form of Convertible Unsecured Promissory Note.
      10.15(b)*       Form of Convertible Unsecured Promissory Note.
      10.17+*         Novocastra Laboratories Ltd. Distribution Agreement dated August 19,
                      1992.
      10.18+*         LJL BioSystems, Inc. Techmate 250 Production Agreement dated May 1,
                      1996.
      10.19(a)        Silicon Valley Bank Loan and Security Agreement dated February 20, 1995.
      10.19(b)        Amendment to Silicon Valley Bank Loan and Security Agreement dated
                      March 28, 1996.
      11.1            Statement regarding computation of Per Share Earnings.
      21.1*           Subsidiaries of the Registrant.
      23.1            Consent of Ernst & Young LLP, Independent Auditors (see page II-7).
      23.2            Consent of Ernst & Young LLP, Independent Auditors (see page II-8).
      23.3            Consent of Arthur Andersen LLP, Independent Public Accountants (see page
                      II-9).
      23.4*           Consent of Counsel (included in Exhibit 5.1).
      24.1*           Power of Attorney (see page II-5).
      27.1*           Financial Data Schedule.
</TABLE>
    
 
- ---------------
 
* Previously Filed.
 
 + Confidential Treatment Requested.

<PAGE>   1
                                                                     EXHIBIT 1.1


                                                               ST&B Draft 6/7/96

                        3,000,000 Shares of Common Stock

                          VENTANA MEDICAL SYSTEMS, INC.

                             UNDERWRITING AGREEMENT

                                                    _________ __, 1996

BEAR, STEARNS & CO. INC.
DILLON, READ & CO. INC.
  as Representatives of the
  several Underwriters named in
  Schedule I attached hereto
c/o Bear, Stearns & Co. Inc.
245 Park Avenue
New York, New York  10167

Dear Sirs:

                  Ventana Medical Systems, Inc., a corporation organized and
existing under the laws of Delaware (the "Company"), and certain stockholders of
the Company named in Schedule II hereto (the "Selling Stockholders") propose,
subject to the terms and conditions stated herein, to sell to the several
underwriters named in Schedule I hereto (the "Underwriters") an aggregate of
3,000,000 shares (the "Firm Shares") of the Company's common stock, par value
$0.001 per share (the "Common Stock"). Of the 3,000,000 Firm Shares, 2,200,000
Firm Shares are being sold by the Company and 800,000 Firm Shares are being sold
by the Selling Stockholders. In addition, certain of the Selling Stockholders
propose to grant, for the sole purpose of covering over-allotments in connection
with the sale of the Firm Shares, at the option of the Underwriters, up to an
additional 450,000 shares (the "Additional Shares") of Common Stock. The Firm
Shares and any Additional Shares purchased by the Underwriters are referred to
herein as the "Shares". The Shares are more fully described in the Registration
Statement referred to below.

                  1. Representations and Warranties of the Company. The Company
represents and warrants to, and agrees with, the Underwriters that:

                  (a) The Company has filed with the Securities and Exchange
         Commission (the "Commission") a registration statement, and may have
         filed an amendment or amendments thereto, on Form S-1 (No.
         333-_______), for the registration of the Shares under the Securities
         Act of 1933, as amended
<PAGE>   2
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         (the "Act"). Such registration statement, including the prospectus,
         financial statements and schedules, exhibits and all other documents
         filed as a part thereof, as amended at the time of effectiveness of the
         registration statement, including any information deemed to be a part
         thereof as of the time of effectiveness pursuant to paragraph (b) of
         Rule 430A or Rule 434 of the Rules and Regulations of the Commission
         under the Act (the "Regulations"), is herein called the "Registration
         Statement" and the prospectus, in the form first filed with the
         Commission pursuant to Rule 424(b) of the Regulations or filed as part
         of the Registration Statement at the time of effectiveness if no Rule
         424(b) or Rule 434 filing is required, is herein called the
         "Prospectus". The term "preliminary prospectus" as used herein means a
         preliminary prospectus as described in Rule 430 of the Regulations.

                  (b) At the time of the effectiveness of the Registration
         Statement or the effectiveness of any post-effective amendment to the
         Registration Statement, when the Prospectus is first filed with the
         Commission pursuant to Rule 424(b) or Rule 434 of the Regulations, when
         any supplement to or amendment of the Prospectus is filed with the
         Commission and at the Closing Date and the Additional Closing Date, if
         any, (as hereinafter respectively defined), the Registration Statement
         and the Prospectus and any amendments thereof and supplements thereto
         complied or will comply in all material respects with the applicable
         provisions of the Act and the Regulations and do not or will not
         contain an untrue statement of a material fact and do not or will not
         omit to state any material fact required to be stated therein or
         necessary in order to make the statements therein (i) in the case of
         the Registration Statement, not misleading and (ii) in the case of the
         Prospectus, in light of the circumstances under which they were made,
         not misleading. When any related preliminary prospectus was first filed
         with the Commission (whether filed as part of the registration
         statement for the registration of the Shares or any amendment thereto
         or pursuant to Rule 424(a) of the Regulations) and when any amendment
         thereof or supplement thereto was first filed with the Commission, such
         preliminary prospectus and any amendments thereof and supplements
         thereto complied in all material respects with the applicable
         provisions of the Act and the Regulations and did not contain an untrue
         statement of a material fact and did not omit to state any material
         fact required to be stated therein or necessary in order to make the
         statements therein, in light of the circumstances under which they were
         made, not misleading. No representation and warranty is made in this
         subsection (b), however, with respect to any information contained in
         or omitted from the Registration Statement or the Prospectus or any
         related preliminary prospectus or any amendment thereof or supplement
         thereto in reliance upon and in conformity
<PAGE>   3
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         with information furnished in writing to the Company by or on behalf of
         any Underwriter through you as herein stated expressly for use in
         connection with the preparation thereof. If Rule 434 is used, the
         Company will comply with the requirements of Rule 434.

                  (c) Ernst & Young LLP, who have certified certain financial
         statements and supporting schedules included in the Registration
         Statement, are independent public accountants as required by the Act
         and the Regulations; and Arthur Andersen LLP, who have certified
         certain financial statements and supporting schedules included in the
         Registration Statement, were independent public accountants as required
         by the Act and the Regulations during the periods covered by the
         financial statements on which they reported contained in the
         Registration Statement.

                  (d) Subsequent to the respective dates as of which information
         is given in the Registration Statement and the Prospectus, except as
         set forth in the Registration Statement and the Prospectus, there has
         been no material adverse change or any development involving a
         prospective material adverse change in the business, prospects,
         properties, operations, condition (financial or other) or results of
         operations of the Company and its subsidiaries taken as a whole,
         whether or not arising from transactions in the ordinary course of
         business, and since the date of the latest balance sheet presented in
         the Registration Statement and the Prospectus, neither the Company nor
         any of its subsidiaries has incurred or undertaken any liabilities or
         obligations, direct or contingent, which are material to the Company
         and its subsidiaries, taken as a whole, except for liabilities or
         obligations which are reflected in the Registration Statement and the
         Prospectus.

                  (e) This Agreement and the transactions contemplated herein
         have been duly and validly authorized by the Company and this Agreement
         has been duly and validly executed and delivered by the Company.

                  (f) The execution, delivery, and performance of this Agreement
         and the consummation of the transactions contemplated hereby do not and
         will not (i) conflict with or result in a breach of any of the terms
         and provisions of, or constitute a default (or an event which with
         notice or lapse of time, or both, would constitute a default) under, or
         result in the creation or imposition of any lien, charge or encumbrance
         upon any property or assets of the Company or any of its subsidiaries
         pursuant to, any agreement, instrument, franchise, license or permit to
         which the Company or any of its subsidiaries is a party or by which any
         of such corporations or their respective properties or assets may be
         bound or (ii) violate or conflict with any provision of the certificate
         of incorporation or by-laws of
<PAGE>   4
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         the Company or any of its subsidiaries or any judgment, decree, order,
         statute, rule or regulation of any court or any public, governmental or
         regulatory agency or body having jurisdiction over the Company or any
         of its subsidiaries or any of their respective properties or assets. No
         consent, approval, authorization, order, registration, filing,
         qualification, license or permit of or with any court or any public,
         governmental or regulatory agency or body having jurisdiction over the
         Company or any of its subsidiaries or any of their respective
         properties or assets is required for the execution, delivery and
         performance of this Agreement or the consummation of the transactions
         contemplated hereby, including the issuance, sale and delivery of the
         Shares to be issued, sold and delivered by the Company hereunder,
         except the registration under the Act of the Shares and such consents,
         approvals, authorizations, orders, registrations, filings,
         qualifications, licenses and permits as may be required under state
         securities or Blue Sky laws in connection with the purchase and
         distribution of the Shares by the Underwriters.

                  (g) All of the outstanding shares of Common Stock are duly and
         validly authorized and issued, fully paid and nonassessable and were
         not issued and are not now in violation of or subject to any preemptive
         rights. The Shares, when issued, delivered and sold in accordance with
         this Agreement, will be duly and validly issued and outstanding, fully
         paid and nonassessable, and will not have been issued in violation of
         or be subject to any preemptive rights. The Company had, at March 31,
         1996, an authorized and outstanding capitalization as set forth in the
         Registration Statement and the Prospectus. The Common Stock, the Firm
         Shares and the Additional Shares conform to the descriptions thereof
         contained in the Registration Statement and the Prospectus.

                  (h) Each of the Company and its subsidiaries has been duly
         organized and is validly existing as a corporation in good standing
         under the laws of its jurisdiction of incorporation. Each of the
         Company and its subsidiaries is duly qualified and in good standing as
         a foreign corporation in each jurisdiction in which the character or
         location of its properties (owned, leased or licensed) or the nature or
         conduct of its business makes such qualification necessary, except for
         those failures to be so qualified or in good standing which will not in
         the aggregate have a material adverse effect on the Company and its
         subsidiaries taken as a whole. Each of the Company and its subsidiaries
         has all requisite power and authority, and all necessary consents,
         approvals, authorizations, orders, registrations, qualifications,
         licenses and permits of and from all public, regulatory or governmental
         agencies and bodies, to own, lease and operate its properties and
         conduct its business as now being conducted and as described in the
         Registration
<PAGE>   5
                                                                               5

         Statement and the Prospectus, and no such consent, approval,
         authorization, order, registration, qualification, license or permit
         contains a materially burdensome restriction not adequately disclosed
         in the Registration Statement and the Prospectus.

                  (i) Except as described in the Prospectus, there is no
         litigation or governmental proceeding to which the Company or any of
         its subsidiaries is a party or to which any property of the Company or
         any of its subsidiaries is subject or which is pending or, to the
         knowledge of the Company, contemplated against the Company or any of
         its subsidiaries which might result in any material adverse change or
         development involving a prospective material adverse change in the
         business, prospects, properties, operations, condition (financial or
         other) or results of operations of the Company and its subsidiaries
         taken as a whole or which is required to be disclosed in the
         Registration Statement and the Prospectus.

                  (j) The Company has not taken and will not take, directly or
         indirectly, any action designed to cause or result in, or which
         constitutes or which might reasonably be expected to constitute, the
         stabilization or manipulation of the price of the shares of Common
         Stock to facilitate the sale or resale of the Shares.

                  (k) The financial statements, including the notes thereto, and
         supporting schedules included in the Registration Statement and the
         Prospectus, present fairly the financial position of the Company as of
         the dates indicated and the results of its operations for the periods
         specified; except as otherwise stated in the Registration Statement,
         said financial statements have been prepared in conformity with
         generally accepted accounting principles applied on a consistent basis;
         and the supporting schedules included in the Registration Statement
         present fairly the information required to be stated therein.

                  (l) Except as described in the Prospectus, no holder of
         securities of the Company has any rights to the registration of
         securities of the Company because of the filing of the Registration
         Statement or otherwise in connection with the sale of the Shares
         contemplated hereby.

                  (m) The Company is not, and upon consummation of the
         transactions contemplated hereby will not be, subject to registration
         as an "investment company" under the Investment Company Act of 1940, as
         amended.

                  (n) Except as described in the Prospectus, the Company and
         each of its subsidiaries own or possess adequate rights to use all
         material patents, patent applications, patent rights, inventions, trade
         secrets, know-how, proprietary
<PAGE>   6
                                                                               6

         techniques, including processes and substances, trademarks, service
         marks, trademark registrations, service mark registrations, trade
         names, copyrights and licenses described or referred to in the
         Prospectus or owned or used by it or which are necessary for the
         conduct of its business as described in the Prospectus. Except as
         described in the Prospectus, neither the Company nor any of its
         subsidiaries has received any notice of, or is aware of, any
         infringement of or conflict with asserted rights of others with respect
         to any patents, patent applications, patent rights, inventions, trade
         secrets, know-how, proprietary techniques, including processes and
         substances, trademarks, service marks, trademark registrations, service
         mark registrations, trade names, copyrights or licenses which
         individually or in the aggregate, if the subject of an unfavorable
         decision, ruling or finding might result in a material adverse change
         or development involving a prospective material adverse change in the
         business, prospects, properties, operations, condition (financial or
         other) or results of operations of the Company and its subsidiaries,
         taken as a whole.

                  (o) The Company and each of its subsidiaries, and all of their
         respective business operations, are in compliance in all material
         respects with all applicable statutes, rules and regulations and orders
         administered or issued by any governmental or regulatory authority in
         the jurisdictions in which it is conducting business and by any
         governmental or regulatory authority having jurisdiction over the
         Company or any of its subsidiaries, including, without limitation, the
         United States Food and Drug Administration. All of the descriptions in
         the Registration Statement and the Prospectus of applicable statutes,
         rules and regulations and orders administered or issued by any
         governmental or regulatory authority under the captions "Risk Factors
         -- FDA and Other Government Regulation" and "Business -- Government
         Regulation" and other references therein to regulatory matters are true
         and accurate in all material respects.

                  (p) There are no contracts or other documents which are
         required to be described in the Prospectus or filed as exhibits to the
         Registration Statement by the Act or by the Regulations which have not
         been described in the Prospectus or filed as exhibits to the
         Registration Statement.

                  (q) There has been no storage, disposal, generation,
         manufacture, refinement, transportation, handling or treatment of toxic
         wastes, medical wastes, hazardous wastes or hazardous substances by the
         Company or any of its subsidiaries (or, to the knowledge of the
         Company, any of their predecessors in interest) at, upon or from any of
         the property now or previously owned or leased by the Company or its
         subsidiaries in violation of any applicable law, ordinance, rule,
         regulation, order, judgment, decree or permit or which would require
         remedial action under any
<PAGE>   7
                                                                               7

         applicable law, ordinance, rule, regulation, order, judgment, decree or
         permit, except for any violation or remedial action which would not,
         singularly or in the aggregate with all such violations and remedial
         actions, result in any material adverse change or a development
         involving a prospective material adverse change in the business,
         prospects, properties, operations, condition (financial or other) or
         results of operations of the Company and its subsidiaries taken as a
         whole; there has been no spill, discharge, leak, emission, injection,
         escape, dumping or release of any kind onto such property or into the
         environment surrounding such property of any toxic wastes, medical
         wastes, solid wastes, hazardous wastes or hazardous substances due to
         or caused by the Company or any of its subsidiaries or with respect to
         which the Company or any of its subsidiaries have knowledge, except for
         any such spill, discharge, leak, emission, injection, escape, dumping
         or release which would not, singularly or in the aggregate with all
         such spills, discharges, leaks, emissions, injections, escapes,
         dumpings and releases, result in a material adverse change or
         development involving a prospective material adverse change in the
         business, prospects, properties, operations, condition (financial or
         otherwise), or results of operations of the Company and its
         subsidiaries taken as a whole; and the terms "hazardous wastes", "toxic
         wastes", "hazardous substances" and "medical wastes" shall have the
         meanings specified in any applicable local, state, federal and foreign
         laws or regulations with respect to environmental protection.

                  (r) The Company is in compliance in all material respects with
         all presently applicable provisions of the Employee Retirement Income
         Security Act of 1974, as amended, including the regulations and
         published interpretations thereunder ("ERISA"); no "reportable event"
         (as defined in ERISA) has occurred with respect to any "pension plan"
         (as defined in ERISA) for which the Company would have any liability;
         the Company has not incurred and does not expect to incur liability
         under (i) Title IV of ERISA with respect to termination of, or
         withdrawal from, any "pension plan" or (ii) Sections 412 or 4971 of the
         Internal Revenue Code of 1986, as amended, including the regulations
         and published interpretations thereunder (the "Code"); and each
         "pension plan" for which the Company would have any liability that is
         intended to be qualified under Section 401(a) of the Code is so
         qualified in all material respects and nothing has occurred, whether by
         action or by failure to act, which would cause the loss of such
         qualification.

                  (s) No relationship, direct or indirect, exists between or
         among the Company on the one hand, and the directors, officers,
         stockholders, customers or suppliers of the Company on the other hand,
         which is required to be described in the Prospectus which is not so
         described.
<PAGE>   8
                                                                               8

                  (t) Since the date as of which information is given in the
         Prospectus through the date hereof, and except as may otherwise be
         disclosed in the Prospectus, the Company has not (i) issued or granted
         any securities, (ii) entered into any transaction not in the ordinary
         course of business or (iii) declared or paid any dividend on its
         capital stock.

                  (u) Except as disclosed in Schedule III hereto, each
         stockholder of the Company has entered into or is subject to a lock-up
         agreement (the "Lock-Up Agreements") under which such stockholder has
         agreed not to offer, sell, agree to sell, grant any option for the sale
         of or otherwise dispose of, or agree to dispose of, directly or
         indirectly, any shares of Common Stock, options or warrants to acquire
         shares of Common Stock (or securities exchangeable for, exercisable for
         or convertible into Common Stock) owned by them for a period of 180
         days after the date of the Prospectus, without the prior written
         consent of Bear, Stearns & Co. Inc.; each Lock-Up Agreement constitutes
         the legal, valid and binding obligations of the stockholder or
         stockholders party thereto enforceable against each such stockholder in
         accordance with its terms.

                  2.  Representations and Warranties of the Selling
Stockholders.  Each Selling Stockholder severally represents and warrants to, 
and agrees that:

                  (a) Such Selling Stockholder has, and immediately prior to the
         Closing Date and the Additional Closing Date, if any, will have good
         and valid title to the Shares to be sold by such Selling Stockholder
         hereunder on such date, free and clear of all liens, encumbrances,
         equities or claims; and upon delivery of such Shares and payment
         therefor pursuant hereto, good and valid title to such Shares, free and
         clear of all liens, encumbrances, equities or claims, will pass to the
         several Underwriters.

                  (b) Such Selling Stockholder has placed in custody under a
         custody agreement (the "Custody Agreement" and, together with all other
         similar agreements executed by the other Selling Stockholders, the
         "Custody Agreements") with Norwest Bank Minnesota, N.A., as custodian
         (the "Custodian"), for delivery under this Agreement, certificates in
         negotiable form (with signature guaranteed by a commercial bank or
         trust company having an office or correspondent in the United States or
         a member firm of the New York or American Stock Exchanges) representing
         the Shares to be sold by such Selling Stockholder hereunder.

                  (c) Such Selling Stockholder has duly and irrevocably executed
         and delivered a power of attorney (the "Power of Attorney" and,
         together with all other similar agreements executed by the other
         Selling Stockholders, the "Powers of Attorney") appointing the
         Custodian and one or more other
<PAGE>   9
                                                                               9

         persons, as attorneys-in-fact, with full power of substitution, and
         with full authority (exercisable by any one or more of them) to execute
         and deliver this Agreement and to take such other action as may be
         necessary or desirable to carry out the provisions hereof on behalf of
         such Selling Stockholder.

                  (d) Such Selling Stockholder has full right, power and
         authority to enter into this Agreement, the Power of Attorney and the
         Custody Agreement; the execution, delivery and performance of this
         Agreement, the Power of Attorney and the Custody Agreement by such
         Selling Stockholder and the consummation by such Selling Stockholder of
         the transactions contemplated hereby will not conflict with or result
         in a breach or violation of any of the terms or provisions of, or
         constitute a default under, any indenture, mortgage, deed of trust,
         loan agreement or other agreement or instrument to which such Selling
         Stockholder is a party or by which such Selling Stockholder is bound or
         to which any of the property or assets of such Selling Stockholder is
         subject, nor will such actions result in any violation of the
         provisions of the constituent documents of such Selling Stockholder, if
         any, or any statute or any order, rule or regulation of any court or
         governmental agency or body having jurisdiction over such Selling
         Stockholder or the property or assets of such Selling Stockholder; and,
         except for the registration of the Shares under the Act and such
         consents, approvals, authorizations, registrations or qualifications as
         may be required under applicable state securities laws in connection
         with the purchase and distribution of the Shares by the Underwriters,
         no consent, approval, authorization or order of, or filing or
         registration with, any such court or governmental agency or body is
         required for the execution, delivery and performance of this Agreement,
         the Power of Attorney or the Custody Agreement by such Selling
         Stockholder and the consummation by such Selling Stockholder of the
         transactions contemplated hereby.

                  (e) To the extent that any statements or omissions made in the
         Registration Statement, the Prospectus or any amendment or supplement
         thereto are made in reliance upon and in conformity with written
         information furnished to the Company by such Selling Stockholder
         specifically for use therein, the Registration Statement and the
         Prospectus and any amendments or supplements thereto will not, when
         they become effective or are filed with the Commission, as the case may
         be, contain any untrue statement of a material fact or omit to state
         any material fact required to be stated therein or necessary to make
         the statements therein not misleading; and no facts have come to the
         attention of such Selling Stockholder which lead such Selling
         Stockholder to believe that the Registration Statement or the
         Prospectus or any amendments or supplements thereto will, when they
         become effective or are filed with the Commission, as the case may
<PAGE>   10
                                                                              10

         be, contain any untrue statement of any other material fact or omit to
         state any other material fact required to be stated therein or
         necessary to make the statements therein not misleading.

                  (f) Such Selling Stockholder has not taken and will not take,
         directly or indirectly, any action which is designed to or which has
         constituted or which might reasonably be expected to cause or result in
         the stabilization or manipulation of the price of any security of the
         Company to facilitate the sale or resale of the Shares.

                  3.  Purchase, Sale and Delivery of the Shares.

                  (a) On the basis of the representations, warranties, covenants
and agreements herein contained, but subject to the terms and conditions herein
set forth, the Company agrees to sell 2,200,000 Firm Shares and each Selling
Stockholder hereby agrees to sell the number of Firm Shares set opposite its
name in Schedule II hereto, severally and not jointly, to the Underwriters and
the Underwriters, severally and not jointly, agree to purchase from the Company
and the Selling Stockholders, at a purchase price per share of $_____, the
number of Firm Shares set forth opposite the respective names of the
Underwriters in Schedule I hereto plus any additional number of Shares which
such Underwriter may become obligated to purchase pursuant to the provisions of
Section 11 hereof.

                  (b) Payment of the purchase price for, and delivery of
certificates for, the Firm Shares shall be made at the office of Bear, Stearns &
Co. Inc., 245 Park Avenue, New York, New York 10167, or at such other place as
shall be agreed upon by you and the Company, at 10:00 A.M. on the third or
fourth business day (as permitted under Rule 15c6-1 under the Securities
Exchange Act of 1934, as amended (the "Exchange Act") (unless postponed in
accordance with the provisions of Section 11 hereof) following the date of the
effectiveness of the Registration Statement (or, if the Company has elected to
rely upon Rule 430A of the Regulations, the third or fourth business day (as
permitted under Rule 15c6-1 under the Exchange Act) after the determination of
the initial public offering price of the Firm Shares), or such other time not
later than ten business days after such date as shall be agreed upon by you and
the Company (such time and date of payment and delivery being herein called the
"Closing Date"). Payment shall be made to the Company and the Selling
Stockholders by certified or official bank check or checks drawn in New York
Clearing House funds or similar next day funds payable to the order of the
Company and the Selling Stockholders, against delivery to you for the respective
accounts of the Underwriters of certificates for the Shares to be purchased by
them. Certificates for the Shares shall be registered in such name or names and
in such authorized denominations as you may request in
<PAGE>   11
                                                                              11

writing at least two full business days prior to the Closing Date. The Company
and the Selling Stockholders will permit you to examine and package such
certificates for delivery at least one full business day prior to the Closing
Date.

                  (c) In addition, the Selling Stockholders so designated in
Schedule II hereto (the "Option Stockholders") hereby grant to the Underwriters
the option to purchase up to 450,000 Additional Shares at the same purchase
price per share to be paid by the Underwriters to the Company and the Selling
Stockholders for the Firm Shares as set forth in this Section 3, for the sole
purpose of covering over-allotments in the sale of Firm Shares by the
Underwriters. This option may be exercised at any time, in whole or in part, on
or before the thirtieth day following the date of the Prospectus, by written
notice by you to the Option Stockholders. Such notice shall set forth the
aggregate number of Additional Shares as to which the option is being exercised
and the date and time, as reasonably determined by you, when the Additional
Shares are to be delivered (such date and time being herein sometimes referred
to as the "Additional Closing Date"); provided, however, that the Additional
Closing Date shall not be earlier than the Closing Date or earlier than the
second full business day after the date on which the option shall have been
exercised nor later than the eighth full business day after the date on which
the option shall have been exercised (unless such time and date are postponed in
accordance with the provisions of Section 11 hereof). Certificates for the
Additional Shares shall be registered in such name or names and in such
authorized denominations as you may request in writing at least two full
business days prior to the Additional Closing Date. The Option Stockholders
shall permit you to examine and package such certificates for delivery at least
one full business day prior to the Additional Closing Date.

                  The number of Additional Shares to be sold to each Underwriter
shall be the number which bears the same ratio to the aggregate number of
Additional Shares being purchased as the number of Firm Shares set forth
opposite the name of such Underwriter in Schedule I hereto (or such number
increased as set forth in Section 11 hereof) bears to 3,000,000 subject,
however, to such adjustments to eliminate any fractional shares as you in your
sole discretion shall make. The number of Additional Shares to be sold by each
Option Stockholder shall be the number which bears the same ratio to the
aggregate number of Additional Shares being purchased as the number of Firm
Shares set forth opposite the name of such Option Stockholder bears to the total
number of Firm Shares being purchased by all Option Stockholders subject,
however, to such adjustments to eliminate any fractional shares as the Custodian
in its sole discretion shall make.

                  Payment for the Additional Shares shall be made by certified
or official bank check or checks, in New York Clearing House or similar next day
funds, each payable to the order of the Option Stockholders at the offices of
Bear, Stearns & Co. Inc.,
<PAGE>   12
                                                                              12

245 Park Avenue, New York, New York 10167, or such other location as may be
mutually acceptable, upon delivery of the certificates for the Additional Shares
to you for the respective accounts of the Underwriters.

                  4. Offering. Upon your authorization of the release of the
Firm Shares, the Underwriters propose to offer the Shares for sale to the public
upon the terms set forth in the Prospectus.

                  5. Covenants of the Company. The Company covenants and agrees
with the Underwriters that:

                  (a) If the Registration Statement has not yet been declared
         effective, the Company will use its best efforts to cause the
         Registration Statement and any amendments thereto to become effective
         as promptly as possible, and if Rule 430A is used or the filing of the
         Prospectus is otherwise required under Rule 424(b) or Rule 434, the
         Company will file the Prospectus (properly completed if Rule 430A has
         been used) pursuant to Rule 424(b) or Rule 434 within the prescribed
         time period and will provide evidence satisfactory to you of such
         timely filing. If the Company elects to rely on Rule 434, the Company
         will prepare and file a term sheet that complies with the requirements
         of Rule 434.

                  The Company will notify you immediately (and, if requested by
         you, will confirm such notice in writing) (i) when the Registration
         Statement and any amendments thereto become effective, (ii) of any
         request by the Commission for any amendment of or supplement to the
         Registration Statement or the Prospectus or for any additional
         information, (iii) of the mailing or the delivery to the Commission for
         filing of any amendment of or supplement to the Registration Statement
         or the Prospectus, (iv) of the issuance by the Commission of any stop
         order suspending the effectiveness of the Registration Statement or any
         post-effective amendment thereto or of the initiation, or the
         threatening, of any proceedings therefor, (v) of the receipt of any
         comments from the Commission, and (vi) of the receipt by the Company of
         any notification with respect to the suspension of the qualification of
         the Shares for sale in any jurisdiction or the initiation or
         threatening of any proceeding for that purpose. If the Commission shall
         propose or enter a stop order at any time, the Company shall make every
         reasonable effort to prevent the issuance of any such stop order and,
         if issued, to obtain the lifting of such order as soon as possible. The
         Company will not file any amendment to the Registration Statement or
         any amendment of or supplement to the Prospectus (including the
         prospectus required to be filed pursuant to Rule 424(b) or Rule 434)
         that differs from the prospectus on file at the time of the
         effectiveness of the Registration Statement before or after the
         effective
<PAGE>   13
                                                                              13

         date of the Registration Statement to which you shall reasonably object
         in writing after being timely furnished in advance a copy thereof.

                  (b) If at any time when a prospectus relating to the Shares is
         required to be delivered under the Act any event shall have occurred as
         a result of which the Prospectus as then amended or supplemented would,
         in the judgment of the Underwriters or the Company include an untrue
         statement of a material fact or omit to state any material fact
         required to be stated therein or necessary to make the statements
         therein, in the light of the circumstances under which they were made,
         not misleading, or if it shall be necessary at any time to amend or
         supplement the Prospectus or Registration Statement to comply with the
         Act or the Regulations, the Company will notify you promptly and
         prepare and file with the Commission an appropriate amendment or
         supplement (in form and substance satisfactory to you) which will
         correct such statement or omission and will use its best efforts to
         have any amendment to the Registration Statement declared effective as
         soon as possible.

                  (c) The Company will promptly deliver to you signed copies of
         the Registration Statement, including exhibits and all amendments
         thereto, and the Company will promptly deliver to each of the
         Underwriters such number of copies of any preliminary prospectus, the
         Prospectus, the Registration Statement, and all amendments of and
         supplements to such documents, if any, as you may reasonably request.

                  (d) The Company will endeavor in good faith, in cooperation
         with you, at or prior to the time of effectiveness of the Registration
         Statement, to qualify the Shares for offering and sale under the
         securities laws relating to the offering or sale of the Shares of such
         jurisdictions as you may designate and to maintain such qualification
         in effect for so long as required for the distribution thereof; except
         that in no event shall the Company be obligated in connection therewith
         to qualify as a foreign corporation or to execute a general consent to
         service of process.

                  (e) The Company will make generally available (within the
         meaning of Section 11(a) of the Act) to its security holders and to you
         as soon as practicable, but not later than 45 days after the end of its
         fiscal quarter in which the first anniversary date of the effective
         date of the Registration Statement occurs, an earning statement (in
         form complying with the provisions of Rule 158 of the Regulations)
         covering a period of at least twelve consecutive months beginning after
         the effective date of the Registration Statement.
<PAGE>   14
                                                                              14

                  (f) During the period of 180 days from the date of the
         Prospectus, the Company will not, without the prior written consent of
         Bear, Stearns & Co. Inc., issue, sell, offer or agree to sell, grant
         any option for the sale of, or otherwise dispose of, directly or
         indirectly, any Common Stock (or any securities convertible into,
         exercisable for or exchangeable for Common Stock), and the Company will
         obtain the undertaking of each of its officers and directors not to
         engage in any of the aforementioned transactions on their own behalf,
         other than the sale of Shares hereunder and the Company's issuance of
         Common Stock and options to purchase Common Stock under the Company's
         1996 Employee Stock Purchase Plan and 1996 Stock Option Plan as
         described in the Prospectus.

                  (g) During a period of three years from the effective date of
         the Registration Statement, the Company will furnish to you copies of
         (i) all reports to its shareholders, and (ii) all reports, financial
         statements and proxy or information statements filed by the Company
         with the Commission or the National Association of Securities Dealers,
         Inc.

                  (h) The Company will apply the proceeds from the sale of the
         Shares as set forth under the caption "Use of Proceeds" in the
         Prospectus.

                  (i) The Company will use its best efforts to cause the Shares
         to be authorized for inclusion in the National Association of
         Securities Dealers Automated Quotation (National Market) System.

                  (j) The Company will file with the Commission such reports on
         Form SR as may be required pursuant to Rule 463 of the Regulations.

                  (k) During the period of 180 days from the date of the
         Prospectus, the Company will strictly enforce each Lock-Up Agreement.

                  6.   Covenants of the Selling Stockholders.  Each Selling 
Stockholder covenants and agrees that:

                  (a) For a period of 180 days from the date of the Prospectus,
         it will not, directly or indirectly, sell, offer or agree to sell,
         grant any option for the sale of, or otherwise dispose of, directly or
         indirectly, any Common Stock (or any securities convertible into,
         exercisable for or exchangeable for Common Stock), without the prior
         written consent of Bear, Stearns & Co. Inc.

                  (b) The Shares to be sold by such Selling Stockholder
         hereunder, which are represented by the certificates held in custody
         for such Selling Stockholder, are subject to the
<PAGE>   15
                                                                              15

         interest of the Underwriters and the other Selling Stockholders
         thereunder, the arrangements made by such Selling Stockholder for such
         custody are to that extent irrevocable, and the obligations of such
         Selling Stockholder hereunder will not be terminated by any act of such
         Selling Stockholder, by operation of law, by the death or incapacity of
         any individual Selling Stockholder or, in the case of a trust, by the
         death or incapacity of any executor or trustee or the termination of
         such trust, or the occurrence of any other event.

                  (c) If at any time when a prospectus relating to the Shares is
         required to be delivered under the Act any information which such
         Selling Stockholder has provided to the Company or the Underwriters
         becomes incorrect, or if it shall be necessary at any time to amend or
         supplement any information provided by such Selling Stockholder to the
         Company for inclusion in the Prospectus or Registration Statement to
         comply with the Act or the Regulations, such Selling Stockholder will
         notify the Company and the Underwriters promptly so that the Company
         may prepare and file with the Commission an appropriate amendment or
         supplement (in form and substance satisfactory to the Underwriters)
         which will correct such statement or omission.

                  (d) Such Selling Stockholder will deliver to the
         Representatives prior to the Closing Date a properly completed and
         executed United States Treasury Department Form W-8 (if such Selling
         Stockholder is a non-United States person) or Form W-9 (if such Selling
         Stockholder is a United States person.)

                  7. Payment of Expenses. Whether or not the transactions
contemplated in this Agreement are consummated or this Agreement is terminated,
the Company hereby agrees to pay all costs and expenses incident to the
performance of the obligations of the Company and the Selling Stockholders
hereunder, including those in connection with (i) preparing, printing,
duplicating, filing and distributing the Registration Statement, as originally
filed and all amendments thereto (including all exhibits thereto), any
preliminary prospectus, the Prospectus and any amendments or supplements thereto
(including, without limitation, fees and expenses of the Company's accountants
and counsel), the underwriting documents (including, without limitation, this
Agreement, the Agreement Among Underwriters and the Selling Agreement) and all
other documents related to the public offering of the Shares (including those
supplied to the Underwriters in quantities as hereinabove stated), (ii) the
issuance, transfer and delivery of the Shares to the Underwriters, including any
transfer or other taxes payable thereon, (iii) the costs of delivering and
distributing the Custody Agreements and the Powers of Attorney, (iv) the
qualification of the Shares under state securities or Blue Sky laws, including
the costs of printing and mailing a preliminary
<PAGE>   16
                                                                              16

and final "Blue Sky Survey" and the fees of counsel for the Underwriters and
such counsel's disbursements in relation thereto, (v) quotation of the Shares on
the National Association of Securities Dealers Automated Quotation (National
Market) System, (vi) filing fees of the Commission and the National Association
of Securities Dealers, Inc., (vii) the cost of printing certificates
representing the Shares and (viii) the cost and charges of any transfer agent or
registrar; provided that the Selling Stockholders shall pay the fees and
expenses of their counsel, the Custodian (and any other attorney-in-fact) and
any transfer taxes payable in connection with their respective sales of Shares
to the Underwriters and reimburse the Company for their pro rata share of the
fees and expenses paid by the Company in connection with the offering of the
Shares.

                  8. Conditions of Underwriters' Obligations. The obligations of
the Underwriters to purchase and pay for the Firm Shares and the Additional
Shares, as provided herein, shall be subject to the accuracy of the
representations and warranties of the Company and the Selling Stockholders
herein contained, as of the date hereof and as of the Closing Date (for purposes
of this Section 8, "Closing Date" shall refer to the Closing Date for the Firm
Shares and any Additional Closing Date, if different, for the Additional
Shares), to the absence from any certificates, opinions, written statements or
letters furnished to you or to Simpson Thacher & Bartlett ("Underwriters'
Counsel") pursuant to this Section 8 of any misstatement or omission, to the
performance by the Company and the Selling Stockholders of their respective
obligations hereunder, and to the following additional conditions:

                  (a) The Registration Statement shall have become effective not
         later than 5:30 P.M., New York time, on the date of this Agreement, or
         at such later time and date as shall have been consented to in writing
         by you; if the Company shall have elected to rely upon Rule 430A or
         Rule 434 of the Regulations, the Prospectus shall have been filed with
         the Commission in a timely fashion in accordance with Section 5(a)
         hereof; and, at or prior to the Closing Date no stop order suspending
         the effectiveness of the Registration Statement or any post-effective
         amendment thereof shall have been issued and no proceedings therefor
         shall have been initiated or threatened by the Commission.

                  (b) At the Closing Date you shall have received the opinion of
         Wilson Sonsini Goodrich & Rosati, Professional Corporation, counsel for
         the Company, dated the Closing Date addressed to the Underwriters and
         in form and substance satisfactory to Underwriters' Counsel, to the
         effect that:

                                  (i) Each of the Company and its U.S.
                  subsidiaries has been duly organized and is validly existing
                  as a corporation in good standing under the laws of its
                  jurisdiction of incorporation. Each of the
<PAGE>   17
                                                                              17

                  Company and its subsidiaries is duly qualified and in good
                  standing as a foreign corporation in each U.S. jurisdiction in
                  which the character or location of its properties (owned,
                  leased or licensed) or the nature or conduct of its business
                  makes such qualification necessary, except for those failures
                  to be so qualified or in good standing which will not in the
                  aggregate have a material adverse effect on the Company and
                  its subsidiaries taken as a whole. Each of the Company and its
                  U.S. subsidiaries has all requisite corporate authority to
                  own, lease and operate its respective properties and conduct
                  its business as now being conducted and as described in the
                  Registration Statement and the Prospectus. All of the issued
                  and outstanding capital stock of each subsidiary of the
                  Company has been duly and validly issued and is fully paid and
                  nonassessable and was not issued in violation of preemptive
                  rights and, is owned directly or indirectly by the Company,
                  free and clear of any lien, encumbrance, claim, security
                  interest, restriction on transfer, shareholders' agreement,
                  voting trust or other defect of title whatsoever.

                                 (ii) The Company has an authorized capital
                  stock as set forth in the Registration Statement and the
                  Prospectus. All of the outstanding shares of Common Stock are
                  duly and validly authorized and issued, are fully paid and
                  nonassessable and were not issued in violation of or subject
                  to any preemptive rights. The Shares to be delivered by the
                  Company on the Closing Date have been duly and validly
                  authorized and, when delivered by the Company in accordance
                  with this Agreement, will be duly and validly issued, fully
                  paid and nonassessable and will not have been issued in
                  violation of or subject to any preemptive rights. The Common
                  Stock, the Firm Shares and the Additional Shares conform to
                  the descriptions thereof contained in the Registration
                  Statement and the Prospectus.

                                  (iii) The Shares to be sold under this
                  Agreement to the Underwriters are duly authorized for
                  quotation on the National Association of Securities Dealers
                  Automated Quotation (National Market) System.

                                  (iv) This Agreement has been duly and validly
                  authorized, executed and delivered by the Company.

                                  (v) There is no litigation or governmental or
                  other action, suit, proceeding or investigation before any
                  court or before or by any public, regulatory or governmental
                  agency or body pending or to such counsel's knowledge,
                  threatened against, or involving the properties or business
                  of, the Company or any of its subsidiaries, which is of a
                  character required to
<PAGE>   18
                                                                              18

                  be disclosed in the Registration Statement and the
                  Prospectus which has not been properly disclosed
                  therein.

                                 (vi) The execution, delivery, and performance
                  of this Agreement and the consummation of the transactions
                  contemplated hereby by the Company do not and will not (A)
                  conflict with or result in a breach of any of the terms and
                  provisions of, or constitute a default (or an event which with
                  notice or lapse of time, or both, would constitute a default)
                  under, or result in the creation or imposition of any lien,
                  charge or encumbrance upon any property or assets of the
                  Company or any of its U.S. subsidiaries pursuant to, any
                  agreement, instrument, franchise, license or permit known to
                  such counsel to which the Company or any of its U.S.
                  subsidiaries is a party or by which any of such corporations
                  or their respective properties or assets may be bound or (B)
                  violate or conflict with any provision of the certificate of
                  incorporation or by-laws of the Company or any of its U.S.
                  subsidiaries, or, to the best knowledge of such counsel, any
                  judgment, decree, order, statute, rule or regulation of any
                  court or any public, governmental or regulatory agency or body
                  having jurisdiction over the Company or any of its U.S.
                  subsidiaries or any of their respective properties or assets.
                  No consent, approval, authorization, order, registration,
                  filing, qualification, license or permit of or with any court
                  or any public, governmental, or regulatory agency or body
                  having jurisdiction over the Company or any of its
                  subsidiaries or any of their respective properties or assets
                  is required for the execution, delivery and performance of
                  this Agreement or the consummation of the transactions
                  contemplated hereby, except for (1) such as may be required
                  under state securities or Blue Sky laws in connection with the
                  purchase and distribution of the Shares by the Underwriters
                  (as to which such counsel need express no opinion) and (2)
                  such as have been made or obtained under the Act.

                                (vii) The Registration Statement and the
                  Prospectus and any amendments thereof or supplements thereto
                  (other than the financial statements and schedules and other
                  financial data included therein, as to which no opinion need
                  be rendered) comply as to form in all material respects with
                  the requirements of the Act and the Regulations.

                               (viii) The Registration Statement is effective
                  under the Act, and, to the best knowledge of such counsel, no
                  stop order suspending the effectiveness of the Registration
                  Statement or any post-effective amendment thereof has been
                  issued and no proceedings
<PAGE>   19
                                                                              19

                  therefor have been initiated or threatened by the Commission
                  and all filings required by Rule 424(b) of the Regulations
                  have been made.

                                 (ix) The statements contained in the Prospectus
                  under the caption "Risk Factors - FDA and Other Government
                  Regulation" and "Business - Government Regulation" and other
                  references therein to food and drug regulatory matters are
                  complete and accurate in all material respects.

                                  (x) Except as disclosed in Schedule III
                  hereto, each stockholder of the Company has entered into or is
                  subject to a Lock-Up Agreement under which such stockholder
                  has agreed not to offer, sell, agree to sell, grant any option
                  for the sale of or otherwise dispose of, or agree to dispose
                  of, directly or indirectly, any shares of Common Stock,
                  options or warrants to acquire shares of Common Stock (or
                  securities exchangeable for exercisable for or convertible
                  into Common Stock) owned by them for a period of 180 days
                  after the date of the Prospectus, without the prior written
                  consent of Bear, Stearns & Co. Inc.; each Lock-Up Agreement
                  constitutes the legal, valid and binding obligations of the
                  stockholder or stockholders party thereto enforceable against
                  each such stockholder in accordance with its terms.

                                 (xi) In addition, such opinion shall also
                  contain a statement that such counsel has participated in
                  conferences with officers and representatives of the Company,
                  representatives of the independent public accountants for the
                  Company and the Underwriters at which the contents of the
                  Prospectus and related matters were discussed and, no facts
                  have come to the attention of such counsel which would cause
                  such counsel to believe that either the Registration Statement
                  at the time it became effective (including the information
                  deemed to be part of the Registration Statement at the time of
                  effectiveness pursuant to Rule 430A(b) or Rule 434, if
                  applicable), or any amendment thereof made prior to the
                  Closing Date as of the date of such amendment, contained an
                  untrue statement of a material fact or omitted to state any
                  material fact required to be stated therein or necessary to
                  make the statements therein not misleading or that the
                  Prospectus as of its date (or any amendment thereof or
                  supplement thereto made prior to the Closing Date as of the
                  date of such amendment or supplement) and as of the Closing
                  Date contained or contains an untrue statement of a material
                  fact or omitted or omits to state any material fact required
                  to be stated therein or necessary to make the statements
                  therein, in light of the circumstances under which they were
                  made, not
<PAGE>   20
                                                                              20

                  misleading (it being understood that such counsel need express
                  no belief or opinion with respect to the financial statements
                  and schedules and other financial data included or
                  incorporated by reference therein).

                  In rendering such opinion, such counsel may rely (A) as to
         matters involving the application of laws other than the laws of the
         United States and jurisdictions in which they are admitted, to the
         extent such counsel deems proper and to the extent specified in such
         opinion, if at all, upon an opinion or opinions (in form and substance
         reasonably satisfactory to Underwriters' Counsel) of other counsel
         reasonably acceptable to Underwriters' Counsel, familiar with the
         applicable laws; (B) as to matters of fact, to the extent they deem
         proper, on certificates of responsible officers of the Company and
         certificates or other written statements of officers of departments of
         various jurisdictions having custody of documents respecting the
         corporate existence or good standing of the Company and its
         subsidiaries, provided that copies of any such statements or
         certificates shall be delivered to Underwriters' Counsel. The opinion
         of such counsel for the Company shall state that the opinion of any
         such other counsel is in form satisfactory to such counsel and, in
         their opinion, you and they are justified in relying thereon.

                  (c) At the Closing Date, you shall have received the opinion
         of _______, French counsel for the Company, dated the Closing Date
         addressed to the Underwriters and in form and substance satisfactory to
         Underwriters' Counsel to the effect that:

                               (i) Ventana Medical Systems, S.A. is a
                  corporation duly organized and validly existing and in good
                  standing under the laws of France, and has all requisite
                  corporate authority to own, lease and operate its properties
                  and conduct its business as now being conducted and as
                  described in the Registration Statement and the Prospectus.

                              (ii) There is no litigation or governmental or
                  other action, suit, proceeding or investigation before any
                  court or before or by any public, regulatory or governmental
                  body pending or to such counsel's knowledge, threatened
                  against, or involving the properties or business of, Ventana
                  Medical Systems, S.A.

                             (iii) The execution, delivery and performance of
                  this Agreement and the consummation of the transactions
                  contemplated hereby by the Company do not and will not
                  conflict with or result in a breach of any of the terms and
                  provisions of, or constitute a default (or an event which with
                  notice or lapse of time, or both, would
<PAGE>   21
                                                                              21

                  constitute a default) under, or result in the creation or
                  imposition of any lien, charge or encumbrance upon any
                  property or assets of Ventana Medical Systems, S.A. pursuant
                  to any agreement, instrument, franchise, license or permit
                  known to such counsel to which Ventana Medical Systems, S.A.
                  is a party or by which Ventana Medical Systems, S.A. or its
                  properties or assets may be bound or violate or conflict with
                  any provision of the certificate of incorporation or by-laws
                  of Ventana Medical Systems, S.A., or, to such counsel's
                  knowledge, any judgment, decree, order, statute, rule or
                  regulation of any court or any public, governmental or
                  regulatory agency or body having jurisdiction over Ventana
                  Medical Systems, S.A. or any of its properties or assets.

                              (iv) No consent, approval, authorization, order,
                  registration, filing, qualification, license or permit of or
                  with any court or any public, governmental, or regulatory
                  agency or body having jurisdiction over such corporation or
                  any of its properties or assets is required for the execution,
                  delivery and performance of this Agreement or the consummation
                  of the transactions contemplated hereby.

                               (v) All of the issued and outstanding capital
                  stock of Ventana Medical Systems, S.A. has been duly and
                  validly issued and is fully paid and nonassessable and was not
                  issued in violation of preemptive rights and is owned directly
                  by the Company, free and clear of any lien, encumbrance,
                  claim, security interest, restriction on transfer,
                  shareholders' agreement, voting trust or other defect of title
                  whatsoever.

                  (d) At the Closing Date, you shall have received the opinion
         of __________, German counsel for the Company, dated the Closing Date
         addressed to the Underwriters and in form and substance satisfactory to
         Underwriters' Counsel to the effect that:

                               (i) Ventana Medical Systems GmbH is a corporation
                  duly organized and validly existing and in good standing under
                  the laws of Germany, and has all requisite corporate authority
                  to own, lease and operate its properties and conduct its
                  business as now being conducted and as described in the
                  Registration Statement and the Prospectus.

                              (ii) There is no litigation or governmental or
                  other action, suit, proceeding or investigation before any
                  court or before or by any public, regulatory or governmental
                  body pending or to such counsel's knowledge, threatened
                  against, or involving the
<PAGE>   22
                                                                              22

                  properties or business of, Ventana Medical Systems
                  GmbH.

                             (iii) The execution, delivery and performance of
                  this Agreement and the consummation of the transactions
                  contemplated hereby by the Company do not and will not
                  conflict with or result in a breach of any of the terms and
                  provisions of, or constitute a default (or an event which with
                  notice or lapse of time, or both, would constitute a default)
                  under, or result in the creation or imposition of any lien,
                  charge or encumbrance upon any property or assets of Ventana
                  Medical Systems GmbH pursuant to any agreement, instrument,
                  franchise, license or permit known to such counsel to which
                  Ventana Medical Systems GmbH is a party or by which Ventana
                  Medical Systems GmbH or its properties or assets may be bound
                  or violate or conflict with any provision of the certificate
                  of incorporation or by-laws of Ventana Medical Systems GmbH,
                  or, to such counsel's knowledge, any judgment, decree, order,
                  statute, rule or regulation of any court or any public,
                  governmental or regulatory agency or body having jurisdiction
                  over Ventana Medical Systems GmbH or any of its properties or
                  assets.

                              (iv) No consent, approval, authorization, order,
                  registration, filing, qualification, license or permit of or
                  with any court or any public, governmental, or regulatory
                  agency or body having jurisdiction over such corporation or
                  any of its properties or assets is required for the execution,
                  delivery and performance of this Agreement or the consummation
                  of the transactions contemplated hereby.

                               (v) All of the issued and outstanding capital
                  stock of Ventana Medical Systems GmbH has been duly and
                  validly issued and is fully paid and non-assessable and was
                  not issued in violation of any preemptive rights and is owned
                  directly by the Company, free and clear of any lien,
                  encumbrance, claim, security interest, restriction on
                  transfer, shareholders' agreement, voting trust or other
                  defect of title whatsoever.

                  (e) At the Closing Date, you shall have received an opinion of
         Skjerven, Morrill, MacPherson, Franklin & Friel, patent counsel to the
         Company, dated the Closing Date addressed to the Underwriters and in
         form and substance satisfactory to Underwriters' Counsel to the effect
         that the statements in the Registration Statement and the Prospectus
         under the captions "Risk Factors -- Patents and Proprietary Rights",
         "Business -- Patents and Proprietary Rights" and "Business -- Legal
         Proceedings" and other references therein to patent matters have been
         reviewed by such counsel and are complete and accurate in all material
         respects.
<PAGE>   23
                                                                              23

                  (f) Kirkland & Ellis, counsel for the entities affiliated with
         Marquette Venture Partners, (each a "Marquette Entity" and collectively
         the "Marquette Entities"), shall have furnished to the Underwriters
         their written opinion, as counsel to the Marquette Entities, addressed
         to the Underwriters and dated the Closing Date, in form and substance
         satisfactory to the Underwriters, to the effect that:

                               (i) Each Marquette Entity has full right, power
                  and authority to enter into this Agreement, the Power of
                  Attorney and the Custody Agreement; the execution, delivery
                  and performance of this Agreement, the Power of Attorney and
                  the Custody Agreement by each Marquette Entity and the
                  consummation by each Marquette Entity of the transactions
                  contemplated hereby and thereby will not conflict with or
                  result in a breach or violation of any of the terms or
                  provisions of, or constitute a default under, any statute,
                  indenture, mortgage, deed of trust, loan agreement or other
                  agreement or instrument known to such counsel to which each
                  Marquette Entity is a party or by which each Marquette Entity
                  is bound or to which any of the property or assets of each
                  Marquette Entity is subject, nor will such actions result in
                  any violation of the provisions of the constituent documents
                  of each Marquette Entity, if any, or any statute or any order,
                  rule or regulation known to such counsel of any court or
                  governmental agency or body having jurisdiction over each
                  Marquette Entity or the property or assets of each Marquette
                  Entity; and, except for the registration of the Shares under
                  the Act and such consents, approvals, authorizations,
                  registrations or qualifications as may be required under
                  applicable state securities laws in connection with the
                  purchase and distribution of the Shares by the Underwriters,
                  no consent, approval, authorization or order of, or filing or
                  registration with, any such court or governmental agency or
                  body is required for the execution, delivery and performance
                  of this Agreement, the Power of Attorney or the Custody
                  Agreement by each Marquette Entity and the consummation by
                  each Marquette Entity of the transactions contemplated hereby
                  and thereby;

                             (ii) This Agreement has been duly authorized,
                  executed and delivered by or on behalf of each Marquette
                  Entity;

                             (iii) A Power-of-Attorney and a Custody Agreement
                  have been duly authorized, executed and delivered by each
                  Marquette Entity and constitute valid and binding agreements
                  of each Marquette Entity; and
<PAGE>   24
                                                                              24

                              (iv) Upon payment for, and delivery of, the Shares
                  to be sold by each Marquette Entity under this Agreement in
                  accordance with the terms hereof, the Underwriters will
                  acquire all of the rights of each Marquette Entity in such
                  Shares and will also acquire the interest of each Marquette
                  Entity in such Shares free of any adverse claim (within the
                  meaning of the Uniform Commercial Code).

                           In rendering such opinions, such counsel may rely as
         to matters of fact, to the extent they deem proper, on certificates of
         each Marquette Entity, provided that such counsel shall provide copies
         of any such certificates to Underwriters' Counsel and shall state that
         you and they are justified in relying thereon.

                  (g) Wilson Sonsini Goodrich and Rosati, Professional
         Corporation, counsel for the Selling Stockholders other than the
         Marquette Entities, shall have furnished to the Underwriters their
         written opinion, as counsel to each such Selling Stockholder, addressed
         to the Underwriters and dated the Closing Date, in form and substance
         satisfactory to the Underwriters, to the effect that:

                           (i) Each such Selling Stockholder has full right,
                  power and authority to enter into this Agreement, the Power of
                  Attorney and the Custody Agreement; the execution, delivery
                  and performance of this Agreement, the Power of Attorney and
                  the Custody Agreement by each such Selling Stockholder and the
                  consummation by each such Selling Stockholder of the
                  transactions contemplated hereby and thereby will not conflict
                  with or result in a breach or violation of any of the terms or
                  provisions of, or constitute a default under, any statute,
                  indenture, mortgage, deed of trust, loan agreement or other
                  agreement or instrument known to such counsel to which such
                  Selling Stockholder is a party or by which such Selling
                  Stockholder is bound or to which any of the property or assets
                  of such Selling Stockholder is subject, nor will such actions
                  result in any violation of the provisions of the constituent
                  documents of each such Selling Stockholder, if any, or any
                  statute or any order, rule or regulation known to such counsel
                  of any court or governmental agency or body having
                  jurisdiction over such Selling Stockholder or the property or
                  assets of such Selling Stockholder; and, except for the
                  registration of the Shares under the Act and such consents,
                  approvals, authorizations, registrations or qualifications as
                  may be required under applicable state securities laws in
                  connection with the purchase and distribution of the Shares by
                  the Underwriters, no consent, approval, authorization or order
                  of, or filing or registration with, any such court or
                  governmental agency or body is required for
<PAGE>   25
                                                                              25

                  the execution, delivery and performance of this Agreement, the
                  Power of Attorney or the Custody Agreement by each such
                  Selling Stockholder and the consummation by each such Selling
                  Stockholder of the transactions contemplated hereby and
                  thereby;

                           (ii)  This Agreement has been duly executed and
                  delivered by or on behalf of each such Selling Stockholder;

                           (iii) A Power-of-Attorney and a Custody Agreement
                  have been duly executed and delivered by each such Selling
                  Stockholder and constitute valid and binding agreements of
                  each such Selling Stockholder; and

                           (iv) Upon payment for, and delivery of, the Shares to
                  be sold by each such Selling Stockholder under this Agreement
                  in accordance with the terms hereof, the Underwriters will
                  acquire all of the rights of such Selling Stockholder in such
                  Shares and will also acquire the interest of such Selling
                  Stockholder in such Shares free of any adverse claim (within
                  the meaning of the Uniform Commercial Code).

                           In rendering such opinion, such counsel may rely as
         to matters of fact, to the extent they deem proper, on certificates of
         the Selling Stockholders, provided that such counsel shall provide
         copies of any such certificates to Underwriters' Counsel and shall
         state that you and they are justified in relying thereon.

                  (h) All proceedings taken in connection with the sale of the
         Firm Shares and the Additional Shares as herein contemplated shall be
         satisfactory in form and substance to you and to Underwriters' Counsel,
         and the Underwriters shall have received from said Underwriters'
         Counsel a favorable opinion, dated as of the Closing Date with respect
         to the issuance and sale of the Shares, the Registration Statement and
         the Prospectus and such other related matters as you may reasonably
         require, and the Company and the Selling Stockholders shall have
         furnished to Underwriters' Counsel such documents as they request for
         the purpose of enabling them to pass upon such matters.

                  (i) At the Closing Date, you shall have received a certificate
         of the Chief Executive Officer and Chief Financial Officer of the
         Company, dated the Closing Date to the effect that (i) the condition
         set forth in subsection (a) of this Section 8 has been satisfied, (ii)
         as of the date hereof and as of the Closing Date the representations
         and warranties of the Company set forth in Section 1 hereof are
         accurate, (iii) as of the Closing Date the obligations of the Company
         to be performed hereunder on or prior thereto have been duly performed
         and (iv) subsequent to the
<PAGE>   26
                                                                              26

         respective dates as of which information is given in the Registration
         Statement and the Prospectus, the Company and its subsidiaries have not
         sustained any material loss or interference with their respective
         businesses or properties from fire, flood, hurricane, accident or other
         calamity, whether or not covered by insurance, or from any labor
         dispute or any legal or governmental proceeding, and there has not been
         any material adverse change, or any development involving a prospective
         material adverse change, in the business, prospects, properties,
         operations, condition (financial or otherwise), or results of
         operations of the Company and its subsidiaries taken as a whole, except
         in each case as described in or contemplated by the Prospectus.

                  (j) At the Closing Date, you shall have received a Certificate
         of each Selling Stockholder (or the Custodian or one or more
         attorneys-in-fact on behalf of the Selling Stockholders), dated the
         Closing Date, signed by, or on behalf of, the Selling Stockholder (or
         the Custodian or one or more attorneys-in-fact) stating that (i) as of
         the date hereof and as of the Closing Date, the representations and
         warranties of the Selling Stockholders set forth in Section 2 hereof
         are accurate and (ii) each Selling Stockholder has complied with all
         agreements contained herein to be performed by each Selling Stockholder
         at or prior to the Closing Date.

                  (k) At the time this Agreement is executed and at the Closing
         Date, you shall have received a letter, from Ernst & Young LLP,
         independent public accountants for the Company, dated, respectively, as
         of the date of this Agreement and as of the Closing Date addressed to
         the Underwriters and in form and substance satisfactory to you, to the
         effect that: (i) they are independent certified public accountants with
         respect to the Company within the meaning of the Act and the
         Regulations and stating that the answer to Item 10 of the Registration
         Statement is correct insofar as it relates to them; (ii) stating that,
         in their opinion, the financial statements and schedules of the Company
         included in the Registration Statement and the Prospectus and covered
         by their opinion therein comply as to form in all material respects
         with the applicable accounting requirements of the Act and the
         applicable published rules and regulations of the Commission
         thereunder; (iii) on the basis of procedures consisting of a reading of
         the latest available unaudited interim consolidated financial
         statements of the Company, and its subsidiaries, a reading of the
         minutes of meetings and consents of the stockholders and boards of
         directors of the Company and its subsidiaries and the committees of
         such boards subsequent to December 31, 1995, inquiries of officers and
         other employees of the Company and its subsidiaries who have
         responsibility for financial and accounting matters of the Company and
         its subsidiaries with respect to transactions and events subsequent to
<PAGE>   27
                                                                              27

         December 31, 1995 and other specified procedures and inquiries to a
         date not more than five days prior to the date of such letter, nothing
         has come to their attention that would cause them to believe that: (A)
         the Unaudited Consolidated Financial Statements and the Unaudited Pro
         Forma Condensed Consolidated Financial Statements and related schedules
         of the Company presented in the Registration Statement and the
         Prospectus do not comply as to form in all material respects with the
         applicable accounting requirements of the Act and, if applicable, the
         Exchange Act and the applicable published rules and regulations of the
         Commission thereunder or that such financial statements are not fairly
         presented in conformity with generally accepted accounting principles
         applied on a basis substantially consistent with that of the audited
         consolidated financial statements included in the Registration
         Statement and the Prospectus; (B) the pro forma adjustments in the
         Unaudited Pro Forma Condensed Consolidated Financial Statements have
         not been properly applied to the historical amounts in the compilation
         of those statements; (C) with respect to the period subsequent to
         December 31, 1995 there were, as of the date of the most recent
         available monthly consolidated financial statements of the Company and
         its subsidiaries, if any, and as of a specified date not more than five
         days prior to the date of such letter, any changes in the capital stock
         or long-term indebtedness of the Company or any decrease in the net
         current assets or stockholders' equity of the Company, in each case as
         compared with the amounts shown in the most recent audited balance
         sheet presented in the Registration Statement and the Prospectus,
         except for changes or decreases which the Registration Statement and
         the Prospectus disclose have occurred or may occur or which are set
         forth in such letter or (D) that during the period from December 31,
         1995 to the date of the most recent available monthly consolidated
         financial statements of the Company and its subsidiaries, if any, and
         to a specified date not more than five days prior to the date of such
         letter, there was any decrease, as compared with the corresponding
         period in the prior fiscal year, in total revenues, or increase in
         total or per share net loss, except for changes which the Registration
         Statement and the Prospectus disclose have occurred or may occur or
         which are set forth in such letter; and (iv) stating that they have
         compared specific dollar amounts, numbers of shares, percentages of
         revenues and gross margins, and other financial information pertaining
         to the Company and its subsidiaries set forth in the Registration
         Statement and the Prospectus, which have been specified by you prior to
         the date of this Agreement, to the extent that such amounts, numbers,
         percentages, and information may be derived from the general accounting
         and financial records of the Company and its subsidiaries or from
         schedules furnished by the Company, and excluding any questions
         requiring an interpretation by legal counsel, with
<PAGE>   28
                                                                              28

         the results obtained from the application of specified readings,
         inquiries, and other appropriate procedures specified by you set forth
         in such letter, and found them to be in agreement.

                  (l) At the time this Agreement is executed and at the Closing
         Date, you shall have received a letter, from Arthur Andersen LLP,
         independent public accountants, dated, respectively, as of the date of
         this Agreement and as of the Closing Date addressed to the Underwriters
         and in form and substance satisfactory to you, to the effect that: (i)
         they are independent certified public accountants within the meaning of
         the Act and the Regulations and stating that the answer to Item 10 of
         the Registration Statement is correct insofar as it relates to them;
         and (ii) stating that, in their opinion, the financial statements and
         schedules of BioTek Solutions, Inc. included in the Registration
         Statement and the Prospectus and covered by their opinion therein
         comply as to form in all material respects with the applicable
         accounting requirements of the Act and the applicable published rules
         and regulations of the Commission thereunder.

                  (m) Prior to the Closing Date the Company and the Selling
         Stockholders shall have furnished to you such further information,
         certificates and documents as you may reasonably request.

                  (n) You shall have received from each person who is a director
         or officer of the Company and each stockholder (except those named in
         Schedule III hereto) an agreement to the effect that such person will
         not, directly or indirectly, without your prior written consent, offer,
         sell, offer or agree to sell, grant any option to purchase or otherwise
         dispose (or announce any offer, sale, grant of an option to purchase or
         other disposition) of any shares of Common Stock (or any securities
         convertible into, exercisable for or exchangeable or exercisable for
         shares of Common Stock) for a period of 180 days after the date of the
         Prospectus.

                  (o) At the Closing Date, the Shares shall have been approved
         for quotation on the National Association of Securities Dealers
         Automated Quotation (National Market) System.

                  If any of the conditions specified in this Section 8 shall not
have been fulfilled when and as required by this Agreement, or if any of the
certificates, opinions, written statements or letters furnished to you or to
Underwriters' Counsel pursuant to this Section 8 shall not be in all material
respects reasonably satisfactory in form and substance to you and to
Underwriters' Counsel, all obligations of the Underwriters hereunder may be
cancelled by you at, or at any time prior to,
<PAGE>   29
                                                                              29

the Closing Date and the obligations of the Underwriters to purchase the
Additional Shares may be cancelled by you at, or at any time prior to, the
Additional Closing Date. Notice of such cancellation shall be given to the
Company and the Selling Stockholders in writing, or by telephone, telex or
telegraph, confirmed in writing.

                  9.  Indemnification.

                  (a) The Company agrees to indemnify and hold harmless each
Underwriter and each person, if any, who controls any Underwriter within the
meaning of Section 15 of the Act or Section 20(a) of the Exchange Act, against
any and all losses, liabilities, claims, damages and expenses whatsoever as
incurred (including but not limited to attorneys' fees and any and all expenses
whatsoever incurred in investigating, preparing or defending against any
litigation, commenced or threatened, or any claim whatsoever, and any and all
amounts paid in settlement of any claim or litigation), joint or several, to
which they or any of them may become subject under the Act, the Exchange Act or
otherwise, insofar as such losses, liabilities, claims, damages or expenses (or
actions in respect thereof) arise out of or are based upon any untrue statement
or alleged untrue statement of a material fact contained in the registration
statement for the registration of the Shares, as originally filed or any
amendment thereof, or any related preliminary prospectus or the Prospectus, or
in any supplement thereto or amendment thereof, or arise out of or are based
upon the omission or alleged omission to state therein a material fact required
to be stated therein or necessary to make the statements therein not misleading;
provided, however, that the Company will not be liable in any such case to the
extent but only to the extent that any such loss, liability, claim, damage or
expense arises out of or is based upon any such untrue statement or alleged
untrue statement or omission or alleged omission made therein in reliance upon
and in conformity with written information furnished to the Company by or on
behalf of any Underwriter through you expressly for use therein. This indemnity
agreement will be in addition to any liability which the Company may otherwise
have, including under this Agreement.

                  (b) Each Selling Stockholder agrees to indemnify and hold
harmless each Underwriter and each person, if any, who controls any Underwriter
within the meaning of Section 15 of the Act or Section 20(a) of the Exchange
Act, against any and all losses, liabilities, claims, damages and expenses
whatsoever as incurred (including but not limited to attorneys' fees and any and
all expenses whatsoever incurred in investigating, preparing or defending
against any litigation, commenced or threatened, or any claim whatsoever, and
any and all amounts paid in settlement of any claim or litigation), joint or
several, to which they or any of them may become subject under the Act, the
Exchange Act or otherwise, insofar as such losses, liabilities, claims, damages
or expenses (or actions in respect thereof) arise out of or are
<PAGE>   30
                                                                              30

based upon any untrue statement or alleged untrue statement of a material fact
contained in the registration statement for the registration of the Shares, as
originally filed or any amendment thereof, or any related preliminary prospectus
or the Prospectus, or in any supplement thereto or amendment thereof, or arise
out of or are based upon the omission or alleged omission to state therein a
material fact required to be stated therein or necessary to make the statements
therein not misleading, but in each case only to the extent that the untrue
statement or alleged untrue statement or omission or alleged omission was made
in reliance upon and in conformity with written information furnished to the
Company by or on behalf of such Selling Stockholder specifically for inclusion
therein. Notwithstanding the provisions of this Section 9(b), the aggregate
liability of any Selling Stockholder under this Section 9(b) shall not exceed
the proceeds received by such Selling Stockholder from the sale of Shares under
this Agreement. This indemnity agreement will be in addition to any liability
which the Selling Stockholders may otherwise have, including under this
Agreement.

                  (c) Each Underwriter severally, and not jointly, agrees to
indemnify and hold harmless the Company, the Selling Stockholders, each of the
directors of the Company, each of the officers of the Company who shall have
signed the Registration Statement, each other person, if any, who controls the
Company or the Selling Stockholders within the meaning of Section 15 of the Act
or Section 20(a) of the Exchange Act, against any losses, liabilities, claims,
damages and expenses whatsoever as incurred (including but not limited to
attorneys' fees and any and all expenses whatsoever incurred in investigating,
preparing or defending against any litigation, commenced or threatened, or any
claim whatsoever, and any and all amounts paid in settlement of any claim or
litigation, jointly or severally, to which they or any of them may become
subject under the Act, the Exchange Act or otherwise, insofar as such losses,
liabilities, claims, damages or expenses (or actions in respect thereof) arise
out of or are based upon any untrue statement or alleged untrue statement of a
material fact contained in the registration statement for the registration of
the Shares, as originally filed or any amendment thereof, or any related
preliminary prospectus or the Prospectus, or in any amendment thereof or
supplement thereto, or arise out of or are based upon the omission or alleged
omission to state therein a material fact required to be stated therein or
necessary to make the statements therein not misleading, in each case to the
extent, but only to the extent, that any such loss, liability, claim, damage or
expense arises out of or is based upon any such untrue statement or alleged
untrue statement or omission or alleged omission made therein in reliance upon
and in conformity with written information furnished to the Company by or on
behalf of such Underwriter through you expressly for use therein; provided,
however, that in no case shall any Underwriter be liable or responsible for any
amount in excess of the underwriting discount applicable to the Shares purchased
by such Underwriter hereunder. This indemnity will be in addition to any
<PAGE>   31
                                                                              31

liability which any Underwriter may otherwise have, including under this
Agreement. The Company acknowledges that the statements set forth in the last
paragraph of the cover page and in the first through sixth and the ninth and
tenth paragraphs under the caption "Underwriting" in the Prospectus constitute
the only information furnished in writing by or on behalf of any Underwriter
expressly for use in the registration statement relating to the Shares as
originally filed or in any amendment thereof, any related preliminary prospectus
or the Prospectus or in any amendment thereof or supplement thereto, as the case
may be.

                  (d) Promptly after receipt by an indemnified party under
subsection (a), (b) or (c) above of notice of the commencement of any action,
such indemnified party shall, if a claim in respect thereof is to be made
against the indemnifying party under such subsection, notify each party against
whom indemnification is to be sought in writing of the commencement thereof (but
the failure so to notify an indemnifying party shall not relieve it from any
liability which it may have under this Section 9). In case any such action is
brought against any indemnified party, and it notifies an indemnifying party of
the commencement thereof, the indemnifying party will be entitled to participate
therein, and to the extent it may elect by written notice delivered to the
indemnified party promptly after receiving the aforesaid notice from such
indemnified party, to assume the defense thereof with counsel satisfactory to
such indemnified party. Notwithstanding the foregoing, the indemnified party or
parties shall have the right to employ its or their own counsel in any such
case, but the fees and expenses of such counsel shall be at the expense of such
indemnified party or parties unless (i) the employment of such counsel shall
have been authorized in writing by one of the indemnifying parties in connection
with the defense of such action, (ii) the indemnifying parties shall not have
employed counsel to have charge of the defense of such action within a
reasonable time after notice of commencement of the action, or (iii) such
indemnified party or parties shall have reasonably concluded that there may be
defenses available to it or them which are different from or additional to those
available to one or all of the indemnifying parties (in which case the
indemnifying parties shall not have the right to direct the defense of such
action on behalf of the indemnified party or parties), in any of which events
such fees and expenses shall be borne by the indemnifying parties. Anything in
this subsection to the contrary notwithstanding, an indemnifying party shall not
be liable for any settlement of any claim or action effected without its written
consent; provided, however, that such consent was not unreasonably withheld.

                  10. Contribution. In order to provide for contribution in
circumstances in which the indemnification provided for in Section 9 hereof is
for any reason held to be unavailable from any indemnifying party or is
insufficient to hold harmless a party indemnified thereunder, the Company, the
<PAGE>   32
                                                                              32

Selling Stockholders and the Underwriters shall contribute to the aggregate
losses, claims, damages, liabilities and expenses of the nature contemplated by
such indemnification provision (including any investigation, legal and other
expenses incurred in connection with, and any amount paid in settlement of, any
action, suit or proceeding or any claims asserted, but after deducting in the
case of losses, claims, damages, liabilities and expenses suffered by the
Company or the Selling Stockholders any contribution received by the Company or
the Selling Stockholders, as the case may be, from persons, other than the
Underwriters, who may also be liable for contribution, including persons who
control the Company or the Selling Stockholders within the meaning of Section 15
of the Act or Section 20(a) of the Exchange Act, officers of the Company who
signed the Registration Statement and directors of the Company) as incurred to
which the Company, the Selling Stockholders, and one or more of the Underwriters
may be subject, in such proportions as is appropriate to reflect the relative
benefits received by the Company and the Selling Stockholders on the one hand
and the Underwriters on the other from the offering of the Shares or, if such
allocation is not permitted by applicable law or indemnification is not
available as a result of the indemnifying party not having received notice as
provided in Section 9 hereof, in such proportion as is appropriate to reflect
not only the relative benefits referred to above but also the relative fault of
the Company and the Selling Stockholders on the one hand and the Underwriters on
the other in connection with the statements or omissions which resulted in such
losses, claims, damages, liabilities or expenses, as well as any other relevant
equitable considerations. The relative benefits received by the Company and the
Selling Stockholders on the one hand and the Underwriters on the other shall be
deemed to be in the same proportion as (x) the total proceeds from the offering
(net of underwriting discounts and commissions but before deducting expenses)
received by the Company and the Selling Stockholders and (y) the underwriting
discounts and commissions received by the Underwriters, respectively, in each
case as set forth in the table on the cover page of the Prospectus. The relative
fault of the Company, the Selling Stockholders and the Underwriters shall be
determined by reference to, among other things, whether the untrue or alleged
untrue statement of a material fact or the omission or alleged omission to state
a material fact relates to information supplied by the Company, the Selling
Stockholders or the Underwriters and the parties' relative intent, knowledge,
access to information and opportunity to correct or prevent such statement or
omission. The Company, the Selling Stockholders and the Underwriters agree that
it would not be just and equitable if contribution pursuant to this Section 10
were determined by pro rata allocation (even if the Underwriters were treated as
one entity for such purpose) or by any other method of allocation which does not
take account of the equitable considerations referred to above. Notwithstanding
the provisions of this Section 10 and the preceding sentence, (i) in no case
shall any Underwriter be liable or responsible for any amount in excess of
<PAGE>   33
                                                                              33

the underwriting discount applicable to the Shares purchased by such Underwriter
hereunder, and (ii) no person guilty of fraudulent misrepresentation (within the
meaning of Section 11(f) of the Act) shall be entitled to contribution from any
person who was not guilty of such fraudulent misrepresentation. Notwithstanding
the provisions of this Section 10, no Underwriter shall be required to
contribute any amount in excess of the amount by which the total price at which
the Shares underwritten by it and distributed to the public were offered to the
public exceeds the amount of any damages that such Underwriter has otherwise
been required to pay by reason of such untrue or alleged untrue statement or
omission or alleged omission. For purposes of this Section 10, each person, if
any, who controls an Underwriter within the meaning of Section 15 of the Act or
Section 20(a) of the Exchange Act shall have the same rights to contribution as
such Underwriter, each person, if any, who controls a Selling Stockholder within
the meaning of Section 15 of the Act or Section 20(a) of the Exchange Act shall
have the same rights to contribution as such Selling Stockholder and each
person, if any, who controls the Company within the meaning of Section 15 of the
Act or Section 20(a) of the Exchange Act, each officer of the Company who shall
have signed the Registration Statement and each director of the Company shall
have the same rights to contribution as the Company, subject in each case to
clauses (i) and (ii) of this Section 10. Any party entitled to contribution
will, promptly after receipt of notice of commencement of any action, suit or
proceeding against such party in respect of which a claim for contribution may
be made against another party or parties, notify each party or parties from whom
contribution may be sought, but the omission to so notify such party or parties
shall not relieve the party or parties from whom contribution may be sought from
any obligation it or they may have under this Section 10 or otherwise. No party
shall be liable for contribution with respect to any action or claim settled
without its consent; provided, however, that such consent was not unreasonably
withheld.

                  11. Default by an Underwriter.

                  (a) If any Underwriter or Underwriters shall default in its or
their obligation to purchase Firm Shares or Additional Shares hereunder, and if
the Firm Shares or Additional Shares with respect to which such default relates
do not (after giving effect to arrangements, if any, made by you pursuant to
subsection (b) below) exceed in the aggregate 10% of the number of Firm Shares
or Additional Shares, the Firm Shares or Additional Shares to which the default
relates shall be purchased by the non-defaulting Underwriters in proportion to
the respective proportions which the numbers of Firm Shares set forth opposite
their respective names in Schedule I hereto bear to the aggregate number of Firm
Shares set forth opposite the names of the non-defaulting Underwriters.
<PAGE>   34
                                                                              34

                  (b) In the event that such default relates to more than 10% of
the Firm Shares or Additional Shares, as the case may be, you may in your
discretion arrange for yourself or for another party or parties (including any
non-defaulting Underwriter or Underwriters who so agree) to purchase such Firm
Shares or Additional Shares, as the case may be, to which such default relates
on the terms contained herein. In the event that within five calendar days after
such a default you do not arrange for the purchase of the Firm Shares or
Additional Shares, as the case may be, to which such default relates as provided
in this Section 11, this Agreement or, in the case of a default with respect to
the Additional Shares, the obligations of the Underwriters to purchase and of
the Option Stockholders to sell the Additional Shares shall thereupon terminate,
without liability on the part of the Company or such Option Stockholders with
respect thereto (except in each case as provided in Section 7, 9(a) and 10
hereof) or the Underwriters, but nothing in this Agreement shall relieve a
defaulting Underwriter or Underwriters of its or their liability, if any, to the
other Underwriters, the Company and the Selling Stockholders for damages
occasioned by its or their default hereunder.

                  (c) In the event that the Firm Shares or Additional Shares to
which the default relates are to be purchased by the non-defaulting
Underwriters, or are to be purchased by another party or parties as aforesaid,
you, the Company or the Selling Stockholders shall have the right to postpone
the Closing Date or Additional Closing Date, as the case may be for a period,
not exceeding five business days, in order to effect whatever changes may
thereby be made necessary in the Registration Statement or the Prospectus or in
any other documents and arrangements, and the Company agrees to file promptly
any amendment or supplement to the Registration Statement or the Prospectus
which, in the opinion of Underwriters' Counsel, may thereby be made necessary or
advisable. The term "Underwriter" as used in this Agreement shall include any
party substituted under this Section 11 with like effect as if it had originally
been a party to this Agreement with respect to such Firm Shares and Additional
Shares.

                  12. Survival of Representations and Agreements. All
representations and warranties, covenants and agreements of the Underwriters,
the Company and the Selling Stockholders contained in this Agreement, including
the agreements contained in Section 7, the indemnity agreements contained in
Section 9 and the contribution agreements contained in Section 10, shall remain
operative and in full force and effect regardless of any investigation made by
or on behalf of any Underwriter or any controlling person thereof or by or on
behalf of the Company, any of its officers and directors or any controlling
person thereof, or by or on behalf of any Selling Stockholder or controlling
person thereof and shall survive delivery of and payment for the Shares to and
by the Underwriters. The representations contained in Sections 1 and 2 and the
agreements contained in Sections 7, 9, 10 and 13(d) hereof shall survive the
termination of this
<PAGE>   35
                                                                              35

Agreement, including termination pursuant to Section 11 or 13 hereof.

                  13. Effective Date of Agreement; Termination. (a) This
Agreement shall become effective, upon the later of (i) when you, the Company
and the Selling Stockholders shall have received notification of the
effectiveness of the Registration Statement or (ii) the execution of this
Agreement. If either the initial public offering price or the purchase price per
Share has not been agreed upon prior to 5:00 P.M., New York time, on the fifth
full business day after the Registration Statement shall have become effective,
this Agreement shall thereupon terminate without liability to the Company, the
Selling Stockholders or the Underwriters except as herein expressly provided.
Until this Agreement becomes effective as aforesaid, it may be terminated by the
Company by notifying you and the Selling Stockholders or by you notifying the
Company and the Selling Stockholders. Notwithstanding the foregoing, the
provisions of this Section 13 and of Sections 1, 2, 7, 9 and 10 hereof shall at
all times be in full force and effect.

                  (b) You shall have the right to terminate this Agreement at
any time prior to the Closing Date or the obligations of the Underwriters to
purchase the Additional Shares at any time prior to the Additional Closing Date,
as the case may be, if (i) any domestic or international event or act or
occurrence has materially disrupted, or in your opinion will in the immediate
future materially disrupt, the market for the Company's securities or securities
in general, (ii) if trading on the National Association of Securities Dealers
Automated Quotation (National Market) System, New York or American Stock
Exchanges shall have been suspended, or minimum or maximum prices for trading
shall have been fixed, or maximum ranges for prices for securities shall have
been required, on the National Association of Securities Dealers Automated
Quotation (National Market) System, the New York or American Stock Exchanges or
by order of the Commission or any other governmental authority having
jurisdiction, (iii) if a banking moratorium has been declared by a state or
federal authority or if any new restriction materially adversely affecting the
distribution of the Firm Shares or the Additional Shares, as the case may be,
shall have become effective, or (iv) (A) if the United States becomes engaged in
hostilities or there is an escalation of hostilities involving the United States
or there is a declaration of a national emergency or war by the United States or
(B) if there shall have been such change in political, financial or economic
conditions if the effect of any such event in (A) or (B) as in your judgment
makes it impracticable or inadvisable to proceed with the offering, sale and
delivery of the Firm Shares or the Additional Shares, as the case may be, on the
terms contemplated by the Prospectus.
<PAGE>   36
                                                                              36

                  (c) Any notice of termination pursuant to this Section 13
shall be by telephone, telex, or telegraph, confirmed in writing by letter.

                  (d) If this Agreement shall be terminated pursuant to any of
the provisions hereof (otherwise than pursuant to (i) notification by you as
provided in Section 13(a) hereof or (ii) Section 11(b) or 13(b) hereof), or if
the sale of the Shares provided for herein is not consummated because any
condition to the obligations of the Underwriters set forth herein is not
satisfied or because of any refusal, inability or failure on the part of the
Company or the Selling Stockholders to perform any agreement herein or comply
with any provision hereof, the Company will, subject to demand by you, reimburse
the Underwriters for all out-of-pocket expenses (including the fees and expenses
of their counsel), incurred by the Underwriters in connection herewith.

                  14. Notice. All communications hereunder, except as may be
otherwise specifically provided herein, shall be in writing and, if sent to any
Underwriter, shall be mailed, delivered, or telexed or telegraphed and confirmed
in writing, to such Underwriter c/o Bear, Stearns & Co. Inc., 245 Park Avenue,
New York, New York 10167, Attention: Mark R. Goldstein, Vice President; if sent
to the Company, shall be mailed, delivered, or telegraphed and confirmed in
writing to the Company, 3865 North Business Center Drive, Tucson, Arizona 85705,
Attention: [R. James Danehy, President and Chief Executive Officer]; and if sent
to any Selling Stockholder, shall be mailed, delivered or telegraphed and
confirmed in writing to such Selling Stockholder at the address set forth in
Schedule II hereto.

                  15. Parties. This Agreement shall insure solely to the benefit
of, and shall be binding upon, the Underwriters, the Selling Stockholders, the
Company and the controlling persons, directors, officers, employees and agents
referred to in Section 9 and 10, and their respective successors and assigns,
and no other person shall have or be construed to have any legal or equitable
right, remedy or claim under or in respect of or by virtue of this Agreement or
any provision herein contained. The term "successors and assigns" shall not
include a purchaser, in its capacity as such, of Shares from any of the
Underwriters.

                  16. Governing Law. THIS AGREEMENT SHALL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK, BUT WITHOUT
REGARD TO PRINCIPLES OF CONFLICTS OF LAW.
<PAGE>   37
                                                                              37

                  If the foregoing correctly sets forth the understanding among
you, the Company and the Selling Stockholders, please so indicate in the space
provided below for that purpose, whereupon this letter shall constitute a
binding agreement among us.

                                       Very truly yours,

                                       VENTANA MEDICAL SYSTEMS, INC.

                                       By:
                                           -------------------------------
                                           Title:

                                       The Selling Stockholders named
                                         in Schedule II to this Agreement

                                       By:
                                           -------------------------------
                                           Attorney-in-fact

Accepted as of the date first above written

BEAR, STEARNS & CO. INC.
DILLON, READ & CO. INC.

By:BEAR, STEARNS & CO. INC.

By:
   ----------------------------
   Title:

On behalf of themselves and the other 
Underwriters named in Schedule I hereto.
<PAGE>   38
                                   SCHEDULE I
<TABLE>
<CAPTION>
                                                       Number of Firm
Name of Underwriter                                    Shares to be Purchased
- -------------------                                    ----------------------
<S>                                                         <C>
Bear, Stearns & Co. Inc. . . . . . . .
Dillon, Read & Co. Inc.  . . . . . . .





                    Total. . . . . . .
                                                       ----------------------
                                                            3,000,000
</TABLE>
<PAGE>   39
                                   SCHEDULE II
<TABLE>
<CAPTION>
                                                                                               Number of
                                                                                              Firm Shares
Name and Address of Selling Stockholder                                                       to be Sold
- ---------------------------------------                                                       -----------
<S>                                                                                             <C> 
Entities affiliated with Marquette Venture Partners*
520 Lake Cook Rd., Suite 450
Deerfield, IL 60015 .................................................................           444,017
The CIT Group/Venture Capital, Inc.* ................................................           101,945
Interwest Partners IV, L.P.* ........................................................            86,265
Victoria Bannister* .................................................................            10,744
W. Ross Humphreys ...................................................................            73,558
J. David Lowell .....................................................................            28,428
David Nunnery* ......................................................................               931
Jan Karel Smeets ....................................................................            15,635
Douglas F. Sweet* ...................................................................               716
Richard B. Peterson* ................................................................             5,157
Thomas B. Healey ....................................................................            10,441
Dorothy L. O'Neal Revocable Trust ...................................................             8,814
Wm. Kent Wonders ....................................................................             1,895
Entities affiliated with the Myron S. and Joan D 
  Eichen Family Trust* ..............................................................             2,043
Charles J. Casebeer* ................................................................               260
Jessica Youle .......................................................................             4,264
Mary Cawley .........................................................................             3,326
Lawrance A. Brown, Jr.* .............................................................               613
Philip E. McCarthy* .................................................................                96
Entities affiliated with the Thomas H. and Rosemary
  S. Tisch Trust* ...................................................................               546
Ned M. Weinshenker Money Purchase Pension Plan* .....................................               210
Wayne L. Clevenger Pension Plan* ....................................................                96
                                                                                                -------
Total ...............................................................................           800,000
</TABLE>


*   Denotes Selling Stockholders who have granted an option to the Underwriters
    pursuant to Section 3(c) of this Agreement.
<PAGE>   40
                                  SCHEDULE III

Stockholders not subject to 180 day lock-up provisions

                            Number of Shares
                               Immediately             Number of Shares
Name of Stockholder              Saleable              Saleable after 90 days
- -------------------             ----------             ----------------------




<PAGE>   1
                                                               EXHIBIT 3.1(i)(b)



              AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF

                          VENTANA MEDICAL SYSTEMS, INC.

         Ventana Medical Systems, Inc., a corporation organized and existing
under the laws of the State of Delaware, hereby certifies as follows:

         The original Certificate of Incorporation of Ventana Medical Systems,
Inc. was filed with the Secretary of State of the State of Delaware on February
26, 1993. Pursuant to Sections 228, 242 and 245 of the General Corporation Law
of the State of Delaware, this Amended and Restated Certificate of Incorporation
restates and integrates and further amends the provisions of the Certificate of
Incorporation of this corporation.

         The text of the Certificate of Incorporation as heretofore amended or
supplemented is hereby amended and restated in its entirety to read as follows:

                                    ARTICLE I

         The name of this corporation is Ventana Medical Systems, Inc.

                                   ARTICLE II

         The address of the corporation's registered office in the State of
Delaware is 1209 Orange Street, in the City of Wilmington, County of New Castle.
The name of its registered agent at such office is The Corporation Trust
Company.

                                   ARTICLE III

         The purpose of the corporation is to engage in any lawful act or
activity for which corporations may be organized under the General Corporation
Law of Delaware.



<PAGE>   2
                                   ARTICLE IV

         This corporation is authorized to issue two classes of stock to be
designated Common Stock and Preferred Stock. The total number of shares of
Common Stock which this corporation is autho rized to issue is 50,000,000, and
the total number of shares of Preferred Stock which this corporation is
authorized to issue is 5,000,000. Each share of Common Stock and each share of
Preferred Stock has a par value of $0.001. The Preferred Stock may be issued
from time to time in one or more series pursuant to a resolution or resolutions
providing for such issue duly adopted by the Board of Directors (authority to do
so being expressly vested in the Board). The Board of Directors is hereby
further authorized to fix or alter the voting powers, designations, preferences
and qualifications, limitations or restrictions granted to or imposed upon
additional series of Preferred Stock, and the number of shares constituting any
such series and the designation thereof. Subject to compliance with applicable
protective rights which have been or may be granted to Preferred Stock or series
thereof in Certificates of Designation or the Corporation's Certificate of
Incorporation, the rights, privileges, preferences and restrictions of any such
additional series may be subordinate to or pari passu with (including, without
limitation, inclusion of provisions with respect to liquidation and acquisition
and dividend preferences, or approval of matters by vote or written consent),
the rights of any present or future class or series of Preferred Stock or Common
Stock.

                                    ARTICLE V

         The corporation is to have perpetual existence.

                                   ARTICLE VI

         In furtherance and not in limitation of the powers conferred by
statute, the Board of Directors is expressly authorized to make, alter, amend or
repeal the Bylaws of the corporation.

                                   ARTICLE VII

         The number of directors which constitute the whole Board of Directors
of the corporation shall be as specified in the Bylaws of the corporation.

                                  ARTICLE VIII

         Meetings of stockholders may be held within or without the State of
Delaware, as the Bylaws may provide. The books of the corporation may be kept
(subject to any provisions contained in the statutes) outside the State of
Delaware at such place or places as may be designated from time to time by the
Board of Directors or in the Bylaws of the corporation.



                                       -2-
<PAGE>   3
                                   ARTICLE IX

         Holders of stock of any class or series of the corporation shall not be
entitled to cumulate their votes for the election of directors or any other
matter submitted to a vote of the stockholders.

                                    ARTICLE X

         No action shall be taken by the stockholders of the corporation except
at an annual or special meeting of the stockholders called in accordance with
the Bylaws and no action shall be taken by the stockholders by written consent.
The affirmative vote of sixty-six and two thirds percent (662/3%) of the then
outstanding voting securities of the corporation, voting together as a single
class, shall be required for the amendment, repeal or modification of the
provisions of Article IX or X of this Amended and Restated Certificate of
Incorporation or Sections 2.3 and 2.5 of the corporation's Bylaws.

                                   ARTICLE XI

         To the fullest extent permitted by the Delaware General Corporation
Law, a director of the corporation shall not be personally liable to the
corporation or its stockholders for monetary damages for breach of fiduciary
duty as a director. Neither any amendment nor repeal of this Article X nor the
adoption of any provision of this Certificate of Incorporation inconsistent with
this Article X, shall eliminate or reduce the effect of this Article X in
respect of any matter occurring, or any cause of action, suit or claim that, but
for this Article X, would accrue or arise, prior to such amendment, repeal or
adoption of an inconsistent provision.

                                   ARTICLE XII

         1. The corporation shall indemnify each of the corporation's directors
and officers in each and every situation where, under Section 145 of the General
Corporation Law of the State of Delaware, as amended from time to time ("Section
145"), the corporation is permitted or empowered to make such indemnification.
The corporation may, in the sole discretion of the Board of Directors of the
corporation, indemnify any other person who may be indemnified pursuant to
Section 145 to the extent the Board of Directors deems advisable, as permitted
by Section 145. The corporation shall promptly make or cause to be made any
determination required to be made pursuant to Section 145.

         2. No person shall be personally liable to the corporation or its
stockholders for monetary damages for breach of fiduciary duty as a director,
provided, however, that the foregoing shall not eliminate or limit the liability
of a director (i) for any breach of the director's duty of loyalty to the
corporation or its stockholders, (ii) for acts or omissions not in good faith or
which involve intentional misconduct or a knowing violation of law, (iii) under
Section 174 of the General Corporation Law of the State of Delaware or (iv) for
any transaction from which the director derived



                                       -3-
<PAGE>   4
an improper personal benefit. If the General Corporation Law of the State of
Delaware is subsequently amended to further eliminate or limit the liability of
a director, then a director of the corporation, in addition to the circumstances
in which a director is not personally liable as set forth in the preceding
sentence, shall not be liable to the fullest extent permitted by the amended
General Corporation Law of the State of Delaware. For purposes of this Article
XI, "fiduciary duty as a director" shall include any fiduciary duty arising out
of serving at the corporation's request as a director of another corporation,
partnership, joint venture or other enterprise, and "personal liability to the
corporation or its stockholders" shall include any liability to such other
corporation, partnership, joint venture, trust or other enterprise, and any
liability to the corporation in its capacity as a security holder, joint
venturer, partner, beneficiary, creditor or investor of or in any such other
corporation, partnership, joint venture, trust or other enterprise.

                                  ARTICLE XIII

         Advance notice of new business and stockholder nominations for the
election of directors shall be given in the manner and to the extent provided in
the Bylaws of the corporation.

                                   ARTICLE XIV

         The corporation reserves the right to amend, alter, change or repeal
any provisions contained in this Certificate, in the manner now or hereafter
prescribed by statute, and all rights conferred upon stockholders herein are
granted subject to this reservation.



                                       -4-
<PAGE>   5
         IN WITNESS WHEREOF, the corporation has caused this Certificate to be
signed by R. James Danehy, its President, and attested by R. Michael Rodgers,
the Secretary of the corporation. The signatures below shall constitute the
affirmation or acknowledgment, under penalties of perjury, that the facts herein
stated are true, this ____ day of July, 1996.

                                       VENTANA MEDICAL SYSTEMS, INC.

                                       By:
                                            -----------------------------------
                                            R. James Danehy,
                                            President and Chief Executive 
                                            Officer

ATTEST:

- -----------------------------------------
R. Michael Rodgers, Secretary



                                       -5-


<PAGE>   1
                                                              EXHIBIT 3.1(ii)(b)

                                     BYLAWS

                                       OF

                          VENTANA MEDICAL SYSTEMS, INC.
                            (A DELAWARE CORPORATION)


                      ADOPTED EFFECTIVE AS OF JUNE 28, 1996
<PAGE>   2
                                    BYLAWS OF

                          VENTANA MEDICAL SYSTEMS, INC.
                            (A DELAWARE CORPORATION)

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                            Page
<S>                                                                         <C>
 ARTICLE I

     CORPORATE OFFICES....................................................     1
     1.1    REGISTERED OFFICE.............................................     1
     1.2    OTHER OFFICES.................................................     1
                                                                                
 ARTICLE II                                                                     
                                                                                
      MEETINGS OF STOCKHOLDERS............................................     1
      2.1   PLACE OF MEETINGS.............................................     1
      2.2   ANNUAL MEETING................................................     1
      2.3   SPECIAL MEETING...............................................     2
      2.4   NOTICE OF STOCKHOLDERS' MEETINGS..............................     2
      2.5   ADVANCE NOTICE OF STOCKHOLDER NOMINEES AND STOCKHOLDER              
            BUSINESS......................................................     2
      2.6   MANNER OF GIVING NOTICE; AFFIDAVIT OF NOTICE..................     4
      2.7   QUORUM........................................................     4
      2.8   ADJOURNED MEETING; NOTICE.....................................     4
      2.9   VOTING........................................................     5
      2.10  STOCKHOLDER ACTION BY WRITTEN CONSENT                               
            WITHOUT A MEETING.............................................     5
      2.11  RECORD DATE FOR STOCKHOLDER NOTICE; VOTING....................     5
      2.12  PROXIES.......................................................     6
      2.13  ORGANIZATION..................................................     6
      2.14  LIST OF STOCKHOLDERS ENTITLED TO VOTE.........................     7
      2.15  WAIVER OF NOTICE..............................................     7
                                                                                
 ARTICLE III                                                                    
                                                                                
      DIRECTORS...........................................................     7
      3.1   POWERS........................................................     7
      3.2   NUMBER OF DIRECTORS...........................................     7
      3.3   ELECTION AND TERM OF OFFICE OF DIRECTORS......................     8
</TABLE>
                                                                               
                                       -i-
<PAGE>   3
                                TABLE OF CONTENTS

                                   (CONTINUED)

<TABLE>
<CAPTION>
                                                                    Page
<S>                                                                 <C>
      3.4   RESIGNATION AND VACANCIES..........................        8
      3.5   REMOVAL OF DIRECTORS...............................        9
      3.6   PLACE OF MEETINGS; MEETINGS BY TELEPHONE...........        9
      3.7   FIRST MEETINGS.....................................        9
      3.8   REGULAR MEETINGS...................................       10
      3.9   SPECIAL MEETINGS; NOTICE...........................       10
      3.10  QUORUM.............................................       10
      3.11  WAIVER OF NOTICE...................................       10
      3.12  ADJOURNMENT........................................       11
      3.13  NOTICE OF ADJOURNMENT..............................       11
      3.14  BOARD ACTION BY WRITTEN CONSENT WITHOUT A MEETING..       11
      3.15  FEES AND COMPENSATION OF DIRECTORS.................       11
      3.16  APPROVAL OF LOANS TO OFFICERS......................       11
      3.17  SOLE DIRECTOR PROVIDED BY CERTIFICATE OF                    
            INCORPORATION......................................       12
                                                                        
 ARTICLE IV                                                             
                                                                        
      COMMITTEES...............................................       12
      4.1    COMMITTEES OF DIRECTORS...........................       12
      4.2    MEETINGS AND ACTION OF COMMITTEES.................       12
      4.3    COMMITTEE MINUTES.................................       13
                                                                        
 ARTICLE V                                                              
                                                                        
      OFFICERS.................................................       13
      5.1    OFFICERS..........................................       13
      5.2    ELECTION OF OFFICERS..............................       13
      5.3    SUBORDINATE OFFICERS..............................       13
      5.4    REMOVAL AND RESIGNATION OF OFFICERS...............       14
      5.5    VACANCIES IN OFFICES..............................       14
      5.6    CHAIRMAN OF THE BOARD.............................       14
      5.7    PRESIDENT.........................................       14
      5.8    VICE PRESIDENTS...................................       15
      5.9    SECRETARY.........................................       15
      5.10   CHIEF FINANCIAL OFFICER...........................       15
      5.11   ASSISTANT SECRETARY...............................       16
</TABLE>
                                                           
                                      -ii-
<PAGE>   4
                                TABLE OF CONTENTS

                                   (CONTINUED)

<TABLE>
<CAPTION>
                                                                            Page
<S>                                                                         <C>
      5.12   ADMINISTRATIVE OFFICERS...................................       16
      5.13   AUTHORITY AND DUTIES OF OFFICERS..........................       16
                                                                                
 ARTICLE VI                                                                     
                                                                                
      INDEMNIFICATION OF DIRECTORS, OFFICERS, EMPLOYEES                         
      AND OTHER AGENTS.................................................       17
      6.1    INDEMNIFICATION OF DIRECTORS AND OFFICERS.................       17
      6.2    INDEMNIFICATION OF OTHERS.................................       18
      6.3    INSURANCE.................................................       18
                                                                                
 ARTICLE VII                                                                    
                                                                                
      RECORDS AND REPORTS..............................................       18
      7.1    MAINTENANCE AND INSPECTION OF RECORDS.....................       18
      7.2    INSPECTION BY DIRECTORS...................................       19
      7.3    ANNUAL STATEMENT TO STOCKHOLDERS..........................       19
      7.4    REPRESENTATION OF SHARES OF OTHER CORPORATIONS............       19
      7.5    CERTIFICATION AND INSPECTION OF BYLAWS....................       19
                                                                                
 ARTICLE VIII                                                                   
                                                                                
      GENERAL MATTERS..................................................       19
      8.1    RECORD DATE FOR PURPOSES OTHER THAN NOTICE AND                     
             VOTING....................................................       19
      8.2    CHECKS; DRAFTS; EVIDENCES OF INDEBTEDNESS.................       20
      8.3    CORPORATE CONTRACTS AND INSTRUMENTS:  HOW EXECUTED........       20
      8.4    STOCK CERTIFICATES; TRANSFER; PARTLY PAID SHARES..........       20
      8.5    SPECIAL DESIGNATION ON CERTIFICATES.......................       21
      8.6    LOST CERTIFICATES.........................................       21
      8.7    TRANSFER AGENTS AND REGISTRARS............................       22
      8.8    CONSTRUCTION; DEFINITIONS.................................       22
                                                                                
 ARTICLE IX                                                                     
                                                                                
      AMENDMENTS.......................................................       22
</TABLE>



                                      -iii-

<PAGE>   5
                                     BYLAWS

                                       OF

                          VENTANA MEDICAL SYSTEMS, INC.
                            (a Delaware corporation)

                                    ARTICLE I

                                CORPORATE OFFICES

      1.1 REGISTERED OFFICE

      The registered office of the corporation shall be fixed in the certificate
of incorporation of the corporation.

      1.2 OTHER OFFICES

      The board of directors may at any time establish branch or subordinate
offices at any place or places where the corporation is qualified to do
business.

                                   ARTICLE II

                            MEETINGS OF STOCKHOLDERS

      2.1 PLACE OF MEETINGS

      Meetings of stockholders shall be held at any place within or outside the
State of Delaware designated by the board of directors. In the absence of any
such designation, stockholders' meetings shall be held at the principal
executive office of the corporation.

      2.2 ANNUAL MEETING

      The annual meeting of stockholders shall be held each year on a date and
at a time designated by the board of directors. In the absence of such
designation, the annual meeting of stockholders shall be held on the second
Tuesday in May in each year at 10:00 a.m. However, if such day falls on a legal
holiday, then the meeting shall be held at the same time and place on the next
succeeding full business day. At the meeting, directors shall be elected, and
any other proper business may be transacted.
<PAGE>   6
      2.3 SPECIAL MEETING

      A special meeting of the stockholders may be called at any time by the
board of directors, by the chairman of the board or by the president. No other
person or persons are permitted to call a special meeting.

      If a special meeting is called by any person or persons other than the
board of directors, then the request shall be in writing, specifying the time of
such meeting and the general nature of the business proposed to be transacted,
and shall be delivered personally or sent by registered mail or by telegraphic
or other facsimile transmission to the chairman of the board, the president, or
the secretary of the corporation. The officer receiving the request shall cause
notice to be promptly given to the stockholders entitled to vote, in accordance
with the provisions of Sections 2.4 and 2.6 of these bylaws, that a meeting will
be held at the time requested by the person or persons calling the meeting, so
long as that time is not less than thirty-five (35) nor more than sixty (60)
days after the receipt of the request. If the notice is not given within twenty
(20) days after receipt of the request, then the person or persons requesting
the meeting may give the notice. Nothing contained in this paragraph of this
Section 2.3 shall be construed as limiting, fixing or affecting the time when a
meeting of stockholders called by action of the board of directors may be held.

      2.4 NOTICE OF STOCKHOLDERS' MEETINGS

      All notices of meetings of stockholders shall be sent or otherwise given
in accordance with Section 2.6 of these bylaws not less than ten (10) nor more
than sixty (60) days before the date of the meeting. The notice shall specify
the place, date and hour of the meeting and (i) in the case of a special
meeting, the purpose or purposes for which the meeting is called (no business
other than that specified in the notice may be transacted) or (ii) in the case
of the annual meeting, those matters which the board of directors, at the time
of giving the notice, intends to present for action by the stockholders (but any
proper matter may be presented at the meeting for such action). The notice of
any meeting at which directors are to be elected shall include the name of any
nominee or nominees who, at the time of the notice, the board intends to present
for election.

      2.5 ADVANCE NOTICE OF STOCKHOLDER NOMINEES AND STOCKHOLDER BUSINESS

      Subject to the rights of holders of any class or series of stock having a
preference over the Common Stock as to dividends or upon liquidation,

      (a) nominations for the election of directors, and

      (b) business proposed to be brought before any stockholder meeting

may be made by the board of directors or proxy committee appointed by the board
of directors or by any stockholder entitled to vote in the election of directors
generally if such nomination or business proposed

                                       -2-
<PAGE>   7
is otherwise proper business before such meeting. However, any such stockholder
may nominate one or more persons for election as directors at a meeting or
propose business to be brought before a meeting, or both, only if such
stockholder has given timely notice in proper written form of their intent to
make such nomination or nominations or to propose such business. To be timely,
such stockholder's notice must be delivered to or mailed and received at the
principal executive offices of the corporation not less than one hundred twenty
(120) calendar days in advance of the date specified in the corporation's proxy
statement released to stockholders in connection with the previous year's annual
meeting of stockholders; provided, however, that in the event that no annual
meeting was held in the previous year or the date of the annual meeting has been
changed by more than thirty (30) days from the date contemplated at the time of
the previous year's proxy statement, notice by the stockholder to be timely must
be so received a reasonable time before the solicitation is made. To be in
proper form, a stockholder's notice to the secretary shall set forth:

      (i) the name and address of the stockholder who intends to make the
      nominations or propose the business and, as the case may be, of the person
      or persons to be nominated or of the business to be proposed;

      (ii) a representation that the stockholder is a holder of record of stock
      of the corporation entitled to vote at such meeting and, if applicable,
      intends to appear in person or by proxy at the meeting to nominate the
      person or persons specified in the notice;

      (iii) if applicable, a description of all arrangements or understandings
      between the stockholder and each nominee and any other person or persons
      (naming such person or persons) pursuant to which the nomination or
      nominations are to be made by the stockholder;

      (iv) such other information regarding each nominee or each matter of
      business to be proposed by such stockholder as would be required to be
      included in a proxy statement filed pursuant to the proxy rules of the
      Securities and Exchange Commission had the nominee been nominated, or
      intended to be nominated, or the matter been proposed, or intended to be
      proposed by the board of directors; and

      (v) if applicable, the consent of each nominee to serve as director of the
      corporation if so elected.

      The chairman of the meeting shall refuse to acknowledge the nomination of
any person or the proposal of any business not made in compliance with the
foregoing procedure.

      2.6 MANNER OF GIVING NOTICE; AFFIDAVIT OF NOTICE

      Written notice of any meeting of stockholders shall be given either
personally or by first-class mail or by telegraphic or other written
communication. Notices not personally delivered shall be sent charges prepaid
and shall be addressed to the stockholder at the address of that stockholder
appearing on the

                                       -3-
<PAGE>   8
books of the corporation or given by the stockholder to the corporation for the
purpose of notice. Notice shall be deemed to have been given at the time when
delivered personally or deposited in the mail or sent by telegram or other means
of written communication.

      An affidavit of the mailing or other means of giving any notice of any
stockholders' meeting, executed by the secretary, assistant secretary or any
transfer agent of the corporation giving the notice, shall be prima facie
evidence of the giving of such notice.

      2.7 QUORUM

      The holders of a majority in voting power of the stock issued and
outstanding and entitled to vote thereat, present in person or represented by
proxy, shall constitute a quorum at all meetings of the stock holders for the
transaction of business except as otherwise provided by statute or by the
certificate of incorporation. If, however, such quorum is not present or
represented at any meeting of the stockholders, then either (i) the chairman of
the meeting or (ii) the stockholders entitled to vote thereat, present in person
or represented by proxy, shall have power to adjourn the meeting in accordance
with Section 2.7 of these bylaws.

      When a quorum is present at any meeting, the vote of the holders of a
majority of the stock having voting power present in person or represented by
proxy shall decide any question brought before such meeting, unless the question
is one upon which, by express provision of the laws of the State of Delaware or
of the certificate of incorporation or these bylaws, a different vote is
required, in which case such express provision shall govern and control the
decision of the question.

      If a quorum be initially present, the stockholders may continue to
transact business until adjournment, notwithstanding the withdrawal of enough
stockholders to leave less than a quorum, if any action taken is approved by a
majority of the stockholders initially constituting the quorum.

      2.8 ADJOURNED MEETING; NOTICE

      When a meeting is adjourned to another time and place, unless these bylaws
otherwise require, notice need not be given of the adjourned meeting if the time
and place thereof are announced at the meeting at which the adjournment is
taken. At the adjourned meeting the corporation may transact any business that
might have been transacted at the original meeting. If the adjournment is for
more than thirty (30) days, or if after the adjournment a new record date is
fixed for the adjourned meeting, a notice of the adjourned meeting shall be
given to each stockholder of record entitled to vote at the meeting.

      2.9 VOTING

      The stockholders entitled to vote at any meeting of stockholders shall be
determined in accordance with the provisions of Section 2.11 of these bylaws,
subject to the provisions of Sections 217

                                       -4-
<PAGE>   9
and 218 of the General Corporation Law of Delaware (relating to voting rights of
fiduciaries, pledgors and joint owners, and to voting trusts and other voting
agreements).

      Except as may be otherwise provided in the certificate of incorporation or
these bylaws, each stockholder shall be entitled to one vote for each share of
capital stock held by such stockholder and stockholders shall not be entitled to
cumulate their votes in the election of directors or with respect to any matter
submitted to a vote of the stockholders.

      2.10 STOCKHOLDER ACTION BY WRITTEN CONSENT WITHOUT A MEETING

      Unless otherwise provided in the certificate of incorporation, any action
required or permitted to be taken at any annual or special meeting of
stockholders may be taken without a meeting, without prior notice and without a
vote, if a consent or consents in writing, setting forth the action so taken,
shall be signed by the holders of outstanding stock having not less than the
minimum number of votes that would be necessary to authorize or take such action
at a meeting at which all shares entitled to vote thereon were present and
voted. Such consents shall be delivered to the corporation by delivery to its
registered office in the state of Delaware, its principal place of business, or
an officer or agent of the corporation having custody of the book in which
proceedings of meetings of stockholders are recorded. Delivery made to the
corporation's registered office shall be by hand or by certified or registered
mail, return receipt requested.

      2.11 RECORD DATE FOR STOCKHOLDER NOTICE; VOTING

      For purposes of determining the stockholders entitled to notice of any
meeting or to vote thereat, the board of directors may fix, in advance, a record
date, which shall not precede the date upon which the resolution fixing the
record date is adopted by the board of directors and which shall not be more
than sixty (60) days nor less than ten (10) days before the date of any such
meeting, and in such event only stockholders of record on the date so fixed are
entitled to notice and to vote, notwithstanding any transfer of any shares on
the books of the corporation after the record date.

      If the board of directors does not so fix a record date, the record date
for determining stockholders entitled to notice of or to vote at a meeting of
stockholders shall be at the close of business on the business day next
preceding the day on which notice is given, or, if notice is waived, at the
close of business on the business day next preceding the day on which the
meeting is held.

      A determination of stockholders of record entitled to notice of or to vote
at a meeting of stockholders shall apply to any adjournment of the meeting
unless the board of directors fixes a new record date for the adjourned meeting,
but the board of directors shall fix a new record date if the meeting is
adjourned for more than thirty (30) days from the date set for the original
meeting.

      The record date for any other purpose shall be as provided in Section 8.1
of these bylaws.

                                       -5-
<PAGE>   10
      2.12 PROXIES

      Every person entitled to vote for directors, or on any other matter, shall
have the right to do so either in person or by one or more agents authorized by
a written proxy signed by the person and filed with the secretary of the
corporation, but no such proxy shall be voted or acted upon after three (3)
years from its date, unless the proxy provides for a longer period. A proxy
shall be deemed signed if the stockholder's name is placed on the proxy (whether
by manual signature, typewriting, telegraphic transmission, telecopy or
otherwise) by the stockholder or the stockholder's attorney-in-fact. The
revocability of a proxy that states on its face that it is irrevocable shall be
governed by the provisions of Section 212(e) of the General Corporation Law of
Delaware.

      2.13 ORGANIZATION

      The president, or in the absence of the president, the chairman of the
board, or, in the absence of the president and the chairman of the board, one of
the corporation's vice presidents, shall call the meeting of the stockholders to
order, and shall act as chairman of the meeting. In the absence of the
president, the chairman of the board, and all of the vice presidents, the
stockholders shall appoint a chairman for such meeting. The chairman of any
meeting of stockholders shall determine the order of business and the procedures
at the meeting, including such matters as the regulation of the manner of voting
and the conduct of business. The secretary of the corporation shall act as
secretary of all meetings of the stockholders, but in the absence of the
secretary at any meeting of the stockholders, the chairman of the meeting may
appoint any person to act as secretary of the meeting.

      2.14 LIST OF STOCKHOLDERS ENTITLED TO VOTE

      The officer who has charge of the stock ledger of the corporation shall
prepare and make, at least ten (10) days before every meeting of stockholders, a
complete list of the stockholders entitled to vote at the meeting, arranged in
alphabetical order, and showing the address of each stockholder and the number
of shares registered in the name of each stockholder. Such list shall be open to
the examination of any stockholder, for any purpose germane to the meeting,
during ordinary business hours, for a period of at least ten (10) days prior to
the meeting, either at a place within the city where the meeting is to be held,
which place shall be specified in the notice of the meeting, or, if not so
specified, at the place where the meeting is to be held. The list shall also be
produced and kept at the time and place of the meeting during the whole time
thereof, and may be inspected by any stockholder who is present.

      2.15 WAIVER OF NOTICE

      Whenever notice is required to be given under any provision of the General
Corporation Law of Delaware or of the certificate of incorporation or these
bylaws, a written waiver thereof, signed by the person entitled to notice,
whether before or after the time stated therein, shall be deemed equivalent to
notice. Attendance of a person at a meeting shall constitute a waiver of notice
of such meeting, except when the person attends a meeting for the express
purpose of objecting, at the beginning of the meeting, to the transaction of any
business because the meeting is not lawfully called or convened. Neither the

                                       -6-
<PAGE>   11
business to be transacted at, nor the purpose of, any regular or special meeting
of the stockholders need be specified in any written waiver of notice unless so
required by the certificate of incorporation or these bylaws.

                                   ARTICLE III

                                    DIRECTORS

      3.1 POWERS

      Subject to the provisions of the General Corporation Law of Delaware and
to any limitations in the certificate of incorporation or these bylaws relating
to action required to be approved by the stockholders or by the outstanding
shares, the business and affairs of the corporation shall be managed and all
corporate powers shall be exercised by or under the direction of the board of
directors.

      3.2 NUMBER OF DIRECTORS

      The board of directors shall consist of ten (10) members. The number of
directors may be changed by an amendment to this bylaw, duly adopted by the
board of directors or by the stockholders, or by a duly adopted amendment to the
certificate of incorporation. Upon the closing of the first sale of the
corporation's common stock pursuant to a firmly underwritten registered public
offering (the "IPO"), the directors shall be divided into three classes, with
the term of office of the first class, which class shall initially consist of
three (3) directors, to expire at the first annual meeting of stockholders held
after the IPO; the term of office of the second class, which class shall
initially consist of three (3) directors, to expire at the second annual meeting
of stockholders held after the IPO; the term of office of the third class, which
class shall initially consist of four (4) directors, to expire at the third
annual meeting of stockholders held after the IPO; and thereafter for each such
term to expire at each third succeeding annual meeting of stockholders held
after such election.

      3.3 ELECTION AND TERM OF OFFICE OF DIRECTORS

      Except as provided in Section 3.4 of these bylaws, directors shall be
elected at each annual meeting of stockholders to hold office as provided in
Section 3.2 of these bylaws. Each director, including a director elected or
appointed to fill a vacancy, shall hold office until the expiration of the term
for which elected and until a successor has been elected and qualified.

      3.4 RESIGNATION AND VACANCIES

      Any director may resign effective on giving written notice to the chairman
of the board, the president, the secretary or the board of directors, unless the
notice specifies a later time for that resignation to become effective. If the
resignation of a director is effective at a future time, the board of directors
may elect a successor to take office when the resignation becomes effective.

                                       -7-
<PAGE>   12
      Vacancies in the board of directors may be filled by a majority of the
remaining directors, even if less than a quorum, or by a sole remaining
director; however, a vacancy created by the removal of a director by the vote of
the stockholders or by court order may be filled only by the affirmative vote of
a majority of the shares represented and voting at a duly held meeting at which
a quorum is present (which shares voting affirmatively also constitute a
majority of the required quorum). Each director so elected shall hold office for
a term expiring at the next annual meeting of the stockholders at which the term
of office of the class to which such director has been elected expires.

      Unless otherwise provided in the certificate of incorporation or these
bylaws:

          (i) Vacancies and newly created directorships resulting from any
increase in the authorized number of directors elected by all of the
stockholders having the right to vote as a single class may be filled by a
majority of the directors then in office, although less than a quorum, or by a
sole remaining director.

          (ii) Whenever the holders of any class or classes of stock or series
thereof are entitled to elect one or more directors by the provisions of the
certificate of incorporation, vacancies and newly created directorships of such
class or classes or series may be filled by a majority of the directors elected
by such class or classes or series thereof then in office, or by a sole
remaining director so elected.

      If at any time, by reason of death or resignation or other cause, the
corporation should have no directors in office, then any officer or any
stockholder or an executor, administrator, trustee or guardian of a stockholder,
or other fiduciary entrusted with like responsibility for the person or estate
of a stockholder, may call a special meeting of stockholders in accordance with
the provisions of the certificate of incorporation or these bylaws, or may apply
to the Court of Chancery for a decree summarily ordering an election as provided
in Section 211 of the General Corporation Law of Delaware.

      If, at the time of filling any vacancy or any newly created directorship,
the directors then in office constitute less than a majority of the whole board
(as constituted immediately prior to any such increase), then the Court of
Chancery may, upon application of any stockholder or stockholders holding at
least ten (10) percent of the total number of the shares at the time outstanding
having the right to vote for such directors, summarily order an election to be
held to fill any such vacancies or newly created directorships, or to replace
the directors chosen by the directors then in office as aforesaid, which
election shall be governed by the provisions of Section 211 of the General
Corporation Law of Delaware as far as applicable.

      3.5 REMOVAL OF DIRECTORS

      Unless otherwise restricted by statute, by the certificate of
incorporation or by these bylaws, any director or the entire board of directors
may be removed, with or without cause, by the holders of a majority of the
shares then entitled to vote at an election of directors; provided, however,
that, if and so long as stockholders of the corporation are entitled to
cumulative voting, if less than the entire board is

                                       -8-
<PAGE>   13
to be removed, no director may be removed without cause if the votes cast
against his removal would be sufficient to elect him if then cumulatively voted
at an election of the entire board of directors.

      3.6 PLACE OF MEETINGS; MEETINGS BY TELEPHONE

      Regular meetings of the board of directors may be held at any place within
or outside the State of Delaware that has been designated from time to time by
resolution of the board. In the absence of such a designation, regular meetings
shall be held at the principal executive office of the corporation. Special
meetings of the board may be held at any place within or outside the State of
Delaware that has been designated in the notice of the meeting or, if not stated
in the notice or if there is no notice, at the principal executive office of the
corporation.

      Any meeting of the board, regular or special, may be held by conference
telephone or similar communication equipment, so long as all directors
participating in the meeting can hear one another; and all such participating
directors shall be deemed to be present in person at the meeting.

      3.7 FIRST MEETINGS

      The first meeting of each newly elected board of directors shall be held
at such time and place as shall be fixed by the vote of the stockholders at the
annual meeting. In the event of the failure of the stockholders to fix the time
or place of such first meeting of the newly elected board of directors, or in
the event such meeting is not held at the time and place so fixed by the
stockholders, the meeting may be held at such time and place as shall be
specified in a notice given as hereinafter provided for special meetings of the
board of directors, or as shall be specified in a written waiver signed by all
of the directors.

      3.8 REGULAR MEETINGS

      Regular meetings of the board of directors may be held without notice at
such time as shall from time to time be determined by the board of directors. If
any regular meeting day shall fall on a legal holiday, then the meeting shall be
held at the same time and place on the next succeeding full business day.

      3.9 SPECIAL MEETINGS; NOTICE

      Special meetings of the board of directors for any purpose or purposes may
be called at any time by the chairman of the board, the president, any vice
president, the secretary or any two directors.

      Notice of the time and place of special meetings shall be delivered
personally or by telephone to each director or sent by first-class mail,
telecopy or telegram, charges prepaid, addressed to each director at that
director's address as it is shown on the records of the corporation. If the
notice is mailed, it shall be deposited in the United States mail at least four
(4) days before the time of the holding of the meeting. If the notice is
delivered personally or by telephone, telecopy or telegram, it shall be
delivered personally

                                       -9-
<PAGE>   14
or by telephone or to the telegraph company at least forty-eight (48) hours
before the time of the holding of the meeting. Any oral notice given personally
or by telephone may be communicated either to the director or to a person at the
office of the director who the person giving the notice has reason to believe
will promptly communicate it to the director. The notice need not specify the
purpose or the place of the meeting, if the meeting is to be held at the
principal executive office of the corporation.

      3.10 QUORUM

      A majority of the authorized number of directors shall constitute a quorum
for the transaction of business, except to adjourn as provided in Section 3.12
of these bylaws. Every act or decision done or made by a majority of the
directors present at a duly held meeting at which a quorum is present shall be
regarded as the act of the board of directors, subject to the provisions of the
certificate of incorporation and applicable law.

      A meeting at which a quorum is initially present may continue to transact
business notwithstanding the withdrawal of directors, if any action taken is
approved by at least a majority of the quorum for that meeting.

      3.11 WAIVER OF NOTICE

      Notice of a meeting need not be given to any director (i) who signs a
waiver of notice, whether before or after the meeting, or (ii) who attends the
meeting other than for the express purpose of objecting at the beginning of the
meeting to the transaction of any business because the meeting is not lawfully
called or convened. All such waivers shall be filed with the corporate records
or made part of the minutes of the meeting. A waiver of notice need not specify
the purpose of any regular or special meeting of the board of directors.

      3.12 ADJOURNMENT

      A majority of the directors present, whether or not constituting a quorum,
may adjourn any meeting of the board to another time and place.

      3.13 NOTICE OF ADJOURNMENT

      Notice of the time and place of holding an adjourned meeting of the board
need not be given unless the meeting is adjourned for more than twenty-four (24)
hours. If the meeting is adjourned for more than twenty-four (24) hours, then
notice of the time and place of the adjourned meeting shall be given before the
adjourned meeting takes place, in the manner specified in Section 3.9 of these
bylaws, to the directors who were not present at the time of the adjournment.

                                      -10-
<PAGE>   15
      3.14 BOARD ACTION BY WRITTEN CONSENT WITHOUT A MEETING

      Any action required or permitted to be taken by the board of directors may
be taken without a meeting, provided that all members of the board individually
or collectively consent in writing to that action. Such action by written
consent shall have the same force and effect as a unanimous vote of the board of
directors. Such written consent and any counterparts thereof shall be filed with
the minutes of the proceedings of the board of directors.

      3.15 FEES AND COMPENSATION OF DIRECTORS

      Directors and members of committees may receive such compensation, if any,
for their services and such reimbursement of expenses as may be fixed or
determined by resolution of the board of directors. This Section 3.15 shall not
be construed to preclude any director from serving the corporation in any other
capacity as an officer, agent, employee or otherwise and receiving compensation
for those services.

      3.16 APPROVAL OF LOANS TO OFFICERS

      The corporation may lend money to, or guarantee any obligation of, or
otherwise assist any officer or other employee of the corporation or any of its
subsidiaries, including any officer or employee who is a director of the
corporation or any of its subsidiaries, whenever, in the judgment of the
directors, such loan, guaranty or assistance may reasonably be expected to
benefit the corporation. The loan, guaranty or other assistance may be with or
without interest and may be unsecured, or secured in such manner as the board of
directors shall approve, including, without limitation, a pledge of shares of
stock of the corporation. Nothing contained in this section shall be deemed to
deny, limit or restrict the powers of guaranty or warranty of the corporation at
common law or under any statute.

      3.17 SOLE DIRECTOR PROVIDED BY CERTIFICATE OF INCORPORATION

      In the event only one director is required by these bylaws or the
certificate of incorporation, then any reference herein to notices, waivers,
consents, meetings or other actions by a majority or quorum of the directors
shall be deemed to refer to such notice, waiver, etc., by such sole director,
who shall have all the rights and duties and shall be entitled to exercise all
of the powers and shall assume all the responsibilities otherwise herein
described as given to the board of directors.

                                      -11-
<PAGE>   16
                                   ARTICLE IV

                                   COMMITTEES

      4.1 COMMITTEES OF DIRECTORS

      The board of directors may, by resolution adopted by a majority of the
authorized number of directors, designate one (1) or more committees, each
consisting of two or more directors, to serve at the pleasure of the board. The
board may designate one (1) or more directors as alternate members of any
committee, who may replace any absent or disqualified member at any meeting of
the committee. The appointment of members or alternate members of a committee
requires the vote of a majority of the authorized number of directors. Any
committee, to the extent provided in the resolution of the board, shall have and
may exercise all the powers and authority of the board, but no such committee
shall have the power or authority to: (i) amend the certificate of incorporation
(except that a committee may, to the extent authorized in the resolution or
resolutions providing for the issuance of shares of stock adopted by the board
of directors as provided in Section 151(a) of the General Corporation Law of
Delaware, fix the designations and any of the preferences or rights of such
shares relating to dividends, redemption, dissolution, any distribution of
assets of the corporation or the conversion into, or the exchange of such shares
for, shares of any other class or classes or any other series of the same or any
other class or classes of stock of the corporation); (ii) adopt an agreement of
merger or consolidation under Sections 251 or 252 of the General Corporation Law
of Delaware; (iii) recommend to the stockholders the sale, lease or exchange of
all or substantially all of the corporation's property and assets; (iv)
recommend to the stockholders a dissolution of the corporation or a revocation
of a dissolution; or (v) amend the bylaws of the corporation; and, unless the
board resolution establishing the committee, the bylaws or the certificate of
incorporation expressly so provides, no such committee shall have the power or
authority to declare a dividend, to authorize the issuance of stock, or to adopt
a certificate of ownership and merger pursuant to Section 253 of the General
Corporation Law of Delaware.

      4.2 MEETINGS AND ACTION OF COMMITTEES

      Meetings and actions of committees shall be governed by, and held and
taken in accordance with, the following provisions of Article III of these
bylaws: Section 3.6 (place of meetings; meetings by telephone), Section 3.8
(regular meetings), Section 3.9 (special meetings; notice), Section 3.10
(quorum), Section 3.11 (waiver of notice), Section 3.12 (adjournment), Section
3.13 (notice of adjournment) and Section 3.14 (board action by written consent
without a meeting), with such changes in the context of those bylaws as are
necessary to substitute the committee and its members for the board of directors
and its members; provided, however, that the time of regular meetings of
committees may be determined either by resolution of the board of directors or
by resolution of the committee, that special meetings of committees may also be
called by resolution of the board of directors, and that notice of special
meetings of committees shall also be given to all alternate members, who shall
have the right to attend all meetings of the committee. The board of directors
may adopt rules for the government of any committee not inconsistent with the
provisions of these bylaws.

                                      -12-
<PAGE>   17
      4.3 COMMITTEE MINUTES

      Each committee shall keep regular minutes of its meetings and report the
same to the board of directors when required.

                                    ARTICLE V

                                    OFFICERS

      5.1 OFFICERS

      The Corporate Officers of the corporation shall be a president, a
secretary and a chief financial officer. The corporation may also have, at the
discretion of the board of directors, a chairman of the board, one or more vice
presidents (however denominated), one or more assistant secretaries, a treasurer
and one or more assistant treasurers, and such other officers as may be
appointed in accordance with the provisions of Section 5.3 of these bylaws. Any
number of offices may be held by the same person.

      In addition to the Corporate Officers of the Company described above,
there may also be such Administrative Officers of the corporation as may be
designated and appointed from time to time by the president of the corporation
in accordance with the provisions of Section 5.12 of these bylaws.

      5.2 ELECTION OF OFFICERS

      The Corporate Officers of the corporation, except such officers as may be
appointed in accordance with the provisions of Section 5.3 or Section 5.5 of
these bylaws, shall be chosen by the board of directors, subject to the rights,
if any, of an officer under any contract of employment, and shall hold their
respective offices for such terms as the board of directors may from time to
time determine.

      5.3 SUBORDINATE OFFICERS

      The board of directors may appoint, or may empower the president to
appoint, such other Corporate Officers as the business of the corporation may
require, each of whom shall hold office for such period, have such power and
authority, and perform such duties as are provided in these bylaws or as the
board of directors may from time to time determine.

      The president may from time to time designate and appoint Administrative
Officers of the corporation in accordance with the provisions of Section 5.12 of
these bylaws.

      5.4 REMOVAL AND RESIGNATION OF OFFICERS

      Subject to the rights, if any, of a Corporate Officer under any contract
of employment, any Corporate Officer may be removed, either with or without
cause, by the board of directors at any regular

                                      -13-
<PAGE>   18
or special meeting of the board or, except in case of a Corporate Officer chosen
by the board of directors, by any Corporate Officer upon whom such power of
removal may be conferred by the board of directors.

      Any Corporate Officer may resign at any time by giving written notice to
the corporation. Any resignation shall take effect at the date of the receipt of
that notice or at any later time specified in that notice; and, unless otherwise
specified in that notice, the acceptance of the resignation shall not be
necessary to make it effective. Any resignation is without prejudice to the
rights, if any, of the corporation under any contract to which the Corporate
Officer is a party.

      Any Administrative Officer designated and appointed by the president may
be removed, either with or without cause, at any time by the president. Any
Administrative Officer may resign at any time by giving written notice to the
president or to the secretary of the corporation.

      5.5 VACANCIES IN OFFICES

      A vacancy in any office because of death, resignation, removal,
disqualification or any other cause shall be filled in the manner prescribed in
these bylaws for regular appointments to that office.

      5.6 CHAIRMAN OF THE BOARD

      The chairman of the board, if such an officer be elected, shall, if
present, preside at meetings of the board of directors and exercise such other
powers and perform such other duties as may from time to time be assigned to him
by the board of directors or as may be prescribed by these bylaws. If there is
no president, then the chairman of the board shall also be the chief executive
officer of the corporation and shall have the powers and duties prescribed in
Section 5.7 of these bylaws.

      5.7 PRESIDENT

      Subject to such supervisory powers, if any, as may be given by the board
of directors to the chairman of the board, if there be such an officer, the
president shall be the chief executive officer of the corporation and shall,
subject to the control of the board of directors, have general supervision,
direction and control of the business and the officers of the corporation. He or
she shall preside at all meetings of the stockholders and, in the absence or
nonexistence of a chairman of the board, at all meetings of the board of
directors. He or she shall have the general powers and duties of management
usually vested in the office of president of a corporation, and shall have such
other powers and perform such other duties as may be prescribed by the board of
directors or these bylaws.

      5.8 VICE PRESIDENTS

      In the absence or disability of the president, and if there is no chairman
of the board, the vice presidents, if any, in order of their rank as fixed by
the board of directors or, if not ranked, a vice president designated by the
board of directors, shall perform all the duties of the president and when so
acting shall have all the powers of, and be subject to all the restrictions
upon, the president. The vice

                                      -14-
<PAGE>   19
presidents shall have such other powers and perform such other duties as from
time to time may be prescribed for them respectively by the board of directors,
these bylaws, the president or the chairman of the board.

      5.9 SECRETARY

      The secretary shall keep or cause to be kept, at the principal executive
office of the corporation or such other place as the board of directors may
direct, a book of minutes of all meetings and actions of the board of directors,
committees of directors and stockholders. The minutes shall show the time and
place of each meeting, whether regular or special (and, if special, how
authorized and the notice given), the names of those present at directors'
meetings or committee meetings, the number of shares present or represented at
stockholders' meetings and the proceedings thereof.

      The secretary shall keep, or cause to be kept, at the principal executive
office of the corporation or at the office of the corporation's transfer agent
or registrar, as determined by resolution of the board of directors, a share
register or a duplicate share register, showing the names of all stockholders
and their addresses, the number and classes of shares held by each, the number
and date of certificates evidencing such shares and the number and date of
cancellation of every certificate surrendered for cancellation.

      The secretary shall give, or cause to be given, notice of all meetings of
the stockholders and of the board of directors required to be given by law or by
these bylaws. He or she shall keep the seal of the corporation, if one be
adopted, in safe custody and shall have such other powers and perform such other
duties as may be prescribed by the board of directors or by these bylaws.

      5.10 CHIEF FINANCIAL OFFICER

      The chief financial officer shall keep and maintain, or cause to be kept
and maintained, adequate and correct books and records of accounts of the
properties and business transactions of the corporation, including accounts of
its assets, liabilities, receipts, disbursements, gains, losses, capital,
retained earnings and shares. The books of account shall at all reasonable times
be open to inspection by any director for a purpose reasonably related to his
position as a director.

      The chief financial officer shall deposit all money and other valuables in
the name and to the credit of the corporation with such depositaries as may be
designated by the board of directors. He or she shall disburse the funds of the
corporation as may be ordered by the board of directors, shall render to the
president and directors, whenever they request it, an account of all of his or
her transactions as chief financial officer and of the financial condition of
the corporation, and shall have such other powers and perform such other duties
as may be prescribed by the board of directors or these bylaws.

      5.11 ASSISTANT SECRETARY

      The assistant secretary, if any, or, if there is more than one, the
assistant secretaries in the order determined by the board of directors (or if
there be no such determination, then in the order of their

                                      -15-
<PAGE>   20
election) shall, in the absence of the secretary or in the event of his or her
inability or refusal to act, perform the duties and exercise the powers of the
secretary and shall perform such other duties and have such other powers as the
board of directors may from time to time prescribe.

      5.12 ADMINISTRATIVE OFFICERS

      In addition to the Corporate Officers of the corporation as provided in
Section 5.1 of these bylaws and such subordinate Corporate Officers as may be
appointed in accordance with Section 5.3 of these bylaws, there may also be such
Administrative Officers of the corporation as may be designated and appointed
from time to time by the president of the corporation. Administrative Officers
shall perform such duties and have such powers as from time to time may be
determined by the president or the board of directors in order to assist the
Corporate Officers in the furtherance of their duties. In the performance of
such duties and the exercise of such powers, however, such Administrative
Officers shall have limited authority to act on behalf of the corporation as the
board of directors shall establish, including but not limited to limitations on
the dollar amount and on the scope of agreements or commitments that may be made
by such Administrative Officers on behalf of the corporation, which limitations
may not be exceeded by such individuals or altered by the president without
further approval by the board of directors.

      5.13 AUTHORITY AND DUTIES OF OFFICERS

      In addition to the foregoing powers, authority and duties, all officers of
the corporation shall respectively have such authority and powers and perform
such duties in the management of the business of the corporation as may be
designated from time to time by the board of directors.

                                      -16-
<PAGE>   21
                                   ARTICLE VI

                INDEMNIFICATION OF DIRECTORS, OFFICERS, EMPLOYEES
                                AND OTHER AGENTS

      6.1 INDEMNIFICATION OF DIRECTORS AND OFFICERS

      The corporation shall, to the maximum extent and in the manner permitted
by the General Corporation Law of Delaware as the same now exists or may
hereafter be amended, indemnify any person against expenses (including
attorneys' fees), judgments, fines, and amounts paid in settlement actually and
reasonably incurred in connection with any threatened, pending or completed
action, suit, or proceeding in which such person was or is a party or is
threatened to be made a party by reason of the fact that such person is or was a
director or officer of the corporation. For purposes of this Section 6.1, a
"director" or "officer" of the corporation shall mean any person (i) who is or
was a director or officer of the corporation, (ii) who is or was serving at the
request of the corporation as a director or officer of another corporation,
partnership, joint venture, trust or other enterprise, or (iii) who was a
director or officer of a corporation which was a predecessor corporation of the
corporation or of another enterprise at the request of such predecessor
corporation.

      The corporation shall be required to indemnify a director or officer in
connection with an action, suit, or proceeding (or part thereof) initiated by
such director or officer only if the initiation of such action, suit, or
proceeding (or part thereof) by the director or officer was authorized by the
board of directors of the corporation.

      The corporation shall pay the expenses (including attorney's fees)
incurred by a director or officer of the corporation entitled to indemnification
hereunder in defending any action, suit or proceeding referred to in this
Section 6.1 in advance of its final disposition; provided, however, that payment
of expenses incurred by a director or officer of the corporation in advance of
the final disposition of such action, suit or proceeding shall be made only upon
receipt of an undertaking by the director or officer to repay all amounts
advanced if it should ultimately be determined that the director of officer is
not entitled to be indemnified under this Section 6.1 or otherwise.

      The rights conferred on any person by this Article VI shall not be
exclusive of any other rights which such person may have or hereafter acquire
under any statute, provision of the corporation's certificate of incorporation,
these bylaws, agreement, vote of the stockholders or disinterested directors or
otherwise.

      Any repeal or modification of the foregoing provisions of this Article VI
shall not adversely affect any right or protection hereunder of any person in
respect of any act or omission occurring prior to the time of such repeal or
modification.

                                      -17-
<PAGE>   22
      6.2 INDEMNIFICATION OF OTHERS

      The corporation shall have the power, to the maximum extent and in the
manner permitted by the General Corporation Law of Delaware as the same now
exists or may hereafter be amended, to indemnify any person (other than
directors and officers) against expenses (including attorneys' fees), judgments,
fines, and amounts paid in settlement actually and reasonably incurred in
connection with any threatened, pending or completed action, suit, or
proceeding, in which such person was or is a party or is threatened to be made a
party by reason of the fact that such person is or was an employee or agent of
the corporation. For purposes of this Section 6.2, an "employee" or "agent" of
the corporation (other than a director or officer) shall mean any person (i) who
is or was an employee or agent of the corporation, (ii) who is or was serving at
the request of the corporation as an employee or agent of another corporation,
partnership, joint venture, trust or other enterprise, or (iii) who was an
employee or agent of a corporation which was a predecessor corporation of the
corporation or of another enterprise at the request of such predecessor
corporation.

      6.3 INSURANCE

      The corporation may purchase and maintain insurance on behalf of any
person who is or was a director, officer, employee or agent of the corporation,
or is or was serving at the request of the corporation as a director, officer,
employee or agent of another corporation, partnership, joint venture, trust or
other enterprise against any liability asserted against him or her and incurred
by him or her in any such capacity, or arising out of his or her status as such,
whether or not the corporation would have the power to indemnify him or her
against such liability under the provisions of the General Corporation Law of
Delaware.

                                   ARTICLE VII

                               RECORDS AND REPORTS

      7.1 MAINTENANCE AND INSPECTION OF RECORDS

      The corporation shall, either at its principal executive office or at such
place or places as designated by the board of directors, keep a record of its
stockholders listing their names and addresses and the number and class of
shares held by each stockholder, a copy of these bylaws as amended to date,
accounting books and other records of its business and properties.

      Any stockholder of record, in person or by attorney or other agent, shall,
upon written demand under oath stating the purpose thereof, have the right
during the usual hours for business to inspect for any proper purpose the
corporation's stock ledger, a list of its stockholders, and its other books and
records and to make copies or extracts therefrom. A proper purpose shall mean a
purpose reasonably related to such person's interest as a stockholder. In every
instance where an attorney or other agent is the person who seeks the right to
inspection, the demand under oath shall be accompanied by a power

                                      -18-
<PAGE>   23
of attorney or such other writing that authorizes the attorney or other agent to
so act on behalf of the stockholder. The demand under oath shall be directed to
the corporation at its registered office in Delaware or at its principal place
of business.

      7.2 INSPECTION BY DIRECTORS

      Any director shall have the right to examine (and to make copies of) the
corporation's stock ledger, a list of its stockholders and its other books and
records for a purpose reasonably related to his or her position as a director.

      7.3 ANNUAL STATEMENT TO STOCKHOLDERS

      The board of directors shall present at each annual meeting, and at any
special meeting of the stockholders when called for by vote of the stockholders,
a full and clear statement of the business and condition of the corporation.

      7.4 REPRESENTATION OF SHARES OF OTHER CORPORATIONS

      The chairman of the board, if any, the president, any vice president, the
chief financial officer, the secretary or any assistant secretary of this
corporation, or any other person authorized by the board of directors or the
president or a vice president, is authorized to vote, represent and exercise on
behalf of this corporation all rights incident to any and all shares of the
stock of any other corporation or corporations standing in the name of this
corporation. The authority herein granted may be exercised either by such person
directly or by any other person authorized to do so by proxy or power of
attorney duly executed by such person having the authority.

      7.5 CERTIFICATION AND INSPECTION OF BYLAWS

      The original or a copy of these bylaws, as amended or otherwise altered to
date, certified by the secretary, shall be kept at the corporation's principal
executive office and shall be open to inspection by the stockholders of the
corporation, at all reasonable times during office hours.

                                  ARTICLE VIII

                                 GENERAL MATTERS

      8.1 RECORD DATE FOR PURPOSES OTHER THAN NOTICE AND VOTING

      For purposes of determining the stockholders entitled to receive payment
of any dividend or other distribution or allotment of any rights or the
stockholders entitled to exercise any rights in respect of any change,
conversion or exchange of stock, or for the purpose of any other lawful action,
the board of directors may fix, in advance, a record date, which shall not
precede the date upon which the resolution

                                      -19-
<PAGE>   24
fixing the record date is adopted and which shall not be more than sixty (60)
days before any such action. In that case, only stockholders of record at the
close of business on the date so fixed are entitled to receive the dividend,
distribution or allotment of rights, or to exercise such rights, as the case may
be, notwithstanding any transfer of any shares on the books of the corporation
after the record date so fixed, except as otherwise provided by law.

      If the board of directors does not so fix a record date, then the record
date for determining stockholders for any such purpose shall be at the close of
business on the day on which the board of directors adopts the applicable
resolution.

      8.2 CHECKS; DRAFTS; EVIDENCES OF INDEBTEDNESS

      From time to time, the board of directors shall determine by resolution
which person or persons may sign or endorse all checks, drafts, other orders for
payment of money, notes or other evidences of indebtedness that are issued in
the name of or payable to the corporation, and only the persons so authorized
shall sign or endorse those instruments.

      8.3 CORPORATE CONTRACTS AND INSTRUMENTS: HOW EXECUTED

      The board of directors, except as otherwise provided in these bylaws, may
authorize and empower any officer or officers, or agent or agents, to enter into
any contract or execute any instrument in the name of and on behalf of the
corporation; such power and authority may be general or confined to specific
instances. Unless so authorized or ratified by the board of directors or within
the agency power of an officer, no officer, agent or employee shall have any
power or authority to bind the corporation by any contract or engagement or to
pledge its credit or to render it liable for any purpose or for any amount.

      8.4 STOCK CERTIFICATES; TRANSFER; PARTLY PAID SHARES

      The shares of the corporation shall be represented by certificates,
provided that the board of directors of the corporation may provide by
resolution or resolutions that some or all of any or all classes or series of
its stock shall be uncertificated shares. Any such resolution shall not apply to
shares represented by a certificate until such certificate is surrendered to the
corporation. Notwithstanding the adoption of such a resolution by the board of
directors, every holder of stock represented by certificates and, upon request,
every holder of uncertificated shares, shall be entitled to have a certificate
signed by, or in the name of the corporation by, the chairman or vice-chairman
of the board of directors, or the president or vice-president, and by the
treasurer or an assistant treasurer, or the secretary or an assistant secretary
of such corporation representing the number of shares registered in certificate
form. Any or all of the signatures on the certificate may be a facsimile. In
case any officer, transfer agent or registrar who has signed or whose facsimile
signature has been placed upon a certificate has ceased to be such officer,
transfer agent or registrar before such certificate is issued, it may be issued
by the corporation with the same effect as if he or she were such officer,
transfer agent or registrar at the date of issue.

                                      -20-
<PAGE>   25
      Certificates for shares shall be of such form and device as the board of
directors may designate and shall state the name of the record holder of the
shares represented thereby; its number; date of issuance; the number of shares
for which it is issued; a summary statement or reference to the powers,
designations, preferences or other special rights of such stock and the
qualifications, limitations or restrictions of such preferences and/or rights,
if any; a statement or summary of liens, if any; a conspicuous notice of
restrictions upon transfer or registration of transfer, if any; a statement as
to any applicable voting trust agreement; if the shares be assessable, or, if
assessments are collectible by personal action, a plain statement of such facts.

      Upon surrender to the secretary or transfer agent of the corporation of a
certificate for shares duly endorsed or accompanied by proper evidence of
succession, assignment or authority to transfer, it shall be the duty of the
corporation to issue a new certificate to the person entitled thereto, cancel
the old certificate and record the transaction upon its books.

      The corporation may issue the whole or any part of its shares as partly
paid and subject to call for the remainder of the consideration to be paid
therefor. Upon the face or back of each stock certificate issued to represent
any such partly paid shares, or upon the books and records of the corporation in
the case of uncertificated partly paid shares, the total amount of the
consideration to be paid therefor and the amount paid thereon shall be stated.
Upon the declaration of any dividend on fully paid shares, the corporation shall
declare a dividend upon partly paid shares of the same class, but only upon the
basis of the percentage of the consideration actually paid thereon.

      8.5 SPECIAL DESIGNATION ON CERTIFICATES

      If the corporation is authorized to issue more than one class of stock or
more than one series of any class, then the powers, the designations, the
preferences and the relative, participating, optional or other special rights of
each class of stock or series thereof and the qualifications, limitations or
restrictions of such preferences and/or rights shall be set forth in full or
summarized on the face or back of the certificate that the corporation shall
issue to represent such class or series of stock; provided, however, that,
except as otherwise provided in Section 202 of the General Corporation Law of
Delaware, in lieu of the foregoing requirements there may be set forth on the
face or back of the certificate that the corporation shall issue to represent
such class or series of stock a statement that the corporation will furnish
without charge to each stockholder who so requests the powers, the designations,
the preferences and the relative, participating, optional or other special
rights of each class of stock or series thereof and the qualifications,
limitations or restrictions of such preferences and/or rights.

      8.6 LOST CERTIFICATES

      Except as provided in this Section 8.6, no new certificates for shares
shall be issued to replace a previously issued certificate unless the latter is
surrendered to the corporation and cancelled at the same time. The board of
directors may, in case any share certificate or certificate for any other
security is lost, stolen or destroyed, authorize the issuance of replacement
certificates on such terms and conditions as the board may require; the board
may require indemnification of the corporation secured by a bond or

                                      -21-
<PAGE>   26
other adequate security sufficient to protect the corporation against any claim
that may be made against it, including any expense or liability, on account of
the alleged loss, theft or destruction of the certificate or the issuance of the
replacement certificate.

      8.7 TRANSFER AGENTS AND REGISTRARS

      The board of directors may appoint one or more transfer agents or transfer
clerks, and one or more registrars, each of which shall be an incorporated bank
or trust company, either domestic or foreign, who shall be appointed at such
times and places as the requirements of the corporation may necessitate and the
board of directors may designate.

      8.8 CONSTRUCTION; DEFINITIONS

      Unless the context requires otherwise, the general provisions, rules of
construction and definitions in the General Corporation Law of Delaware shall
govern the construction of these bylaws. Without limiting the generality of this
provision, as used in these bylaws, the singular number includes the plural, the
plural number includes the singular, and the term "person" includes both an
entity and a natural person.

                                   ARTICLE IX

                                   AMENDMENTS

      The original or other bylaws of the corporation may be adopted, amended or
repealed by the stockholders entitled to vote or by the board of directors of
the corporation. The fact that such power has been so conferred upon the
directors shall not divest the stockholders of the power, nor limit their power
to adopt, amend or repeal bylaws.

      Whenever an amendment or new bylaw is adopted, it shall be copied in the
book of bylaws with the original bylaws, in the appropriate place. If any bylaw
is repealed, the fact of repeal with the date of the meeting at which the repeal
was enacted or the filing of the operative written consent(s) shall be stated in
said book.

                                      -22-
<PAGE>   27
                        CERTIFICATE OF ADOPTION OF BYLAWS

                                       OF

                          VENTANA MEDICAL SYSTEMS, INC.

      The undersigned hereby certifies that he is the duly elected, qualified,
and acting Secretary of Ventana Medical Systems, Inc. and that the foregoing
Bylaws were adopted as the Bylaws of the corporation effective as of June 28,
1996 by the board of directors of the corporation and by written consent of the
stockholders of the corporation effective as of such date..

      IN WITNESS WHEREOF, the undersigned has hereunto set his hand and affixed
the corporate seal this ___ day of June 1996.



                                      __________________________________  
                                      R. Michael Rodgers,
                                      Secretary



                                      -23-



<PAGE>   1
                                                                    EXHIBIT 4.1


                                 [VENTANA LOGO]

                         VENTANA MEDICAL SYSTEMS, INC.
              INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE

      This Certificate is transferable in Minneapolis, MN or New York, NY

     See reverse for statements relating to rights, preferences, privileges
                           and restrictions, if any.


                              This Certifies that


                   -----------------------------------------

                                is the owner of


                   ------------------------------------------

             FULLY PAID AND NON-ASSESSABLE SHARES OF COMMON STOCK,
                         PAR VALUE $.001 PER SHARE, OF

                         VENTANA MEDICAL SYSTEMS, INC.

transferable only on the books of the Corporation by the holder hereof in
person or by duly authorized Attorney upon surrender of this certificate
properly endorsed. This certificate is not valid until countersigned and
registered by the Transfer Agent and Registrar.

       WITNESS the facsimile signatures of its duly authorized officers.

Dated

/s/ R. Michael Rodgers                  /s/   James Danehy
- -------------------------               -----------------------
Vice President, Chief                   President and Chief
Financial Officer                       Executive Officer
and Secretary



Countersigned and registered:
Norwest Bank Minnesota, N.A.
Transfer Agent and Registrar

By: _________________________
    Authorized Signature

<PAGE>   2



                         VENTANA MEDICAL SYSTEMS, INC.

     A statement of the powers, designations, preferences and relative, 
participating, optional or other special rights of each class of stock or
series thereof and the qualifications, limitations or restrictions of such
preferences and/or rights as established, from time to time, by the Certificate
of Incorporation of the Corporation and by any certificate of determination,
the number of shares constituting each class and series, and the designations
thereof, may be obtained by the holder hereof upon request and without charge
at the principal office of the Corporation.

     The following abbreviations, when used in the inscription on the face of
this certificate, shall be construed as though they were written out in full
according to applicable laws or regulations:

TEN COM -- as tenants in common
TEN ENT -- as tenants by the entireties
JT TEN  -- as joint tenants with right of 
           survivorship and not as tenants
           in common



UNIF GFT MIN ACT -- _______________ Custodian _________________
                       (Cust)                    (Minor)
                    under Uniform Gifts to Minors
                    Act________________________________________
                                 (State)
UNIF TRF MIN ACT -- _______________ Custodian (until age _____)
                       (Cust)
                    ____________________under Uniform Transfers
                       (Minor)
                    to Minors Act______________________________
                                           (State)

    Additional abbreviations may also be used though not in the above list.


FOR VALUE RECEIVED, _______________ hereby sell, assign and transfer unto

PLEASE INSERT SOCIAL SECURITY OR OTHER
   IDENTIFYING NUMBER OF ASSIGNEE
______________________________________

______________________________________

________________________________________________________________________________
  (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE)

________________________________________________________________________________

________________________________________________________________________________

__________________________________________________________________________Shares
of the capital stock represented by the within Certificate, and do hereby 
irrevocably constitute and appoint

________________________________________________________________________Attorney
to transfer the said stock on the books of the within named Corporation with
full power of substitution in the premises.

Dated_____________________________



                               X________________________________________________

                               X________________________________________________
                                THE SIGNATURE(S) TO THIS ASSIGNMENT MUST
                        NOTICE: CORRESPOND WITH THE NAME(S) AS WRITTEN UPON THE 
                                FACE OF THE CERTIFICATE IN EVERY PARTICULAR, 
                                WITHOUT ALTERATION OR ENLARGEMENT OR ANY 
                                CHANGE WHATEVER.

Signature(s) Guaranteed



By_______________________________________
THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN
ELIGIBLE GUARANTOR INSTITUTION (BANKS,
STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS
AND CREDIT UNIONS WITH MEMBERSHIP IN AN
APPROVED SIGNATURE GUARANTEE MEDALLION 
PROGRAM, PURSUANT TO S.E.C. RULE 17Ad-15.



<PAGE>   1
                                                                 EXHIBIT 10.2(a)

         THIS NOTE HAS BEEN ACQUIRED SOLELY FOR INVESTMENT AND HAS NOT BEEN
         REGISTERED UNDER THE SECURITIES ACT OF 1933 OR QUALIFIED UNDER ANY
         STATE SECURITIES LAWS. THIS NOTE MAY NOT BE SOLD OR TRANSFERRED IN THE
         ABSENCE OF SUCH REGISTRATION AND QUALIFICATION OR AN EXEMPTION
         THEREFROM. THIS NOTE CONTAINS RESTRICTIONS ON TRANSFER OR ASSIGNMENT.

                             BIOTEK SOLUTIONS, INC.

                             SECURED PROMISSORY NOTE

400,000                                                Santa Barbara, California
                                                                December 9, 1994

         FOR VALUE RECEIVED, BIOTEK SOLUTIONS, INC., a California corporation
("Maker"), unconditionally promises to pay to the order of DAKO A/S, a Danish
corporation ("Payee"), in lawful money of the United States of America by check
to the address of Payee maintained in the records of Maker, the principal amount
of $400,000 or such lesser amount that shall remain unpaid or unrecouped (as
described in Section 3 below) on the Maturity Date (defined below).

         Maker also promises to pay interest on the unpaid principal amount
hereof (in lawful money of the United States of America by check to the address
of Payee maintained in the records of Maker) from the date hereof until paid in
full at a rate per annum equal to 5%. Interest on this Note shall be payable in
arrears on March 31, June 30, September 30 and December 31 of each year
commencing March 31, 1995, upon any prepayment of this Note (to the extent
accrued on the amount being prepaid) and at maturity. All computations of
interest shall be made by Payee on the basis of a 365-day year, for the actual
number of days elapsed in the relevant periods (including the first day, but
excluding the last day).

         1. Issuance Pursuant to Agreement. This Note is issued pursuant to the
Distribution Agreement between the Maker and the Payee dated as of September 27,
1994 (as the same may hereinafter be amended, the "Distribution Agreement"). All
terms defined in the Distribution Agreement shall have the same meaning in this
Note unless otherwise defined in this Note.
<PAGE>   2
         2. Maturity Date. This Note is due and payable:

         (a) in full, on the termination date of the Distribution Agreement, if
         such termination is made by the Maker; or

         (b) in twelve (12) equal quarterly installments commencing on the first
         day of the fiscal quarter which immediately follows the earlier of the
         following events:

                  (1) the date on which Payee makes the election set forth in
                  Section 21g(y) of the Distribution Agreement and sends written
                  notice thereof (which election relates to the occurrence of a
                  Delivery Failure by Maker); or

                  (2) the termination date of the Distribution Agreement (other
                  than due to a breach by the Maker in its obligations
                  thereunder), if such termination is made by the Payee.

         3. Reduction of Principal Amount Due. In the event and to the extent
that the Payee recoups the Kollsman Prepayment pursuant to Section 20b of the
Distribution Agreement, the principal amount of this Note shall be reduced in an
amount equal to such recoupment.

         4. Prepayments. Maker shall have the right at any time and from time to
time to prepay the principal of this Note in whole or in part without premium or
penalty.

         5. Security Interest.

         (a) As security for the payment of this Note, Maker hereby grants to
         Payee a security interest in the assets described in Schedule A hereto
         (the "Collateral").

         (b) Concurrently with the delivery of this Note, Maker will execute,
         file and/or record in the appropriate jurisdiction a UCC-1 Financing
         Statement covering the Collateral and naming Payee as secured party.
         Maker will give, execute, file and/or record any further notice,
         financing statement, instrument, document or agreement that Payee may
         reasonably consider necessary or desirable to create, preserve,
         continue, perfect or validate the security interest granted hereby or
         which Payee may reasonably consider necessary or desirable to exercise
         or enforce its rights hereunder with respect to such security interest;
         provided, however, Payee acknowledges that its security interest shall
         remain subordinate to those of Maker's present Senior Secured Note
         Holders.

                                        2
<PAGE>   3
         6. Covenant. Maker covenants and agrees that until this Note is paid in
full, Maker will, promptly upon the occurrence of an Event of Default (defined
below) or any event, act or condition which, with notice or lapse of time or
both, would constitute an Event of Default, provide Payee with a certificate of
the chief executive officer or chief financial officer of Maker specifying the
nature thereof and Maker's proposed response thereto.

         7. Representations and Warranties. Maker hereby represents and warrants
to Payee that:

         (a) Maker is a duly incorporated and validly existing corporation in
good standing under the laws of the jurisdiction of its incorporation and has
the corporate power and authority to own and operate is properties, to transact
the business in which it is now engaged and to execute and deliver this Note;

         (b) this Note constitutes the duly authorized, legally valid and
binding obligation of Maker, enforceable against Maker in accordance with its
terms, except as may be limited by bankruptcy, moratorium, insolvency,
reorganization and other similar laws relating to or affecting creditor's rights
generally and by general principles or equity; and

         (c) the execution, delivery and performance by Maker of this Note will
not violate any law, governmental rule or regulation, court order to agreement
to which its is subject or by which its properties are bound or the Articles of
Incorporation or Bylaws of Maker.

         8. Events of Default. The occurrence of any of the following events
shall constitute an "Event of Default":

         (a) failure of Maker to pay any principal under this Note when due, by
acceleration, by notice of prepayment or otherwise; provided, however, that the
failure of Maker to pay principal under this Note pursuant to Section 2(b)
hereof shall only constitute an Event of Default hereunder in the event that
such payment remains unpaid thirty (30) days after the same has become due and
payable pursuant to said Section 2(b); or

         (b) failure of Maker to pay any interest due under this Note within 15
days after the date due; or

         (c) the Maker shall receive: (i) a notice of sale pursuant to
California Commercial Code Section 9504, (ii) a notice of intent to retain
possession pursuant to California Commercial Code Section 9505, or (iii) a
notice of any similar action or proceeding by a creditor asserting a lien
against an asset of the Maker; or

                                        3
<PAGE>   4
         (d) (i) a court having jurisdiction over the Maker shall enter a decree
or order for relief in respect of Maker in an involuntary case under Title 11 of
the United States Code entitled "Bankruptcy" (as now and hereinafter in effect,
or any successor thereto the "Bankruptcy Code") or any applicable bankruptcy,
insolvency or other similar law now or hereafter in effect, which decree or
order is not stayed; or (ii) an involuntary case shall be commenced against
Maker under any applicable bankruptcy, insolvency or other similar law now or
hereafter in effect; or a decree or order of a court having jurisdiction over
the Maker for the appointment of a receiver, liquidator, sequestrator, trustee,
custodian or other officer having similar powers over Maker over all or a
substantial part of its property shall have been entered; or the involuntary
appointment of an interim receiver, trustee or other custodian of Maker of all
or a substantial part of its property shall have occurred; or a warrant of
attachment, execution or similar process shall have been issued against any
substantial part of the property of Maker; or

         (e) an order for relief under the Bankruptcy Code shall have been
entered with respect to Maker or Maker shall have commenced a voluntary case
under the Bankruptcy Code or any applicable bankruptcy, insolvency or other
similar law now or hereafter in effect, or shall consent to the entry of an
order for relief in an involuntary case, or to the conversion of an involuntary
case to a voluntary case, under any such law, or shall consent to the
appointment of or taking possession by a receiver, trustee or other custodian
for all or a substantial part of its property; or Maker shall make an assignment
for the benefit of creditors; or Maker shall be unable or fail, or shall admit
in writing its inability, to pay its debts as such debts become due.

         9. Remedies. Upon the occurrence of any Event of Default, the unpaid
principal amount of this Note shall become immediately due and payable, without
presentment, demand, notice, protest or other requirements of any kind (all of
which are hereby expressly waived by Maker), and Payee shall have all of the
rights and remedies of a secured party under the Uniform Commercial Code as in
force in the State of California and any other applicable laws.

         10. Restrictions of Transfer. THIS NOTE MAY NOT BE TRANSFERRED, SOLD,
PLEDGED, HYPOTHECATED OR ASSIGNED BY PAYEE UNLESS PRIOR TO SUCH TRANSFER, SALE,
PLEDGE, HYPOTHECATION OR ASSIGNMENT PAYEE HAS PROVIDED MAKER WITH AN OPINION OF
COUNSEL, REASONABLY SATISFACTORY TO MAKER AND ITS COUNSEL, TO THE EFFECT THAT
SUCH TRANSFER, SALE, PLEDGE, HYPOTHECATION OR ASSIGNMENT IS EXEMPT FROM
REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND ALL RELEVANT
STATE SECURITIES LAWS.

                                        4
<PAGE>   5
         11. Miscellaneous.

         (a) All notices and other communications provided for hereunder shall
be in writing (including telegraphic, telex, telecopier or cable communication)
and mailed, telegraphed, telexed, telecopied, cabled or delivered as follows: if
to Maker, at its address specified opposite its signature below; and if to
Payee, at Payee's address as shown in the records of Maker; or in each case at
such other address as shall be designated by Payee or Maker in a written notice
to the other. All such notices and communications shall, when mailed,
telegraphed, telexed, telecopied or cabled or sent by overnight courier, be
effective when deposited in the mails, delivered to the telegraph company, cable
company or overnight courier, as the case may be, or sent by telex or
telecopier.

         (b) THIS NOTE AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES HEREUNDER
SHALL BE GOVERNED BY, AND CONSTRUED AND ENFORCED IN ACCORDANCE WITH, THE LAWS OF
THE STATE OF CALIFORNIA.

         Maker shall pay to the holder of this Note all reasonable costs and
expenses (including reasonable attorneys' fees) incurred by the holder in
collecting amounts due under this Note or enforcing the terms hereof.

         IN WITNESS WHEREOF, Maker has caused this Note to be executed and
delivered by its duly authorized officer as of the day and year and at the place
first above written.

                                              BIOTEK SOLUTIONS, INC.



                                              By:  /s/ MICHAEL C. MILLER
                                                   -----------------------------
                                                   Michael C. Miller, CEO


                                              Address:
                                              120-B Cremona Drive
                                              Santa Barbara, CA  93117


                                        5
<PAGE>   6
                                   SCHEDULE A

         The collateral in which the security interest is created (hereinafter
referred to as the "Collateral") shall consist of:

                  (a) Any and all of BioTek Solution Inc.'s ("BioTek's")
accounts, contract rights, and other rights to the payment of monies, now
existing or hereafter acquired, including all repossessions and returns (the
"Accounts"), and all proceeds of the Accounts;

                  (b) Any and all of BioTek's inventory in all of its forms, now
or hereafter existing, including but not limited to all finished goods, work in
process and raw materials, and goods which are returned to or repossessed by
BioTek (the "Inventory"), and all proceeds of the Inventory;

                  (c) Any and all of BioTek's equipment, now or hereafter
acquired, used in manufacture or otherwise used in the conduct of BioTek's
business, including but not limited to manufacturing equipment, field service
equipment, office equipment, furniture and fixtures and leasehold improvements
to the full extent of BioTek's interest in all of the above (the "Equipment"),
and all proceeds of the Equipment, provided, that the Collateral shall not
include Equipment (or BioTek's leasehold interest therein) presently being
purchased or leased by BioTek to the extent that the inclusion of such Equipment
(or BioTek's leasehold interest therein) would violate the terms of such
agreements;

                  (d) Any and all patents, patent rights, inventions, processes,
formulas, licenses, trade secrets, know-how and other proprietary rights and
data, engineering calculations, technical plans, drawings and data, trademarks,
trademark rights, service marks, service mark rights, trade name, trade name
rights, copyrights, copyright rights, mask works and all other technology or
proprietary rights of BioTek, and all applications to acquire any such rights,
in each case, whether now owned or hereafter created, acquired or issued
(collectively, the "Technology");

                  (e) Any and all licenses, sublicenses and franchises, whether
now owned or hereafter acquired, granted in any of the Technology, including,
without limitation, any present or future right of BioTek to receive royalties
or other payments from those to whom licenses, sublicenses or franchises have
been or will be granted;

                  (f) All presently existing and hereafter arising general
intangibles (as that term is defined in the California Uniform Commercial Code);

                  (g) All other personal property and fixtures of BioTek,
whether now or hereafter existing, or now owned or hereafter acquired and
wherever located, of every kind and description, tangible and intangible,
including, but not limited to, the balance of every deposit account, now or
hereafter existing of BioTek with any bank or financial institution and all
money,

                                        6
<PAGE>   7
goods, instruments, securities, documents, chattel paper, accounts, contract
rights, general intangibles, credits, claims, demands, precious metals and any
other property rights and interests of BioTek; and

                  (h) Any and all proceeds (including insurance proceeds) and
products of any and all of the foregoing.



                                        7

<PAGE>   1
                                                                EXHIBIT 10.2(b)

         THIS NOTE HAS BEEN ACQUIRED SOLELY FOR INVESTMENT AND HAS NOT BEEN
         REGISTERED UNDER THE SECURITIES ACT OF 1933 OR QUALIFIED UNDER ANY
         STATE SECURITIES LAWS. THIS NOTE MAY NOT BE SOLD OR TRANSFERRED IN THE
         ABSENCE OF SUCH REGISTRATION AND QUALIFICATION OR AN EXEMPTION
         THEREFROM. THIS NOTE CONTAINS RESTRICTIONS ON TRANSFER OR ASSIGNMENT.

                             BIOTEK SOLUTIONS, INC.

                             SECURED PROMISSORY NOTE

$1,700,000                                             Santa Barbara, California
                                                                  March 24, 1995

         FOR VALUE RECEIVED, BIOTEK SOLUTIONS, INC., a California corporation
("Maker"), unconditionally promises to pay to the order of DAKO A/S, a Danish
corporation ("Payee"), in lawful money of the United States of America by check
to the address of Payee maintained in the records of Maker, the principal amount
of $1,700,000 or such lesser amount that shall (a) actually have been advanced
by Payee to Maker pursuant to Section 21 of the Distribution Agreement (defined
below) or (b) remain unpaid or unrecouped (as described in Section 3 below) on
the Maturity Date (defined below).

         1. Issuance Pursuant to Agreement. This Note is issued pursuant to the
Distribution Agreement between the Maker and the Payee dated as of September 27,
1994 and amended on March 24, 1995 (the "Distribution Agreement"). All terms
defined in the Distribution Agreement shall have the same meaning in this Note
unless otherwise defined in this Note.

         2. Maturity Date. This Note is due and payable:

         (a) in full, on the termination date of the Distribution Agreement, if
         such termination is made by the Maker; or

         (b) in twelve (12) equal quarterly installments commencing on the first
         day of the fiscal quarter which immediately follows the earlier of the
         following events:

                  (1) the date on which Payee makes the election set forth in
                  Section 21d(i)(2) of the Distribution Agreement and sends
                  written notice thereof (which election relates to the
                  occurrence of a Milestone Default by Payee); or
<PAGE>   2
                  (2) the date on which Payee sends Maker a Sales Failure Notice
                  pursuant to Section 21f of the Distribution Agreement; or

                  (3) the date on which Payee makes the election set forth in
                  Section 21g(y) of the Distribution Agreement and sends written
                  notice thereof (which election relates to the occurrence of a
                  Delivery Failure by Maker); or

                  (4) the termination date of the Distribution Agreement (other
                  than due to a breach by the Maker in its obligations
                  thereunder), if such termination is made by the Payee.

         3. Reduction of Principal Amount Due. In the event and to the extent
that the Payee recoups the Development Prepayment pursuant to Section 21e of the
Distribution Agreement, the principal amount of this Note shall be reduced in an
amount equal to such recoupment.

         4. Prepayments. Maker shall have the right at any time and from time to
time to prepay the principal of this Note in whole or in part without premium or
penalty.

         5. Security Agreement. The obligations of the Maker hereunder are
secured by the security interest granted in the Collateral of the Maker pursuant
to Section 23 of the Distribution Agreement.

         6. Covenant. Maker covenants and agrees that until this Note is paid in
full, Maker will, promptly upon the occurrence of an Event of Default (defined
below) or any event, act or condition which, with notice or lapse of time or
both, would constitute an Event of Default, provide Payee with a certificate of
the chief executive officer or chief financial officer of Maker specifying the
nature thereof and Maker's proposed response thereto.

         7. Representations and Warranties. Maker hereby represents and warrants
to Payee that:

         (a) Maker is a duly incorporated and validly existing corporation in
good standing under the laws of the jurisdiction of its incorporation and has
the corporate power and authority to own and operate is properties, to transact
the business in which it is now engaged and to execute and deliver this Note;

         (b) this Note constitutes the duly authorized, legally valid and
binding obligation of Maker, enforceable against Maker in accordance with its
terms, except as may be limited by bankruptcy, moratorium, insolvency,
reorganization and other similar laws relating to or affecting creditor's rights
generally and by general principles or equity; and

                                        2
<PAGE>   3
         (c) the execution, delivery and performance by Maker of this Note will
not violate any law, governmental rule or regulation, court order to agreement
to which its is subject or by which its properties are bound or the Articles of
Incorporation or Bylaws of Maker.

         8. Events of Default. The occurrence of any of the following events
shall constitute an "Event of Default":

         (a) failure of Maker to pay an principal under this Note when due, by
acceleration, by notice of prepayment or otherwise; provided, however, that the
failure of Maker to pay principal under this Note pursuant to Section 2(b)
hereof shall only constitute an Event of Default hereunder in the event that
such payment remains unpaid thirty (30) days after the same has become due and
payable pursuant to said Section 2(b); or

         (b) the Maker shall receive: (i) a notice of sale pursuant to
California Commercial Code Section 9504, (ii) a notice of intent to retain
possession pursuant to California Commercial Code Section 9505, or (iii) a 
notice of any similar action or proceeding by a creditor asserting a lien 
against an asset of the Maker; or

         (c) (i) a court having jurisdiction over the Maker shall enter a decree
or order for relief in respect of Maker in an involuntary case under Title 11 of
the United States Code entitled "Bankruptcy" (as now and hereinafter in effect,
or any successor thereto, the "Bankruptcy Code") or any applicable bankruptcy,
insolvency or other similar law now or hereafter in effect, which decree or
order is not stayed; or (ii) an involuntary case shall be commenced against
Maker under any applicable bankruptcy, insolvency or other similar law now or
hereafter in effect; or a decree or order of a court having jurisdiction over
the Maker for the appointment of a receiver, liquidator, sequestrator, trustee,
custodian or other officer having similar powers over Maker over all or a
substantial part of its property shall have been entered; or the involuntary
appointment of an interim receiver, trustee or other custodian of Maker of all
or a substantial part of its property shall have occurred; or a warrant of
attachment, execution or similar process shall have been issued against any
substantial part of the property of Maker; or

         (d) an order for relief under the Bankruptcy Code shall have been
entered with respect to Maker or Maker shall have commenced a voluntary case
under the Bankruptcy Code or any applicable bankruptcy, insolvency or other
similar law now or hereafter in effect, or shall consent to the entry of an
order for relief in an involuntary case, or to the conversion of an involuntary
case to a voluntary case, under any such law, or shall consent to the
appointment of or taking possession by a receiver, trustee or other custodian
for all or a substantial part of its property; or Maker shall make an assignment
for the benefit of creditors; or Maker shall be unable or fail, or shall admit
in writing its inability, to pay its debts as such debts become due.

                                        3
<PAGE>   4
         9. Remedies. Upon the occurrence of any Event of Default, the unpaid
principal amount of this Note shall become immediately due and payable, without
presentment, demand, notice, protest or other requirements of any kind (all of
which are hereby expressly waived by Maker), and Payee shall have all of the
rights and remedies of a secured party under the Uniform Commercial Code as in
force in the State of California and any other applicable laws.

         10. Restrictions of Transfer. THIS NOTE MAY NOT BE TRANSFERRED, SOLD,
PLEDGED, HYPOTHECATED OR ASSIGNED BY PAYEE UNLESS PRIOR TO SUCH TRANSFER, SALE,
PLEDGE, HYPOTHECATION OR ASSIGNMENT PAYEE HAS PROVIDED MAKER WITH AN OPINION OF
COUNSEL, REASONABLY SATISFACTORY TO MAKER AND ITS COUNSEL, TO THE EFFECT THAT
SUCH TRANSFER, SALE, PLEDGE, HYPOTHECATION OR ASSIGNMENT IS EXEMPT FROM
REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND ALL RELEVANT
STATE SECURITIES LAWS.

         11. Termination. Maker's obligations under this Note shall
automatically terminate in the event that the Payee sends Maker the Termination
Notice referenced in Section 21d(ii) of the Distribution Agreement.

         12. Miscellaneous.

         (a) All notices and other communications provided for hereunder shall
be in writing (including telegraphic, telex, telecopier or cable communication)
and mailed, telegraphed, telexed, telecopied, cabled or delivered as follows: if
to Maker, at its address specified opposite its signature below; and if to
Payee, at Payee's address as shown in the records of Maker; or in each case at
such other address as shall be designated by Payee or Maker in a written notice
to the other. All such notices and communications shall, when mailed,
telegraphed, telexed, telecopied or cabled or sent by overnight courier, be
effective when deposited in the mails, delivered to the telegraph company, cable
company or overnight courier, as the case may be, or sent by telex or
telecopier.

         (b) THIS NOTE AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES HEREUNDER
SHALL BE GOVERNED BY, AND CONSTRUED AND ENFORCED IN ACCORDANCE WITH, THE LAWS OF
THE STATE OF CALIFORNIA.

         Maker shall pay to the holder of this Note all reasonable costs and
expenses (including reasonable attorneys' fees) incurred by the holder in
collecting amounts due under this Note or enforcing the terms hereof.

                                        4
<PAGE>   5
         IN WITNESS WHEREOF, Maker has caused this Note to be executed and
delivered by its duly authorized officer as of the day and year and at the place
first above written.

                                       BIOTEK SOLUTIONS, INC.


                                       By:  /s/ MICHAEL C. MILLER
                                            ------------------------------------
                                            Michael C. Miller, CEO


                                       Address:
                                       120-B Cremona Drive
                                       Santa Barbara, CA  93117



                                        5

<PAGE>   1
                                                                    EXHIBIT 10.6


                          VENTANA MEDICAL SYSTEMS, INC.

                            INDEMNIFICATION AGREEMENT

      This Indemnification Agreement ("Agreement") is effective as of _______,
199__ by and between Ventana Medical Systems, Inc., a Delaware corporation (the
"Company"), and ___________ ("Indemnitee").

      WHEREAS, the Company desires to attract and retain the services of highly
qualified individuals, such as Indemnitee, to serve the Company and its related
entities;

      WHEREAS, in order to induce Indemnitee to continue to provide services to
the Company, the Company wishes to provide for the indemnification of, and the
advancement of expenses to, Indemnitee to the maximum extent permitted by law;

      WHEREAS, the Company and Indemnitee further recognize the substantial
increase in corporate litigation in general, subjecting directors, officers,
employees, agents and fiduciaries to expensive litigation risks at the same time
as the availability and coverage of liability insurance has been limited; and

      WHEREAS, the Company and Indemnitee desire to continue to have in place
the additional protection provided by an indemnification agreement to provide
indemnification and advancement of expenses to the Indemnitee to the maximum
extent permitted by Delaware law;

      WHEREAS, in view of the considerations set forth above, the Company
desires that Indemnitee shall be indemnified and advanced expenses by the
Company as set forth herein;

      NOW, THEREFORE, the Company and Indemnitee hereby agree as set forth
below.

      1. Certain Definitions.

         a. "Change in Control" shall mean, and shall be deemed to have occurred
if, on or after the date of this Agreement, (i) any "person" (as such term is
used in Sections 13(d) and 14(d) of the Securities Exchange Act of 1934, as
amended), other than a trustee or other fiduciary holding securities under an
employee benefit plan of the Company acting in such capacity or a corporation
owned directly or indirectly by the stockholders of the Company in substantially
the same proportions as their ownership of stock of the Company, becomes the
"beneficial owner" (as defined in Rule 13d-3 under said Act), directly or
indirectly, of securities of the Company representing more than 50% of the total
voting power represented by the Company's then outstanding Voting Securities,
(ii) during any period of two consecutive years, individuals who at the
beginning of such period constitute the Board of Directors of the Company and
any new director whose election by the Board of Directors or nomination for
election by the Company's stockholders was approved by a vote of at least two
thirds (2/3) of the directors then still in office who either were directors at
the beginning of the period or whose election or nomination for election was
previously so approved, cease for any reason to constitute a majority thereof,
(iii) the stockholders of the Company approve a merger or consolidation of the
Company with any other corporation other than a merger or consolidation which
would result in the Voting Securities of the
<PAGE>   2
Company outstanding immediately prior thereto continuing to represent (either by
remaining outstanding or by being converted into Voting Securities of the
surviving entity) at least 80% of the total voting power represented by the
Voting Securities of the Company or such surviving entity outstanding
immediately after such merger or consolidation, or (iv) the stockholders of the
Company approve a plan of complete liquidation of the Company or an agreement
for the sale or disposition by the Company of (in one transaction or a series of
related transactions) all or substantially all of the Company's assets.

         b. "Claim" shall mean with respect to a Covered Event: any threatened,
pending or completed action, suit, proceeding or alternative dispute resolution
mechanism, or any hearing, inquiry or investigation that Indemnitee in good
faith believes might lead to the institution of any such action, suit,
proceeding or alternative dispute resolution mechanism, whether civil, criminal,
administrative, investigative or other.

         c. References to the "Company" shall include, in addition to Ventana
Medical Systems, Inc., any constituent corporation (including any constituent of
a constituent) absorbed in a consolidation or merger to which Ventana Medical
Systems, Inc. (or any of its wholly owned subsidiaries) is a party which, if its
separate existence had continued, would have had power and authority to
indemnify its directors, officers, employees, agents or fiduciaries, so that if
Indemnitee is or was a director, officer, employee, agent or fiduciary of such
constituent corporation, or is or was serving at the request of such constituent
corporation as a director, officer, employee, agent or fiduciary of another
corporation, partnership, joint venture, employee benefit plan, trust or other
enterprise, Indemnitee shall stand in the same position under the provisions of
this Agreement with respect to the resulting or surviving corporation as
Indemnitee would have with respect to such constituent corporation if its
separate existence had continued.

         d. "Covered Event" shall mean any event or occurrence related to the
fact that Indemnitee is or was a director, officer, employee, agent or fiduciary
of the Company, or any subsidiary of the Company, or is or was serving at the
request of the Company as a director, officer, employee, agent or fiduciary of
another corporation, partnership, joint venture, trust or other enterprise, or
by reason of any action or inaction on the part of Indemnitee while serving in
such capacity.

         e. "Expenses" shall mean any and all expenses (including attorneys'
fees and all other costs, expenses and obligations incurred in connection with
investigating, defending, being a witness in or participating in (including on
appeal), or preparing to defend, to be a witness in or to participate in, any
action, suit, proceeding, alternative dispute resolution mechanism, hearing,
inquiry or investigation), judgments, fines, penalties and amounts paid in
settlement (if such settlement is approved in advance by the Company, which
approval shall not be unreasonably withheld) of any Claim and any federal,
state, local or foreign taxes imposed on the Indemnitee as a result of the
actual or deemed receipt of any payments under this Agreement.

         f. "Expense Advance" shall mean a payment to Indemnitee pursuant to
Section 3 of Expenses in advance of the settlement of or final judgement in any
action, suit, proceeding or alternative dispute resolution mechanism, hearing,
inquiry or investigation which constitutes a Claim.


                                       -2-
<PAGE>   3
         g. "Independent Legal Counsel" shall mean an attorney or firm of
attorneys, selected in accordance with the provisions of Section 2(d) hereof,
who shall not have otherwise performed services for the Company or Indemnitee
within the last three years (other than with respect to matters concerning the
rights of Indemnitee under this Agreement, or of other Indemnitees under similar
indemnity agreements).

         h. References to "other enterprises" shall include employee benefit
plans; references to "fines" shall include any excise taxes assessed on
Indemnitee with respect to an employee benefit plan; and references to "serving
at the request of the Company" shall include any service as a director, officer,
employee, agent or fiduciary of the Company which imposes duties on, or involves
services by, such director, officer, employee, agent or fiduciary with respect
to an employee benefit plan, its participants or its beneficiaries; and if
Indemnitee acted in good faith and in a manner Indemnitee reasonably believed to
be in the interest of the participants and beneficiaries of an employee benefit
plan, Indemnitee shall be deemed to have acted in a manner "not opposed to the
best interests of the Company" as referred to in this Agreement.

         i. "Reviewing Party" shall mean, subject to the provisions of Section
2(d), any person or body appointed by the Board of Directors in accordance with
applicable law to review the Company's obligations hereunder and under
applicable law, which may include a member or members of the Company's Board of
Directors, Independent Legal Counsel or any other person or body not a party to
the particular Claim for which Indemnitee is seeking indemnification.

         j. "Section" refers to a section of this Agreement unless otherwise
indicated.

         k. "Voting Securities" shall mean any securities of the Company that
vote generally in the election of directors.

      2. Indemnification.

         a. Indemnification of Expenses. Subject to the provisions of Section
2(b) below, the Company shall indemnify Indemnitee for Expenses to the fullest
extent permitted by law if Indemnitee was or is or becomes a party to or witness
or other participant in, or is threatened to be made a party to or witness or
other participant in, any Claim (whether by reason of or arising in part out of
a Covered Event), including all interest, assessments and other charges paid or
payable in connection with or in respect of such Expenses.

         b. Review of Indemnification Obligations. Notwithstanding the
foregoing, in the event any Reviewing Party shall have determined (in a written
opinion, in any case in which Independent Legal Counsel is the Reviewing Party)
that Indemnitee is not entitled to be indemnified hereunder under applicable
law, (i) the Company shall have no further obligation under Section 2(a) to make
any payments to Indemnitee not made prior to such determination by such
Reviewing Party, and (ii) the Company shall be entitled to be reimbursed by
Indemnitee (who hereby agrees to reimburse the Company) for all Expenses
theretofore paid to Indemnitee to which Indemnitee is not entitled hereunder
under applicable law; provided, however, that if Indemnitee has commenced or
thereafter commences legal proceedings


                                       -3-
<PAGE>   4
in a court of competent jurisdiction to secure a determination that Indemnitee
is entitled to be indemnified hereunder under applicable law, any determination
made by any Reviewing Party that Indemnitee is not entitled to be indemnified
hereunder under applicable law shall not be binding and Indemnitee shall not be
required to reimburse the Company for any Expenses theretofore paid in
indemnifying Indemnitee until a final judicial determination is made with
respect thereto (as to which all rights of appeal therefrom have been exhausted
or lapsed). Indemnitee's obligation to reimburse the Company for any Expenses
shall be unsecured and no interest shall be charged thereon.

         c. Indemnitee Rights on Unfavorable Determination; Binding Effect. If
any Reviewing Party determines that Indemnitee substantively is not entitled to
be indemnified hereunder in whole or in part under applicable law, Indemnitee
shall have the right to commence litigation seeking an initial determination by
the court or challenging any such determination by such Reviewing Party or any
aspect thereof, including the legal or factual bases therefor, and, subject to
the provisions of Section 15, the Company hereby consents to service of process
and to appear in any such proceeding. Absent such litigation, any determination
by any Reviewing Party shall be conclusive and binding on the Company and
Indemnitee.

         d. Selection of Reviewing Party; Change in Control. If there has not
been a Change in Control, any Reviewing Party shall be selected by the Board of
Directors, and if there has been such a Change in Control (other than a Change
in Control which has been approved by a majority of the Company's Board of
Directors who were directors immediately prior to such Change in Control), any
Reviewing Party with respect to all matters thereafter arising concerning the
rights of Indemnitee to indemnification of Expenses under this Agreement or any
other agreement or under the Company's Certificate of Incorporation or Bylaws as
now or hereafter in effect, or under any other applicable law, if desired by
Indemnitee, shall be Independent Legal Counsel selected by Indemnitee and
approved by the Company (which approval shall not be unreasonably withheld).
Such counsel, among other things, shall render its written opinion to the
Company and Indemnitee as to whether and to what extent Indemnitee would be
entitled to be indemnified hereunder under applicable law and the Company agrees
to abide by such opinion. The Company agrees to pay the reasonable fees of the
Independent Legal Counsel referred to above and to indemnify fully such counsel
against any and all expenses (including attorneys' fees), claims, liabilities
and damages arising out of or relating to this Agreement or its engagement
pursuant hereto. Notwithstanding any other provision of this Agreement, the
Company shall not be required to pay Expenses of more than one Independent Legal
Counsel in connection with all matters concerning a single Indemnitee, and such
Independent Legal Counsel shall be the Independent Legal Counsel for any or all
other Indemnitees unless (i) the employment of separate counsel by one or more
Indemnitees has been previously authorized by the Company in writing, or (ii) an
Indemnitee shall have provided to the Company a written statement that such
Indemnitee has reasonably concluded that there may be a conflict of interest
between such Indemnitee and the other Indemnitees with respect to the matters
arising under this Agreement.

         e. Mandatory Payment of Expenses. Notwithstanding any other provision
of this Agreement other than Section 10 hereof, to the extent that Indemnitee
has been successful on the merits or otherwise, including, without limitation,
the dismissal of an action without prejudice, in defense of any Claim,
Indemnitee shall be indemnified against all Expenses incurred by Indemnitee in
connection


                                       -4-
<PAGE>   5
therewith.

      3. Expense Advances.

         a. Obligation to Make Expense Advances. Upon receipt of a written
undertaking by or on behalf of the Indemnitee to repay such amounts if it shall
ultimately be determined that the Indemnitee is not entitled to be indemnified
therefore by the Company hereunder under applicable law, the Company shall make
Expense Advances to Indemnitee.

         b. Form of Undertaking. Any obligation to repay any Expense Advances
hereunder pursuant to a written undertaking by the Indemnitee shall be unsecured
and no interest shall be charged thereon.

         c. Determination of Reasonable Expense Advances. The parties agree that
for the purposes of any Expense Advance for which Indemnitee has made written
demand to the Company in accordance with this Agreement, all Expenses included
in such Expense Advance that are certified by affidavit of Indemnitee's counsel
as being reasonable shall be presumed conclusively to be reasonable.

      4. Procedures for Indemnification and Expense Advances.

         a. Timing of Payments. All payments of Expenses (including without
limitation Expense Advances) by the Company to the Indemnitee pursuant to this
Agreement shall be made to the fullest extent permitted by law as soon as
practicable after written demand by Indemnitee therefor is presented to the
Company, but in no event later than thirty (30) business days after such written
demand by Indemnitee is presented to the Company, except in the case of Expense
Advances, which shall be made no later than ten (10) business days after such
written demand by Indemnitee is presented to the Company.

         b. Notice/Cooperation by Indemnitee. Indemnitee shall, as a condition
precedent to Indemnitee's right to be indemnified or Indemnitee's right to
receive Expense Advances under this Agreement, give the Company notice in
writing as soon as practicable of any Claim made against Indemnitee for which
indemnification will or could be sought under this Agreement. Notice to the
Company shall be directed to the Chief Executive Officer of the Company at the
address shown on the signature page of this Agreement (or such other address as
the Company shall designate in writing to Indemnitee). In addition, Indemnitee
shall give the Company such information and cooperation as it may reasonably
require and as shall be within Indemnitee's power.

         c. No Presumptions; Burden of Proof. For purposes of this Agreement,
the termination of any Claim by judgment, order, settlement (whether with or
without court approval) or conviction, or upon a plea of nolo contendere, or its
equivalent, shall not create a presumption that Indemnitee did not meet any
particular standard of conduct or have any particular belief or that a court has
determined that indemnification is not permitted by this Agreement or applicable
law. In addition, neither the failure of any Reviewing Party to have made a
determination as to whether Indemnitee has met any particular standard of
conduct or had any particular belief, nor an actual determination by any


                                       -5-
<PAGE>   6
Reviewing Party that Indemnitee has not met such standard of conduct or did not
have such belief, prior to the commencement of legal proceedings by Indemnitee
to secure a judicial determination that Indemnitee should be indemnified under
this Agreement under applicable law, shall be a defense to Indemnitee's claim or
create a presumption that Indemnitee has not met any particular standard of
conduct or did not have any particular belief. In connection with any
determination by any Reviewing Party or otherwise as to whether the Indemnitee
is entitled to be indemnified hereunder under applicable law, the burden of
proof shall be on the Company to establish that Indemnitee is not so entitled.

         d. Notice to Insurers. If, at the time of the receipt by the Company of
a notice of a Claim pursuant to Section 4(b) hereof, the Company has liability
insurance in effect which may cover such Claim, the Company shall give prompt
notice of the commencement of such Claim to the insurers in accordance with the
procedures set forth in the respective policies. The Company shall thereafter
take all necessary or desirable action to cause such insurers to pay, on behalf
of the Indemnitee, all amounts payable as a result of such Claim in accordance
with the terms of such policies.

         e. Selection of Counsel. In the event the Company shall be obligated
hereunder to provide indemnification for or make any Expense Advances with
respect to the Expenses of any Claim, the Company, if appropriate, shall be
entitled to assume the defense of such Claim with counsel approved by Indemnitee
(which approval shall not be unreasonably withheld) upon the delivery to
Indemnitee of written notice of the Company's election to do so. After delivery
of such notice, approval of such counsel by Indemnitee and the retention of such
counsel by the Company, the Company will not be liable to Indemnitee under this
Agreement for any fees or expenses of separate counsel subsequently retained by
or on behalf of Indemnitee with respect to the same Claim; provided that, (i)
Indemnitee shall have the right to employ Indemnitee's separate counsel in any
such Claim at Indemnitee's expense and (ii) if (A) the employment of separate
counsel by Indemnitee has been previously authorized by the Company, (B)
Indemnitee shall have reasonably concluded that there may be a conflict of
interest between the Company and Indemnitee in the conduct of any such defense,
or (C) the Company shall not continue to retain such counsel to defend such
Claim, then the fees and expenses of Indemnitee's separate counsel shall be
Expenses for which Indemnitee may receive indemnification or Expense Advances
hereunder.

      5. Additional Indemnification Rights; Nonexclusivity.

         a. Scope. The Company hereby agrees to indemnify the Indemnitee to the
fullest extent permitted by law, notwithstanding that such indemnification is
not specifically authorized by the other provisions of this Agreement, the
Company's Certificate of Incorporation, the Company's Bylaws or by statute. In
the event of any change after the date of this Agreement in any applicable law,
statute or rule which expands the right of a Delaware corporation to indemnify a
member of its board of directors or an officer, employee, agent or fiduciary, it
is the intent of the parties hereto that Indemnitee shall enjoy by this
Agreement the greater benefits afforded by such change. In the event of any
change in any applicable law, statute or rule which narrows the right of a
Delaware corporation to indemnify a member of its board of directors or an
officer, employee, agent or fiduciary, such change, to the extent not otherwise
required by such law, statute or rule to be applied to this Agreement, shall
have no effect on this Agreement or the parties' rights and obligations
hereunder except as set forth in Section 10(a) hereof.


                                       -6-
<PAGE>   7
         b. Nonexclusivity. The indemnification and the payment of Expense
Advances provided by this Agreement shall be in addition to any rights to which
Indemnitee may be entitled under the Company's Certificate of Incorporation, its
Bylaws, any other agreement, any vote of stockholders or disinterested
directors, the General Corporation Law of the State of Delaware, or otherwise.
The indemnification and the payment of Expense Advances provided under this
Agreement shall continue as to Indemnitee for any action taken or not taken
while serving in an indemnified capacity even though subsequent thereto
Indemnitee may have ceased to serve in such capacity.

      6. No Duplication of Payments. The Company shall not be liable under this
Agreement to make any payment in connection with any Claim made against
Indemnitee to the extent Indemnitee has otherwise actually received payment
(under any insurance policy, provision of the Company's Certificate of
Incorporation, Bylaws or otherwise) of the amounts otherwise payable hereunder.

      7. Partial Indemnification. If Indemnitee is entitled under any provision
of this Agreement to indemnification by the Company for some or a portion of
Expenses incurred in connection with any Claim, but not, however, for all of the
total amount thereof, the Company shall nevertheless indemnify Indemnitee for
the portion of such Expenses to which Indemnitee is entitled.

      8. Mutual Acknowledgment. Both the Company and Indemnitee acknowledge that
in certain instances, federal law or applicable public policy may prohibit the
Company from indemnifying its directors, officers, employees, agents or
fiduciaries under this Agreement or otherwise. Indemnitee understands and
acknowledges that the Company has undertaken or may be required in the future to
undertake with the Securities and Exchange Commission to submit the question of
indemnification to a court in certain circumstances for a determination of the
Company's right under public policy to indemnify Indemnitee.

      9. Liability Insurance. To the extent the Company maintains liability
insurance applicable to directors, officers, employees, agents or fiduciaries,
Indemnitee shall be covered by such policies in such a manner as to provide
Indemnitee the same rights and benefits as are provided to the most favorably
insured of the Company's directors, if Indemnitee is a director; or of the
Company's officers, if Indemnitee is not a director of the Company but is an
officer; or of the Company's key employees, agents or fiduciaries, if Indemnitee
is not an officer or director but is a key employee, agent or fiduciary.

     10. Exceptions. Notwithstanding any other provision of this Agreement, the
Company shall not be obligated pursuant to the terms of this Agreement:

         a. Excluded Actions or Omissions. To indemnify or make Expense Advances
to Indemnitee with respect to Claims arising out of acts, omissions or
transactions for which Indemnitee is prohibited from receiving indemnification
under applicable law.

         b. Claims Initiated by Indemnitee. To indemnify or make Expense
Advances to Indemnitee with respect to Claims initiated or brought voluntarily
by Indemnitee and not by way of defense, counterclaim or crossclaim, except (i)
with respect to actions or proceedings brought to establish or enforce a right
to indemnification under this Agreement or any other agreement or insurance
policy


                                       -7-
<PAGE>   8
or under the Company's Certificate of Incorporation or Bylaws now or hereafter
in effect relating to Claims for Covered Events, (ii) in specific cases if the
Board of Directors has approved the initiation or bringing of such Claim, or
(iii) as otherwise required under Section 145 of the Delaware General
Corporation Law, regardless of whether Indemnitee ultimately is determined to be
entitled to such indemnification, Expense Advances, or insurance recovery, as
the case may be.

         c. Lack of Good Faith. To indemnify Indemnitee for any Expenses
incurred by the Indemnitee with respect to any action instituted (i) by
Indemnitee to enforce or interpret this Agreement, if a court having
jurisdiction over such action determines as provided in Section 13 that each of
the material assertions made by the Indemnitee as a basis for such action was
not made in good faith or was frivolous, or (ii) by or in the name of the
Company to enforce or interpret this Agreement, if a court having jurisdiction
over such action determines as provided in Section 13 that each of the material
defenses asserted by Indemnitee in such action was made in bad faith or was
frivolous.

         d. Claims Under Section 16(b). To indemnify Indemnitee for Expenses and
the payment of profits arising from the purchase and sale by Indemnitee of
securities in violation of Section 16(b) of the Securities Exchange Act of 1934,
as amended, or any similar successor statute.

     11. Counterparts. This Agreement may be executed in one or more
counterparts, each of which shall constitute an original.

     12. Binding Effect; Successors and Assigns. This Agreement shall be binding
upon and inure to the benefit of and be enforceable by the parties hereto and
their respective successors, assigns (including any direct or indirect successor
by purchase, merger, consolidation or otherwise to all or substantially all of
the business or assets of the Company), spouses, heirs and personal and legal
representatives. The Company shall require and cause any successor (whether
direct or indirect, and whether by purchase, merger, consolidation or otherwise)
to all, substantially all, or a substantial part, of the business or assets of
the Company, by written agreement in form and substance satisfactory to
Indemnitee, expressly to assume and agree to perform this Agreement in the same
manner and to the same extent that the Company would be required to perform if
no such succession had taken place. This Agreement shall continue in effect
regardless of whether Indemnitee continues to serve as a director, officer,
employee, agent or fiduciary (as applicable) of the Company or of any other
enterprise at the Company's request.

     13. Expenses Incurred in Action Relating to Enforcement or Interpretation.
In the event that any action is instituted by Indemnitee under this Agreement or
under any liability insurance policies maintained by the Company to enforce or
interpret any of the terms hereof or thereof, Indemnitee shall be entitled to be
indemnified for all Expenses incurred by Indemnitee with respect to such action
(including without limitation attorneys' fees), regardless of whether Indemnitee
is ultimately successful in such action, unless as a part of such action a court
having jurisdiction over such action makes a final judicial determination (as to
which all rights of appeal therefrom have been exhausted or lapsed) that each of
the material assertions made by Indemnitee as a basis for such action was not
made in good faith or was frivolous; provided, however, that until such final
judicial determination is made, Indemnitee shall be entitled under Section 3 to
receive payment of Expense Advances hereunder with respect to such


                                       -8-
<PAGE>   9
action. In the event of an action instituted by or in the name of the Company
under this Agreement to enforce or interpret any of the terms of this Agreement,
Indemnitee shall be entitled to be indemnified for all Expenses incurred by
Indemnitee in defense of such action (including without limitation costs and
expenses incurred with respect to Indemnitee's counterclaims and cross-claims
made in such action), unless as a part of such action a court having
jurisdiction over such action makes a final judicial determination (as to which
all rights of appeal therefrom have been exhausted or lapsed) that each of the
material defenses asserted by Indemnitee in such action was made in bad faith or
was frivolous; provided, however, that until such final judicial determination
is made, Indemnitee shall be entitled under Section 3 to receive payment of
Expense Advances hereunder with respect to such action.

     14. Period of Limitations. No legal action shall be brought and no cause of
action shall be asserted by or in the right of the Company against Indemnitee,
Indemnitee's estate, spouse, heirs, executors or personal or legal
representatives after the expiration of two years from the date of accrual of
such cause of action, and any claim or cause of action of the Company shall be
extinguished and deemed released unless asserted by the timely filing of a legal
action within such two year period; provided, however, that if any shorter
period of limitations is otherwise applicable to any such cause of action, such
shorter period shall govern.

     15. Notice. All notices, requests, demands and other communications under
this Agreement shall be in writing and shall be deemed duly given (i) if
delivered by hand and signed for by the party addressed, on the date of such
delivery, or (ii) if mailed by domestic certified or registered mail with
postage prepaid, on the third business day after the date postmarked. Addresses
for notice to either party are as shown on the signature page of this Agreement,
or as subsequently modified by written notice.

     16. Consent to Jurisdiction. The Company and Indemnitee each hereby
irrevocably consent to the jurisdiction of the courts of the State of Delaware
for all purposes in connection with any action or proceeding which arises out of
or relates to this Agreement and agree that any action instituted under this
Agreement shall be commenced, prosecuted and continued only in the Court of
Chancery of the State of Delaware in and for New Castle County, which shall be
the exclusive and only proper forum for adjudicating such a claim.

     17. Severability. The provisions of this Agreement shall be severable in
the event that any of the provisions hereof (including any provision within a
single section, paragraph or sentence) are held by a court of competent
jurisdiction to be invalid, void or otherwise unenforceable, and the remaining
provisions shall remain enforceable to the fullest extent permitted by law.
Furthermore, to the fullest extent possible, the provisions of this Agreement
(including without limitation each portion of this Agreement containing any
provision held to be invalid, void or otherwise unenforceable, that is not
itself invalid, void or unenforceable) shall be construed so as to give effect
to the intent manifested by the provision held invalid, illegal or
unenforceable.


                                       -9-
<PAGE>   10
     18. Choice of Law. This Agreement, and all rights, remedies, liabilities,
powers and duties of the parties to this Agreement, shall be governed by and
construed in accordance with the laws of the State of Delaware as applied to
contracts between Delaware residents entered into and to be performed entirely
in the State of Delaware without regard to principles of conflicts of laws.

     19. Subrogation. In the event of payment under this Agreement, the Company
shall be subrogated to the extent of such payment to all of the rights of
recovery of Indemnitee, who shall execute all documents required and shall do
all acts that may be necessary to secure such rights and to enable the Company
effectively to bring suit to enforce such rights.

     20. Amendment and Termination. No amendment, modification, termination or
cancellation of this Agreement shall be effective unless it is in writing signed
by both the parties hereto. No waiver of any of the provisions of this Agreement
shall be deemed to be or shall constitute a waiver of any other provisions
hereof (whether or not similar), nor shall such waiver constitute a continuing
waiver.

     21. Integration and Entire Agreement. This Agreement sets forth the entire
understanding between the parties hereto and supersedes and merges all previous
written and oral negotiations, commitments, understandings and agreements
relating to the subject matter hereof between the parties hereto.

     22. No Construction as Employment Agreement. Nothing contained in this
Agreement shall be construed as giving Indemnitee any right to be retained in
the employ of the Company or any of its subsidiaries or affiliated entities.


                                      -10-
<PAGE>   11
     IN WITNESS WHEREOF, the parties hereto have executed this Indemnification
Agreement as of the date first above written.

VENTANA MEDICAL SYSTEMS, INC.

By:     _____________________________

Name:   _____________________________
 
Title:  _____________________________

Address:  3865 North Business Center Drive
          Tucson, Arizona 85705





                                       AGREED TO AND ACCEPTED

                                       INDEMNITEE:

                                       ______________________________________
                                       (signature)

                                       ______________________________________
                                       Name

                                       ______________________________________
                                       Address
                                       ______________________________________



                                      -11-




<PAGE>   1
                                                                 EXHIBIT 10.8(c)


                          VENTANA MEDICAL SYSTEMS, INC.

                            1996 DIRECTOR OPTION PLAN

      1.  Purposes of the Plan. The purposes of this 1996 Director Option Plan
are to attract and retain the best available personnel for service as Outside
Directors (as defined herein) of the Company, to provide additional incentive to
the Outside Directors of the Company to serve as Directors, and to encourage
their continued service on the Board.

          All options granted hereunder shall be nonstatutory stock options.

      2.  Definitions.  As used herein, the following definitions shall apply:

          (a) "Board" means the Board of Directors of the Company.

          (b) "Code" means the Internal Revenue Code of 1986, as amended.

          (c) "Common Stock" means the Common Stock of the Company.

          (d) "Company" means Ventana Medical Systems, Inc., a Delaware
corporation.

          (e) "Director" means a member of the Board.

          (f) "Employee" means any person, including officers and Directors,
employed by the Company or any Parent or Subsidiary of the Company. The payment
of a Director's fee by the Company shall not be sufficient in and of itself to
constitute "employment" by the Company.

          (g) "Exchange Act" means the Securities Exchange Act of 1934, as
amended.

          (h) "Fair Market Value" means, as of any date, the value of Common
Stock determined as follows:

              (i) If the Common Stock is listed on any established stock
exchange or a national market system, including without limitation the Nasdaq
National Market or The Nasdaq SmallCap Market of The Nasdaq Stock Market, its
Fair Market Value shall be the closing sales price for such stock (or the
closing bid, if no sales were reported) as quoted on such exchange or system for
the last market trading day prior to the time of determination, as reported in
The Wall Street Journal or such other source as the Administrator deems
reliable;

              (ii) If the Common Stock is regularly quoted by a recognized
securities dealer but selling prices are not reported, the Fair Market Value of
a Share of Common Stock shall be the mean between the high bid and low asked
prices for the Common Stock on the date of
<PAGE>   2
determination, as reported in The Wall Street Journal or such other source as 
the Board deems reliable, or;

              (iii) In the absence of an established market for the Common
Stock, the Fair Market Value thereof shall be determined in good faith by the
Board.

          (i) "Inside Director" means a Director who is an Employee.

          (j) "Option" means a stock option granted pursuant to the Plan.

          (k) "Optioned Stock" means the Common Stock subject to an Option.

          (l) "Optionee" means a Director who holds an Option.

          (m) "Outside Director" means a Director who is not an Employee.

          (n) "Parent" means a "parent corporation," whether now or hereafter
existing, as defined in Section 424(e) of the Code.

          (o) "Plan" means this 1996 Director Option Plan.

          (p) "Share" means a share of the Common Stock, as adjusted in
accordance with Section 10 of the Plan.

          (q) "Subsidiary" means a "subsidiary corporation," whether now or
hereafter existing, as defined in Section 424(f) of the Internal Revenue Code of
1986.

      3.  Stock Subject to the Plan. Subject to the provisions of Section 10 of
the Plan, the maximum aggregate number of Shares which may be optioned and sold
under the Plan is 250,000 Shares of Common Stock (the "Pool"). The Shares may be
authorized, but unissued, or reacquired Common Stock.

          If an Option expires or becomes unexercisable without having been
exercised in full, the unpurchased Shares which were subject thereto shall
become available for future grant or sale under the Plan (unless the Plan has
terminated). Shares that have actually been issued under the Plan shall not be
returned to the Plan and shall not become available for future distribution
under the Plan.

      4.  Administration and Grants of Options under the Plan.

          (a) Procedure for Grants. The provisions set forth in this Section
4(a) shall not be amended more than once every six months, other than to comport
with changes in the Code, the Employee Retirement Income Security Act of 1974,
as amended, or the rules thereunder. All grants of Options to Outside Directors
under this Plan shall be automatic and nondiscretionary and shall be made
strictly in accordance with the following provisions:


                                       -2-
<PAGE>   3
              (i) No person shall have any discretion to select which Outside
Directors shall be granted Options or to determine the number of Shares to be
covered by Options granted to Outside Directors.

              (ii) Each Outside Director shall be automatically granted an
Option to purchase that number of Shares equal to 5,000 Shares multiplied by the
Determination Fraction (as defined below) on the date of each annual meeting of
stockholders of the corporation, commencing with the first annual meeting of
stockholders held after January 1, 1997, and provided that such Outside Director
was elected or reelected at such annual meeting of stockholders. The
"Determination Fraction" shall be as follows: the numerator of the Determination
Fraction shall be $15 and the denominator of the Determination Fraction shall be
the Fair Market Value of the Common Stock on the Date of Grant. Notwithstanding
the foregoing, each annual Option grant will be for at least 3,300 Shares and
will not be in excess of 6,700 Shares.

              (iii) Notwithstanding the provisions of subsections (ii) and (iii)
hereof, any exercise of an Option granted before the Company has obtained
shareholder approval of the Plan in accordance with Section 16 hereof shall be
conditioned upon obtaining such shareholder approval of the Plan in accordance
with Section 16 hereof.

              (iv)  The terms of Options granted hereunder shall be as follows:

                    (A) the term of the Option shall be ten (10) years.

                    (B) the Option shall be exercisable only while the Outside
Director remains a Director of the Company, except as set forth in Sections 8
and 10 hereof.

                    (C) the exercise price per Share shall be 100% of the Fair
Market Value per Share on the date of grant of the Option. In the event that the
date of grant of the


                                       -3-
<PAGE>   4
Option is not a trading day, the exercise price per Share shall be the Fair
Market Value on the next trading day immediately following the date of grant of
the Option.

                    (D) subject to Section 10 hereof, the Option shall become
exercisable as to 1/12th of the Shares subject to the Option every month over
one year from the date of grant, provided that the Optionee continues to serve
as a Director on such monthly vesting dates.

              (v)   In the event that any Option granted under the Plan would
cause the number of Shares subject to outstanding Options plus the number of
Shares previously purchased under Options to exceed the Pool, then the remaining
Shares available for Option grant shall be granted under Options to the Outside
Directors on a pro rata basis. No further grants shall be made until such time,
if any, as additional Shares become available for grant under the Plan through
action of the Board or the shareholders to increase the number of Shares which
may be issued under the Plan or through cancellation or expiration of Options
previously granted hereunder.

      5. Eligibility. Options may be granted only to Outside Directors. All
Options shall be automatically granted in accordance with the terms set forth in
Section 4 hereof.

         The Plan shall not confer upon any Optionee any right with respect to
continuation of service as a Director or nomination to serve as a Director, nor
shall it interfere in any way with any rights which the Director or the Company
may have to terminate the Director's relationship with the Company at any time.

      6. Term of Plan. The Plan shall become effective upon the effective date
of the initial public offering of the Common Stock of the Company that is
registered with the Securities and Exchange Commission. It shall continue in
effect for a term of five (5) years unless sooner terminated under Section 11 of
the Plan.

      7. Form of Consideration. The consideration to be paid for the Shares to
be issued upon exercise of an Option, including the method of payment, shall
consist of (i) cash, (ii) check, (iii) other shares which (x) in the case of
Shares acquired upon exercise of an Option, have been owned by the Optionee for
more than six (6) months on the date of surrender, and (y) have a Fair Market
Value on the date of surrender equal to the aggregate exercise price of the
Shares as to which said Option shall be exercised, (iv) delivery of a properly
executed exercise notice together with such other documentation as the Company
and the broker, if applicable, shall require to effect an exercise of the Option
and delivery to the Company of the sale or loan proceeds required to pay the
exercise price, or (v) any combination of the foregoing methods of payment.

      8. Exercise of Option.

         (a) Procedure for Exercise; Rights as a Shareholder. Any Option granted
hereunder shall be exercisable at such times as are set forth in Section 4
hereof; provided, however, that no Options shall be exercisable until
shareholder approval of the Plan in accordance with Section 16 hereof has been
obtained.


                                       -4-
<PAGE>   5
         An Option may not be exercised for a fraction of a Share.

         An Option shall be deemed to be exercised when written notice of such
exercise has been given to the Company in accordance with the terms of the
Option by the person entitled to exercise the Option and full payment for the
Shares with respect to which the Option is exercised has been received by the
Company. Full payment may consist of any consideration and method of payment
allowable under Section 7 of the Plan. Until the issuance (as evidenced by the
appropriate entry on the books of the Company or of a duly authorized transfer
agent of the Company) of the stock certificate evidencing such Shares, no right
to vote or receive dividends or any other rights as a shareholder shall exist
with respect to the Optioned Stock, notwithstanding the exercise of the Option.
A share certificate for the number of Shares so acquired shall be issued to the
Optionee as soon as practicable after exercise of the Option. No adjustment
shall be made for a dividend or other right for which the record date is prior
to the date the stock certificate is issued, except as provided in Section 10 of
the Plan.

         Exercise of an Option in any manner shall result in a decrease in the
number of Shares which thereafter may be available, both for purposes of the
Plan and for sale under the Option, by the number of Shares as to which the
Option is exercised.

         (b) Rule 16b-3. Options granted to Outside Directors must comply with
the applicable provisions of Rule 16b-3 promulgated under the Exchange Act or
any successor thereto and shall contain such additional conditions or
restrictions as may be required thereunder to qualify Plan transactions, and
other transactions by Outside Directors that otherwise could be matched with
Plan transactions, for the maximum exemption from Section 16 of the Exchange
Act.

         (c) Termination of Continuous Status as a Director. Subject to Section
10 hereof, in the event an Optionee's status as a Director terminates (other
than upon the Optionee's death or total and permanent disability (as defined in
Section 22(e)(3) of the Code)), the Optionee may exercise his or her Option, but
only within three (3) months following the date of such termination, and only to
the extent that the Optionee was entitled to exercise it on the date of such
termination (but in no event later than the expiration of its ten (10) year
term). To the extent that the Optionee was not entitled to exercise an Option on
the date of such termination, and to the extent that the Optionee does not
exercise such Option (to the extent otherwise so entitled) within the time
specified herein, the Option shall terminate.

         (d) Disability of Optionee. In the event Optionee's status as a
Director terminates as a result of total and permanent disability (as defined in
Section 22(e)(3) of the Code), the Optionee may exercise his or her Option, but
only within twelve (12) months following the date of such termination, and only
to the extent that the Optionee was entitled to exercise it on the date of such
termination (but in no event later than the expiration of its ten (10) year
term). To the extent that the Optionee was not entitled to exercise an Option on
the date of termination, or if he or she does not exercise such Option (to the
extent otherwise so entitled) within the time specified herein, the Option shall
terminate.


                                       -5-
<PAGE>   6
         (e) Death of Optionee. In the event of an Optionee's death, the
Optionee's estate or a person who acquired the right to exercise the Option by
bequest or inheritance may exercise the Option, but only within twelve (12)
months following the date of death, and only to the extent that the Optionee was
entitled to exercise it on the date of death (but in no event later than the
expiration of its ten (10) year term). To the extent that the Optionee was not
entitled to exercise an Option on the date of death, and to the extent that the
Optionee's estate or a person who acquired the right to exercise such Option
does not exercise such Option (to the extent otherwise so entitled) within the
time specified herein, the Option shall terminate.

      9. Non-Transferability of Options. The Option may not be sold, pledged,
assigned, hypothecated, transferred, or disposed of in any manner other than by
will or by the laws of descent or distribution and may be exercised, during the
lifetime of the Optionee, only by the Optionee.

     10. Adjustments Upon Changes in Capitalization, Dissolution, Merger or
Asset Sale.

         (a) Changes in Capitalization. Subject to any required action by the
shareholders of the Company, the number of Shares covered by each outstanding
Option, the number of Shares which have been authorized for issuance under the
Plan but as to which no Options have yet been granted or which have been
returned to the Plan upon cancellation or expiration of an Option, as well as
the price per Share covered by each such outstanding Option, and the number of
Shares issuable pursuant to the automatic grant provisions of Section 4 hereof
shall be proportionately adjusted for any increase or decrease in the number of
issued Shares resulting from a stock split, reverse stock split, stock dividend,
combination or reclassification of the Common Stock, or any other increase or
decrease in the number of issued Shares effected without receipt of
consideration by the Company; provided, however, that conversion of any
convertible securities of the Company shall not be deemed to have been "effected
without receipt of consideration." Except as expressly provided herein, no
issuance by the Company of shares of stock of any class, or securities
convertible into shares of stock of any class, shall affect, and no adjustment
by reason thereof shall be made with respect to, the number or price of Shares
subject to an Option.

         (b) Dissolution or Liquidation. In the event of the proposed
dissolution or liquidation of the Company, to the extent that an Option has not
been previously exercised, it shall terminate immediately prior to the
consummation of such proposed action.

         (c) Merger or Asset Sale. In the event of a merger of the Company with
or into another corporation or the sale of substantially all of the assets of
the Company, outstanding Options may be assumed or equivalent options may be
substituted by the successor corporation or a Parent or Subsidiary thereof (the
"Successor Corporation"). If an Option is assumed or substituted for, the Option
or equivalent option shall continue to be exercisable as provided in Section 4
hereof for so long as the Optionee serves as a Director or a director of the
Successor Corporation. Following such assumption or substitution, if the
Optionee's status as a Director or director of the Successor Corporation, as
applicable, is terminated other than upon a voluntary resignation by the
Optionee, the Option or option shall become fully exercisable, including as to
Shares for which it would not


                                       -6-
<PAGE>   7
otherwise be exercisable. Thereafter, the Option or option shall remain
exercisable in accordance with Sections 8(c) through (e) above.

     If the Successor Corporation does not assume an outstanding Option or
substitute for it an equivalent option, the Option shall become fully vested and
exercisable, including as to Shares for which it would not otherwise be
exercisable. In such event the Board shall notify the Optionee that the Option
shall be fully exercisable for a period of thirty (30) days from the date of
such notice, and upon the expiration of such period the Option shall terminate.

     For the purposes of this Section 10(c), an Option shall be considered
assumed if, following the merger or sale of assets, the Option confers the right
to purchase or receive, for each Share of Optioned Stock subject to the Option
immediately prior to the merger or sale of assets, the consideration (whether
stock, cash, or other securities or property) received in the merger or sale of
assets by holders of Common Stock for each Share held on the effective date of
the transaction (and if holders were offered a choice of consideration, the type
of consideration chosen by the holders of a majority of the outstanding Shares).

     11. Amendment and Termination of the Plan.

         (a) Amendment and Termination. Except as set forth in Section 4, the
Board may at any time amend, alter, suspend, or discontinue the Plan, but no
amendment, alteration, suspension, or discontinuation shall be made which would
impair the rights of any Optionee under any grant theretofore made, without his
or her consent. In addition, to the extent necessary and desirable to comply
with Rule 16b-3 under the Exchange Act (or any other applicable law or
regulation), the Company shall obtain shareholder approval of any Plan amendment
in such a manner and to such a degree as required.

         (b) Effect of Amendment or Termination. Any such amendment or
termination of the Plan shall not affect Options already granted and such
Options shall remain in full force and effect as if this Plan had not been
amended or terminated.

     12. Time of Granting Options. The date of grant of an Option shall, for all
purposes, be the date determined in accordance with Section 4 hereof.

     13. Conditions Upon Issuance of Shares. Shares shall not be issued pursuant
to the exercise of an Option unless the exercise of such Option and the issuance
and delivery of such Shares pursuant thereto shall comply with all relevant
provisions of law, including, without limitation, the Securities Act of 1933, as
amended, the Exchange Act, the rules and regulations promulgated there under,
state securities laws, and the requirements of any stock exchange upon which the
Shares may then be listed, and shall be further subject to the approval of
counsel for the Company with respect to such compliance.

         As a condition to the exercise of an Option, the Company may require
the person exercising such Option to represent and warrant at the time of any
such exercise that the Shares are


                                       -7-
<PAGE>   8
being purchased only for investment and without any present intention to sell or
distribute such Shares, if, in the opinion of counsel for the Company, such a
representation is required by any of the aforementioned relevant provisions of
law.

         Inability of the Company to obtain authority from any regulatory body
having jurisdiction, which authority is deemed by the Company's counsel to be
necessary to the lawful issuance and sale of any Shares hereunder, shall relieve
the Company of any liability in respect of the failure to issue or sell such
Shares as to which such requisite authority shall not have been obtained.

     14. Reservation of Shares. The Company, during the term of this Plan, will
at all times reserve and keep available such number of Shares as shall be
sufficient to satisfy the requirements of the Plan.

     15. Option Agreement. Options shall be evidenced by written option
agreements in such form as the Board shall approve.

     16. Shareholder Approval. Continuance of the Plan shall be subject to
approval by the shareholders of the Company at or prior to the first annual
meeting of shareholders held subsequent to the granting of an Option hereunder.
Such shareholder approval shall be obtained in the degree and manner required
under applicable state and federal law.


                                       -8-


<PAGE>   1
                                                                EXHIBIT 10.19(a)

- --------------------------------------------------------------------------------
                          VENTANA MEDICAL SYSTEMS, INC.

                           LOAN AND SECURITY AGREEMENT

- --------------------------------------------------------------------------------
<PAGE>   2
                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                 Page
                                                                                 ----
<S>                                                                              <C>
1.    DEFINITIONS AND CONSTRUCTION..............................................   1
      1.1               Definitions.............................................   1
      1.2               Accounting Terms........................................   6
                                                                                    
2.    LOAN AND TERMS OF PAYMENT.................................................   6
      2.1               Revolving Advances......................................   6
      2.2               Overadvances............................................   7
      2.3               Interest Rates, Payments, and Calculations..............   7
      2.4               Crediting Payments......................................   8
      2.5               Fees....................................................   8
      2.6               Additional Costs........................................   8
      2.7               Term....................................................   8
                                                                                    
3.    CONDITIONS OF LOANS.......................................................   9
      3.1               Conditions Precedent to Initial Loan....................   9
      3.2               Conditions Precedent to all Loans.......................   9
                                                                                    
4.    CREATION OF SECURITY INTEREST.............................................   9
      4.1               Grant of Security Interest..............................   9
      4.2               Delivery of Additional Documentation Required...........   9
      4.3               Right to Inspect........................................  10
                                                                                    
5.    REPRESENTATIONS AND WARRANTIES............................................  10
      5.1               Due Organization and Qualification......................  10
      5.2               Due Authorization; No Conflict..........................  10
      5.3               No Prior Encumbrances...................................  10
      5.4               Bona Fide Accounts......................................  10
      5.5               Merchantable Inventory..................................  10
      5.6               Name; Location of Chief Executive Office................  10
      5.7               Intellectual Property...................................  11
      5.8               Litigation..............................................  11
      5.9               No Material Adverse Change in Financial Statements......  11
      5.10              Solvency................................................  11
      5.11              Regulatory Compliance...................................  11
      5.12              Environmental Condition.................................  11
      5.13              Taxes...................................................  11
      5.14              Subsidiaries............................................  12
      5.15              Government Consents.....................................  12
      5.16              Full Disclosure.........................................  12
                                                                                    
6.    AFFIRMATIVE COVENANTS.....................................................  12
      6.1               Good Standing...........................................  12
      6.2               Government Compliance...................................  12
      6.3               Financial Statements, Reports, Certificates.............  12
      6.4               Returns.................................................  13
      6.5               Taxes...................................................  13
      6.6               Insurance...............................................  13
      6.7               Principal Depository....................................  13
      6.8               Quick Ratio.............................................  13
      6.9               Tangible Net Worth......................................  13
</TABLE>

                                       i
<PAGE>   3
<TABLE>
<S>                                                                              <C>
      6.10              Debt-Net Worth Ratio....................................  13
      6.11              Profitability...........................................  13
      6.12              Vendor Financing Program................................  14
      6.13              Additional Equity.......................................  14
      6.14              Further Assurances......................................  14
                                                                                    
7.    NEGATIVE COVENANTS........................................................  14
      7.1               Extraordinary Transactions and Disposal of Assets.......  14
      7.2               Loans; Contingent Liabilities...........................  14
      7.3               Restructure.............................................  14
      7.4               Mergers or Acquisitions.................................  14
      7.5               Indebtedness............................................  14
      7.6               Encumbrances............................................  14
      7.7               Distributions...........................................  14
      7.8               Investments.............................................  14
      7.9               Transactions with Affiliates............................  15
      7.10              Subordinated Debt.......................................  15
      7.11              Compliance..............................................  15
                                                                                    
8.    EVENTS OF DEFAULT.........................................................  15
      8.1               Payment Default.........................................  15
      8.2               Covenant Default........................................  15
      8.3               Material Adverse Change.................................  15
      8.4               Attachment..............................................  15
      8.5               Insolvency..............................................  15
      8.6               Other Agreements........................................  16
      8.7               Subordinated Debt.......................................  16
      8.8               Judgments...............................................  16
      8.9               Misrepresentations......................................  16
                                                                                    
9.    BANK'S RIGHTS AND REMEDIES................................................  16
      9.1               Rights and Remedies.....................................  16
      9.2               Power of Attorney.......................................  17
      9.3               Accounts Collection.....................................  17
      9.4               Bank Expenses...........................................  17
      9.5               Remedies Cumulative.....................................  17
                                                                                    
10.   WAIVERS; INDEMNIFICATION..................................................  18
      10.1              Demand; Protest.........................................  18
      10.2              Bank's Liability for Collateral.........................  18
      10.3              Indemnification.........................................  18
                                                                                    
11.   NOTICES...................................................................  18
                                                                                    
12.   CHOICE OF LAW AND VENUE; JURY TRIAL WAIVER................................  18
                                                                                    
13.   GENERAL PROVISIONS........................................................  19
      13.1              Successors and Assigns..................................  19
      13.2              Time of Essence.........................................  19
      13.3              Severability of Provisions..............................  19
      13.4              Amendments in Writing, Integration......................  19
      13.5              Counterparts............................................  19
      13.6              Survival................................................  19
</TABLE>

                                       ii
<PAGE>   4
         This LOAN AND SECURITY AGREEMENT is entered into as of February 20,
1995, by and between SILICON VALLEY BANK ("Bank") and VENTANA MEDICAL SYSTEMS,
INC., a Delaware corporation ("Borrower").

                                    RECITALS

         Borrower wishes to borrow money from time to time from Bank, and Bank
desires to lead money to Borrower. This Agreement sets forth the terms on which
Bank will lend to Borrower, and Borrower will repay the loan to Bank.

                                    AGREEMENT

         The parties agree as follows:

         1. DEFINITIONS AND CONSTRUCTION

            1.1 Definitions. As used in this Agreement, the following terms
shall have the following definitions:

                "Accounts" means all presently existing and hereafter arising
accounts, contract rights, and all other forms of obligations owing to Borrower
arising out of the sale or lease of goods or the rendering of services by
Borrower, whether or not earned by performance, and any and all credit
insurance, guaranties, and other security therefor, as well as all merchandise
returned to or reclaimed by Borrower and Borrower's Books relating to any of the
foregoing.

                "Affiliate" means any person or entity that owns or controls
directly or indirectly more than ten percent or more of the stock of another
entity, any person that controls or is controlled by or is under common control
with such persons or any Affiliate of such persons or each of such person's
officers, directors, joint ventures or partners.

                "Bank Expenses" means all: reasonable costs or expenses
(including reasonable attorneys' fees and expenses) incurred in connection with
the preparation, negotiation, administration; and enforcement of the Loan
Documents; and Bank's reasonable attorneys' fees and expenses incurred in
amending, enforcing or defending the Loan Documents, whether or not suit is
brought.

                "Borrower's Books" means all of Borrower's books and records
including: ledgers; records concerning Borrower's assets or liabilities, the
Collateral, business operations or financial condition; and all computer
programs, or tape files, and the equipment, containing such information.

                "Borrowing Base" has the meaning set forth in Section 2.1
hereof.

                "Business Day" means any day that is not a Saturday, Sunday, or
other day on which banks in the State of California are authorized or required
to close.

                "Closing Date" means the date of this Agreement.

                "Code" means the Uniform Commercial Code, as adopted by the
State of California and in effect from time to time.

                "Collateral" means the property described on Exhibit A attached
hereto.



                                        1
<PAGE>   5
                "Committed Line" means Two Million Seven Hundred Fifty Thousand
Dollars ($2,750,000).

                "Contingent Obligation" means, as applied to any person, any
direct or indirect liability, contingent or otherwise, of that person with
respect to any indebtedness, lease, dividend, letter of credit or other
obligation of another, including, without limitation, any such obligation
directly or indirectly guaranteed, endorsed (otherwise than for collection or
deposit in the ordinary course of business), co-made or discounted or sold with
recourse by that person, or in respect of which that person is otherwise
directly or indirectly liable. The amount of any Contingent Obligation shall be
equal to the amount of the obligation so guaranteed or otherwise supported.

                "Current Assets" means, as of any applicable date, all amounts
that should, in accordance with generally accepted accounting principles, be
included as current assets on the balance sheet of Borrower as at such date.

                "Current Liabilities" means as of any applicable date, all
amounts that should, in accordance with generally accepted accounting
principles, be included as current liabilities on the balance sheet of Borrower
as at such date, plus, to the extent not already included therein, all Advances
made under this Agreement, and all Indebtedness that is payable upon demand or
within one year from the date of determination thereof unless such Indebtedness
is renewable or extendable at the option of Borrower or any subsidiary to a date
more than one year from the date of determination.

                "Daily Balance" means the amount of the Obligations owed at the
end of a given day. 

                "Eligible Accounts" means those Accounts that arise in the
ordinary course of Borrower's business from Borrower's sale or lease of goods or
rendering of services that have been validly assigned and comply with all of
Borrower's representations and warranties to Bank and that are and at all times
shall continue to be acceptable to Bank in all respects, together with Accounts
of a like character acquired by Borrower from other entities; provided, that
standards of eligibility may be fixed and revised from time to time by Bank in
Bank's reasonable judgment and upon notification thereof to the Borrower in
accordance with the provisions hereof. Unless otherwise agreed to by Bank,
Eligible Accounts shall not include the following:

                (a) Accounts that the account debtor has failed to pay within
ninety (90) days of invoice date;

                (b) Accounts with respect to an account debtor, fifty percent
(50%) of whose Accounts the account debtor has failed to pay within ninety (90)
days of invoice date;

                (c) Accounts with respect to which the account debtor is an
officer, employee, or agent of Borrower;

                (d) Accounts with respect to which goods are placed on
consignment, guaranteed sale, sale or return, sale on approval, bill and hold,
or other terms by reason of which the payment by the account debtor may be
conditional;

                (e) Accounts with respect to which the account debtor is an
Affiliate of Borrower;

                (f) Accounts with respect to which the account debtor is not a
resident of the United States unless Bank shall have approved specific such
Accounts in its sole discretion;

                (g) Accounts with respect to which the account debtor is the
United States or any department, agency, or instrumentality of the United
States;



                                        2
<PAGE>   6
                (h) Accounts with respect to which Borrower is liable to the
account debtor for goods sold or services rendered by the account debtor to
Borrower, but only to the extent of any amounts owing to the account debtor
against amounts owed to Borrower;

                (i) Accounts with respect to an account debtor, including
subsidiaries and affiliates, whose total obligations to Borrower exceed
twenty-five percent (25%) of all Accounts, to the extent such obligations exceed
the aforementioned percentage;

                (j) Accounts with respect to which the account debtor disputes
liability or makes any claim with respect thereto as to which Bank believes, in
its sole discretion, that there may be a basis for dispute (but only to the
extent of the amount subject to such dispute or claim), or is subject to any
Insolvency Proceeding, or becomes insolvent, or goes out of business; and

                (k) Accounts the collection of which Bank reasonably determines
after reasonable inquiry to be doubtful by reason of the account debtor's
financial condition.

                "Equipment" means machinery, equipment, furniture, fixtures,
vehicles, tools, parts and attachments.

                "ERISA" means the Employment Retirement Income Security Act of
1974, as amended, and the regulations thereunder.

                "GAAP" means generally accepted accounting principles as in
effect from time to time.

                "General Intangibles" means general intangibles and other
personal property (including chooses or things in action, goodwill, patents,
trade names, trademarks, servicemarks, copyrights, blueprints, drawings,
purchase orders, customer lists, monies due or recoverable from pension funds,
route lists, monies due under any royalty or licensing agreements,
infringements, claims, computer programs, computer discs, computer tapes,
literature, reports, catalogs, deposit accounts, insurance premium rebates, tax
refunds, and tax refund claims) other than goods, Equipment and Accounts, and
Borrower's Books relating to any of the foregoing.

                "Indebtedness" means (a) all indebtedness for borrowed money or
the deferred purchase price of property or services, including without
limitation reimbursement and other obligations with respect to surety bonds and
team of credit, (b) all obligations evidenced by notes, bonds, debentures or
similar instruments, (c) all capital lease obligations, and (d) all Contingent
Obligations.

                "Insolvency Proceeding" means any proceeding commenced by or
against any person or entity under any provision of the United States Bankruptcy
Code, as amended, or under any other bankruptcy or insolvency law, including
assignments for the benefit of creditors, formal or informal moratoria,
compositions, extension generally with its creditors, or proceedings seeking
reorganization, arrangement, or other relief.

                "Inventory" means all present and future inventory in which
Borrower has any interest, including merchandise, raw materials, parts,
supplies, packing and shipping materials, work in process and finished products
intended for sale or lease or to be furnished under a contract of service, of
every kind and description now or at any time hereafter owned by or in the
custody or possession, actual or constructive, of Borrower, including such
inventory as is temporarily out of its custody or possession or in transit and
including any returns upon any accounts or other proceeds, including insurance
proceeds, resulting from the sale or disposition of any of the foregoing and any
documents of title representing any of the above, and Borrower's Books relating
to any of the foregoing.



                                        3
<PAGE>   7
                "IRC" means the Internal Revenue Code of 1986, as amended, and
the regulations thereunder.

                "Loan Documents" means, collectively, this Agreement, any note
or notes executed by Borrower, and any other agreement entered into between
Borrower and Bank in connection with this Agreement, all as amended or extended
from time to time.

                "Maturity Date" means January 15, 1996.

                "Negotiable Collateral" means all of Borrower's present and
future letters of credit of which it is a beneficiary, notes, drafts,
instruments, documents of title, and chattel paper, and Borrower's Books
relating to any of the foregoing.

                "Obligations" means all debt, principal, interest and other
amounts (including all amounts charged to Borrower's loan account pursuant to
any agreement authorizing Bank to charge Borrower's loan account), obligations,
covenants, and duties owing by Borrower to Bank of any kind and description
(whether pursuant to or evidenced by the Loan Documents, or by any other
agreement between Bank and Borrower, and whether or not for the payment of
money), whether direct or indirect, absolute or contingent, due or to become
due, now existing or hereafter arising, and including any debt, liability, or
obligation owing from Borrower to others that Bank may have obtained by
assignment or otherwise, and further including all interest not paid when due
and all Bank Expenses that Borrower is required to pay or reimburse by the Loan
Documents, by law, or otherwise.

                "Periodic Payments" means all installments or similar recurring
payments that Borrower may now or hereafter become obligated to pay to Bank
pursuant to the terms and provisions of any instrument, or agreement now or
hereafter in existence between Borrower and Bank.

                "Permitted Indebtedness" means:

                (a) Indebtedness of Borrower in favor of Bank arising under this
Agreement;

                (b) The existing Indebtedness disclosed on the schedule of
exceptions attached hereto (the "Schedule");

                (c) Subordinated Debt;

                (d) Indebtedness under capital leases and/or similar equipment
financings, but only to the extent of the Permitted Liens securing the same;

                (e) Indebtedness to trade creditors incurred in the ordinary
course of business; and

                (f) Extensions of any of items of Permitted Indebtedness (a)
through (d) above, provided that the principal amount thereof is not increased
or the terms thereof are not modified to impose more burdensome terms upon
Borrower.

                "Permitted Investment" means:

                (a) Investments existing on the Closing Date disclosed in the
Schedule;

                (b) (i) marketable direct obligations issued or unconditionally
guaranteed by the United States of America or any agency or any State thereof
maturing within one (1) year from the date of acquisition thereof, (ii)
commercial paper maturing no more than one (1) year from the date of creation
thereof



                                        4
<PAGE>   8
and currently having the highest rating obtainable from either Standard & Poor's
Corporation or Moody's Investors Service, Inc., and (iii) certificates of
deposit maturing no more than one (1) year from the date of investment therein
issued by Bank.

                "Permitted Liens means the following:

                (a) Any Liens existing as of the date hereof and disclosed in
the Schedule;

                (b) Liens for taxes, fees, assessments or other governmental
charges or levies, either not delinquent or being contested in good faith by
appropriate proceedings, provided the same have no priority over any of Bank's
security interests;

                (c) Liens (i) upon or in any equipment acquired or held by the
Borrower or any of its subsidiaries to secure the purchase price of such
equipment or indebtedness incurred solely for the purpose of financing the
acquisition of such equipment, or (ii) existing on such equipment at the time of
its acquisition, provided that the Lien is confined solely to the property so
acquired and improvements thereon, and the proceeds of such equipment; and

                (d) Liens incurred in connection with the extension, renewal or
refinancing of the indebtedness secured by Liens of the type described in
clauses (a) and (c) above, provided that any extension, renewal or replacement
Lien shall be limited to the property encumbered by the existing Lien and the
principal amount of the indebtedness being extended, renewed or refinanced does
not increase.

                "Prime Rate" means the variable rate of interest per annum, most
recently announced by Bank, as its "prime rate," whether or not such announced
rate is the lowest rate available from Bank.

                "Quick Assets" means at any date as of which the amount thereof
shall be determined, the consolidated cash, accounts receivable and investments
with maturities not to exceed 90 days of Borrower.

                "Revolving Facility" means the facility under which Borrower may
request Bank to issue cash advances or commercial letters of credit or enter
into foreign currency transactions, as specified in Section 2.1 hereof.

                "Revolving Note" means a promissory note in substantially the
form of Exhibit B attached hereto.

                "Subordinated Debt" means any debt subordinated to the debt
owing by Borrower to Bank on terms acceptable to Bank.

                "Tangible Net Worth" means at any date as of which the amount
thereof shall be determined, the total assets of Borrower on an unconsolidated
basis minus (i) the sum of any amounts attributable to (a) goodwill, (b)
intangible items such as unamortized debt discount and expense, patents, trade
and service marks and names, copyrights and research and development expenses
except prepaid expenses, (c) all reserves not already deducted from assets, and
(d) investments in any other person or entity and (ii) Total Liabilities.

                "Total Liabilities" means at any date as of which the amount
thereof shall be determined, all obligations that should, in accordance with
GAAP be classified as liabilities on the consolidated balance sheet of Borrower,
including in any event all Indebtedness, but specifically excluding Subordinated
Debt.



                                        5
<PAGE>   9
            1.2 Accounting Terms. All accounting terms not specifically defined
herein shall be construed in accordance with GAAP. When used herein, the terms
"financial statements" shall include the notes and schedules thereto.

         2. LOAN AND TERMS OF PAYMENT

            2.1 Revolving Advances. Subject to the terms and conditions of this
Agreement, Bank agrees to make revolving advances ("Advances") and to issue
letters of credit ("Letters of Credit") to Borrower and to arrange the purchase
by Borrower of spot and future foreign exchange contracts (the "Exchange
Contracts"), together at any one time in an amount not to exceed the lesser of
the Committed Line or the Borrowing Base (the "Maximum Availability"). For
purposes of this Agreement "Borrowing Base" shall mean an amount equal to eighty
percent (80%) of Eligible Accounts.

         To evidence the Advances, Borrower shall execute and deliver to Bank on
the date hereof the Revolving Note.

         Whenever Borrower desires an Advance, Borrower will notify Bank by
facsimile transmission or telephone no later than 11:00 a.m. California time,
one Business Day before the day the Advance is to be made. Each such
notification shall be promptly confirmed by a Borrowing Certificate in
substantially the form of Schedule 2.1 hereto.

         Bank is authorized to make Advances under this Agreement, based upon
instructions received from an officer of Borrower, or without instructions if in
Bank's discretion such Advances are necessary to meet Obligations which have
become due and remain unpaid. Bank will credit the amount of Advances made under
this Section 2.1 to Borrower's loan account. Amounts borrowed pursuant to this
Section 2.1 may be repaid and reborrowed at any time during the term of this
Agreement so long as no Event of Default has occurred and is continuing.

         The Revolving Facility shall terminate on the Maturity Date, at which
time all amounts advanced under this Section 2. shall be immediately due and
payable.

                (a) Letter of Credit Sublimit. Subject to the terms and
conditions of this Agreement and in reliance upon the representations and
warranties of Borrower set forth herein, at any time and from time to time from
the date hereof through the Business Day immediately prior to the Maturity Date,
Bank shall issue for the account of Borrower such Letters of Credit as Borrower
may request, which request shall be made by delivering to Bank a duly executed
letter of credit application on Bank's standard form. Notwithstanding anything
to the contrary contained in this Agreement, upon issuing any such Letter of
Credit, the aggregate principal amount outstanding and undrawn under all Letters
of Credit together with all outstanding Advances and Foreign Exchange Reserve
shall not exceed One Million Dollars ($1,000,000). No Letter of Credit shall
have an expiration date that is later than the Maturity Date. All Letters of
Credit shall be, in form and substance, acceptable to Bank in its sole
discretion and shall be subject to the terms and conditions of Bank's form
application and letter of credit agreement.

                (b) Foreign Exchange Sublimit. Borrower may utilize the
Committed Line for Exchange Contracts, provided that all Exchange Contracts must
provide for delivery or settlement on or before the Maturity Date.
Notwithstanding anything to the contrary contained in this Agreement, after
giving effect to any such Exchange Contract, the aggregate principal amount of
Advances outstanding, the outstanding and undrawn amount of Letters of Credit
and the Foreign Exchange Reserve shall not exceed the Maximum Availability. The
Foreign Exchange Reserve on each day (the "Determination Date") shall mean: (i)
on all outstanding Exchange Contracts on which delivery is to be affected or
settlement allowed more than two business days from the Determination Date, 10%
of the gross amount of the Exchange Contracts; plus (ii) on all outstanding
Exchange Contracts on which delivery is to be effected or settlement allowed
within two business days after the Determination Date, 100% of the gross amount
of the Exchange Contracts. In lieu of the Foreign



                                        6
<PAGE>   10
Exchange Reserve for 100% of the gross amount of any Exchange Contract, the
Borrower may request that Bank debit the Borrower's bank account with Bank for
such amount, provided Borrower has immediately available funds in such amounts
in its bank account.

            Bank may, in its discretion, terminate the Exchange Contracts at any
time (a) that an Event of Default occurs or (b) that there is no sufficient
availability under the Committed Line and Borrower does not have available funds
in its bank account to satisfy the Foreign Exchange Reserve. If Bank terminates
the Exchange Contracts, and without limitation of the FX Indemnity Provisions
(as referred to below), Borrower agrees to reimburse Bank for any and all fees,
costs and expenses relating thereto or arising in connection therewith.

            Borrower shall not permit the total gross amount of all Exchange
Contracts on which delivery is to be effected and settlement allowed in any two
business day period to be more than One Million Dollars ($1,000,000), nor shall
Borrower permit the total gross amount of all Exchange Contracts to which
Borrower is a party, outstanding at any one time, to exceed the lesser of (a)
One Million Dollars ($1,000,000) and (b) the Maximum Availability.

            The Borrower shall execute all standard form applications and
agreements of Bank in connection with the Exchange Contracts, and without
limiting any of the terms of such applications and agreements the Borrower will
pay all standard fees and charges of Bank in connection with the Exchange
Contracts.

            Without limiting any of the other terms of this Agreement or any
such standard form applications and agreement of Bank, Borrower agrees to
indemnify Bank and hold it harmless, from and against any and all claims, debts,
liabilities, demands, obligations, actions, costs and expenses (including,
without limitation, attorneys fees of counsel of Bank's choice), of every nature
and description which it way sustain or incur, based upon, arising out of, or in
any way relating to any of the Exchange Contracts or any transactions relating
thereto or contemplated thereby (collectively referred to as the "FX Indemnity
Provisions").

            2.2 Overadvances. If, at any time or for any reason, the amount of
Obligations owed by Borrower to Bank pursuant to Section 2.1 of this Agreement
is greater than the lesser of (i) the Committed Line or (ii) the Borrowing Base,
Borrower shall immediately pay to Bank, in cash, the amount of such excess.

            2.3 Interest Rates, Payments, and Calculations.

                (a) Interest Rate. Any Advances evidenced by the Note shall bear
interests, on the average Daily Balance, at a rate per annum equal to two
percentage points (2.00%) above the Prime Rate.

                (b) Default Rate. All Obligations shall bear interest, from and
after the occurrence of an Event of Default, at a rate equal to five (5)
percentage points above the interest rate applicable immediately prior to the
occurrence of the Event of Default.

                (c) Payments. Interest on Advances shall be due and payable on
the last Business Day of each calendar month during the term hereof. Bank shall,
at its option, charge such interest, all Bank Expenses, and all Periodic
Payments against Borrower's deposit account or against the Committed Line, in
which case those amounts shall thereafter accrue interest at the rate then
applicable hereunder. Any interest not paid when due shall be compounded by
becoming a part of the Obligations, and such interest shall thereafter accrue
interest at the rate then applicable hereunder.

                (d) Computation. In the event the Prime Rate is changed from
time to time hereafter, the applicable rate of interest hereunder shall be
increased or decreased contemporaneously with such change by an amount equal to
such change in the Prime Rate. All interest chargeable under the Loan Documents
shall be computed on the basis of a three hundred sixty (360) day year for the
actual number of days elapsed.



                                        7
<PAGE>   11
            2.4 Crediting Payments. The receipt by Bank of any wire transfer of
funds, check, or other item of payment shall be immediately applied to
conditionally reduce obligations, but shall not be considered a payment on
account unless such wire transfer is of immediately available federal funds and
is made to the appropriate deposit account of Bank or unless and until such
check or other item of payment is honored when presented for payment.
Notwithstanding anything to the contrary contained herein, any wire transfer or
payment received by Bank after 11:00 a.m. California time shall be deemed to
have been received by Bank as of the opening of business on the immediately
following Business Day.

            2.5 Fees. Borrower shall pay to Bank the following:

                (a) Loan Fee. Upon the date hereof, a nonrefundable Loan Fee
equal to Twenty-Seven Thousand, Five Hundred Dollars ($27,500), which shall be
due upon the date of this Agreement and shall be fully earned and nonrefundable;

                (b) Letter of Credit Fees. Bank's customary fees and commissions
for standby and commercial letters of credit;

                (c) Financial Examination and Appraisal Fees. Bank's customary
fees and out- of-pocket expenses for Bank's audits of Borrower's Accounts and
Inventory, and for each appraisal of Collateral and financial analysis and
examination of Borrower performed from time to time by Bank or its agents; and

                (d) Bank Expenses. Upon the date hereof, all Bank Expenses
incurred through the date hereof, including reasonable attorneys' fees and
expenses.

            2.6 Additional Costs. In case any law, regulation, treaty or
official directive or the interpretation or application thereof by any court of
any governmental authority charged with the administration thereof or the
compliance with any guideline or request of any central bank or other
governmental authority (whether or not having the force of law):

                (a) subjects Bank to any tax with respect to payments of
principal or interest or any other amounts payable hereunder by Borrower or
otherwise with respect to the transactions contemplated hereby (except for taxes
on the overall net income of Bank imposed by the United States of America or any
political subdivision thereof); or

                (b) imposes, modifies or deems applicable any deposit insurance,
reserve, special deposit or similar requirement against assets held by, or
deposits in or for the account of, or loans by, Bank; or

                (c) imposes upon Bank any other condition with respect to its
performance under this Agreement,

and the result of any of the foregoing is to increase the cost to Bank, reduce
the income receivable by Bank or impose any expense upon Bank with respect to
any loans, Bank shall notify Borrower thereof. Borrower agrees to pay to Bank
the amount of such increase in cost, reduction in income or additional expense
as and when such cost, reduction or expense is incurred or determined, upon
presentation by Bank of a statement in the amount and setting forth Bank's
calculation thereof, which statement shall be deemed true and correct absent
manifest error.

            2.7 Term. This Agreement shall become effective upon acceptance by
Bank and shall continue in full force and effect for a term ending on the
Maturity Date. Notwithstanding the foregoing, Bank shall have the right to
terminate this Agreement immediately and without notice upon the occurrence of
an Event of Default.



                                        8
<PAGE>   12
         3. CONDITIONS OF LOANS

            3.1 Conditions Precedent to Initial Loan. The obligation of Bank to
make the initial Advance is subject to the condition precedent that Bank shall
have received, in form and substance satisfactory to Bank, the following:

                (a) this Agreement and the Note, each duly executed by Borrower;

                (b) a certificate of the secretary of Borrower with respect to
incumbency and resolutions authorizing the execution and delivery of this
Agreement;

                (c) an accounts receivable audit;

                (d) a collateral assignment and patent mortgage to be filed with
the United States Patent and Trademark Office;

                (e) a financing statement on Form UCC-1;

                (f) payment of the fees and Bank Expenses then due specified in
section 2.5 hereof; and

                (g) such other documents, and completion of such other matters,
as Bank may deem necessary or appropriate.

            3.2 Conditions Precedent to all Loans. The obligation of Bank to
make each Advance, including the initial Advance, is further subject to the
following conditions:

                (a) timely receipt by Bank of the Notice of Borrowing as
provided in Section 2.1; and

                (b) the representations and warranties contained in Section 5
shall be true and accurate in all material respects on and as of the date of
such Notice of Borrowing and on the effective date of each Advance as though
made at and as of each such date, and no Event of Default shall have occurred
and be continuing, or would result from such Advance.

         The making of each Advance shall be deemed to be a representation and
warranty by Borrower on the date of such Advance as to the accuracy of the facts
referred to in subsection (b) of this Section 3.2.

         4. CREATION OF SECURITY INTEREST

            4.1 Grant of Security Interest. Borrower grants to Bank a continuing
security interest in all presently existing and hereafter acquired or arising
Collateral in order to secure prompt repayment of any and all Obligations and in
order to secure prompt performance by Borrower of each of its covenants and
duties under the Loan Documents. Such security interest constitutes a valid,
first priority security interest in the Collateral.

            4.2 Delivery of Additional Documentation Required. Borrower shall
from time to time execute and deliver to Bank, at the request of Bank, all
financing statements, registrations and assignments of intellectual property and
other documents that Bank may reasonably request, in form satisfactory to Bank,
to perfect and continue perfected Bank's security interests in the Collateral
and in order to fully consummate all of the transactions contemplated under the
Loan Documents.



                                        9
<PAGE>   13
            4.3 Right to Inspect. Bank (through any of its officers, employees,
or agents) shall have the right, upon reasonable prior notice, from time to time
during Borrower's usual business hours, to inspect Borrower's Books and to make
copies thereof and to check, test, and appraise the Collateral in order to
verify Borrower's financial condition or the amount, condition of, or any other
matter relating to, the Collateral.

         5. REPRESENTATIONS AND WARRANTIES

            Borrower represents, warrants and covenants as follows:

            5.1 Due Organization and Qualification. Borrower is a corporation
duly existing and in good standing under the laws of its state of incorporation
and qualified and licensed to do business in, and is in good standing in, any
state in which the conduct of its business or its ownership of property requires
that it be so qualified, except for such states as to which any failure so to
qualify would not have a material adverse effect on Borrower.

            5.2 Due Authorization; No Conflict. The execution, delivery, and
performance of the Loan Documents are within Borrower's powers, have been duly
authorized, and are not in conflict with nor constitute a breach of any
provision contained in Borrower's Certificate of Incorporation or Bylaws, nor
will they constitute an event of default under any material agreement to which
Borrower is a party or by which Borrower is bound. Borrower is not in default
under any agreement to which it is a party or by which it is bound, which
default could have a material adverse effect on the financial condition or
business operations of Borrower.

            5.3 No Prior Encumbrances. Borrower has good and indefeasible title
to the Collateral, free and clear of liens, claims, security interests, or
encumbrances, except as held by Bank and except for Permitted Liens. Except as
disclosed in the Schedule, Borrower has not acquired any part of the Collateral
from an assignor outside the ordinary course of such assignor's business.

            5.4 Bona Fide Accounts. The Eligible Accounts are and shall remain
bona fide existing obligations created by the sale and delivery of Inventory or
the rendition of services to account debtors in the ordinary course of
Borrower's business, unconditionally owed to Borrower without defenses,
disputes, offsets, counterclaims, or rights of return or cancellation. The
property giving rise to such Eligible Accounts has been delivered to the account
debtor or to the account debtor's agent for immediate shipment to and
unconditional acceptance by the account debtor. Borrower has not, and at all
times hereafter, shall not have, received notice of actual or imminent
bankruptcy or insolvency of any account debtor at the time an account due from
such account debtor is included in any Borrowing Base as an Eligible Account.

            5.5 Merchantable Inventory. All Inventory is now and at all times
hereafter shall be in all material respects of good and marketable quality, and
free from all material defects. Without the Bank's prior consent, the Inventory
is not now and shall not at any time hereafter be stored with a bailee,
warehouseman, or similar party unless Bank has received a pledge of the
warehouse receipt covering such Inventory. Except for Inventory sold in the
ordinary course of business and except for such other locations as Bank may
approve in writing, Borrower shall keep the Inventory only at the location set
forth in Section 11 hereof and such other locations of which Borrower gives Bank
prior written notice and as to which Borrower signs and files a financing
statement where needed to perfect Bank's security interest.

            5.6 Name; Location of Chief Executive Office. Except as disclosed in
the Schedule, Borrower has not done business under any name other than that
specified on the signature page hereof. The chief executive office of Borrower
is located at the address indicated in Section 11 hereof. Borrower will not,
without thirty (30) days prior written notification to Bank, relocate such chief
executive office.



                                       10
<PAGE>   14
            5.7 Intellectual Property. Borrower and, to the best of Borrower's
knowledge, each of Borrower's subsidiaries, possess and own all necessary
trademarks, trade names, copyrights, patents, patent rights, and licenses which
are material to the conduct of its business as now operated. All copyrights
material to the conduct of Borrower's and its subsidiaries' business have been
registered in the United States Copyright Office. Borrower and, to the best of
Borrower's knowledge, each of Borrower's subsidiaries conducts its business
without infringement or, to the best of Borrower's knowledge, claim of
infringement of any trademark, trade name, trade secret, service mark, patent,
copyright, license or other intellectual property right of others. There is no
infringement or, to the best of Borrower's knowledge, claim of infringement by
others of any material trademark, trade name, trade secret, service mark,
patent, copyright, license or other intellectual property right of Borrower or
any of Borrower's subsidiaries.

            5.8 Litigation. There are no actions or proceedings pending by or
against Borrower before any court or administrative agency in which an adverse
decision could have a material adverse effect on Borrower or the Collateral.
Borrower does not have knowledge of any such pending or threatened actions or
proceedings. Borrower will promptly notify Bank in writing if any action,
proceeding or governmental investigation involving Borrower is commenced that
may result in damages or costs to Borrower of One Hundred Thousand Dollars
($100,000) or more.

            5.9 No Material Adverse Change in Financial Statements. All
financial statements relating to Borrower or any Affiliate that have been or may
hereafter be delivered by Borrower to Bank fairly present in all material
respects Borrower's financial condition as of the date thereof and Borrower's
results of operations for the period then ended. There has not been a material
adverse change in the financial condition of Borrower since the date of the most
recent of such financial statements submitted to Bank.

            5.10 Solvency. Borrower and each of Borrower's subsidiaries is
solvent and able to pay its debts (including trade debts) as they mature.

            5.11 Regulatory Compliance. Borrower has met and at all times will
meet the minimum funding requirements of ERISA with respect to any employee
benefit plans subject to ERISA. No event has occurred resulting from Borrower's
failure to comply with ERISA that is reasonably likely to result in Borrower's
incurring any liability that could have a material adverse effect on the
financial condition or business operations of Borrower. Borrower is not an
"investment company" or a company "controlled" by an "investment company" within
the meaning of the Investment Company Act of 1940. Borrower is not engaged
principally, or as one of the important activities, in the business of extending
credit for the purpose of purchasing or carrying margin stock (within the
meaning of Regulations G, T and U of the Board of Governors of the Federal
Reserve System), and the proceeds of the Advances will not be used for such
purpose. Borrower has complied with all the provisions of the Federal Fair Labor
Standards Act.

            5.12 Environmental Condition. Except as set forth on Schedule 5.12
hereto, none of Borrower's properties or assets has ever been used by Borrower
or, to the best of Borrower's knowledge, by previous owners or operators in the
disposal of, or to produce, store, handle, treat, release, or transport, any
hazardous waste or hazardous substance other than in accordance with applicable
law; none of Borrower's properties or assets has ever been designated or
identified in any manner pursuant to any environmental protection statute as a
hazardous waste or hazardous substance disposal site, or a candidate for closure
pursuant to any environmental protection statute; no lien arising under any
environmental protection statute has attached to any revenues or to any real or
personal property owned by Borrower; and Borrower has not received a summons,
citation, notice, or directive from the Environmental Protection Agency or any
other federal or state governmental agency concerning any action or omission by
Borrower resulting in the releasing, or otherwise disposing of hazardous waste
or hazardous substances into the environment.

            5.13 Taxes. Borrower has filed or caused to be filed all tax returns
required to be filed, and has paid, or has made adequate provision for the
payment of, all taxes that are due and payable.



                                       11
<PAGE>   15
            5.14 Subsidiaries. Borrower does not own any stock, partnership
interest or other equity securities of any entity, except for (i) 100% of the
capital stock of Ventana France, a corporation organized under the laws of
France, (ii) 100% of the capital stock of Ventana GMBH, a corporation organized
under the laws of Germany, and (iii) Permitted Investments.

            5.15 Government Consents. Borrower has obtained all consents,
approvals and authorizations of, made all declarations or filings with, and
given all notices to, all governmental authorities that are necessary for the
continued operation of Borrower's business as currently conducted.

            5.16 Full Disclosure. No representation, warranty or other statement
made by Borrower in any certificate or written statement furnished to Lender
contains any untrue statement of a material fact or omits to state a material
fact necessary in order to make the statements contained in such certificates or
statements not misleading.

         6. AFFIRMATIVE COVENANTS

            Borrower covenants and agrees that, until payment in full of the
Obligations, Borrower shall do all of the following:

            6.1 Good Standing. Borrower shall maintain its corporate existence
and its good standing in its jurisdiction of incorporation and maintain
qualification in each jurisdiction in which the failure to so qualify could have
a material adverse effect on the financial condition, operations or business of
Borrower. Borrower shall maintain in form all licenses, approvals and
agreements, the loss of which could have a material adverse effect on its
financial condition, operations or business.

            6.2 Government Compliance. Borrower shall, and shall cause each of
its subsidiaries to, comply with all statutes, laws, ordinances and government
rules and regulations to which it is subject, noncompliance with which could
materially adversely affect the financial condition, operations or business of
Borrower.

            6.3 Financial Statements, Reports, Certificates. Borrower shall
deliver to Bank: (a) as soon as available, but in any event within thirty (30)
days after the end of each month, company prepared consolidated and
consolidating balance sheets, income statements and cash flow statements
covering Borrower's operations during such period, certified by an officer of
Borrower reasonably acceptable to Bank; (b) as soon as available, but in any
event within ninety (90) days after the end of Borrower's fiscal year, audited
consolidated financial statements of Borrower prepared in accordance with GAAP,
consistently applied, together with an unqualified opinion on such financial
statements of an independent certified public accounting firm reasonably
acceptable to Bank, the auditor-prepared consolidating financial statements, and
(at the time of filing with the appropriate tax authorities) the tax returns of
Borrower, (c) promptly upon becoming available, copies of all statements,
reports and notices sent or made available generally by Borrower to its security
holders; (d) immediately upon receipt of notice thereof, a report of any
material legal actions pending or threatened against Borrower; and (e) such
budgets, sales projections, operating plans or other financial information as
Bank may reasonably request from time to time.

         Within fifteen (15) days of the last day of each month, Borrower shall
deliver to Bank a borrowing base certificate signed by an officer of Borrower in
substantially the form of Schedule 6.3(a) hereto, together with aged listings of
accounts receivable and accounts payable.

         Borrower shall deliver to Bank with the monthly financial statements a
compliance certificate signed by an officer of Borrower in substantially the
form of Schedule 6.3(b) hereto.



                                       12
<PAGE>   16
         Bank shall have a right from time to time thereafter to audit
Borrower's Accounts at Borrower's expense, provided that such audits will be
conducted no more often than every six (6) months unless an Event of Default has
occurred.

            6.4 Returns. Returns and allowances, if any, as between Borrower and
its account debtors shall be on the same basis and in accordance with the usual
customary practices of Borrower, as they exist at the time of the execution and
delivery of this Agreement. Borrower shall promptly notify Bank of all returns
and recoveries and of all disputes and claims, where the return, recovery,
dispute or claim involves more than Fifty Thousand Dollars ($50,000).

            6.5 Taxes. Borrower shall make due and timely payment or deposit of
all federal, state, and local taxes, assessments, or contributions required of
it by law, and will execute and deliver to Bank, on demand, appropriate
certificates attesting to the payment or deposit thereof; and Borrower will make
timely payment or deposit of all tax payments and withholding taxes required of
it by applicable laws, including, but not limited to, those laws concerning
F.I.C.A., F.U.T.A., state disability, and local, state, and federal income
taxes, and will, upon request, furnish Bank with proof satisfactory to Bank
indicating that Borrower has made such payments or deposits; provided that
Borrower need not make any payment if the amount or validity of such payment is
contested in good faith by appropriate proceedings and is adequately reserved
against by Borrower.

            6.6 Insurance.

                (a) Borrower, at its expense, shall keep the Collateral insured
against loss or damage by fire, theft, explosion, sprinklers, and all other
hazardous and risks, and in such amounts, as ordinarily insured against by other
owners in similar businesses conducted in the locations where Borrower's
business is conducted on the date hereof. Borrower shall also maintain insurance
relating to Borrower's ownership and use of the Collateral in amounts and of a
type that are customary to businesses similar to Borrower's.

                (b) All such policies of insurance shall be in such form, with
such companies, and in such amounts as reasonably satisfactory to Bank. All such
policies of insurance shall contain a lender's loss payable endorsement, in a
form satisfactory to Bank, showing Bank as an additional loss payee thereof, and
shall specify that the insurer must give at least twenty (20) days notice to
Bank before canceling its policy for any reason. Borrower shall deliver to Bank
certified copies of such policies of insurance and evidence of the payments of
all premiums therefor. All proceeds payable under any such policy shall, at the
option of Bank, be payable to Bank to be applied on account of the Obligations.

            6.7 Principal Depository. Borrower shall maintain its primary
depository and operating accounts with Bank.

            6.8 Quick Ratio. Borrower shall maintain, on a monthly basis and
without consolidation, a ratio of Quick Assets to Current Liabilities of at
least 1.00:1.

            6.9 Tangible Net Worth. Borrower shall maintain, on a monthly basis
and without consolidation, a tangible net worth of not less than Three Million
Five Hundred Thousand Dollars ($3,500,000).

            6.10 Debt-Net Worth Ratio. Borrower shall maintain, an a monthly
basis and without consolidation, a ratio of Total Liabilities to Tangible Net
Worth of not more than 0.85:1.00.

            6.11 Profitability. Borrower, on a consolidated basis, shall be
profitable before taxes and after taxes for each fiscal quarter, beginning with
the quarter ending December 31, 1995. Quarterly losses on a consolidated basis
on an after tax basis shall not exceed ($800,000) for the quarter ended March
31, 1995; ($550,000) for the quarter ended June 30, 1995; and ($250,000) for the
quarter ended September 30, 1995.



                                       13
<PAGE>   17
            6.12 Vendor Financing Program. Borrower shall maintain its current
vendor financing program with Copelco, or a similar vendor financing program
acceptable to Bank.

            6.13 Further Assurances. At any time and from time to time Borrower
shall execute and deliver such further instruments and take such further action
as may reasonably be requested by Bank to effect the purposes of this Agreement.

         7. NEGATIVE COVENANTS

            Borrower covenants and agrees that, so long as any credit hereunder
shall be available and until payment in full of the Obligations, Borrower will
not do any of the following:

            7.1 Extraordinary Transactions and Disposal of Assets. Unless
otherwise approved by Bank, enter into any transaction not in the ordinary and
usual course of Borrower's business, including, but not limited to, the sale,
lease, or other disposition of, moving, relocation, or transfer, whether by sale
or otherwise, of Borrower's assets, other than (i) sales of Inventory in the
ordinary and usual course of Borrower's business as presently conducted and (ii)
sales or other dispositions in the ordinary course of business of assets that
have become worn out or obsolete or that are promptly being replaced.

            7.2 Loans; Contingent Liabilities. Except for Permitted Investments
or as otherwise permitted by Section 7.8 below, make or accrue any loans or
advances of money to any third party, or, except for Permitted Indebtedness,
guarantee or otherwise become in any way liable with respect to the obligations
of any third party except by endorsement of instruments or items of payment for
deposit to the account of Borrower or which are transmitted or turned over to
Bank.

            7.3 Restructure. Change Borrower's name; make any material change in
Borrower's financial structure or business operations; cause, permit, or suffer
any material change in Borrower's ownership; or suspend operation of Borrower's
business.

            7.4 Mergers or Acquisitions. Merge or consolidate with or into any
other business organization, or acquire directly or indirectly all or
substantially all of the capital stock or property of another person, without
the express written consent of the Bank. Such consent, as to acquisitions by
Borrower, shall not be unreasonably withheld.

            7.5 Indebtedness. Create, incur, assume or be or remain liable with
respect to any Indebtedness other than Permitted Indebtedness.

            7.6 Encumbrances. Create, incur, assume or suffer to exist any
mortgage, lien, security interest or other encumbrance with respect to any of
its property, or assign or otherwise convey any right to receive income,
including the sale of any Accounts, except for Permitted Liens.

            7.7 Distributions. Pay any dividends or make any other distribution
or payment on account of or in redemption, retirement or purchase of any capital
stock.

            7.8 Investments. Directly or indirectly make or own any beneficial
interest in (including stock, partnership interest, or other securities of), or
make any loan, advance, or capital contribution to, any corporation,
association, person, or entity, other than (i) Permitted Investments, and (ii)
investments in subsidiaries in the ordinary course of business.



                                       14
<PAGE>   18
            7.9 Transactions with Affiliates. Directly or indirectly enter into
or permit to exist any material transaction with any person or entity
controlling, controlled by, or under common control (whether by contract,
ownership of voting securities, or otherwise) with Borrower (each, an
"Affiliate" and each such transaction, an "Affiliate Transaction") except for
Affiliate Transactions that are in the ordinary course of Borrower's business,
upon fair and reasonable terms that are no less favorable to Borrower than would
be obtained in an arm's length transaction with a nonaffiliated person or
entity.

            7.10 Subordinated Debt. Make any payment in respect of any
Subordinated Debt except in compliance with the terms of such Subordinated Debt,
or amend any provision contained in any documentation relating to the
Subordinated Debt if such amendment would adversely affect the interests of
Bank.

            7.11 Compliance. Fail to meet the minimum funding requirements of
ERISA, permit a Reportable Event or Prohibited Transaction, as defined in ERISA,
to occur, or violate any law or regulation, which violation could have a
material adverse effect on the condition or prospects of Borrower.

         8. EVENTS OF DEFAULT

            Any one or more of the following events shall constitute an Event of
Default by Borrower under this Agreement:

            8.1 Payment Default. If Borrower fails to pay when due and payable
or when declared due and payable in accordance with the Loan Documents, any
portion of the Obligations;

            8.2 Covenant Default. If Borrower fails to perform any obligation
under Sections 6.6, 6.7, 6.8, 6.9, 6.10 or 6.11, or violates any of the
covenants contained in Article 7 of this Agreement, or fails or neglects to
perform, keep, or observe any other material term, provision, condition,
covenant, or agreement contained in this Agreement, in any of the Loan
Documents, or in any other present or future agreement between Borrower and Bank
and as to any default under such other term, provision, condition, covenant or
agreement that can be cured, has failed to cure such default within five (5)
days after the occurrence of such default (provided that no Advances will be
made during such cure period);

            8.3 Material Adverse Change. If there occurs a material adverse
change in Borrower's business, or if there is a material impairment of the
prospect of repayment of any portion of the Obligations owing to Bank or a
material impairment of the value or priority of Bank's security interests in the
Collateral;

            8.4 Attachment. If any material portion of Borrower's assets is
attached, seized, subjected to a writ or distress warrant, or is levied upon, or
comes into the possession of any trustee, receiver or person acting in a similar
capacity and such attachment, seizure, writ or distress warrant or levy has not
been removed, discharged or rescinded within ten (10) days, or if Borrower is
enjoined, restrained, or in any way prevented by court order from continuing to
conduct all or any material part of its business affairs, or if a judgment or
other claim becomes a lien or encumbrance upon any material portion of
Borrower's assets, or if a notice of lien, levy, or assessment is filed of
record with respect to any of Borrower's assets by the United States Government,
or any department, agency, or instrumentality thereof, or by any state, county,
municipal, or governmental agency, and the same is not paid within ten (10) days
after Borrower receives notice thereof, provided that none of the foregoing
shall constitute an Event of Default where such action or event is stayed or an
adequate bond has been posted pending a good faith contesting by Borrower
(provided that no Advances will be made during such cure period);

            8.5 Insolvency. If an Insolvency Proceeding is commenced by
Borrower, or if an Insolvency Proceeding is commenced against Borrower and is
not dismissed within ten (10) days (provided that no Advances will be made prior
to the dismissal of such case);



                                       15
<PAGE>   19
            8.6 Other Agreements. If there is a default in any agreement to
which Borrower is a party with a third party or parties resulting in a right by
such third party or parties, whether or not exercised, to accelerate the
maturity of any Indebtedness;

            8.7 Subordinated Debt. If Borrower makes any payment on account of
Subordinated Debt, except to the extent such payment is allowed under any
subordination agreement entered into with Bank;

            8.8 Judgments. If a judgment or judgments for the payment of money
in an amount, individually or in the aggregate, of at least One Hundred Thousand
Dollars ($100,000) shall be rendered against Borrower and shall remain
unsatisfied and unstayed for a period of ten (10) days (provided that no
Advances will be made prior to the satisfaction or stay of such judgment); or

            8.9 Misrepresentations. If any material misrepresentation or
material misstatement exists now or hereafter in any warranty, representation,
statement, or report made to Bank by Borrower or any officer, employee, agent,
or director of Borrower.

         9. BANK'S RIGHTS AND REMEDIES

            9.1 Rights and Remedies. Upon the occurrence of an Event of Default,
Bank may, at its election, without notice of its election and without demand, do
any one or more of the following, all of which are authorized by Borrower:

                (a) Declare all Obligations, whether evidenced by this
Agreement, by any of the other Loan Documents, or otherwise, immediately due and
payable (provided that upon the occurrence of an Event of Default described in
Section 8.5 all Obligations shall become immediately due and payable without any
action by Bank);

                (b) Cease advancing money or extending credit to or for the
benefit of Borrower under this Agreement or under any other agreement between
Borrower and Bank;

                (c) Settle or adjust disputes and claims directly with account
debtors for amounts, upon terms and in whatever order that Bank reasonably
considers advisable;

                (d) Without notice to or demand upon Borrower, make such
payments and do such acts as Bank considers necessary or reasonable to protect
its security interest in the Collateral. Borrower agrees to assemble the
Collateral if Bank so requires, and to make the Collateral available to Bank as
Bank may designate. Borrower authorizes Bank to enter the premises where the
Collateral is located, to take and maintain possession of the Collateral, or any
part of it, and to pay, purchase, contest, or compromise any encumbrance,
charge, or lien which in Bank's determination appears to be prior or superior to
its security interest and to pay all expenses incurred in connection therewith.
With respect to any of Borrower's owned premises, Borrower hereby grants Bank a
license to enter into possession of such premises and to occupy the same,
without charge, for up to one hundred twenty (120) days in order to exercise any
of Bank's rights or remedies provided herein, at law, in equity, or otherwise;

                (e) Without notice to Borrower set off and apply to the
Obligations any and all (i) balances and deposits of Borrower held by Bank, or
(ii) indebtedness at any time owing to or for the credit or the account of
Borrower held by Bank;

                (f) Ship, reclaim, recover, store, finish, maintain, repair,
prepare for sale, advertise for sale, and sell (in the manner provided for
herein) the Collateral. Without limiting any rights granted Bank in any other
Loan Document, Bank is hereby granted a license or other right, solely pursuant
to the provisions of this section 9.1, to use, without charge, Borrower's
labels, patents, copyrights, rights of use of any name, trade secrets, trade
names, trademarks, service marks, and advertising matter, or any property of a



                                       16
<PAGE>   20
similar nature, as it pertains to the Collateral, in completing production of,
advertising for sale, and selling any Collateral and, in connection with Bank's
exercise of its rights under this section 9.1, Borrower's rights under all
licenses and all franchise agreements shall inure to Bank's benefit;

                (g) Sell the Collateral at either a public or private sale, or
both, by way of one or more contracts or transactions, for cash or on terms, in
such manner and at such places (including Borrower's premises) as Bank
determines is commercially reasonable;

                (h) Bank may credit bid and purchase at any public sale; and

                (i) Any deficiency that exists after disposition of the
Collateral as provided above will be paid immediately by Borrower.

            9.2 Power of Attorney. Borrower hereby irrevocably and appoints Bank
(and any of Bank's designated officers, or employees) as Borrower's true and
lawful attorney to: (a) send requests for verification of Accounts or notify
account debtors of Bank's security interests in the Accounts; (b) endorse
Borrower's name on any checks or other forms of payment or security that may
come into Bank's possession; (c) sign the name of Borrower on any of the
documents described in Section 4.2; (d) sign Borrower's name on any invoice or
bill of lading relating to any Account, drafts against account debtors,
schedules and assignments of Accounts, verifications of Accounts, and notices to
account debtors; (e) make, settle, and adjust all claims under and decisions
with respect to Borrower's policies of insurance; and (f) settle and adjust
disputes and claims respecting the accounts directly with account debtors, for
amounts and upon terms which Bank determines to be reasonable. The appointment
of Bank as Borrower's attorney in fact, and each and every one of Bank's rights
and powers, being coupled with an interest, is irrevocable until all of the
Obligations have been fully repaid and performed and Bank's obligation to
provide advances hereunder is terminated.

            9.3 Accounts Collection. Upon the occurrence of an Event of Default,
Borrower shall, upon the request of Bank and in addition to all other rights or
remedies available to Bank, open and maintain with Bank an account (the
"Collateral Account") into which all funds received by Borrower from any source
shall immediately be deposited. Borrower shall direct all account debtors or
other persons owing money to Borrower who make payments by electronic transfer
of funds to wire such funds directly to the Collateral Account. Borrower
irrevocably authorizes Bank to transfer to the Collateral Account any funds that
have been deposited into any other accounts or that Bank has otherwise raised.
Upon the occurrence of an Event of Default and if requested by Bank, Borrower
shall not establish or maintain any accounts with any person other than Bank
except for accounts opened in the ordinary course of business from which all
funds are transferred on a daily basis to the Collateral Account.

            9.4 Bank Expenses. If Borrower fails to pay any amounts or furnish
any required proof of payment due to third persons or entities, as required
under the terms of this Agreement, then Bank may do any or all of the following:
(a) make payment of the same or any part thereof; (b) set up such reserves in
Borrower's loan account as Bank deems necessary to protect Bank from the
exposure created by such failure; or (c) obtain and maintain insurance policies
of the type discussed in Section 6.6 of this Agreement, and take any action with
respect to such policies as Bank deems prudent. Any amounts paid or deposited by
Bank shall constitute Bank Expenses, shall be immediately due and payable, and
shall bear interest at the then applicable rate hereinabove provided, and shall
be secured by the Collateral. Any payments made by Bank shall not constitute an
agreement by Bank to make similar payments in the future or a waiver by Bank of
any Event of Default under this Agreement.

            9.5 Remedies Cumulative. Bank's rights and remedies under this
Agreement, the Loan Documents, and all other agreements shall be cumulative.
Bank shall have all other rights and remedies not inconsistent herewith as
provided under the Code, by law, or in equity. No exercise by Bank of one right
or remedy shall be deemed an election, and no waiver by Bank of any Event of
Default on Borrower's part shall be deemed a continuing waiver. No delay by Bank
shall constitute a waiver, election, or acquiescence by it.



                                       17
<PAGE>   21
         10. WAIVERS; INDEMNIFICATION

             10.1 Demand; Protest. Borrower waives demand, protest, notice of
protest, notice of default or dishonor, notice of payment and nonpayment, notice
of any default, nonpayment at maturity, release, compromise, settlement,
extension, or renewal of accounts, documents, instruments, chattel paper, and
guarantees at any time held by Bank on which Borrower may in any way be liable.

             10.2 Bank's Liability for Collateral. So long as Bank complies with
its obligations, if any, under Section 9207 of the Code and reasonable banking
practices, Bank shall not in any way or manner be liable or responsible for: (a)
the safekeeping of the Collateral; (b) any loss or damage thereto occurring or
arising in any manner or fashion from any cause; (c) any diminution in the value
thereof; or (d) any act or default of any carrier, warehouseman, bailee,
forwarding agency, or other person whomsoever. All risk of loss, damage or
destruction of the Collateral shall be borne by Borrower.

             10.3 Indemnification. Borrower shall defend, indemnify and hold
harmless Bank and its officers, employees, and agents against: (a) all
obligations, demands, claims, and liabilities claimed or asserted by any other
party in connection with the transactions contemplated by this Agreement, and
(b) all losses or Bank Expenses in any way suffered, incurred, or paid by Bank
as a result of or in any way arising out of, following, or consequential to
transactions between Bank and Borrower whether under this Agreement, or
otherwise (including without limitation attorneys fees and expenses), except for
losses caused by Bank's gross negligence or willful misconduct.

         11. NOTICES

             Unless otherwise provided in this Agreement, all notices or demands
by any party relating to this Agreement or any other agreement entered into in
connection herewith shall be in writing and (except for financial statements and
other informational documents which may be sent by first-class mail, postage
prepaid) shall be personally delivered or sent by certified mail, postage
prepaid, return receipt requested, or by prepaid telefacsimile to Borrower or to
Bank, as the case may be, at its addresses set forth below:

         If to Borrower:          Ventana Medical Systems, Inc.
                                  3865 North Business Center Drive
                                  Tucson, Arizona 85705
                                  Attn:  Chief Financial Officer
                                  FAX:  (602) 887-2558

         If to Bank:              Silicon Valley Bank
                                  3000 Lakeside Drive
                                  Santa Clara, CA 95054
                                  Attn:  Legal Department
                                  FAX:  (408) 748-9478

         The parties hereto may change the address at which they are to receive
notices hereunder, by notice in writing in the foregoing manner given to the
other.

         12. CHOICE OF LAW AND VENUE; JURY TRIAL WAIVER

             This Agreement shall be governed by, and construed in accordance
with, the internal laws of the State of California, without regard to principles
of conflicts of law. Each of Borrower and Bank hereby submits to the exclusive
jurisdiction of the state and Federal courts located in the County of Santa
Clara, State of California. Borrower and Bank hereby waive their respective
rights to a jury trial of any claim or cause of action based upon or arising out
of any of the Loan Documents or any of the transactions contemplated therein,
including contract claims, tort claims, breach of duty claims, and all other
common law or statutory claims.



                                       18
<PAGE>   22
         13. GENERAL PROVISIONS

             13.1 Successors and Assigns. This Agreement shall bind and inure to
the benefit of the respective successors and permitted assigns of each of the
parties; provided, however, that neither this Agreement nor any rights hereunder
may be assigned by Borrower without Bank's prior written consent, which consent
may be granted or withheld in Bank's sole discretion. Bank shall have the right
without the consent of or notice to Borrower to sell, transfer, negotiate, or
grant participations in all or any part of, or any interest in Bank's rights and
benefits hereunder.

             13.2 Time of Essence. Time is of the essence for the performance of
all obligations set forth in this Agreement.

             13.3 Severability of Provisions. Each provision of this Agreement
shall be severable from every other provision of this Agreement for the purpose
of determining the legal enforceability of any specific provision.

             13.4 Amendments in Writing, Integration. This Agreement cannot be
changed or terminated orally. All prior agreements, understandings,
representations, warranties, and negotiations between the parties hereto with
respect to the subject matter of this Agreement, if any, are merged into this
Agreement.

             13.5 Counterparts. This Agreement may be executed in any number of
counterparts and by different parties on separate counterparts, each of which,
when executed and delivered, shall be deemed to be an original, and all of
which, when taken together, shall constitute but one and the same Agreement.

             13.6 Survival. All covenants, representations and warranties made
in this Agreement shall continue in full force and effect so long as any
Obligations remain outstanding. The obligations of Borrower to indemnify Bank
with respect to the expenses, damages, losses, costs and liabilities described
in Section 10.3 shall survive until all applicable statute of limitations
periods with respect to actions that may be brought against Bank have run.

         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed as of the date first above written.

                                      VENTANA MEDICAL SYSTEMS, INC.


                                      By:  /s/ R. MICHAEL RODGERS
                                         ---------------------------
                                      Title:  Vice President
                                            ------------------------


                                      SILICON VALLEY BANK


                                      By:  /s/ DEBRA R. GUERIN
                                         ---------------------------
                                      Title:  Vice President
                                            ------------------------


                                       19
<PAGE>   23
                                    EXHIBIT A

         The Collateral shall consist of all right, title and interest of
Borrower in and to the following:

         (a) All goods and equipment now owned or hereafter acquired, including,
without limitation, all machinery, fixtures, vehicles (including motor vehicles
and trailers), and any interest in any of the foregoing, and all attachments,
accessories, accessions, replacements, substitutions, additions, and
improvements to any of the foregoing, wherever located;

         (b) All inventory, now owned or hereafter acquired, including, without
limitation, all merchandise, raw materials, parts, supplies, packing and
shipping materials, work in process and finished products including such
inventory as is temporarily out of Borrower's custody or possession or in
transit and including any returns upon any accounts or other proceeds, including
insurance proceeds, resulting from the sale or disposition of any of the
foregoing and any documents of title representing any of the above, and
Borrower's Books relating to any of the foregoing;

         (c) All contract rights and general intangibles now owned or hereafter
acquired, including, without limitation, goodwill, trademarks, servicemarks,
trade styles, trade names, patents, patent applications, leases, license
agreements, franchise agreements, blueprints, drawings, purchase orders,
customer lists, route lists, infringements, claims, computer programs, computer
discs, computer tapes, literature, reports, catalogs, design rights, income tax
refunds, payments of insurance and tights to payment of any kind;

         (d) All now existing and hereafter arising accounts, contract rights,
royalties, license rights and all other forms of obligations owing to Borrower
arising out of the sale or lease of goods, the licensing of technology or the
rendering of services by Borrower, whether or not earned by performance, and any
and all credit insurance, guaranties, and other security therefor, as well as
all merchandise returned to or reclaimed by Borrower and Borrower's Books
relating to any of the foregoing;

         (e) All documents, cash, deposit accounts, securities, letters of
credit, certificates of deposit, instruments and chattel paper now owned or
hereafter acquired and Borrower's Books relating to the foregoing;

         (f) All copyright rights, copyright applications, copyright
registrations and like protections in each work of authorship and derivative
work thereof, whether published or unpublished, registered or unregistered, now
owned or hereafter acquired;

         (g) All trade secret rights, including all rights to unpatented
inventions, know-how, operating manuals, license rights and agreements and
confidential information, now owned or hereafter acquired;

         (h) All claims for damages by way of any past, present and future
infringement of any of the rights described above; and

         (i) Any and all claims, rights and interests in any of the above and
all substitutions for, additions and accessions to and proceeds thereof.

         The Collateral shall specifically exclude equipment manufactured by
Borrower and sold to a third party vendor financing entity for inclusion in the
Borrower's vendor financing program.
<PAGE>   24
                                    EXHIBIT B

                            Revolving Promissory Note

U.S. $ 2,750,000.                                        Santa Clara, California
                                                               February 20, 1995


         FOR VALUE RECEIVED, the undersigned, VENTANA MEDICAL SYSTEMS, INC. (the
"Borrower"), promises to pay to the order of Silicon Valley Bank ("Bank"), at
such place as the holder hereof may designate, in lawful money of the United
States of America, the aggregate unpaid principal amount of all advances
("Advances") made by Bank to Borrower under the terms of this Note, up to a
maximum principal amount of Two Million Seven Hundred Fifty Thousand Dollars
($2,750,000). Borrower shall also pay interest on the aggregate unpaid principal
amount of such Advances at the rates and in accordance with the terms of the
Loan and Security Agreement between Borrower and Bank of even date herewith, as
amended from time to time (the "Loan Agreement"). The entire principal amount
and all accrued interest shall be due and payable on the Maturity Date (as
defined in the Loan Agreement).

         Borrower irrevocably waives the right to direct the application of any
and all payments at any time hereafter received by Bank from or on behalf of
Borrower, and Borrower irrevocably agrees that Bank shall have the continuing
exclusive right to apply any and all such payments against the then due and
owing obligations of Borrower as Bank may deem advisable. In the absence of a
specific determination by Bank with respect thereto, all payments shall be
applied in the following order: (a) then due and payable fees and expenses; (b)
then due and payable interest payments and mandatory prepayments; and (c) then
due and payable principal payments and optional prepayments.

         Bank is hereby authorized by Borrower to endorse on Bank's books and
records each Advance made by Bank under this Note and the amount of each payment
or prepayment of principal of each such Advance received by Bank; it being
understood, however, that failure to make any such endorsement (or any errors in
notation) shall not affect the obligations of Borrower with respect to Advances
made hereunder, and payments of principal by Borrower shall be credited to
Borrower notwithstanding the failure to make a notation (or any errors in
notation) thereof on such books and records.

         Borrower promises to pay Bank all costs and expenses of collection of
this Note and to pay all reasonable attorneys' fees incurred in such collection
or in any suit or action to collect this Note or in any appeal thereof. Borrower
waives presentment, demand, protest, notice of protest, notice of dishonor,
notice of nonpayment, and any and all other notices and demands in connection
with the delivery, acceptance, performance, default or enforcement of this Note,
as well as any applicable statute of limitations. No delay by Bank in exercising
any power or right hereunder shall operate as a waiver of any power or right.
Time is of the essence as to all obligations hereunder.

         This Note is issued pursuant to the Loan Agreement, which shall govern
the rights and obligations of Borrower with respect to all obligations
hereunder.

         This Note shall be deemed to be made under, and shall be construed in
accordance with and governed by, the laws of the State of California, excluding
conflicts of laws principles.

                                            VENTANA MEDICAL SYSTEMS, INC.

                                            By:  /s/ R. MICHAEL RODGERS
                                               ---------------------------
                                            Title:  Vice President
                                                  ------------------------
<PAGE>   25
                                  SCHEDULE 2.1

                              BORROWING CERTIFICATE


         The undersigned hereby certifies as follows:

         I, __________________, am the duly elected and acting
__________________ of VENTANA MEDICAL SYSTEMS, INC. ("Borrower").

         This certificate is delivered pursuant to Section 2.1 of that certain
Loan and Security Agreement by and between Borrower and Silicon Valley Bank
("Bank") (the "Loan Agreement"). The terms used in this Borrowing Certificate
which are defined in the Loan Agreement have the same meaning herein as ascribed
to them therein.

         Borrower is confirming its telephone request made on __________, 19__
for an Advance as follows:

            (a) The date on which the Advance is to be made is ____________,
19__.

            (b) The amount of the Advance is to be $__________.

         All representations and warranties of Borrower stated in the Loan
Agreement are true, accurate and complete in all material respects as of the
date of the telephone request for and Advance confirmed by this Borrowing
Certificate; provided, however, that those representations and warranties
expressly referring to another date shall be true, accurate and complete in all
material respects as of such date.

         IN WITNESS WHEREOF, this Borrowing Certificate is executed by the
undersigned as of this _____ day of __________, 199__.

                                            VENTANA MEDICAL SYSTEMS, INC.

                                            By:
                                               ---------------------------

                                            Title:
                                                  ------------------------


                                       22
<PAGE>   26
                                 SCHEDULE 6.3(a)
                           BORROWING BASE CERTIFICATE

Borrower.    Ventana Medical Systems, Inc.       Lender.   Silicon Valley Bank
             3865 North Business Center Drive              3000 Lakeside Drive
             Tucson, Arizona 85705                         Santa Clara, CA 95054

Commitment Amount:  $2,750,000

<TABLE>
<S>                                                                      <C>          <C>
ACCOUNTS RECEIVABLE
     1.      Accounts Receivable Book Value as of _____                               $____________
     2.      Additions (please explain on reverse)                                    $____________
     3.      TOTAL ACCOUNTS RECEIVABLE                                                $____________

ACCOUNTS RECEIVABLE DEDUCTIONS

     4.      Amounts over 90 days past invoice date (excluding
             credit balances                                             $_________
     5.      Balance of 50% over 90 day accounts                         $_________
     6.      Concentration Limits                                        $_________
     7.      Foreign Accounts                                            $_________
     8.      Governmental Accounts                                       $_________
     9.      Contra Accounts                                             $_________
     10.     Promotion or Demo Accounts                                  $_________
     11.     Intercompany/Employee Accounts                              $_________
     12.     Other (please explain on reverse)                           $_________
     13.     TOTAL ACCOUNTS RECEIVABLE DEDUCTIONS                                     $____________
     14.     Eligible Accounts (No. 3-No. 14)                                         $____________
     15.     LOAN VALUE OF ACCOUNTS (70% of No. 14)                                   $____________


BALANCES

16.  Maximum Loan Amount                                                 $2,750,000
17.  Total Funds Available (Lesser of #16 or #15)                                     $____________
18.  Present balance owing on Line of Credit                                          $____________
19.  Outstanding under Sublimits (Letter of Credit, Foreign Exchange)                 $____________
20.  RESERVE POSITIVE (#17-#l8 and #19)                                               $____________
</TABLE>

The undersigned represents and warrants that the foregoing is true, complete and
correct, and that the information reflected in this Borrowing Base Certificate
complies with the representations and warranties set forth in the Loan and
Security Agreement between the undersigned and Silicon Valley Bank.

COMMENTS:

                                                                   BANK USE ONLY

                                                      Rec'd By:_________________
                                                                  Auth. Signer

                                                      Date:_____________________
Ventana Medical Systems, Inc.

                                                      Verified:_________________
By:______________________                                         Auth. Signer
     Authorized Signer                                Date:_____________________
                                                      __________________________
<PAGE>   27
                                 SCHEDULE 6.3(b)
                             COMPLIANCE CERTIFICATE

TO:     Silicon Valley Bank
        3000 Lakeside Drive
        Santa Clara, CA 95054

FROM:   Ventana Medical Systems, Inc.
        3865 North Business Center Drive
        Tucson, Arizona 85705

         The undersigned authorized officer of Ventana Medical Systems, Inc.
hereby certifies that in accordance with the terms and conditions of the Loan
and Security Agreement between Borrower and Bank (the "Agreement"), (i) Borrower
is in complete compliance for the period ending ____________ of all required
conditions and terms except as noted below and (ii) all representations and
warranties of Borrower stated in the Agreement are true, accurate and complete
in all material respects as of the date hereof. Attached herewith are the
required documents supporting the above certification. The Officer further
certifies that these are prepared in accordance with Generally Accepted
Accounting Principals (GAAP) and are consistency from one period to the next
except as explained in an accompanying letter or footnotes.


 PLEASE INDICATE COMPLIANCE STATUS BY CIRCLING YES/NO UNDER "COMPLIES" COLUMN.

<TABLE>
<CAPTION>
Reporting Covenant                                   Required                         Complies
- ------------------                                   --------                         --------
<S>                                                  <C>                        <C>             <C>
Monthly financial statements                         Monthly within 30 days     Yes             No
Annual (CPA Audited)                                 FYE within 90 days         Yes             No
A/R & A/P Agings and Borrowing Base Certificate      Monthly within 15 days     Yes             No
A/R Audit                                            Initial and Semi-Annual    Yes             No
</TABLE>


<TABLE>
<CAPTION>
     Financial Covenant                       Required                       Actual                Complies
     ------------------                       --------                       ------                --------
<S>                                      <C>                              <C>                 <C>            <C>
Maintain on a Monthly Basis:
  Minimum Quick Ratio                    1.00:1.00                        ___________:1.0     Yes            No
  Minimum TNW                            $3,500,000                       $______________     Yes            No
  Maximum quarterly loss after tax       0.85:1.00                        ___________:1.0     Yes            No
                                         3/31/95 ($800,000)               _______________     Yes            No
                                         6/30/95 ($550,000),              _______________     Yes            No
                                         9/30/95 ($250,000),              _______________     Yes            No
  Profitability                          12/31/95 and thereafter, on
                                         both a before and after tax
                                         basis
</TABLE>

COMMENTS REGARDING EXCEPTIONS:


                                                            BANK USE ONLY

                                                   Received by:_________________
Sincerely,                                                     AUTHORIZED SIGNER

                                                   Date:________________________
________________________
SIGNATURE                                          Verified:____________________
                                                               AUTHORIZED SIGNER
________________________
TITLE                                              Date:________________________

________________________                           Compliance Status:   Yes   No
DATE
<PAGE>   28
                            Revolving Promissory Note

U.S. $ 2,750,000.                                        Santa Clara, California
                                                               February 20, 1995


FOR VALUE RECEIVED, the undersigned, Ventana Medical Systems, Inc. (the
"Borrower"), promises to pay to the order of Silicon Valley Bank ("Bank"), at
such place as the holder hereof may designate, in lawful money of the United
States of America, the aggregate unpaid principal amount of all advances
("Advances") made by Bank to Borrower under the terms of this Note, up to a
maximum principal amount of Two Million Seven Hundred Fifty Thousand Dollars
($2,700,000). Borrower shall also pay interest on the aggregate unpaid principal
amount of such Advances at the rates and in accordance with the terms of the
Loan and Security Agreement between Borrower and Bank of even date herewith, as
amended from time to time (the "Loan Agreement"). The entire principal amount
and all accrued interest shall be due and payable on the Maturity Date (as
defined in the Loan Agreement).

         Borrower irrevocably waives the right to direct the application of any
and all payments at any time hereafter received by Bank from or on behalf of
Borrower, and Borrower irrevocably agrees that Bank shall have the continuing
exclusive right to apply any and all such payments against the then due and
owing obligations of Borrower as Bank may deem advisable. In the absence of a
specific determination by Bank with respect thereto, all payments shall be
applied in the following order: (a) then due and payable fees and expenses; (b)
then due and payable interest payments and mandatory prepayments; and (c) then
due and payable principal payments and optional prepayments.

         Bank is hereby authorized by Borrower to endorse on Bank's books and
records each Advance made by Bank under this Note and the amount of each payment
or prepayment of principal of each such Advance received by Bank; it being
understood, however, that failure to make any such endorsement (or any errors in
notation) shall not affect the obligations of Borrower with respect to Advances
made hereunder, and payments of principal by Borrower shall be credited to
Borrower notwithstanding the failure to make a notation (or any errors in
notation) thereof on such books and records.

         Borrower promises to pay Bank all costs and expenses of collection of
this Note and to pay all reasonable attorneys' fees incurred in such collection
or in any suit or action to collect this Note or in any appeal thereof. Borrower
waives presentment, demand, protest, notice of protest, notice of dishonor,
notice of nonpayment and any and all other notices and demands in connection
with the delivery, acceptance, performance, default or enforcement of this Note,
as well as any applicable statute of limitations. No delay by Bank in exercising
any power or right hereunder shall operate as a waiver of any power or right.
Time is of the essence as to all obligations hereunder.

         This Note is issued pursuant to the Loan Agreement, which shall govern
the rights and obligations of Borrower with respect to all obligations
hereunder.

         This Note shall be deemed to be made under, and shall be construed in
accordance with and governed by, the laws of the State of California, excluding
conflicts of laws principles.

                                                   Ventana Medical Systems, Inc.

                                                   By: /s/ R. MICHAEL RODGERS
                                                       -------------------------
                                                   Title:   Vice President
                                                         -----------------------
<PAGE>   29
REORDER FROM
REGISTRE, INC.                                   NOTE: SHEET 2 SIGNED SEPARATELY
514 PIERCE ST.
P.O. BOX 218
ANOKA, MN 55303
(612) 421-1713


<TABLE>
<CAPTION>
Approved by The Secretary of State of Arizona, Rev. 10/90 FORM UCC-1        Space below used by filing office
- --------------------------------------------------------------------------------------------------------------------








- --------------------------------------------------------------------------------------------------------------------
<S>                                                      <C>
Return copy or recorded original to:                     ARIZONA UNIFORM COMMERCIAL CODE

Silicon Valley Bank                                      FINANCING STATEMENT -- FORM UCC-1                     
Attn:  Loan Services                                     This FINANCING STATEMENT is presented for filing      
3003 Tasman Drive                                        (recording) pursuant to the Arizona Uniform Commercial
Santa Clara, CA 95054                                    Code.
- --------------------------------------------------------------------------------------------------------------------
1. Debtor(s)  (last name first and address):             2. Secured Party(ies) and address:

Bio Tek Solutions, Inc.                                     Silicon Valley Bank
3865 North Business Center Drive                            1731 Embarcadero Road, Suite 220
Tucson, AZ 85705                                            Palo Alto, CA 94303
- --------------------------------------------------------------------------------------------------------------------
3. Name and Address of Assignee of Secured Party(ies):   4. /X/ If checked, products of collateral are also covered.
                                                         -----------------------------------------------------------
                                                         5. This Financing Statement covers the following types (or
                                                            items) of property:

- ------------------------------------------------------      Collateral is described in Exhibit A
                                                            attached.

6. If the collateral is crops, the crops are growing 
   or to be grown on the following described real 
   estate:
- --------------------------------------------------------------------------------------------------------------------

7. If the collateral is (a) goods which are or are to become fixtures; (b) timber to be cut; or (c) minerals or the
   like (including oil and gas), or accounts resulting from the sale thereof at the wellhead or minehead to which 
   the security interest attaches upon extraction, the legal description of the real estate concerned is:



   And, this Financing Statement is to be recorded in the office where a mortgage on such real estate would be
   recorded. If the Debtor does not have an interest of record, the name of a record owner is:
- --------------------------------------------------------------------------------------------------------------------
8. This Financing Statement is signed by the Secured Party instead of the debtor to perfect or continue perfection 
   of a security interest in:

   / / collateral already subject to a security interest in      / / collateral as to which the filing has lapsed 
       jurisdiction when it was brought into this state.             or will lapse.
   / / proceeds of collateral because of a change in type        / / collateral acquired after a change of name, 
       or use.                                                       identity, or corporate structure of the Debtor.
- --------------------------------------------------------------------------------------------------------------------
</TABLE>

Bio Tek Solutions, Inc.                 (Use          Dated:
- -------------------------------       whichever              -------------------
/s/ Bio Tek Solutions, Inc.             

<PAGE>   1
                                                                EXHIBIT 10.19(b)

                    AMENDMENT TO LOAN AND SECURITY AGREEMENT

         This Amendment to Loan and Security Agreement is entered into on this
28th day of March, 1996 by and between Silicon Valley Bank ("Bank") and Ventana
Medical Systems, Inc. ("Borrower").

                                    RECITALS

         Borrower and Bank are parties to that certain Loan and Security
Agreement dated as of February 20, 1995, as amended from time to time (the
"Agreement"). Borrower has acquired the outstanding stock of Bio Tek Solutions,
Inc. ("Bio Tek") and has asked Bank to lend Borrower additional money and
otherwise to amend the Agreement to reflect, among other things, Borrower's
consolidated financial condition. Bank has agreed to do so, provided Borrower
enters into this Amendment and Bio Tek guarantees Borrower's performance under
the Agreement.

         NOW, THEREFORE, the parties agree as follows:

         1. Section 1.1 of the Loan Agreement is amended to include the
            following defined terms:

            "Maturity Date" means March 15, 1999.

            "Revolving Maturity Date" means March 15, 1997.

         2. Section 2.1 of the Loan Agreement is hereby amended by replacing in
each instance the words "Maturity Date" with the words "Revolving Maturity
Date."

         3. Section 1.1 of the Loan Agreement is further amended by amending the
definition of "Eligible Accounts" to include Accounts that arise in the ordinary
course of Bio Tek's business, provided that all of the provisions and exclusions
including those set forth in clauses (a) through (k), relating to Eligible
Accounts shall apply to such Bio Tek Accounts.

         4. The following Section 2.1.1 is added to the Agreement:

            2.1.1 Term Loan. Bank shall make a term loan (the "Term Loan") to
         Borrower consisting of one (1) Advance in the principal amount of Two
         Million Dollars ($2,000,000). Borrower shall pay interest on the Term
         Loan at a rate per annum equal to two percentage points (2.00%) above
         the Prime Rate, beginning on April 15, 1996 and continuing on the
         fifteenth day of each month thereafter through and including March 15,
         1997. Thereafter, Borrower shall repay the Term Loan in twenty-four
         (24) equal monthly installments of principal, plus accrued interest,
         beginning April 15, 1997, and continuing on the fifteenth day of each
         month thereafter through and including the Maturity Date, on which date
         the entire principal balance, any unpaid interest, and all other
         amounts outstanding under this Agreement shall be due and payable.
<PAGE>   2
         5. Sections 6.8, 6.9, 6.10, 6.11, 6.12 and 6.13 are added to the
Agreement, as follows, and Sections 6.12 and 6.13 are added to the Agreement are
renumbered as Sections 6.14 and 6.15, respectively:

            6.8  Quick Ratio: On a consolidated basis, Borrower shall maintain
         as of the last day of each calendar month, a ratio of Quick Assets to
         Current Liabilities of at least 0.85 to 1.0.

            6.9  Debt-Tangible Net Worth. On a consolidated basis, Borrower 
         shall maintain, as of the last day of each calendar month, a ratio of
         Total Liabilities to Tangible Net Worth of not more than 1.5 to 1.0.

            6.10 Profitability. On a consolidated basis, Borrower shall not
         suffer a loss in excess of $2,000,000 for the fiscal quarter ending
         March 31, 1996, a loss in excess of $1,500,000 for the fiscal quarter
         ending June 30, 1996, a loss in excess of $350,000 for the fiscal
         quarter ending September 30, 1996, or a loss in excess of $250,000 for
         the fiscal quarter ending December 31, 1996. Thereafter, Borrower shall
         be profitable for each fiscal quarter.

            6.11 Liquidity Coverage. Subject to Section 6.13, Borrower shall
         maintain, as of the last day of each calendar month, Liquidity Coverage
         that is at least 1.8 times the outstanding balance of the Term Loan.
         "Liquidity Coverage" means the sum of cash and cash equivalents plus
         the Borrowing Base, less the principal amount of Advances outstanding
         hereunder.

            6.12 Tangible Net Worth. On a consolidated basis, Borrower shall
         maintain, as of the last day of each calendar month, a Tangible Net
         Worth of not less than Five Million Dollars ($5,000,000).

            6.13 Debt Service Coverage. From and after the time when Borrower
         has maintained a Debt Service Coverage of at least 2.0 to 1.0 for six
         (6) consecutive months, Borrower shall maintain, as of the last day of
         each calendar month, a Debt Service Coverage of not less than 2.0 to
         1.0. "Debt Service Coverage" means (i) earnings before interest, taxes,
         depreciation and amortization, divided by (ii) the current portion of
         long term debt and lease obligations plus interest expense. From and
         after the date that this covenant becomes effective, Section 6.11 shall
         be of no further force or effect.

            6. Exhibit D of the Loan Agreement is hereby replaced by Exhibit D
attached to this Amendment.




                                       -2-
<PAGE>   3
         7. Conditions Precedent to Effectiveness. The effectiveness of this
Amendment is subject to the conditions precedent that.

            a. Borrower shall have paid to Bank:

                i.   a nonrefundable fee equal to Thirty Three Thousand Seven
Hundred Fifty ($33,750); and

                ii.  all Bank Expenses incurred through the date hereof,
including reasonable attorneys' fees and expenses.

            b. Bank shall have received, in form and substance satisfactory to
Bank:

                i.   a certificate of the secretary of Borrower with respect to
incumbency and resolutions authorizing the execution, delivery and performance
of this Amendment, and confirming that the copies of the Articles of
Incorporation and By Laws previously delivered to Bank have not been amended and
remain in full force and effect;

                ii.  a copy of this Amendment duly executed by Borrower; and

                iii. a Guaranty and Security Agreement of even date herewith
duly executed by Bio Tek and such related instruments and certificates as Bank
may reasonably request.

         8. No Defenses of Borrower. Borrower agrees, as of this date, that it
has no defenses against the obligations to pay any amounts under the
Indebtedness.

         9. Interpretation. Unless otherwise defined, all capitalized terms in
this Amendment shall be as defined in the Agreement. Except as amended, the
Agreement remains in full force and effect.

         10. Representations. Borrower represents and warrants that the
Representations and Warranties contained in the Agreement are true and correct
as of the date of this Amendment, and that no Event of Default has occurred and
is continuing.

         11. Counterparts. This Amendment to Loan and Security Agreement may be
executed in two or more counterparts, each of which shall be deemed an original,
but all of which together shall constitute one instrument.



                                       -3-
<PAGE>   4
         IN WITNESS WHEREOF, the undersigned have executed this Amendment to
Loan and Security Agreement as of the first date above written.


                                                   VENTANA MEDICAL SYSTEMS, INC.


                                                   By:__________________________

                                                   Title:_______________________


                                                   SILICON VALLEY BANK


                                                   By:__________________________

                                                   Title:_______________________



                                      -4-
<PAGE>   5
                                    EXHIBIT C
                           BORROWING BASE CERTIFICATE

Borrower: Ventana Medical Systems, Inc.              Lender: Silicon Valley Bank
Commitment Amount: $2,750,000


                          ACCOUNTS RECEIVABLE ACTIVITY

<TABLE>
<CAPTION>
                                                             VENTANA         BIO TEK
<S>                                                          <C>             <C>               <C>
1. Accounts Receivable Balance as of ___________             $_______        $_______
2. Total Accounts Receivable (Ventana and Bio Tek)                                             $_______
3. Minus: Ineligible Accounts
   Amounts over 90 days                                      $_______        $_______
   Balance of 50% over 90 day accounts                       $_______        $_______
   Excess 25% concentration                                  $_______        $_______
   Credit Balances over 90 days                              $_______        $_______
   Foreign Accounts (other than eligibles)                   $_______        $_______
   Governmental Accounts                                     $_______        $_______
   Contra Accounts                                           $_______        $_______
   Promotion or Demo Accounts                                $_______        $_______
   Intercompany/Employee Accounts                            $_______        $_______
   Other (please explain on reverse)                         $_______        $_______
   Total Ineligible Accounts                                 $_______        $_______
4. Eligible Accounts Receivable (Line 1 - Line 3)            $_______        $_______
5. Funds Available                                           $_______        $_______
                                                             (80%-Line 4)    (80% of Line 4)
6. Total Funds Available (Line 5-Ventana & Bio Tek)                                            $_______

                                  LOAN ACTIVITY

7. Total Funds Available (Lesser of $2,750,000 or Line 6)                                      $_______
8. Loan balance as of __________________                                                       $_______
9. Reserve Position (Line 7 minus Line 8)                                                      $_______
</TABLE>

The undersigned represents and warrants that the foregoing is true, complete and
correct, and that the information reflected in this Borrowing Base complies with
the representations and warranties set forth in the Loan and Security Agreement
as amended from time to time, between the undersigned and Silicon Valley Bank,
as amended.

COMMENTS:                                                  BANK USE ONLY

                                                    Rec'd By:___________________
Ventana Medical Systems, Inc.                       Date:_______________________
                                                    Verified:___________________
Name:_________________________
Title:________________________



                                       -5-
<PAGE>   6
                                    EXHIBIT D

                             COMPLIANCE CERTIFICATE

TO:      SILICON VALLEY BANK

FROM:    VENTANA MEDICAL SYSTEMS, INC.

         The undersigned authorized officer of Ventana Medical Systems, Inc.
hereby certifies that in accordance with the terms and conditions of the Loan
and Security Agreement between Borrower and Bank (the "Agreement"), (i) Borrower
is in complete compliance for the period ending with all required covenants
except as noted below and (ii) all representations and warranties of Borrower
stated in the Agreement are true and correct in all material respects as of the
date hereof. Attached herewith are the required documents supporting the above
certification. The Officer further certifies that these are prepared in
accordance with Generally Accepted Accounting Principles (GAAP) and are
consistently applied from one period to the next except as explained in an
accompanying letter or footnotes.

         Please indicate compliance status by circling Yes/No under "Complies"
column.

<TABLE>
<CAPTION>
         Reporting Covenant               Required                          Complies
         ------------------               --------                          --------
<S>                                       <C>                           <C>           <C>
         Monthly financial statements     Monthly within 30 days        Yes           No
         Annual (CPA Audited)             FYE within 90 days            Yes           No
         A/R & A/P Agings                 Monthly within 15 days        Yes           No
         A/R Audit                        Initial and Semi-Annual       Yes           No
</TABLE>

<TABLE>
<CAPTION>
         Financial Covenant               Required             Actual           Complies
         ------------------               --------             ------           --------
<S>                                       <C>                  <C>           <C>       <C>
         Maintain on a Monthly Basis:
          Minimum Quick Ratio             0.85:1.0             ___:1.0       Yes        No
          Debt/TNW                        1.5:1.0
          Liquidity Coverage              1.8xTerm Balance*    ___:1.0       Yes        No
          Minimum Tangible Net Worth      $5,000,000           $______       Yes        No
          Debt Service Coverage           2.0:1.0**            ___:1.0       Yes        No
          Profitability (Quarterly)       See Agreement        $______       Yes        No
</TABLE>

         * Replaced by Debt Service Coverage after 6 consecutive months of 2:1
           DSC.

         ** Becomes applicable after 6 consecutive months of compliance



                                       -6-
<PAGE>   7
Comments Regarding Exceptions: See                        BANK USE ONLY
Attached.
Sincerely,                                        Received by:__________________
                                                                  AUTHORIZED

___________________________                       SIGNER
SIGNATURE                                         Date:_________________________
                                                  Verified:_____________________
___________________________                                       AUTHORIZED
TITLE                                             SIGNER
                                                  Date:_________________________
___________________________                       Compliance State:    Yes    No
DATE                       



                                       -7-
<PAGE>   8
                         CORPORATE RESOLUTIONS TO BORROW

Borrower: Ventana Medical Systems, Inc.


         I, the undersigned Secretary or Assistant Secretary of Ventana Medical
Systems, Inc. (the "Corporation"), HEREBY CERTIFY that the Corporation is
organized and existing under and by virtue of the laws of the State of Delaware.

         I FURTHER CERTIFY that the Certificate of Incorporation and Bylaws of
the Corporation, previously delivered to Silicon Valley Bank have not been
amended or modified and are in full force and effect on the date hereof.

         I FURTHER CERTIFY that at a meeting of the Directors of the Corporation
duly called and held, at which a quorum was present and voting (or by other duly
authorized corporate action in lieu of a meeting), the following resolutions
were adopted.

         BE IT RESOLVED, that any one (1) of the following named officers,
employees, or agents of this Corporation, whose actual signatures are shown
below:

         NAMES               POSITIONS                   ACTUAL SIGNATURES
_____________________    _________________             _____________________
_____________________    _________________             _____________________
_____________________    _________________             _____________________
_____________________    _________________             _____________________
_____________________    _________________             _____________________

acting for an on behalf of this Corporation and as its act and deed be, and they
hereby are, authorized and empowered:

         BORROW MONEY. To borrow from time to time from Silicon Valley Bank
("Bank'), on such terms as may be agreed upon between the officers, employees,
or agents and Bank, such sum or sums of money as in their judgment should be
borrowed, without limitation, including such sums as are specified in that
certain Loan and Security Agreement dated as of February 20, 1995, as amended by
the Loan Modification Agreement dated as of March 22, 1996 (the "Loan
Agreement").

         EXECUTE NOTES. To execute and deliver to Bank the Loan Agreement and
any promissory note or notes of the Corporation, on Bank's forms, at such rates
of interest and on such terms as may be agreed upon, evidencing the sums of
money so borrowed or any indebtedness of the Corporation to Bank, and also to
execute and deliver to Bank one or more renewals, extensions, modifications,
refinancings, consolidations, or substitutions for one or more of the notes, or
any portion of the notes.



                                       -8-
<PAGE>   9
         GRANT SECURITY. To grant a security interest to Bank in the Collateral
described in the Loan Agreement, which security interest shall secure all of the
Corporation's Obligations, as described in the Loan Agreement.

         NEGOTIATE ITEMS. To draw, endorse, and discount with Bank all drafts,
trade acceptances, promissory notes, or other evidences of indebtedness payable
to or belonging to the Corporation or in which the Corporation may have an
interest, and either to receive cash for the same or to cause such proceeds to
be credited to the account of the Corporation with Bank, or to cause such other
disposition of the proceeds derived therefrom as they may deem advisable.

         FURTHER ACTS. In the case of lines of credit, to designate additional
or alternate individuals as being authorized to request advances thereunder, and
in all cases, to do and perform such other acts and things, to pay any and all
fees and costs, and to execute and deliver such other documents and agreements
as they may in their discretion deem reasonably necessary or proper in order to
carry into effect the provisions of these Resolutions.

         BE IT FURTHER RESOLVED, that any and all acts authorized pursuant to
these resolutions and performed prior to the passage of these resolutions are
hereby ratified and approved, that these Resolutions shall remain in full force
and effect and Bank may rely on these Resolutions until written notice of their
revocation shall have been delivered to and received by Bank. Any such notice
shall not affect any of the Corporation's agreements or commitments in effect at
the time notice is given.

         I FURTHER CERTIFY that the officers, employees, and agents named above
are duly elected, appointed, or employed by or for the Corporation, as the case
may be, and occupy the positions set forth opposite their respective names; that
the foregoing Resolutions now stand of record on the books of the Corporation;
and that the Resolutions are in full force and effect and have not been modified
or revoked in any manner whatsoever.

         IN WITNESS WHEREOF, I have hereunto set my hand on March __, 1996 and
attest that the signatures set opposite the names listed above are their genuine
signatures.

                                                CERTIFY TO AND ATTEST BY:

                                                x_______________________________


                                       -9-
<PAGE>   10
                        CORPORATE RESOLUTION TO GUARANTEE


Guarantor:  Bio Tek Solutions, Inc.

         I, the undersigned Secretary or Assistant Secretary of Bio Tek
Solutions, Inc. (the "Corporation"), HEREBY CERTIFY that the Corporation is
organized and existing under and by virtue of the laws of the State of Delaware.

         I FURTHER CERTIFY that at a meeting of the Directors of the Corporation
duly called and held, at which a quorum was present and voting, (or by other
duly authorized corporate action in lieu of a meeting), the following
resolutions were adopted.

         BE IT RESOLVED, that any one (1) of the following named officers,
employees, or agents of this Corporation, whose actual signatures are shown
below:

         NAMES               POSITIONS                   ACTUAL SIGNATURES
_____________________    _________________             _____________________
_____________________    _________________             _____________________
_____________________    _________________             _____________________
_____________________    _________________             _____________________
_____________________    _________________             _____________________

acting for an on behalf of this Corporation and as its act and deed be, and they
hereby are, authorized and empowered:

         GUARANTEE INDEBTEDNESS. To guarantee amounts borrowed from time to time
from Silicon Valley Bank ("Bank'), by Ventana Medical Systems ("Borrower")
pursuant to that certain Loan and Security Agreement between Bank and Borrower,
as amended from time to time as of March 22, 1996 (the "Loan Agreement).

         EXECUTE GUARANTY. To execute and deliver to Bank the guaranty of the
Corporation (the "Guaranty"), on Bank's forms, and also to execute and deliver
to Bank one or more renewals, extensions, modifications, consolidations, or
substitutions therefor.

         GRANT SECURITY. To grant a security interest to Bank in the Collateral,
if any, described in the Guaranty, which security interest shall secure all of
the Corporation's obligations under the Guaranty.

         FURTHER ACTS. To do and perform such other acts and things, to pay any
and all fees and costs, and to execute and deliver such other documents and
agreements as they may in their



                                      -10-
<PAGE>   11
discretion deem reasonably necessary or proper in order to carry into effect the
provisions of these Resolutions.

BE IT FURTHER RESOLVED, that any and all acts authorized pursuant to these
resolutions and performed prior to the passage of these resolutions are hereby
ratified and approved, that these Resolutions shall remain in full force and
effect and Bank may rely on these Resolutions until written notice of their
revocation shall have been delivered to and received by Bank. Any such notice
shall not affect any of the Corporation's agreements or commitments in effect at
the time notice is given.

         I FURTHER CERTIFY that the officers, employees, and agents named above
are duly elected, appointed, or employed by or for the Corporation, as the case
may be, and occupy the positions set opposite their respective names; that the
foregoing Resolutions now stand of record on the books of the Corporation; and
that the Resolutions are in full force and effect and have not been modified or
revoked in any manner whatsoever.

         IN WITNESS WHEREOF, I have hereunto set my hand on ___________, 1996
and attest that the signatures set opposite the names listed above are their
genuine signatures.

                                                   CERTIFIED TO AND ATTESTED BY:

                                                   x____________________________


                                      -11-
<PAGE>   12
         This SECURITY AGREEMENT is entered into as of March 22, 1996 by and
between SILICON VALLEY BANK ("Bank") and BIO TEK SOLUTIONS, INC. ("Guarantor").


                                    RECITALS

         Ventana Medical Systems, Inc. wishes to obtain credit from time to time
from Bank pursuant to a Loan and Security Agreement, as amended by an Amendment
to Loan and Security Agreement of even date (the "Loan Agreement"). Bank has
agreed to enter into the Loan Agreement, provided Guarantor guarantees payment
and performance obligations under the Loan Agreement in accordance with the
terms of the Guaranty, and secures the Guaranty pursuant to the terms of this
Agreement.


                                    AGREEMENT

         The parties agree as follows:

         1. DEFINITIONS AND CONSTRUCTION

                  1.1 Definitions. As used in this Agreement, the following
terms shall have the following definitions:

                           "Bank Expenses" means all: reasonable costs or
expenses (including reasonable attorneys' fees and expenses) incurred in
connection with the preparation, negotiation, administration, and enforcement of
the Loan Documents; and Bank's reasonable attorneys' fees and expenses incurred
in amending, enforcing or defending the Loan Documents, whether or not suit is
brought.

                           "Business Day" means any day that is not a Saturday,
Sunday, or other day on which banks in the State of California are authorized or
required to close.

                           "Code" means the California Uniform Commercial Code.

                           "Collateral" means the property described on Exhibit
A attached hereto.

                           "Contingent Obligation" means, as applied to any
Person, any direct or indirect liability, contingent or otherwise, of that
Person with respect to any indebtedness, lease, dividend, letter of credit or
other obligation of another, including without limitation, any such obligation
directly or indirectly guaranteed, endorsed, co-made or discounted or sold with
recourse by that Person, or in respect of which that Person is otherwise
directly or indirectly liable; provided, however, that the term "Contingent
Obligation" shall not include endorsements for collection or deposit in the
ordinary course of business. The amount of any Contingent Obligation shall be
deemed to be an amount equal to the stated or determined amount of the primary
obligation in respect of which such Contingent Obligation is made or, if not
stated or determinable, the maximum reasonably anticipated liability in respect
thereof as determined by such Person in good faith; provided, however, that such
amount shall not in any event exceed the maximum amount of the obligations under
the guarantee or other support arrangement.

                           "Equipment" means machinery, equipment, tenant
improvements, furniture, fixtures, vehicles, tools, parts and attachments.


<PAGE>   13
                           "ERISA" means the Employment Retirement Income
Security Act of 1974, as amended, and the regulations thereunder.

                           "GAAP" means generally accepted accounting principles
as in effect from time to time.

                           "Guarantor's Books" means all of Guarantor's books
and records including ledgers; records concerning Guarantor's assets or
liabilities, the Collateral, business operations or financial condition; and all
computer programs, or tape files, and the equipment, containing such
information.

                           "Guaranty" means the unconditional guaranty executed
by Guarantor for the benefit of Bank, as amended from time to time.

                           "Indebtedness" means (a) all indebtedness for
borrowed money or the deferred purchase price of property or services, including
without limitation reimbursement and other obligations with respect to surety
bonds and letters of credit, (b) all obligations evidenced by notes, bonds,
debentures or similar instruments, (c) all capital lease obligations and (d) all
Contingent Obligations.

                           "Insolvency Proceeding" means any proceeding
commenced by or against any person or entity under any provision of the United
States Bankruptcy Code, as amended, or under any other bankruptcy or insolvency
law, including assignments for the benefit of creditors, formal or informal
moratoria, compositions, extension generally with its creditors, or proceedings
seeking reorganization, arrangement, or other relief.

                           "IRC" means the Internal Revenue Code of 1986, as
amended, and the regulations thereunder.

                           "Lien" means any mortgage, lien, security interest or
other encumbrance.

                           "Loan Documents" means, collectively, this Agreement,
the Guaranty executed by Guarantor, and any other agreement entered into between
Guarantor and Bank, all as amended or extended from time to time.

                           "Material Adverse Effect" means a material adverse
effect on the business operations or financial condition of Guarantor and its
Subsidiaries taken as a whole.

                           "Negotiable Collateral" means all of Guarantor's
present and future letters of credit of which it is a beneficiary, notes,
drafts, instruments, securities, documents of title, and chattel paper, and
Guarantor's Books relating to any of the foregoing.

                           "Obligations" means all amounts owed to the Bank by
Guarantor pursuant to the Guaranty, this Agreement or any other agreement,
whether absolute or contingent, due or to become due, now existing or hereafter
arising.

                           "Permitted Indebtedness" means:

                           (a) Existing Indebtedness disclosed to Bank in
writing;


                                       -2-
<PAGE>   14
                           (b) Subordinated Debt; and

                           (c) Indebtedness to trade creditors incurred in the
ordinary course of business.

                           "Permitted Investment" means:

                           (a) Investments existing on the Closing Date
disclosed to Bank in writing; and

                           (b) (i) marketable direct obligations issued or
unconditionally guaranteed by the United States of America or any agency or any
State thereof maturing within one (1) year from the date of acquisition thereof,
(ii) commercial paper maturing no more than one (1) year from the date of
creation thereof and currently having the highest rating obtainable from either
Standard & Poor's Corporation or Moody's Investors Service, Inc., and (iii)
certificates of deposit maturing no more than one (1) year from the date of
investment therein issued by Bank.

                           "Permitted Liens" means the following.

                           (a) Any Liens existing as of the date hereof and
disclosed to Bank in writing or arising under this Agreement;

                           (b) Liens for taxes, fees, assessments or other
governmental charges or levies, either not delinquent or being contested in good
faith by appropriate proceedings, provided the same have no priority over any of
Bank's security interests;

                           (c) Liens (i) upon or in any equipment acquired or
held by the Guarantor or any of its subsidiaries to secure the purchase price of
such equipment or indebtedness incurred solely for the purpose of financing the
acquisition of such equipment, or (ii) existing on such equipment at the time of
its acquisition, provided that the Lien is confined solely to the property so
acquired and improvements thereon, and the proceeds of such equipment; and

                           (d) Liens incurred in connection with the extension,
renewal or refinancing of the indebtedness secured by Liens of the type
described in clauses (a) through (d) above, provided that any extension, renewal
or replacement Lien shall be limited to the property encumbered by the existing
Lien and the principal amount of the indebtedness being extended, renewed or
refinanced does not increase.

                           "Person" means any individual, sole proprietorship,
partnership, joint venture, trust, unincorporated organization, association,
corporation, institution, public benefit corporation, firm, joint stock company,
estate, entity or governmental agency.

                           "Subordinated Debt" means any debt incurred by
Guarantor after the date hereof that is subordinated to the debt owing by
Guarantor to Bank on terms acceptable to Bank (and identified as being such by
the Company and the Bank).

                           "Subsidiary" means any corporation or partnership in
which (i) any general partnership interest or (ii) more than 50% of the stock of
which by the terms thereof ordinary voting power


                                       -3-
<PAGE>   15
to elect the Board of Directors, managers or trustees of the entity shall, at
the time as of which any determination is being made, is owned by Guarantor,
either directly or through an Affiliate.

                  1.2 Accounting Terms. All accounting terms not specifically
defined herein shall be construed in accordance with GAAP and all calculations
made hereunder shall be made in accordance with GAAP. When used herein, the
terms "financial statements" shall include the notes and schedules thereto.

         2. CREATION OF SECURITY INTEREST

                  2.1 Grant of Security Interest. Guarantor grants to Bank a
continuing security interest in all presently existing and hereafter acquired or
arising Collateral in order to secure prompt repayment of any and all
Obligations and in order to secure prompt performance by Guarantor of each of
its covenants and duties under the Loan Documents. Such security interest
constitutes a valid, first priority security interest in the presently existing
Collateral, and will constitute a valid, first priority security interest in
Collateral acquired after the date hereof.

                  2.2 Delivery of Additional Documentation Required. Guarantor
shall from time to time execute and deliver to Bank, at the request of Bank, all
Negotiable Collateral, all financing statements and other documents that Bank
may reasonably request, in form satisfactory to Bank, to perfect and continue
perfected Bank's security interests in the Collateral and in order to fully
consummate all of the transactions contemplated under the Loan Documents.

                  2.3 Right to Inspect. Bank (through any of its officers,
employees, or agents) shall have the right, upon reasonable prior notice, from
time to time during Guarantor's usual business hours, to inspect Guarantor's
Books and to make copies thereof and to check, test, and appraise the Collateral
in order to verify Guarantor's financial condition or the amount, condition of,
or any other matter relating to, the Collateral.

         3. REPRESENTATIONS AND WARRANTIES

                  Guarantor represents and warrants as follows:

                  3.1 Due Organization and Qualification. Guarantor is a
corporation duly existing and in good standing under the laws of its state of
incorporation and qualified and licensed to do business in, and is in good
standing in, any state in which the conduct of its business or its ownership of
property requires that it be so qualified.

                  3.2 Due Authorization; No Conflict. The execution, delivery,
and performance of the Loan Documents are within Guarantor's powers, have been
duly authorized and are not in conflict with nor constitute a breach of any
provision contained in Guarantor's Articles of Incorporation or Bylaws, nor will
they constitute an event of default under any material agreement to which
Guarantor is a party or by which Guarantor is bound. Guarantor is not in default
under any agreement to which it is a party or by which it is bound, which
default could have a Material Adverse Effect.

                  3.3 No Prior Encumbrances. Guarantor has good and indefeasible
title to the Collateral, free and clear of Liens, except for Permitted Liens.


                                       -4-
<PAGE>   16
                  3.4 Name; Location of Chief Executive Office. Except as
disclosed in the Schedule, Guarantor has not done business under any name other
than that specified on the signature page hereof. The chief executive office of
Guarantor is located at the address indicated in Section 10 hereof.

                  3.5 Litigation. There are no actions or proceedings pending by
or against Guarantor before any court or administrative agency in which an
adverse decision could have a Material Adverse Effect or a material adverse
effect on Guarantor's interest or Bank's security interest in the Collateral.
Guarantor does not have knowledge of any such pending or threatened actions or
proceedings.

                  3.6 Solvency. Guarantor is solvent and able to pay its debts
(including trade debts) as they mature.

                  3.7 Regulatory Compliance. Guarantor has met the minimum
funding requirements of ERISA with respect to any employee benefit plans subject
to ERISA. No event has occurred resulting from Guarantor's failure to comply
with ERISA that is reasonably likely to result in Guarantor's incurring any
liability that could have a material adverse effect on the financial condition
or business operations of Guarantor. Guarantor is not an "investment company" or
a company of controlled" by an "investment company" within the meaning of the
Investment Company Act of 1940. Guarantor is not engaged principally, or as one
of the important activities, in the business of extending credit for the purpose
of purchasing or carrying margin stock (within the meaning of Regulations G, T
and U of the Board of Governors of the Federal Reserve System). Guarantor has
complied with all the provisions of the Federal Fair Labor Standards Act.

                  3.8 Environmental Condition. None of Guarantor's properties
or assets has ever been used by Guarantor or, to the best of Guarantor's
knowledge, by previous owners or operators, in the disposal of, or to produce,
store, handle, treat, release, or transport, any hazardous waste or hazardous
substance other than in accordance with applicable law; to the best of
Guarantor's knowledge, none of Guarantor's properties or assets has ever been
designated or identified in any manner pursuant to any environmental protection
statute as a hazardous waste or hazardous substance disposal site, or a
candidate for closure pursuant to any environmental protection statute; no lien
arising under any environmental protection statute has attached to any revenues
or to any real or personal property owned by Guarantor; and Guarantor has not
received a summons, citation, notice, or directive from the Environmental
Protection Agency or any other federal or state governmental agency concerning
any action or omission by Guarantor resulting in the releasing, or otherwise
disposing of hazardous waste or hazardous substances into the environment..

                  3.9 Taxes. Guarantor has filed or caused to be filed all tax
returns required to be filed, and has paid, or has made adequate provision for
the payment of, all taxes reflected therein.

                  3.10 Government Consents. Guarantor has obtained all consents,
approvals and authorizations of, made all declarations or filings with, and
given all notices to, all governmental authorities that are necessary for the
continued operation of Guarantor's business as currently conducted.

                  3.11 Full Disclosure. No representation, warranty or other
statement made by Guarantor in any certificate or written statement furnished to
Bank contains any untrue statement of a material fact or omits to state a
material fact necessary in order to make the statements contained in such
certificates or statements not misleading.


                                       -5-
<PAGE>   17
         4. AFFIRMATIVE COVENANTS

                  Guarantor covenants and agrees that, until payment in full of
all outstanding Obligations under the Loan Agreement and this Agreement, and for
so long as Bank may have any commitment to make an Advance under the Loan
Agreement, Guarantor shall do all of the following-.

                  4.1 Good Standing. Guarantor shall maintain its corporate
existence and its good standing in its jurisdiction of incorporation and
maintain qualification in each jurisdiction in which the failure to so qualify
could have a Material Adverse Effect. Guarantor shall maintain in force all
licenses, approvals and agreements, the loss of which could have a Material
Adverse Effect.

                  4.2 Government Compliance. Guarantor shall comply with all
statutes, laws, ordinances and government rules and regulations to which it is
subject, noncompliance with which could have a Material Adverse Effect or a
material adverse effect on the Collateral or the priority of Bank's Lien on the
Collateral.

                  4.3 Inventory; Returns. Guarantor shall keep all Inventory in
good and marketable condition, free from all material defects. Returns and
allowances, if any, as between Guarantor and its account debtors shall be on the
same basis and in accordance with the usual customary practices of Guarantor, as
they exist at the time of the execution and delivery of this Agreement.
Guarantor shall promptly notify Bank of all returns and recoveries and of all
disputes and claims, where the return, recovery, dispute or claim involves more
than Fifty Thousand Dollars ($50,000).

                  4.4 Taxes. Guarantor shall make due and timely payment or
deposit of all material federal, state, and local taxes, assessments, or
contributions required of it by law, and will execute and deliver to Bank, on
demand, appropriate certificates attesting to the payment or deposit thereof;
and Guarantor will make timely payment or deposit of all material tax payments
and withholding taxes required of it by applicable laws, including, but not
limited to, those laws concerning F.I.C.A., F.U.T.A., state disability, and
local, state, and federal income taxes, and will, upon request, furnish Bank
with proof satisfactory to Bank indicating that Guarantor has made such payments
or deposits; provided that Guarantor need not make any payment if the amount or
validity of such payment is contested in good faith by appropriate proceedings
and is reserved against (to the extent required by GAAP) by Guarantor.

                  4.5 Insurance.

                           (a) Guarantor, at its expense, shall keep the
Collateral insured against loss or damage by fire, theft, explosion, sprinklers,
and all other hazards and risks, and in such amounts, as ordinarily insured
against by other owners in similar businesses conducted in the locations where
Guarantor's business is conducted on the date hereof. Guarantor shall also
maintain insurance relating to Guarantor's ownership and use of the Collateral
in amounts and of a type that are customary to businesses similar to Guarantors.

                           (b) All such policies of insurance shall be in such
form, with such companies, and in such amounts as reasonably satisfactory to
Bank. All such policies of property insurance shall contain a tender's loss
payable endorsement, in a form satisfactory to Bank, showing Bank as an
additional loss payee thereof and all liability insurance policies shall show
the Bank as an additional insured, and shall specify that the insurer must give
at least twenty (20) days notice to Bank before canceling its policy 


                                       -6-
<PAGE>   18
for any reason. Guarantor shall deliver to Bank certified copies of such
policies of insurance and evidence of the payments of all premiums therefor. All
proceeds payable under any such policy shall, at the option of Bank, be payable
to Bank to be applied on account of the Obligations.

                  4.6 Further Assurances. At any time and from time to time
Guarantor shall execute and deliver such further instruments and take such
further action as may reasonably be requested by Bank to effect the purposes of
this Agreement.

         5. NEGATIVE COVENANTS

                  Guarantor covenants and agrees that until payment in full of
all outstanding Obligations under the Loan Agreement and this Agreement,
Guarantor will not do any of the following-

                  5.1 Dispositions. Convey, sell, lease, transfer or otherwise
dispose of (collectively, a "Transfer"), all or any part of its business or
property, other than: (i) Transfers in the ordinary course of business; (ii)
Transfers of non-exclusive licenses and similar arrangements for the use of the
property of Guarantor or its Subsidiaries; or (iii) Transfers of worn-out or
obsolete Equipment.

                  5.2 Change in Business. Engage in any business other than the
businesses currently engaged in by Guarantor and any business substantially
similar or related thereto (or incidental thereto), or suffer a material change
in Guarantor's ownership. Guarantor will not, without thirty (30) days prior
written notification to Bank, relocate its chief executive office.

                  5.3 Mergers or Acquisitions. Merge or consolidate, or permit
any of its Subsidiaries to merge or consolidate, with or into any other business
organization, or acquire, or permit any of its Subsidiaries to acquire, all or
substantially all of the capital stock or property of another Person.

                  5.4 Indebtedness. Create, incur, assume or be or remain liable
with respect to any Indebtedness other than Permitted Indebtedness.

                  5.5 Encumbrances. Create, incur, assume or suffer to exist any
Lien with respect to any of its property, or assign or otherwise convey any
right to receive income, including the sale of any Accounts, or permit any of
its Subsidiaries so to do, except for Permitted Liens.

                  5.6 Distributions. Pay any dividends or make any other
distribution or payment on account of or in redemption, retirement or purchase
of any capital stock.

                  5.7 Investments. Directly or indirectly acquire or own any
beneficial interest in (including stock, partnership interest, or other
securities of), or make any loan, advance, or capital contribution to, any
Person, or permit any of its Subsidiaries so to do, other than Permitted
Investments.

                  5.8 Transactions with Affiliates. Directly or indirectly enter
into or permit to exist any material transaction with any Affiliate of Guarantor
except for transactions that are in the ordinary course of Guarantor's business,
upon fair and reasonable terms that are no less favorable to Guarantor than
would be obtained in an arm's length transaction with a nonaffiliated Person or
entity.


                                       -7-
<PAGE>   19
                  5.9 Subordinated Debt. Make any payment in respect of any
Subordinated Debt, or permit any of its Subsidiaries to make any such payment,
except in compliance with the terms of such Subordinated Debt, or amend any
provision contained in any documentation relating to the Subordinated Debt
without Bank's prior written consent.

                  5.10 Inventory. Store the Inventory with a bailee,
warehouseman, or similar party unless Bank has received a pledge of the
warehouse receipt covering such Inventory. Except for Inventory sold in the
ordinary course of business and except for such other locations as Bank may
approve in writing, Guarantor shall keep the Inventory only at the location set
forth in Section 10 hereof and such other locations of which Guarantor gives
Bank prior written notice and as to which Guarantor signs and files a financing
statement where needed to perfect Bank's security interest.

                  5.11 Compliance. Become an "investment company" controlled by
an "investment company," within the meaning of the Investment Company Act of
1940, or become principally engaged in, or undertake as one of its important
activities, the business of extending credit for the purpose of purchasing or
carrying margin stock, or use the proceeds of any Advance for such purpose. Fail
to meet the minimum funding requirements of ERISA, permit a Reportable Event or
Prohibited Transaction, as defined in ERISA, to occur, fail to comply with the
Federal Fair Labor Standards Act or violate any law or regulation, which
violation could have a Material Adverse Effect or a material adverse effect on
the Collateral or the priority of Bank's Lien on the Collateral, or permit any
of its Subsidiaries to do any of the foregoing.

         6. EVENTS OF DEFAULT

                  Any one or more of the following events shall constitute an
Event of Default by Guarantor under the Agreement:

                  6.1 Payment Default. If Guarantor fails to pay any amount
under the Guaranty when due and payable.

                  6.2 Covenant Default. If Guarantor violates any of the
covenants contained in Article 5 of this Agreement, or fails or neglects to
perform, keep, or observe any other material term, provision, condition,
covenant, or agreement contained in the Guaranty or this Agreement, in any of
the Loan Documents, or in any other present or future agreement between
Guarantor and Bank and as to any default under such other term, provision,
condition, covenant or agreement that can be cured, has failed to cure such
default within ten (10) days after the Guarantor receives notice thereof or any
officer of Guarantor become aware thereof (provided that no Advances will be
required to be made during such cure period); provided, however, that if the
default cannot by its nature be cured within the ten (10) day period or cannot
after diligent attempts by Guarantor be cured within such ten (10) day period,
and such default is likely to be cured within a reasonable time, then Guarantor
shall have an additional reasonable period (which shall not in any case exceed
thirty (30) days) to attempt to cure such default, and within such reasonable
time period the failure to have cured such default shall not be deemed an Event
of Default;

                  6.3 Material Adverse Change. If there occurs a material
adverse change in Guarantor's business, or if there is a material impairment of
the prospect of repayment of any portion of the Obligations owing to Bank or a
material impairment of the value or priority of Bank's security interests in the
Collateral;


                                       -8-
<PAGE>   20
                  6.4 Attachment. If any material portion of Guarantor's assets
is attached, seized, subjected to a writ or distress warrant, or is levied upon,
or comes into the possession of any trustee, receiver or person acting in a
similar capacity and such attachment, seizure, writ or distress warrant or levy
has not been removed, discharged or rescinded within ten (10) days, or if
Guarantor is enjoined, restrained, or in any way prevented by court order from
continuing to conduct all or any material part of its business affairs, or if a
judgment or other claim becomes a lien or encumbrance upon any material portion
of Guarantor's assets, or if a notice of lein, levy, or assessment is filed of
record with respect to any of Guarantor's assets by the United States
Government, or any department, agency, or instrumentality thereof, or by any
state, county, municipal, or governmental agency, and the same is not paid
within ten (10) days after Guarantor receives notice thereof, provided that none
of the foregoing shall constitute an Event of Default where such action or event
is stayed or an adequate bond has been posted pending a good faith contesting by
Guarantor;

                  6.5 Insolvency. If an Insolvency Proceeding is commenced by
Guarantor, or if an Insolvency Proceeding is commenced against Guarantor and is
not dismissed or stayed within ten (10) days;

                  6.6 Other Agreements. If there is a default in any agreement
to which Guarantor is a party with a third party or parties resulting in a right
by such third party or parties, whether or not exercised, to accelerate the
maturity of any Indebtedness in an amount in excess of One Hundred Thousand
Dollars ($100,000) or which could have a Material Adverse Effect;

                  6.7 Subordinated Debt. If Guarantor makes any payment on
account of Subordinated Debt, except to the extent such payment is allowed under
any subordination agreement entered into with Bank;

                  6.8 Judgments. If a judgment or judgments for the payment of
money in an amount, individually or in the aggregate, of at least Fifty Thousand
Dollars ($50,000) shall be rendered against Guarantor and shall remain
unsatisfied and unstayed for a period of ten (10) days;

                  6.9 Loan Agreement. ff an Event of Default occurs under the
Loan Agreement; or

                  6.10 Representations. If any material misrepresentation or
material misstatement exists now or hereafter in any warranty or representation
set forth herein or in any certificate delivered to Bank by any Responsible
Officer pursuant to this Agreement or to induce Bank to enter into this
Agreement or any other Loan Document.

         7. BANK'S RIGHT'S AND REMEDIES

                  7.1 Rights and Remedies. Upon the occurrence and during the
continuance of an Event of Default, Bank may, at its election, without notice of
its election and without demand, do any one or more of the following, all of
which are authorized by Guarantor:

                           (a) Declare all Obligations, whether evidenced by
this Agreement, by any of the other Loan Documents, or otherwise, immediately
due and payable (provided that upon the occurrence of an Event of Default
described in Section 6.5 all Obligations shall become immediately due and
payable without any action by Bank);


                                       -9-
<PAGE>   21
                           (b) Settle or adjust disputes and claims directly
with account debtors for amounts, upon terms and in whatever order that Bank
reasonably considers advisable;

                           (c) Without notice to or demand upon Guarantor, make
such payments and do such acts as Bank considers necessary or reasonable to
protect its security interest in the Collateral. Guarantor agrees to assemble
the Collateral if Bank so requires, and to make the Collateral available to Bank
as Bank may designate. Guarantor author Bank to enter the premises where the
Collateral is located, to take and maintain possession of the Collateral, or any
part of it, and to pay, purchase, contest, or compromise any encumbrance,
charge, or lien which in Bank's determination appears to be prior or superior to
its security interest and to pay all expenses incurred in connection therewith.
With respect to any of Guarantor's owned premises, Guarantor hereby grants Bank
a license to enter into possession of such premises and to occupy the same,
without charge, in order to exercise any of Bank's rights or remedies provided
herein, at law, in equity, or otherwise;

                           (d) Without notice to Guarantor set off and apply to
the Obligations any and all 4(i) balances and deposits of Guarantor held by
Bank, or (ii) indebtedness at any time owing to or for the credit or the account
of Guarantor held by Bank;

                           (e) Ship, reclaim, recover, store, finish, maintain,
repair, prepare for sale, advertise for sale, and sell (in the manner provided
for herein) the Collateral. Bank is hereby granted a license or other right,
solely pursuant to the provisions of this Section 7.1, to use, without charge,
Guarantor's labels, patents, copyrights, rights of use of any name, trade
secrets, trade names, trademarks, service marks, and advertising matter, or any
property of a similar nature, as it pertains to the Collateral, in completing
production of, advertising for sale, and selling any Collateral and, in
connection with Bank's exercise of its rights under this Section, Guarantor's
rights under all licenses and all franchise agreements shall inure to Bank's
benefit;

                           (f) Sell the Collateral at either a public or private
sale, or both, by way of one or more contracts or transactions, for cash or on
terms, in such manner and at such places (including Guarantor's premises) as
Bank determines is commercially reasonable;

                           (g) Bank may credit bid and purchase at any public
sale; and

                           (h) Any deficiency that exists after disposition of
the Collateral as provided above will be paid immediately by Guarantor.

                  7.2 Power of Attorney . Effective only upon the occurrence and
during the continuance of an Event of Default, Guarantor hereby irrevocably and
appoints Bank (and any of Bank's designated officers, or employees) as
Guarantor's true and lawful attorney to: (a) send requests for verification of
Accounts or notify account debtors of Bank's security interest in the Accounts;
(b) endorse Guarantor's name on any checks or other forms of payment or
security that may come into Bank's possession; (c) sign Guarantor's name on any
invoice or bill of lading relating to any Account, drafts against account
debtors, schedules and assignments of Accounts, verifications of Accounts, and
notices to account debtors; (d) make, settle, and adjust all claims under and
decisions with respect to Guarantor's policies of insurance; and (e) settle and
adjust disputes and claims respecting the accounts directly with account
debtors, for amounts and upon terms which Bank determines to be reasonable;
provided Bank may exercise such power of attorney to sign the name of Guarantor
on any of the documents described in 


                                      -10-
<PAGE>   22
Section 2.2 regardless of whether an Event of Default has occurred. The
appointment of Bank as Guarantor's attorney in fact, and each and every one of
Bank's rights and powers, being coupled with an interest, is irrevocable until
all of the Obligations have been fully repaid and performed and Bank's
obligation to provide advances hereunder is terminated.

                  7.3 Bank Expenses. If Guarantor fails to pay any amounts or
furnish any required proof of payment due to third persons or entities, as
required under the terms of this Agreement, then Bank may do any or all of the
following: (a) make payment of the same or any part thereof, or (b) obtain and
maintain insurance policies of the type discussed in this Agreement, and take
any action with respect to such policies as Bank deems prudent. Any amounts paid
or deposited by Bank shall constitute Bank Expenses, shall be immediately due
and payable, and shall bear interest at the then applicable rate hereinabove
provided, and shall be secured by the Collateral. Any payments made by Bank
shall not constitute an agreement by Bank to make similar payments in the future
or a waiver by Bank of any Event of Default under this Agreement.

                  7.4 Bank's Liability for Collateral. So long as Bank complies
with reasonable banking practices, Bank shall not in any way or manner be liable
or responsible for: (a) the safekeeping of the Collateral; (b) any loss or
damage thereto occurring or arising in any manner or fashion from any cause; (c)
any diminution in the value thereof; or (d) any act or default of any carrier,
warehouseman, bailee, forwarding agency, or other person whomsoever. All risk of
loss, damage or destruction of the Collateral shall be borne by Guarantor.

                  7.5 Remedies Cumulative. Bank's rights and remedies under this
Agreement, the Loan Documents, and all other agreements shall be cumulative.
Bank shall have all other rights and remedies not inconsistent herewith as
provided under the Code, by law, or in equity. No exercise by Bank of one right
or remedy shall be deemed an election, and no waiver by Bank of any Event of
Default on Guarantor's part shall be deemed a continuing waiver. No delay by
Bank shall constitute a waiver, election, or acquiescence by it.

                  7.6 Demand; Protest. Guarantor waives demand, protest, notice
of protest, notice of default or dishonor, notice of payment and nonpayment,
notice of any default, nonpayment at maturity, release, compromise, settlement,
extension, or renewal of accounts, documents, instruments, chattel paper, and
guarantees at any time held by Bank on which Guarantor may in any way be liable.

         8. NOTICES

                  Unless otherwise provided in this Agreement, all notices or
demands by any party relating to this Agreement or any other agreement entered
into in connection herewith shall be in writing and (except for financial
statements and other informational documents which may be sent by first-class
mail, postage prepaid) shall be personally delivered or sent by certified mail,
postage prepaid, return receipt requested, or by prepaid telefacsimile to
Guarantor or to Bank, as the case may be, at its addresses set forth below:

                  If to Guarantor:  Bio Tek Solutions, Inc.
                                    3865 North Business Center Drive
                                    Tuscon, AZ  85705
                                    Attn:_____________________
                                    FAX:______________________

                                                        -11-

<PAGE>   23
                  If to Bank:       Silicon Valley Bank
                                    1731 Embarcadero Road, Suite 220
                                    Palo Alto, CA 94303
                                    Attn: Kevin Conway
                                    FAX: (415) 812-0640

         The parties hereto may change the address at which they are to receive
notices hereunder, by notice in writing in the foregoing manner given to the
other.

         9. CHOICE OF LAW AND VENUE; JURY TRIAL WAIVER

                  This Agreement shall be governed by, and construed in
accordance with, the internal laws of the State of California, without regard to
principles of conflicts of law. Each of Guarantor and Bank hereby submits to the
exclusive jurisdiction of the state and Federal courts located in the County of
Santa Clara, State of California. GUARANTOR AND BANK EACH HEREBY WAIVE THEIR
RESPECTIVE RIGHTS TO A JURY TRIAL OF ANY CLAIM OR CAUSE OF ACTION BASED UPON OR
ARISING OUT OF ANY OF THE LOAN DOCUMENTS OR ANY OF THE TRANSACTIONS CONTEMPLATED
THEREIN, INCLUDING CONTRACT CLAIMS, TORT CLAIMS, BREACH OF DUTY CLAIMS, AND ALL
OTHER COMMON LAW OR STATUTORY CLAIMS. EACH PARTY RECOGNIZES AND AGREES THAT THE
FOREGOING WAIVER CONSTITUTES A MATERIAL INDUCEMENT FOR IT TO ENTER INTO THIS
AGREEMENT. EACH PARTY REPRESENTS AND WARRANTS THAT IT HAS REVIEWED THIS WAIVER
WITH ITS LEGAL COUNSEL AND THAT IT KNOWINGLY AND VOLUNTARILY WAIVES ITS JURY
TRIAL RIGHTS FOLLOWING CONSULTATION WITH LEGAL COUNSEL.

         10. GENERAL PROVISIONS

                  10.1 Successors and Assigns. This Agreement shall bind and
inure to the benefit of the respective successors and permitted assigns of each
of the parties; provided, however, that neither this Agreement nor any rights
hereunder may be assigned by Guarantor without Bank's prior written consent,
which consent may be granted or withheld in Bank's sole discretion. Bank shall
have the right without the consent of or notice to Guarantor to sell, transfer,
negotiate, or grant participation in all or any part of, or any interest in
Bank's obligations, rights and benefits hereunder.

                  10.2 Indemnification. Guarantor shall defend, indemnify and
hold harmless Bank and its officers, employees, and agents against: (a) all
obligations, demands, claims, and liabilities claimed or asserted by any other
party in connection with the transactions contemplated by this Agreement; and
(b) all losses or Bank Expenses in any way suffered, incurred, or paid by Bank
as a result of or in any way arising out of, following, or consequential to
transactions between Bank and Guarantor whether under this Agreement, or
otherwise (including without limitation reasonable attorneys fees and expenses),
except for losses caused by Bank's gross negligence or willful misconduct.

                  10.3 Time of Essence. Time is of the essence for the
performance of all obligations set forth in this Agreement.

                  10.4 Severability of Provisions. Each provision of this
Agreement shall be severable from every other provision of this Agreement for
the purpose of determining the legal enforceability of any specific provision.

                  10.5 Amendments in Writing, Integration. This Agreement cannot
be changed or terminated orally. All prior agreements, understandings,
representations, warranties, and negotiations between the parties hereto with
respect to the subject matter of this Agreement, if any, are merged into this
Agreement and the Loan Documents.


                                      -12-
<PAGE>   24
                  10.6 Counterparts. This Agreement may be executed in any
number of counterparts and by different parties on separate counterparts, each
of which, when executed and delivered, shall be deemed to be an original, and
all of which, when taken together, shall constitute but one and the same
Agreement.

                  10.7 Survival. All covenants, representations and warranties
made in this Agreement shall continue in full force and effect so long as any
Obligations remain outstanding. The obligations of Guarantor to indemnify Bank
with respect to the expenses, damages, losses, costs and liabilities described
in Section 10.2 shall survive until all applicable statute of limitations
periods with respect to actions that may be brought against Bank have run.

         IN WHEREOF, the parties hereto have caused this Agreement to be
executed as of the date first above written.

                             BIO TEK SOLUTIONS, INC.


                             By:_______________________________________________

                             Title:____________________________________________


                             SILICON VALLEY BANK


                             By:_______________________________________________

                             Title:____________________________________________


                                      -13-
<PAGE>   25
                                    EXHIBIT A


         The Collateral shall consist of all right, title and interest of
Guarantor in and to the following:

         (a) All goods and equipment now owned or hereafter acquired, including,
without limitation, all machinery, fixtures, vehicles (including motor vehicles
and trailers), and any interest in any of the foregoing, and all attachments,
accessories, accessions, replacements, substitutions, additions, and
improvements to any of the foregoing, wherever located;

         (b) All inventory, now owned or hereafter acquired, including, without
limitation, an merchandise, raw materials, parts, supplies, packing and shipping
materials, work in process and finished products including such inventory as is
temporarily out of Guarantor's custody or possession or in transit and including
any returns upon any accounts or other proceeds, including insurance proceeds,
resulting from the sale or disposition of any of the foregoing and any documents
of title representing any of the above, and Guarantor's Books relating to any of
the foregoing;

         (c) All contract rights and general intangibles now owned or hereafter
acquired, including, without limitation, goodwill, trademarks, service marks,
trade styles, trade names, patents, patent applications, leases, license
agreements, franchise agreements, blueprints, drawings, purchase orders,
customer lists, route lists, infringements, claims, computer programs, computer
discs, computer tapes, literature, reports, catalogs, design rights, income tax
refunds, payments of insurance and rights to payment of any kind;

         (d) All now existing and hereafter arising accounts, contract rights,
royalties, license rights and all other forms of obligations owing to Guarantor
arising out of the sale or lease of goods, the licensing of technology or the
rendering of services by Guarantor, whether or not earned by performance, and
any and all credit insurance, guaranties, and other security therefor, as well
as all merchandise returned to or recorded by Guarantor and Guarantor's Books
relating to any of the foregoing;

         (e) All documents, cash, deposit accounts, securities, letters of
credit, certificates of deposit, instruments and chattel paper now owned or
hereafter acquired and Guarantor's Books relating to the foregoing;

         (f) All copyright rights, copyright applications, copyright
registrations and like protections in each work of authorship and derivative
work thereof, whether published or unpublished, now owned or hereafter acquired;
all trade secret rights, including all rights to unpatented inventions,
know-how, operating manuals, license rights and agreements and confidential
information, now owned or hereafter acquired; all mask work or similar rights
available for the protection of semiconductor chips, now owned or hereafter
acquired; all claims for damages by way of any past, present and future
infringement of any of the foregoing; and

         (g) Any and all claims, rights and interests in any of the above and
all substitutions for, additions and accessions to and proceeds thereof.


                                      -14-
<PAGE>   26
- -------------------------------------------------------------------------------


                             BIO TEK SOLUTIONS, INC.

                          GUARANTOR SECURITY AGREEMENT

- -------------------------------------------------------------------------------
<PAGE>   27
<TABLE>
<CAPTION>
                                                                     PAGE
                                                                     ----
<S>      <C>                                                         <C>
1.       DEFINITIONS AND CONSTRUCTION..............................    1
         1.1      Definitions......................................    1
         1.2      Accounting Terms.................................    4

2.       CREATION OF SECURITY INTEREST.............................    4
         2.1      Grant of Security Interest.......................    4
         2.2      Delivery of Additional Documentation Required....    4
         2.3      Right to Inspect.................................    4

3.       REPRESENTATIONS AND WARRANTIES............................    4
         3.1      Due Organization and Qualification...............    4
         3.2      Due Authorization; No Conflict...................    4
         3.3      No Prior Encumbrances............................    4
         3.4      Name; Location of Chief Executive Office.........    4
         3.5      Litigation.......................................    5
         3.6      Solvency.........................................    5
         3.7      Regulatory Compliance............................    5
         3.8      Environmental....................................    5
         3.9      Taxes............................................    5
         3.10     Government Consents..............................    5
         3.11     Full Disclosure..................................    5

4.       AFFIRMATIVE COVENANTS.....................................    5
         4.1      Good Standing....................................    6
         4.2      Government Compliance............................    6
         4.3      Inventory; Returns...............................    6
         4.4      Taxes............................................    6
         4.5      Insurance........................................    6
         4.6      Further Assurances...............................    6

5.       NEGATIVE COVENANTS........................................    7
         5.1      Dispositions.....................................    7
         5.2      Change in Business...............................    7
         5.3      Mergers or Acquisitions..........................    7
         5.4      Indebtedness.....................................    7
         5.5      Encumbrances.....................................    7
         5.6      Distributions....................................    7
         5.7      Investments......................................    7
         5.8      Transactions with Affiliates.....................    7
         5.9      Subordinated Debt................................    7
         5.10     Inventory........................................    7
         5.11     Compliance.......................................    8

6.       EVENTS OF DEFAULT.........................................    8
         6.1      Payment Default..................................    8
         6.2      Covenant Default.................................    8
         6.3      Material Adverse Change..........................    8
         6.4      Attachment.......................................    8
</TABLE>


                                       -i-
<PAGE>   28
                                TABLE OF CONTENTS
                                   (CONTINUED)

<TABLE>
<CAPTION>
                                                                     PAGE
                                                                     ----
<S>      <C>                                                         <C>
         6.5      Insolvency.......................................    9
         6.6      Other Agreements.................................    9
         6.7      Subordinated Debt................................    9
         6.8      Judgments........................................    9
         6.9      Loan Agreement...................................    9
         6.10     Representations..................................    9

7.       BANK'S RIGHT'S AND REMEDIES...............................    9
         7.1      Rights and Remedies..............................    9
         7.2      Power of Attorney ...............................   10
         7.3      Bank Expenses....................................   10
         7.4      Bank's Liability for Collateral..................   10
         7.5      Remedies Cumulative..............................   11
         7.6      Demand; Protest..................................   11

8.       NOTICES...................................................   11

9.       CHOICE OF LAW AND VENUE; JURY TRIAL WAIVER................   11

10.      GENERAL PROVISIONS........................................   12
         10.1     Successors and Assigns...........................   12
         10.2     Indemnification..................................   12
         10.3     Time of Essence..................................   12
         10.4     Severability of Provisions.......................   12
         10.5     Amendments in Writing, Integration...............   12
         10.6     Counterparts.....................................   12
         10.7     Survival.........................................   12
</TABLE>


                                      -ii-



<PAGE>   29
                     COLLATERAL ASSIGNMENT, PATENT MORTGAGE
                             AND SECURITY AGREEMENT

     This Collateral Assignment, Patent Mortgage and Security Agreement is made
as of the 20 day of February, 1995, by and between Ventana Medical Systems,
Inc., a Delaware corporation ("Assignor"), and Silicon Valley Bank, a California
banking corporation ("Assignee").


                                    RECITALS

     A.   Assignee has agreed to lend to Assignor certain funds (the "Loan"), 
pursuant to a Loan and Security Agreement dated as of February 20, 1995 (the
"Loan Agreement") and Assignor desires to borrow such funds from Assignee. The
Loan is or will be by one or more promissory notes (a "Note" or, collectively,
the "Notes") and is secured pursuant to the terms of the Loan Agreement.

     B.   In order to induce Assignee to make or amend the terms of the Loan,
Assignor has agreed to assign certain intangible property to Assignee for
purposes of securing the obligations of Assignor to Assignee.

     NOW, THEREFORE, THE PARTIES HERETO AGREE AS FOLLOWS:

     1.   ASSIGNMENT, PATENT MORTGAGE AND GRANT OF SECURITY INTEREST.  As
collateral security for the prompt and complete payment and performance of all
of Assignor's present or future indebtedness, obligations and liabilities to
Assignee, Assignor hereby assigns, transfers, conveys and grants a security
interest and mortgage to Assignee, as security, but not as an ownership interest
in and to Assignor's entire right, title and interest in, to and under the
following (all of which shall collectively be called the "Collateral"):

          (a)  Any and all copyright rights, copyright applications, copyright
registrations and like protections in each work or authorship and derivative
work thereof, whether published or unpublished and whether or not the same also
constitutes a trade secret, now or hereafter existing, created, acquired or
held, including without limitation those set forth on EXHIBIT A attached hereto
(collectively, the "Copyrights");

          (b)  Any and all trade secrets, and any and all intellectual property
rights in computer software and computer software products now or hereafter
existing, created, acquired or held;

          (c)  Any and all design rights which may be available to Assignor now
or hereafter existing, created, acquired or held;

          (d)  All patents, patent applications and like protections including,
without limitation, improvements, divisions, continuations, renewals, reissues,
extensions and continuations-in-part of the same, including without limitation
the patents and patent applications set forth on EXHIBIT B attached hereto
(collectively, the "Patents");

          (e)  Any trademark and servicemark rights, whether registered or not,
applications to register and registrations of the same and like protections, and
the entire goodwill of the business of Assignor connected with and symbolized by
such trademarks, including without limitation those set forth on EXHIBIT C
attached hereto (collectively, the "Trademarks");

          (f)  Any and all claims for damages by way of past, present and future
infringements of any of the rights included above, with the right, but not the
obligation, to sue for and collect such damages for said use or infringement of
the intellectual property rights identified above;
<PAGE>   30
         (g) All licenses or other rights to use any of the Copyrights, Patents
or Trademarks, and all license fees and royalties arising from such use to the
extent permitted by such license or rights; and

         (h) All amendments, extensions, renewals and extensions of any of the
Copyrights, Trademarks or Patents; and

         (i) All proceeds and products of the foregoing, including without
limitation all payments under insurance or any indemnity or warranty payable in
respect of any of the foregoing.

THE INTEREST IN THE COLLATERAL BEING ASSIGNED HEREUNDER SHALL NOT BE CONSTRUED
AS A CURRENT ASSIGNMENT, BUT AS A CONTINGENT ASSIGNMENT TO SECURE ASSIGNOR'S
OBLIGATIONS TO ASSIGNEE UNDER THE NOTE AND THE LOAN AGREEMENT.

     2. AUTHORIZATION AND REQUEST.  Assignor authorizes and requests that the
Register of Copyrights and the Commissioner of Patents and Trademarks, as
applicable, record this conditional assignment.

     3. COVENANTS AND WARRANTIES.  Assignor represents, warrants, covenants and
agrees as follows:

        (a) Assignor is now the sole owner of the Collateral, except for
non-exclusive licenses granted by Assignor to its customers in the ordinary
course of business;

        (b) Performance of this Assignment does not conflict with or result in a
breach of any agreement to which Assignor is bound, except to the extent that
certain intellectual property agreements prohibit the assignment of the rights
thereunder to a third party without the licensor's or other party's consent and
this Assignment constitutes an assignment;

        (c) During the term of this Agreement, Assignor will not transfer
or otherwise encumber any interest in the Collateral except for non-exclusive
licenses granted by Assignor in the ordinary course of business or as set forth
in this Assignment;

        (d) To its knowledge, each of the Patents is valid and enforceable, and
no part of the Collateral has been judged invalid or unenforceable, in whole or
in part, and no claim has been made that any part of the Collateral violates the
rights of any third party;

        (e) Assignor shall promptly advise Assignee of any material adverse
change in the composition of the Collateral, including but not limited to any
subsequent ownership right of the Assignor in or to any Trademark, Patent or
Copyright not specified in this Assignment;

        (f) Assignor shall (i) protect, defend and maintain the validity and
enforceability of the Trademarks, Patents and Copyrights, (ii) use its best
efforts to detect infringements of the Trademarks, Patents and Copyrights and
promptly advise Assignee in writing of material infringements detected and
(iii) not allow any Trademarks, Patents, or Copyrights to be abandoned,
forfeited or dedicated to the public without the written consent of Assignee,
which shall not be unreasonably withheld unless Assignor determines that
reasonable business practices suggest that abandonment is appropriate.

        (g) Assignor shall promptly register the most recent version of any of
Assignor's Copyrights, if not so already registered, and shall, from time to
time, execute and file such other instruments, and take such further actions as
Assignee may reasonably request from time to time to perfect or continue the
perfection of Assignee's interest in the Collateral;

        (h) This Assignment creates, and in the case of after acquired
Collateral, this Assignment will create at the time Assignor first has rights in
such after acquired Collateral, in favor of Assignee a valid and perfected first
priority

                                      -2-
<PAGE>   31
security interest in the Collateral in the United States securing the
payment and performance of the obligations evidenced by the Note upon making 
the filings referred to in clause (i) below;

                (i)    To its knowledge, except for, and upon, the filing with
the United States Patent and Trademark office with respect to the Patents and
Trademarks and the Register of Copyrights with respect to the Copyrights
necessary to perfect the security interests and assignment created hereunder
and except as has been already made or obtained, no authorization, approval
or other action by, and no notice to or filing with, any U.S. governmental
authority of U.S. regulatory body is required either (i) for the grant by
Assignor of the security interest granted hereby or for the execution, delivery
or performance of this Assignment by Assignor in the U.S. or (ii) for the
perfection in the United States or the exercise by Assignee of its rights and
remedies thereunder;

                (j)    All information heretofore, herein or hereafter supplied
to Assignee by of on behalf of Assignor with respect to the Collateral is
accurate and complete in all respects.

                (k)    Assignor shall not enter into any agreement that would
materially impair or conflict with Assignor's obligations hereunder without
Assignee's prior written consent, which consent shall not be unreasonably
withheld. Assignor shall not permit the inclusion in any material contract to
which it becomes a party of any provisions that could or might in any way
prevent the creation of a security interest in Assignor's rights and interest in
any property included within the definition of the Collateral acquired under
such contracts, except that certain contacts may contain anti-assignment
provisions that could in effect prohibit the creation of a security interest in
such contracts.

                (l)    Upon any executive officer of Assignor obtaining actual
knowledge thereof, Assignor will promptly notify Assignee in writing of any
event that materially adversely affects the value of any material Collateral,
the ability of Assignor to dispose of any material Collateral of the rights and
remedies of Assignee in relation thereto, including the levy of any legal
process against any of the Collateral.

        4.      ASSIGNEE'S RIGHTS.  Assignee shall have the right, but not the
obligation, to take, at Assignor's sole expense, any actions that Assignor is
required under this Assignment to take but which Assignor fails to take, after
fifteen (15) days' notice to Assignor. Assignor shall reimburse and indemnify
Assignee for all reasonable costs and reasonable expenses incurred in the
reasonable exercise of its rights under this Section 4.

        5.      INSPECTION RIGHTS. Assignor hereby grants to Assignee and its
employees, representatives and agents the right to visit, during reasonable
hours upon prior reasonable written notice to Assignor, and any of Assignor's
plants and facilities that manufacture, install of store products (or that have
done so during the prior six-month period) that are sold utilizing any of the
Collateral, and to inspect the products and quality control records relating
thereto upon reasonable written notice to Assignor and as often as may be
reasonably requested, but not more than one (1) in every six (6) months;
provided, however, nothing herein shall entitle Assignee access to Assignor's
trade secrets and other proprietary information.

        6.      FURTHER ASSURANCES; ATTORNEY IN FACT

                (a)    On a continuing basis, Assignor will, subject to any
prior licenses, encumbrances and restrictions and prospective licenses, make,
execute, acknowledge and deliver, and file and record in the proper filing and
recording places in the United States, all such instruments, including,
appropriate financing and continuation statements and collateral agreements and
filings with the United States Patent and Trademarks Office, and the Register of
Copyrights, and take all such action as may reasonably be deemed necessary or
advisable, or as requested by Assignee, to perfect Assignee's security interest
in all Copyrights, Patents and Trademarks and otherwise to carry out the intent
and purposes of this Collateral Assignment, or for assuring and confirming to
Assignee the grant or perfection of a security interest in all Collateral.

                (b)    Assignor hereby irrevocably appoints Assignee as
Assignor's attorney-in-fact, with full authority in the place and stead of
Assignor and in the name of Assignor, Assignee or otherwise, from time to time
in Assignee's discretion, upon Assignor's failure or inability to do so, to take
any action and to execute any instrument which Assignee may deem necessary or
advisable to accomplish the purposes of this Collateral Assignment, including:

                                      -3-
<PAGE>   32
                       (i)    To modify, in its sole discretion, this Collateral
Assignment without first obtaining Assignor's approval of or signature to such
modification by amending Exhibit A, Exhibit B and Exhibit C, thereof, as
appropriate, to include reference to any right, title or interest in any
Copyrights, Patents or Trademarks acquired by Assignor after the execution
hereof or to delete any reference to any right, title of interest in any
Copyrights, Patents or Trademarks in which Assignor no longer has or claim
any right, title or interest; and

                       (ii)   To file, in its sole discretion, one or more
financing or continuation statements and amendments thereto, relative to any of
the Collateral without the signature of Assignor where permitted by law.

        7.      EVENTS OF DEFAULT. The occurrence of any of the following shall
constitute an Event of Default under the Assignment:

                (a)    An Event of Default occurs under the Loan Agreement or
any Note; or

                (b)    Assignor breaches any warranty, covenant or agreement
made by Assignor in this Assignment, of if such breach is capable of being
cured, Assignor fails to cure such breach within five (5) days of the occurrence
of such breach.

        8.      REMEDIES. Upon the occurrence and continuance of an Event of
Default, Assignee shall have the right to exercise all the remedies of a secured
party under the California Uniform Commercial Code, including without limitation
the right to require Assignor to assemble the Collateral and any tangible
property in which Assignee has a security interest and to make it available to
Assignee at a place designated by Assignee, Assignee shall have a nonexclusive,
royalty free license to use the Copyrights, Patents and Trademarks to the extent
reasonably necessity to permit Assignee to exercise its rights and remedies upon
the occurrence of an Event of Default. Assignor will pay any expenses
(including reasonable attorney's fees) incurred by Assignee in connection with
the exercise of any of Assignee's rights hereunder, including without
limitation any expenses incurred in disposing of the Collateral.  All of
Assignee's rights and remedies with respect to the Collateral shall be 
cumulative.

        9.      INDEMNITY. Assignor agrees to defend, indemnify and hold
harmless Assignee and its officers, employees, and agents against: (a) all
obligations, demands, claims, and liabilities claimed or asserted by any other
party on connection with the transactions contemplated by this Agreement, and
(b) all losses or expenses in any way suffered, incurred, or paid by Assignee as
a result of or in any way arising out of, following or consequential to
transactions between Assignee and Assignor, whether under this Assignment or
otherwise (including without limitation, reasonable attorneys fees and
reasonable expenses), except for losses arising from or out of Assignee's gross
negligence of willful misconduct.

        10.     REASSIGNMENT. At such time as Assignor shall completely satisfy
all of the obligations secured hereunder, Assignee shall execute and deliver to
Assignor all deed, assignments, and other instruments as may necessary or proper
to reinvest in Assignor full title to the property assigned hereunder, subject
to any disposition thereof which may have been made by Assignee pursuant hereto.

        11.     COURSE OF DEALING. No course of dealing, nor any failure to
exercise, nor any delay in exercising any right, power or privilege hereunder
shall operate as a waiver thereof.

        12.     ATTORNEYS' FEES. If any action relating to this Assignment is
brought by either party hereto against the other party, the prevailing party
shall be entitled to recover reasonable attorneys fees, costs and disbursements.

        13.     AMENDMENTS. This Assignment may be amended only by a written
instrument signed by both parties hereto.


<PAGE>   33
     14.  COUNTERPARTS. This Assignment may be executed in two or more
counterparts, each of which shall be deemed an original but all of which
together shall constitute the same instrument.

     15.  CALIFORNIA LAW AND JURISDICTION. This Assignment shall be governed by
the laws of the State of California, without regard for choice of law
provisions. Assignor and Assignee consent to the nonexclusive jurisdiction of
any state or federal court located in Santa Clara County, California.

     16.  CONFIDENTIALITY. In handling any confidential information, Assignee
shall exercise the same degree of care that it exercises with respect to its own
proprietary information of the same types to maintain the confidentiality of any
non-public information thereby received or received pursuant to this Assignment
except that the disclosure of this information may be made (i) to the affiliates
of the Assignee, (ii) to prospective transferee or purchasers of an interest in
the obligations secured hereby, provided that they have entered into comparable
confidentiality agreement in favor of Assignor and have delivered a copy to
Assignor, (iii) as required by law, regulation, rule or order, subpoena judicial
order or similar order and (iv) as may be required in connection with the
examination, audit or similar investigation of Assignee.

IN WITNESS WHEREOF, the parties hereto have executed this Assignment on the day
and year first above written.

ADDRESS OF ASSIGNOR:                    ASSIGNOR:

3865 North Business Center Drive        VENTANA MEDICAL SYSTEMS, INC.
Tucson, Arizona 85705
                                        By:    /s/ R. MICHAEL RODGERS
                                               ------------------------
                                        Name:  R. Michael Rodgers
                                               ------------------------
                                        Title: Vice President
                                               ------------------------




ADDRESS OF ASSIGNEE:                    ASSIGNEE:

1731 Embarcadero Road, Suite 220        Silicon Valley Bank
Palo Alto, California 94303
                                        By:    /s/ DEBRA R. GUERIN   
                                               ------------------------
                                        Name:  Debra R. Guerin   
                                               ------------------------
                                        Title: Vice President/Mgr
                                               National Accts. Services
                                               ------------------------




                                      -5-
<PAGE>   34
Exhibit "A" attached to that certain Collateral Assignment, Patent Mortgage and
Security Agreement dated February 20, 1995.

                                   EXHIBIT "A"
                                   COPYRIGHTS


SCHEDULE A - ISSUED COPYRIGHTS
<TABLE>
<CAPTION>

      COPYRIGHT                 REGISTRATION                 DATE OF
     DESCRIPTION                   NUMBER                    ISSUANCE
     -----------                ------------                 ---------
<S>                             <C>                          <C>
     NONE

</TABLE>



SCHEDULE B - PENDING COPYRIGHT APPLICATIONS

<TABLE>
<CAPTION>
                                                                FIRST DATE
     COPYRIGHT       APPLICATION     DATE OF      DATE OF       OF PUBLIC
    DESCRIPTION        NUMBER        FILING       CREATION     DISTRIBUTION
    -----------      -----------     -------      --------     ------------
<S>                  <C>             <C>          <C>          <C>
    NONE
</TABLE>


SCHEDULE C - UNREGISTERED COPYRIGHTS (Where No Copyright Application is Pending)

<TABLE>
<CAPTION>

                                                              DATE AND
                                                             RECORDATION
                                                               NUMBER
                                          ORIGINAL        OF ASSIGNMENT TO
                                          AUTHOR OR      ORIGINAL AUTHOR OR
                                          OWNER OF          ASSIGNOR (IF
                          FIRST DATE      COPYRIGHT      OWNER OF COPYRIGHT
 COPYRIGHT     DATE OF        OF        (IF DIFFERENT     IS DIFFERENT FROM
DESCRIPTION   CREATION   DISTRIBUTION    FROM ASSIGNOR        ASSIGNOR
- ----------    --------   ------------   --------------   ------------------
<S>           <C>        <C>            <C>              <C>
NONE
</TABLE>

<PAGE>   35
Exhibit "B" attached to that certain Collateral Assignment, Patent Mortgage and
Security Agreement dated February 20, 1995.

                                   EXHIBIT "B"
                                     PATENTS

<TABLE>
<CAPTION>
PATENT
DESCRIPTION                            DOCKET NO.     COUNTRY      SERIAL NO.     FILING DATE      STATUS
- -----------                            ----------     -------    ------------     -----------     -------
<S>                                    <C>              <C>      <C>              <C>             <C>
Immunohistochemical Staining
Method and Reagants Therefor             M-1654          US       07/488348         03/02/90      Granted

Immunohistochemical Staining                                                    
Method and Reagants Therefor           M-1654-1P         CA       2077451-7         02/27/91      Pending

Immunohistochemical Staining                                                   
Method and Reagants Therefor           M-1654-1P         EP       91905916.2        02/27/91      Pending

Immunohistochemical Staining
Method and Reagants Therefor           M-1654-1P         JP       505979/91         02/27/91      Pending

Immunohistochemical Staining
Method and Reagants Therefor           M-1654-1P         US       07/924053         08/31/92      Granted

Improved Immunohistochemical
Staining Method and Reagants
Therefor                               M-1654-2D         US       08/212415         03/11/94      Allowed

Automated Biological Reaction
Apparatus                              M-1665-1P         CA       2077452-5         02/28/91      Pending

Automated Biological Reaction
Apparatus                              M-1665-1P         EP       91906210.9        02/28/91      Pending

Automated Biological Reaction
Apparatus                              M-1665-1P         JP       505990/91         02/28/91      Pending

Liquid Dispenser                         M-1767          CA         2116101         09/04/92      Pending

Liquid Dispenser                         M-1767          EP       92920004.6        09/04/92      Pending

Liquid Dispenser                         M-1767          JP       506079/93         03/03/94      Pending

Liquid Dispenser                         M-1767          US       07/762327         09/18/91      Granted

High Temperature Evaporation
Inhibitor Liquid                         M-2450          US       08/155935         11/15/93      Pending


High Temperature Evaporation
Inhibitor Liquid                         M-2450         PCT      US94/12627         11/02/94      Pending


Bisulfite-Based Tissue Fixative          M-2539          US       08/152864         11/15/93      Allowed

Biotin/Avidin Formulation                M-2599          US       08/152864         11/15/93      Pending
</TABLE>


<PAGE>   36
                                 EXHIBIT "B"
                                   PATENTS

<TABLE>
<CAPTION>
PATENT DESCRIPTION                      DOCKET NO.       COUNTRY       SERIAL NO.       FILING DATE       STATUS
- ----------------------------------      ----------       -------       ----------       -----------       ------
<S>                                     <C>              <C>           <C>              <C>               <C>
Automated Biological Reaction           M-1665-2C          US          08/352966         12/09/94         Pending
Apparatus

Specimen Slide with Reagent              M-3164            US           Applied          02/17/95         Pending
Channel and Method for Using
Same
</TABLE>

                                      -2-
<PAGE>   37
Exhibit "C" attached to that certain Collateral Assignment, Patent Mortgage and
Security Agreement dated February 20, 1995.


                                   EXHIBIT "C"

                                   TRADEMARKS
<TABLE>
<CAPTION>

   TRADEMARK
  DESCRIPTION         COUNTRY        SERIAL NO.        REG. NO        STATUS
  -----------         -------        ----------        -------        ------
<S>                   <C>            <C>               <C>            <C>
  NONE
</TABLE>
<PAGE>   38
- --------------------------------------------------------------------------------

                            BIO TEK SOLUTIONS, INC.

                          GUARANTOR SECURITY AGREEMENT

- --------------------------------------------------------------------------------
<PAGE>   39
                               TABLE OF CONTENTS


                                                                            PAGE
                                                                            ----

1.   DEFINITIONS AND CONSTRUCTION..........................................   1
     1.1  Definitions......................................................   1
     1.2  Accounting Terms.................................................   4

2.   CREATION OF SECURITY INTEREST ........................................   4
     2.1  Grant of Security Interest ......................................   4
     2.2  Delivery of Additional Documentation Required ...................   4
     2.3  Right to Inspect ................................................   4

3.   REPRESENTATIONS AND WARRANTIES .......................................   4
     3.1  Due Organization and Qualification ..............................   4
     3.2  Due Authorization; No Conflict ..................................   4
     3.3  No Prior Encumbrances ...........................................   4
     3.4  Name; Location of Chief Executive Office ........................   4
     3.5  Litigation ......................................................   5
     3.6  Solvency ........................................................   5
     3.7  Regulatory Compliance ...........................................   5
     3.8  Environmental ...................................................   5
     3.9  Taxes ...........................................................   5
     3.10 Government Consents .............................................   5
     3.11 Full Disclosure .................................................   5

4.   AFFIRMATIVE COVENANTS ................................................   5
     4.1  Good Standing ...................................................   6
     4.2  Government Compliance ...........................................   6
     4.3  Inventory; Returns ..............................................   6
     4.4  Taxes ...........................................................   6
     4.5  Insurance .......................................................   6
     4.6  Further Assurances ..............................................   6

5.   NEGATIVE COVENANTS ...................................................   7
     5.1  Dispositions ....................................................   7
     5.2  Change in Business ..............................................   7
     5.3  Mergers or Acquisitions .........................................   7
     5.4  Indebtedness ....................................................   7
     5.5  Encumbrances ....................................................   7
     5.6  Distributions ...................................................   7
     5.7  Investments .....................................................   7
     5.8  Transactions with Affiliates ....................................   7
     5.9  Subordinated Debt ...............................................   7
     5.10 Inventory .......................................................   7
     5.11 Compliance ......................................................   8

6.   EVENTS OF DEFAULT ....................................................   8
     6.1  Payment Default .................................................   8
     6.2  Covenant Default ................................................   8
     6.3  Material Adverse Change .........................................   8
     6.4  Attachment ......................................................   8
     6.5  Insolvency ......................................................   9

                                      -i-
<PAGE>   40
                               TABLE OF CONTENTS
                                  (CONTINUED)


                                                                     PAGE
                                                                     ----

       6.6     Other Agreements..................................     9
       6.7     Subordinated Debt.................................     9
       6.8     Judgments.........................................     9
       6.9     Loan Agreement....................................     9
       6.10    Representations...................................     9


7.     BANK'S RIGHT'S AND REMEDIES...............................     9
       7.1     Rights and Remedies...............................     9
       7.2     Power of Attorney.................................    10
       7.3     Bank Expenses.....................................    10
       7.4     Bank's Liability for Collateral...................    10
       7.5     Remedies Cumulative...............................    11
       7.6     Demand; Protest...................................    11

8.     NOTICES...................................................    11

9.     CHOICE OF LAW AND VENUE; JURY TRIAL WAIVER................    11

10.    GENERAL PROVISIONS........................................    12
       10.1    Successors and Assigns............................    12
       10.2    Indemnification...................................    12
       10.3    Time of Essence...................................    12
       10.4    Severability of Provisions........................    12
       10.5    Amendments in Writing, Integration................    12
       10.6    Counterparts......................................    12
       10.7    Survival..........................................    12




                                     -ii-
<PAGE>   41
     This SECURITY AGREEMENT is entered into as of March 22, 1996 by and between
SILICON VALLEY BANK ("Bank") and BIO TEK SOLUTIONS, INC. ("Guarantor").


                                    RECITALS

     Ventana Medical Systems, Inc. wishes to obtain credit from time to time
from Bank pursuant to a Loan and Security Agreement, as amended by an Amendment
to Loan and Security Agreement of even date (the "Loan Agreement"). Bank has
agreed to enter into the Loan Agreement, provided Guarantor guarantees payment
and performance obligations under the Loan Agreement in accordance with the
terms of the Guaranty, and secures the Guaranty pursuant to the terms of this
Agreement.


                                   AGREEMENT

     The parties agree as follows:

     1.   DEFINITIONS AND CONSTRUCTION

          1.1  Definitions.  As used in this Agreement, the following terms
shall have the following definitions.

               "Bank Expenses" means all:  reasonable costs or expenses 
(including reasonable attorneys' fees and expenses) incurred in connection with
the preparation, negotiation, administration, and enforcement of the Loan
Documents; and Bank's reasonable attorneys' fees and expenses incurred in
amending, enforcing or defending the Loan Documents, whether or not suit is
brought.

               "Business Day" means any day that is not a Saturday, Sunday, or
other day on which banks in the State of California are authorized or required
to close.

               "Code" means the California Uniform Commercial Code.

               "Collateral" means the property described on Exhibit A attached
hereto.

               "Contingent Obligation" means, as applied to any Person, any
direct or indirect liability, contingent or otherwise, of that Person with
respect to any indebtedness, lease, dividend, letter of credit or other
obligation of another, including without limitation, any such obligation
directly or indirectly guaranteed, endorsed, co-made or discounted or sold with
recourse by that Person, or in respect of which that Person is otherwise
directly or indirectly liable; provided, however, that the term "Contingent
Obligation" shall not include endorsements for collection or deposit in the
ordinary course of business. The amount of any Contingent Obligation shall be
deemed to be an amount equal to the stated or determined amount of the primary
obligation in respect of which such Contingent Obligation is made or, if not
stated or determinable, the maximum reasonably anticipated liability in respect
thereof as determined by such Person in good faith; provided, however, that such
amount shall not in any event exceed the maximum amount of the obligations under
the guarantee or other support arrangement.

               "Equipment" means machinery, equipment, tenant improvements,
furniture, fixtures, vehicles, tools, parts and attachments.
<PAGE>   42
                     "ERISA" means the Employment Retirement Income Security Act
of 1974, as amended, and the regulations thereunder.

                     "GAAP" means generally accepted accounting principles as in
effect from time to time.

                     "Guarantor's Books" means all of Guarantor's books and
records including ledgers; records concerning Guarantor's assets or liabilities,
the Collateral, business operations or financial condition; and all computer
programs, or tape files, and the equipment, containing such information.

                     "Guaranty" means the unconditional guaranty executed by
Guarantor for the benefit of Bank, as amended from time to time.

                     "Indebtedness" means (a) all indebtedness for borrowed
money or the deferred purchase price of property or services, including without
limitation reimbursement and other obligations with respect to surety bonds and
letters of credit, (b) all obligations evidenced by notes, bonds, debentures or
similar instruments, (c) all capital lease obligations and (d) all Contingent
Obligations.

                     "Insolvency Proceeding" means any proceeding commenced by
or against any person or entity under any provision of the United States
Bankruptcy Code, as amended, or under any other bankruptcy or insolvency law,
including assignments for the benefit of creditors, formal or informal
moratoria, compositions, extension generally with its creditors, or proceedings
seeking reorganization, arrangement, or other relief.

                     "IRC" means the Internal Revenue Code of 1986, as amended,
and the regulations thereunder.

                     "Lien" means any mortgage, hen, security interest or other
encumbrance.

                     "Loan Documents" means, collectively, this Agreement, the
Guaranty executed by Guarantor, and any other agreement entered into between
Guarantor and Bank, all as amended or extended from time to time.

                     "Material Adverse Effect" means a material adverse effect
on the business operations or financial condition of Guarantor and its
Subsidiaries taken as a whole.

                     "Negotiable Collateral" means all of Guarantor's present
and future letters of credit of which it is a beneficiary, notes, drafts,
instruments, securities, documents of title, and chattel paper, and Guarantor's
Books relating to any of the foregoing.

                     "Obligations" means all amounts owned to the Bank by
Guarantor pursuant to the Guaranty, this Agreement or any other agreement,
whether absolute or contingent, due or to become due, now existing or hereafter
arising.

                     "Permitted Indebtedness" means:

                     (a)    Existing Indebtedness disclosed to Bank in writing;

                     (b)    Subordinated Debt; and



                                      -2-
<PAGE>   43
                     (c)    Indebtedness to trade creditors incurred in the
ordinary course of business.

                     "Permitted Investment" means:

                     (a)    Investments existing on the Closing Date disclosed
to Bank in writing; and

                     (b)    (i)  marketable direct obligations issued or
unconditionally guaranteed by the United States of America or any agency or any
State thereof maturing within one (1) year from the date of acquisition thereof,
(ii) commercial paper maturing no more than (1) year from the date of creation
thereof and currently having the highest rating obtainable from either Standard
& Poor's Corporation or Moody's Investors Service, Inc., and (iii) certificates
of deposit maturing no more than one (1) year from the date of investment
therein issued by Bank.

                     "Permitted Liens" means the following.

                     (a)    Any Liens existing as of the date hereof and
disclosed to Bank in writing or arising under this Agreement;

                     (b)    Liens for taxes, fees, assessments or other
governmental charges or levies, either not delinquent or being contested in good
faith by appropriate proceedings, provided the same have no priority over any of
Bank's security interests;

                     (c)    Liens (i) upon or in any equipment acquired or held
by the Guarantor or any of its subsidiaries to secure the purchase price of such
equipment or indebtedness incurred solely for the purpose of financing the
acquisition of such equipment, or (ii) existing on such equipment at the time of
its acquisition, provided that the Lien is confined solely to the property so
acquired and improvements thereon, and the proceeds of such equipment; and

                     (d)    Liens incurred in connection with the extension,
renewal or refinancing of the indebtedness secured by Liens of the type
described in clauses (a) through (d) above, provided that any extension, renewal
or replacement Lien shall be limited to the property encumbered by the existing
Lien and the principal amount of the indebtedness being extended, renewed or
refinanced does not increase.

                     "Person" means any individual, sole proprietorship,
partnership, joint venture, trust, unincorporated organization, association,
corporation, institution, public benefit corporation, firm, joint stock company,
estate, entity or governmental agency.

                     "Subordinated Debt" means any debt incurred by Guarantor
after the date hereof that is subordinated to the debt owing by Guarantor to
Bank on terms acceptable to Bank (and identified as being such by the Company
and the Bank).

                     "Subsidiary" means any corporation or partnership in which
(i) any general partnership interest or (ii) more than 50% of the stock of which
by the terms thereof ordinary voting power to elect the Board of Directors,
managers or trustees of the entity shall, at the time as of which any
determination is being made, is owned by Guarantor, either directly or through
an Affiliate.



                                      -3-
<PAGE>   44
            1.2 Accounting Terms. All accounting terms not specifically, defined
herein shall be construed in accordance with GAAP and all calculations made
hereunder shall be made in accordance with GAAP. When used herein, the terms
"financial statements" shall include the notes and schedules thereto.

         2. CREATION OF SECURITY INTEREST

            2.1 Grant of Security Interest. Guarantor grants to Bank a
continuing security interest in all presently existing and hereafter acquired or
arising Collateral in order to secure prompt repayment of any and all
Obligations and in order to secure prompt performance by Guarantor of each of
its covenants and duties under the Loan Documents. Such security interest
constitutes a valid, first priority security interest in the presently existing
Collateral, and will constitute a valid, first priority security interest in
Collateral acquired after the date hereof.

            2.2 Delivery of Additional Documentation Required. Guarantor shall
from time to time execute and deliver to Bank, at the request of Bank, all
Negotiable Collateral, all financing statements and other documents that Bank
may reasonably request, in form satisfactory to Bank, to perfect and continue
perfected Bank's security interests in the Collateral and in order to fully
consummate all of the transactions contemplated under the Loan Documents.

            2.3 Right to Inspect. Bank (through any of its officers, employees,
or agents) shall have the right, upon reasonable prior notice, from time to time
during Guarantor's usual business hours, to inspect Guarantor's Books and to
make copies thereof and to check, test, and appraise the Collateral in order to
verify Guarantor's financial condition or the amount, condition of, or any other
matter relating to, the Collateral.

         3. REPRESENTATIONS AND WARRANTIES

            Guarantor represents and warrants as follows:

            3.1 Due Organization and Qualification. Guarantor is a corporation
duly existing and in good standing under the laws of its state of incorporation
and qualified and licensed to do business in, and is in good standing in, any
state in which the conduct of its business or its ownership of property requires
that it be so qualified.

            3.2 Due Authorization; No Conflict. The execution, delivery, and
performance of the Loan Documents are within Guarantor's powers, have been duly
authorized and are not in conflict with nor constitute a breach of any provision
contained in Guarantor's Articles of Incorporation or Bylaws, nor will they
constitute an event of default under any material agreement to which Guarantor
is a party or by which Guarantor is bound. Guarantor is not in default under any
agreement to which it is a party or by which it is bound, which default could
have a Material Adverse Effect.

            3.3 No Prior Encumbrances. Guarantor has good and indefeasible title
to the Collateral, free and clear of Liens, except for Permitted Liens.

            3.4 Name; Location of Chief Executive Office. Except as disclosed in
the Schedule, Guarantor has not done business under any name other than that
specified on the signature page hereof. The chief executive office of Guarantor
is located at the address indicated in Section 10 hereof.

                                       -4-
<PAGE>   45
        3.5   Litigation. There are no actions or proceedings pending by or
against Guarantor before any court or administrative agency in which an adverse
decision could have a Material Adverse Effect or a material adverse effect on
Guarantor's interest or Bank's security interest in the Collateral. Guarantor
does not have knowledge of any such pending or threatened actions or
proceedings.
        
        3.6   Solvency. Guarantor is solvent and able to pay its debts
(including trade debts) as they mature.

        3.7   Regulatory Compliance. Guarantor has met the minimum funding
requirements of ERISA with respect to any employee benefit plans subject to
ERISA. No event has occurred resulting from Guarantor's failure to comply with
ERISA that is reasonably likely to result in Guarantor's incurring any
liability that could have a material adverse effect on the financial condition
or business operations of Guarantor. Guarantor is not an "investment company"
or a company of controlled" by an "investment company" within the meaning of the
Investment Company Act of 1940. Guarantor is not engaged principally, or as one
of the important activities, in the business of extending credit for the
purpose of purchasing or carrying margin stock (within the meaning of
Regulations G, T and U of the Board of Governors of the Federal Reserve
System). Guarantor has complied with all the provisions of the Federal Fair
Labor Standards Act.

        3.8   Environment. Condition. None of Guarantor's properties or assets
has ever been used by Guarantor or, to the best of Guarantor's knowledge, by
previous owners or operators, in the disposal of, or to produce, store, handle,
treat, release, or transport, any hazardous waste or hazardous substance other
than in accordance with applicable law; to the best of Guarantor's knowledge,
none of Guarantor's properties or assets has ever been designated or identified
in any manner pursuant to any environmental protection statute as a hazardous
waste or hazardous substance disposal site, or a candidate for closure pursuant
to any environmental protection statute; no lien arising under any
environmental protection statute has attached to any revenues or to any real or
personal property owned by Guarantor; and Guarantor has not received a summons,
citation, notice, or directive from the Environmental Protection Agency or any
other federal or state governmental agency concerning any action or omission by
Guarantor resulting in the releasing, or otherwise disposing of hazardous waste
or hazardous substances into the environment.

        3.9   Taxes. Guarantor has filed or caused to be filed all tax returns
required to be filed, and has paid, or has made adequate provision for the
payment of, all taxes reflected therein.

        3.10   Government Consents. Guarantor has obtained all consents,
approvals and authorizations of, made all declarations or filings with, and
given all notices to, all governmental authorities that are necessary for the
continued operation of Guarantor's business as currently conducted.

        3.11   Full Disclosure. No representation, warranty or other statement
made by Guarantor in any certificate or written statement furnished to Bank
contains any untrue statement of a material fact or omits to state a material
fact necessary in order to make the statements contained in such certificates
or statements not misleading.

        4.   AFFIRMATIVE COVENANTS

        Guarantor covenants and agrees that, until payment in full of all
outstanding Obligations under the Loan Agreement and this Agreement, and for so
long as Bank may have any commitment to make an Advance under the Loan
Agreement, Guarantor shall do all of the following.

                                      -5-


<PAGE>   46
        4.1   Good Standing. Guarantor shall maintain its corporate existence
and its good standing in its jurisdiction of incorporation and maintain
qualification in each jurisdiction in which the failure to so qualify could
have a Material Adverse Effect. Guarantor shall maintain in force all licenses,
approvals and agreements, the loss of which could have a Material Adverse 
Effect.

        4.2   Government Compliance. Guarantor shall comply with all statutes,
laws, ordinances and government rules and regulations to which it is subject,
noncompliance with which could have a Material Adverse Effect or a material
adverse effect on the Collateral or the priority of Bank's Lien on the 
Collateral.

        4.3   Inventory; Returns. Guarantor shall keep all Inventory in good
and marketable condition, free from all material defects. Returns and
allowances, if any, as between Guarantor and its account debtors shall be on
the same basis and in accordance with the usual customary practices of
Guarantor, as they exist at the time of the execution and delivery of this
Agreement. Guarantor shall promptly notify Bank of all returns and recoveries
and of all disputes and claims, where the return, recovery, dispute or claim
involves more that Fifty Thousand Dollars ($50,000).

        4.4   Taxes. Guarantor shall make due and timely payment or deposit of
all material federal, state, and local taxes, assessments, or contributions
required of it by law, and will execute and deliver to Bank, on demand,
appropriate certificates attesting to the payment or deposit thereof; and
Guarantor will make timely payment or deposit of all material tax payments and
withholding taxes required of it by applicable laws, including, but not limited
to, those laws concerning F.I.C.A., F.U.T.A., state disability, and local,
state, and federal income taxes, and will, upon request, furnish Bank with
proof satisfactory to Bank indicating that Guarantor has made such payments or
deposits; provided that Guarantor need not make any payment if the amount or
validity of such payment is contested in good faith by appropriate proceedings
and is reserved against (to the extent required by GAAP) by Guarantor.

        4.5   Insurance.

              (a)  Guarantor, at its expense, shall keep the Collateral
insured against loss or damage by fire, theft, explosion, sprinklers, and all
other hazards and risks, and in such amounts, as ordinarily insured against by
other owners in similar businesses conducted in the locations where Guarantor's
ownership and use of the Collateral in amounts and of a type that are customary
to businesses similar to Guarantors.

              (b)  AU such policies of insurance shall be in such form, with
such companies, and in such amounts as reasonably satisfactory to Bank. All
such policies of property insurance shall contain a tender's loss payable
endorsement, in a form satisfactory to Bank, showing Bank as an additional loss
payee thereof and all liability insurance policies shall show the Bank as an
additional insured, and shall specify that the insurer must give at least
twenty (20) days notice to Bank before canceling its policy for any reason.
Guarantor shall deliver to Bank certified copies of such policies of insurance
and evidence of the payments of all premiums therefor. All proceeds payable
under any such policy shall, at the option of Bank, be payable to Bank to be
applied on account of the Obligations.

        4.6   Further Assurances. At any time and from time to time Guarantor
shall execute and deliver such further instruments and take such further action
as may reasonably be requested by Bank to effect the purposes of this Agreement.

                                      -6-
<PAGE>   47
      5.    NEGATIVE COVENANTS

            Guarantor covenants and agrees that until payment in full of all
outstanding Obligations under the Loan Agreement and this Agreement, Guarantor
will not do any of the following-

            5.1     Dispositions.  Convey, sell, lease, transfer or otherwise
dispose of (collectively, a "Transfer"), all or any part of its business or
property, other than: (i) Transfers in the ordinary course of business; (ii)
Transfers of non-exclusive licenses and similar arrangements for the use of the
property of Guarantor or its Subsidiaries; or (iii) Transfers of worn-out or
obsolete Equipment.

            5.2     Change in Business.  Engage in any business other than the
businesses currently engaged in by Guarantor and any business substantially
similar or related thereto (or incidental thereto), or suffer a material change
in Guarantor's ownership.  Guarantor will not, without thirty (30) days prior
written notification to Bank, relocate its chief executive office.

            5.3     Mergers or Acquisitions.  Merge or consolidate, or permit
any of its Subsidiaries to merge or consolidate, with or into any other business
organization, or acquire, or permit any of its Subsidiaries to acquire, all or
substantially all of the capital stock or property of another Person.

            5.4     Indebtedness.  Create, incur, assume or be or remain liable
with respect to any Indebtedness other than Permitted Indebtedness.

            5.5     Encumbrances.  Create, incur, assume or suffer to exist any
Lien with respect to any of its property, or assign or otherwise convey any
right to receive income, including the sale of any Accounts, or permit any of
its Subsidiaries so to do, except for Permitted Liens.

            5.6     Distributions.  Pay any dividends or make any other
distribution or payment on account of or in redemption, retirement or purchase
of any capital stock.

            5.7     Investments.  Directly or indirectly acquire or own any
beneficial interest in (including stock, partnership interest, or other
securities of), or make any loan, advance, or capital contribution to, any
Person, or permit any of its Subsidiaries so to do, other than Permitted
Investments.

            5.8     Transactions with Affiliates.  Directly or indirectly enter
into or permit to exist any material transaction with any Affiliate of Guarantor
except for transactions that are in the ordinary course of Guarantor's business,
upon fair and reasonable ten-ns that are no less favorable to Guarantor than
would be obtained in an arm's length transaction with a nonaffiliated Person or
entity.

            5.9     Subordinated Debt.  Make any payment in respect of any
Subordinated Debt, or permit any of its Subsidiaries to make any such payment,
except in compliance with the ten-ns of such Subordinated Debt, or amend any
provision contained in any documentation relating to the Subordinated Debt
without Bank's prior written consent.

            5.10    Inventory.  Store the Inventory with a bailee, warehouseman,
or similar party unless Bank has received a pledge of the warehouse receipt
covering such Inventory.  Except of Inventory sold in the ordinary course of
business and except for such other locations as Bank may approve in writing,
Guarantor shall keep the Inventory only at the location set forth in Section 10
hereof and such other locations of which


                                      -7-
<PAGE>   48
Guarantor gives Bank prior written notice as as to which Guarantor signs and
files a financing statement where needed to perfect Bank's security interest.

            5.11    Compliance.  Become an "investment company" controlled by an
"investment company," within the meaning of the Investment Company Act of 1940,
or become principally engaged in, or undertake as one of its important
activities, the business of extending credit for the purpose of purchasing or
carrying margin stock, or use the proceeds of any Advance for such purpose. Fail
to meet the minimum funding requirements of ERISA, permit a Reportable Event or
Prohibited Transaction, as defined in ERISA, to occur, fail to comply with the
Federal Fair Labor Standards Act or violate any law or regulation, which
violation could have a Material Adverse Effect or a material adverse effect on
the Collateral or the priority of Bank's Lien on the Collateral, or permit any
of its Subsidiaries to do any of the foregoing.

      6.    EVENTS OF DEFAULT

            Any one or more of the following events shall constitute an Event of
Default by Guarantor under the Agreement:

            6.1     Payment Default.  If Guarantor fails to pay any amount under
the Guaranty when due and payable.

            6.2     Covenant Default.  If Guarantor violates any of the
covenants contained in Article 5 of this Agreement, or fails or neglects to
perform, keep, or observe any other material term, provision, condition,
covenant, or agreement contained in the Guaranty or this Agreement, in any of
the Loan Documents, or in any other present or future agreement between
Guarantor and Bank and as to any default under such other term, provision,
condition, covenant or agreement that can be cured, has failed to cure such
default within ten (10) days after the Guarantor receives notice thereof or any
officer of Guarantor become aware thereof (provided that no Advances will be
required to be made during such cure period); provided, however, that if the
default cannot by its nature be cured within the ten (10) day period or cannot
after diligent attempts by Guarantor be cured within such ten (10) day period,
and such default is likely to be cured within a reasonable time, then Guarantor
shall have an additional reasonable period (which shall not in any case exceed
thirty (30) days) to attempt to cure such default, and within such reasonable
time period the failure to have cured such default shall not be deemed an Event
of Default;

            6.3     Material Adverse Change.  If there occurs a material adverse
change in Guarantor's business, or if there is a material impairment of the
prospect of repayment of any portion of the Obligations owing to Bank or a
material impairment of the value or priority of Bank's security interests in the
Collateral;

            6.4     Attachment.  If any material portion of Guarantor's assets
is attached, seized, subjected to a writ or distress warrant, or is levied upon,
or comes into the possession of any trustee, receiver or person acting in a
similar capacity and such attachment, seizure, writ or distress warrant or levy
has not been removed, discharged or rescinded within ten (10) days, or if
Guarantor is enjoined, restrained, or in any way prevented by court order from
continuing to conduct all or any material part of its business affairs, or if a
judgment or other claim becomes a lien or encumbrance upon any material portion
of Guarantor's assets, or if a notice of hen, levy, or assessment is filed of
record with respect to any of Guarantor's assets by the United States
Government, or any department, agency, or instrumentality thereof, or by any
state, county, municipal, or governmental agency, and the same is not paid
within ten (10) days after Guarantor receives notice thereof, provided that none
of the foregoing shall constitute an Event of Default where such action or event
is stayed or an adequate bond has been posted pending a good faith contesting by
Guarantor;


                                      -8-
<PAGE>   49
            6.5     Insolvency.  If an Insolvency Proceeding is commenced by
Guarantor, or if an Insolvency Proceeding is commenced against Guarantor is not
dismissed or stayed within the (10) days;

            6.6     Other Agreements.  If there is a default in any agreement
to which Guarantor is a party with a third party or parties resulting in a right
by such third party or parties, whether or not exercised, to accelerate the
maturity of any Indebtedness in an amount in excess of One Hundred Thousand
Dollars ($100,000) or which could have a Material Adverse Effect;

            6.7     Subordinated Debt.  If Guarantor makes any payment on
account of Subordinated Debt, except to the extent such payment is allowed under
any subordination agreement entered into with Bank;

            6.8     Judgments.  If a judgment or judgments for the payment of
money in an amount, individually or in the aggregate, of at least Fifty Thousand
Dollars ($50,000) shall be rendered against Guarantor and shall remain
unsatisfied and unstayed for a period of ten (10) days;

            6.9     Loan Agreement.  ff an Event of Default occurs under the
Loan Agreement; or

            6.10    Representations.  If any material misrepresentation or
material misstatement exists now or hereafter in any warranty or representation
set forth herein or in any certificate delivered to Bank by any Responsible
Officer pursuant to this Agreement or to induce Bank to enter into this
Agreement or any other Loan Document.

      7.    BANK'S RIGHTS AND REMEDIES

            7.1     Rights and Remedies.  Upon the occurrence and during the
continuance of an Event of Default, Bank may, at its election, without notice of
its election and without demand, do any one or more of the following, all of
which are authorized by Guarantor:

                    (a)    Declare all Obligations, whether evidenced by this
Agreement, by any of the other Loan Documents, or otherwise, immediately due and
payable (provided that upon the occurrence of an Event of Default described in
Section 6.5 all Obligations shall become immediately due and payable without any
action by Bank);

                    (b)    Settle or adjust disputes and claims directly with
account debtors for amounts, upon terms and in whatever order that Bank
reasonably considers advisable;

                    (c)    Without notice to or demand upon Guarantor, make such
payments and do such acts as Bank considers necessary or reasonable to protect
its security interest in the Collateral.  Guarantor agrees to assemble the
Collateral if Bank so requires, and to make the Collateral available to Bank as
Bank may designate.  Guarantor author Bank to enter the premises where the
Collateral is located, to take and maintain possession of the Collateral, or any
part of it, and to pay, purchase, contest, or compromise any encumbrance,
charge, or lien which in Bank's determination appears to be prior or superior to
its security interest and to pay all expenses incurred in connection therewith.
With respect to any of Guarantor's owned premises, Guarantor hereby grants Bank
a license to enter into possession of such premises and to occupy the same,
without charge, in order to exercise any of Bank's rights or remedies provided
herein, at law, in equity, or otherwise;




                                      -9-




<PAGE>   50
               (d)  Without notice to Guarantor set off and apply to the
Obligations any and all 4(i) balances and deposits of Guarantor held by Bank, or
(ii) indebtedness at any time owing to or for the credit or the account of
Guarantor held by Bank;

               (e)  Ship, reclaim, recover, store, finish, maintain, repair,
prepare for sale, advertise for sale, and sell (in the manner provided for
herein) the Collateral. Bank is hereby granted a license or other right, solely
pursuant to the provisions of this Section 7.1, to use, without charge,
Guarantor's labels, patents, copyrights, rights of use of any name, trade
secrets, trade names, trademarks, service marks, and advertising matter, or any
property of a similar nature, as it pertains to the Collateral, in completing
production of, advertising for sale, and selling any Collateral and, in
connection with Bank's exercise of its rights under this Section, Guarantor's
rights under all licenses and all franchise agreements shall inure to Bank's
benefit;

               (f)  Sell the Collateral at either a public or private sale, or
both, by way of one or more contracts or transactions, for cash or on terms, in
such manner and at such places (including Guarantor's premises) as Bank
determines is commercially reasonable;

               (g)  Bank may credit bid and purchase at any public sale; and

               (h)  Any deficiency that exists after disposition of the
Collateral as provided above will be paid immediately by Guarantor.

          7.2  Power of Attorney. Effective only upon the occurrence and during
the continuance of an Event of default, Guarantor hereby irrevocably and
appoints Bank (and any of Bank's designated officers, or employees) as
Guarantor's true and lawful attorney to: (a) send requests for verification of
Accounts or notify account debtors of Bank's security interest in the Accounts;
(b) endorse Guarantor's name on any checks or other forms-ns of payment or
security that may come into Bank's possession; (c) sign Guarantor's name on any
invoice or bill of lading relating to any Account, drafts against account
debtors, schedules and assignments of Accounts, verifications of Accounts, and
notices to account debtors; (d) make, settle, and adjust all claims under and
decisions with respect to Guarantor's policies of insurance; and (e) settle and
adjust disputes and claims respecting the accounts directly with account
debtors, for amounts and upon terms which Bank determines to be reasonable;
provided Bank may exercise such power of attorney to sign the name of Guarantor
on any of the documents described in Section 2.2. regardless of whether an Event
of Default has occurred. The appointment of Bank as Guarantor's attorney in
fact, and each and every one of Bank's rights and powers, being coupled with an
interest, is irrevocable until all of the Obligations have been fully repaid and
performed and Bank's obligation to provide advances hereunder is terminated.

          7.3  Bank Expenses. If Guarantor fails to pay any amounts or furnish
any required proof of payment due to third persons or entities, as required
under the terms of this Agreement, then Bank may do any or all of the following:
(a) make payment of the same or any part thereof, or (b) obtain and maintain
insurance policies of the type discussed in this Agreement, and take any action
with respect to such policies as Bank deems prudent. Any amounts paid or
deposited by Bank shall constitute Bank Expenses, shall be immediately due and
payable, and shall bear interest at the then applicable rate hereinabove
provided, and shall be secured by the Collateral. Any payments made by Bank
shall not constitute an agreement by Bank to make similar payments in the future
or a waiver by Bank of any Event of Default under this Agreement.

          7.4  Bank's Liability for Collateral. So long as Bank complies with
reasonable banking practices, Bank shall not in any way or manner be liable or
responsible for: (a) the safekeeping of the Collateral; (b) any loss or damage
thereto occurring or arising in any manner or fashion from any cause; (c) any

                                      -10-
<PAGE>   51
diminution in the value thereof; or (d) any act or default or any carrier,
warehouseman, bailee, forwarding agency, or other person whomsoever. All risk
of loss, damage or destruction of the Collateral shall be borne by Guarantor.

                7.5  Remedies Cumulative.  Bank's rights and remedies under this
Agreement, the Loan Documents, and all other agreements shall be cumulative.
Bank shall have all other rights and remedies not inconsistent herewith as
provided under the Code, by law, or in equity. No exercise by Bank of one right
or remedy shall be deemed an election, and no waiver by Bank of any Event of
Default on Guarantor's part shall be deemed a continuing waiver. No delay by
Bank shall constitute a waiver, election, or acquiescence by it.

                7.6  Demand: Protest.  Guarantor waives demand, protest, notice
of protest, notice of default or dishonor, notice of payment and nonpayment,
notice of any default, nonpayment at maturity, release, compromise, settlement,
extension, or renewal of accounts, documents, instruments, chattel paper, and
guarantees at any time held by Bank on which Guarantor may in any way be
liable.  

        8.  NOTICES

            Unless otherwise provided in this Agreement, all notices or demands
by any party relating to this Agreement or any other agreement entered into in
connection herewith shall be in writing and (except for financial statements
and other informational documents which may be sent by first-class mail,
postage prepaid) shall be personally delivered or sent by certified mail,
postage prepaid, return receipt requested, or by prepaid telefacsimile to
Guarantor or to Bank, as the case may be, at its addresses set forth below:

            If to Guarantor:  Bio Tek Solutions, Inc.
                              3865 North Business Center Drive  
                              Tucson, AZ 85705
                              Attn: ___________________
                              FAX:  ___________________

            If to Bank:       Silicon Valley Bank
                              1731 Embarcadero Road, Suite 220
                              Palo Alto, CA 94303
                              Attn: Kevin Conway
                              FAX: (415) 812-0640

        The parties hereto may change the address at which they are to receive
notices hereunder, by notice in writing in the foregoing manner given to the
other. 

        9.  CHOICE OF LAW AND VENUE: JURY TRIAL WAIVER

                                  
            This Agreement shall be governed by, and construed in accordance
with, the internal laws of the State of California, without regard to principles
of conflicts of law. Each of Guarantor and Bank hereby submits to the exclusive
jurisdiction of the state and Federal courts located in the County of Santa
Clara, State of California. GUARANTOR AND BANK EACH HEREBY WAIVE THEIR
RESPECTIVE RIGHTS TO A JURY TRIAL OF ANY CLAIM OR CAUSE OF ACTION BASED UPON OR
ARISING OUT OF ANY OF THE LOAN DOCUMENTS OR ANY OF THE TRANSACTIONS
CONTEMPLATED THEREIN, INCLUDING CONTRACT CLAIMS, TORT CLAIMS, BREACH OF DUTY
CLAIMS, AND ALL OTHER COMMON LAW OR STATUTORY CLAIMS. EACH PARTY RECOGNIZES AND
AGREES THAT THE FOREGOING WAIVER CONSTITUTES A MATERIAL INDUCEMENT FOR IT TO
ENTER INTO THIS AGREEMENT. EACH PARTY REPRESENTS AND WARRANTS THAT IT HAS
REVIEWED THIS WAIVER WITH ITS LEGAL COUNSEL AND THAT IT KNOWINGLY AND
VOLUNTARILY WAIVES ITS JURY TRIAL RIGHTS FOLLOWING CONSULTATION WITH LEGAL
COUNSEL. 

                                      -11-
<PAGE>   52
        10. GENERAL PROVISIONS

                10.1 Successors and Assigns. This Agreement shall bind and
inure to the benefit of the respective successors and permitted assigns of each
of the parties; provided, however, that neither this Agreement nor any rights
hereunder may be assigned by Guarantor without Bank's prior written consent,
which consent may be granted or withheld in Bank's sole discretion. Bank shall
have the right without the consent of or notice to Guarantor to sell, transfer,
negotiate, or grant participation in all or any part of, or any interest in
Bank's obligations, rights and benefits hereunder.

                10.2 Indemnification. Guarantor shall defend, indemnify and
hold harmless Bank and its officers, employees, and agents against: (a) all
obligations, demands, claims, and liabilities claimed or asserted by any other
party in connection with the transactions contemplated by this Agreement; and
(b) all losses or Bank Expenses in any way suffered, incurred, or paid by Bank
as a result of or in any way arising out of, following, or consequential to
transactions between Bank and Guarantor whether under this Agreement, or
otherwise (including without limitation reasonable attorneys fees and
expenses), except for losses caused by Bank's gross negligence or willful 
misconduct.

                10.3 Time of Essence. Time is of the essence for the
performance of all obligations set forth in this Agreement.

                10.4 Severability of Provisions. Each provision of this
Agreement shall be severable from every other provision of this Agreement for
the purpose of determining the legal enforceability of any specific provision.

                10.5 Amendments in Writing, Integration. This Agreement cannot
be changed or terminated orally. AU prior agreements, understandings,
representations, warranties, and negotiations between the parties hereto with
respect to the subject matter of this Agreement, if any, are merged into this
Agreement and the Loan Documents.

                10.6 Counterparts. This Agreement may be executed in any number
of counterparts and by different parties on separate counterparts, each of
which, when executed and delivered, shall be deemed to be an original, and all
of which, when taken together, shall constitute but one and the same Agreement.

                10.7 Survival. AU covenants, representations and warranties
made in this Agreement shall continue in full force and effect so long as any
Obligations remain outstanding. The obligations of Guarantor to indemnify Bank
with respect to the expenses, damages, losses, costs and liabilities described
in Section 10.2 shall survive until all applicable statute of limitations
periods with respect to actions that may be brought against Bank have run.

        IN WHEREOF, the parties hereto have caused this Agreement to be
executed as of the date first above written.

                                BIO TEK SOLUTIONS, INC.

                                By: 
                                   ------------------------------------

                                Title: 
                                      ---------------------------------


                                SILICON VALLEY BANK


                                By: 
                                   ------------------------------------

                                Title: 
                                      ---------------------------------



                                      -12-

<PAGE>   53

                                   EXHIBIT A


        The Collateral shall consist of all right, title and interest of
Guarantor in and to the following:

        (a)  AU goods and equipment now owned or hereafter acquired, including,
without limitation, all machinery, fixtures, vehicles (including motor vehicles
and trailers), and any interest in any of the foregoing, and all attachments,
accessories, acccssions, replacements, substitutions, additions, and
improvements to any of the foregoing, wherever located;

        (b)  All inventory, now owned or hereafter acquired, including, without
limitation, an merchandise, raw materials, parts, supplies, packing and
shipping materials, work in process and finished products including such
inventory as is temporarily out of Guarantor's custody or possession or in
transit and including any returns upon any accounts or other proceeds,
including insurance proceeds, resulting from the sale of disposition of any of
the foregoing and any documents of title representing any of the above, and
Guarantor's Books relating to any of the foregoing;

        (c)  All contract rights and general intangibles now owned or hereafter
acquired, including, without limitation, goodwill, trademarks, service marks,
trade styles, trade names, patents, patent applications, leases, license
agreements, franchise agreements, blueprints, drawings, purchase orders,
customer lists, route lists, infringements, claims, computer programs, computer
discs, computer tapes, literature, reports, catalogs, design rights, income tax
refunds, payments of insurance and rights to payment of any kind;

        (d)  AU now existing and hereafter arising accounts, contract rights,
royalties, license rights and all other forms of obligations owing to Guarantor
arising out of the sale or lease of goods, the licensing of technology or the
rendering of services by Guarantor, whether or not earned by performance, and
any and all credit insurance, guaranties, and other security therefor, as well
as all merchandise returned to or recorded by Guarantor and Guarantor's Books
relating to any of the foregoing;

        (e)  All documents, cash, deposit accounts, securities, letters of
credit, certificates of deposit, instruments and chattel paper now owned or
hereafter acquired and Guarantor's Books relating to the foregoing;

        (f)  AU copyright rights, copyright applications, copyright
registrations and like protections in each work of authorship and derivative
work thereof, whether published or unpublished, now owned or hereafter
acquired; all trade secret rights, including all rights to unpatented
inventions, know-how, operating manuals, license rights and agreements and
confidential information, now owned or hereafter acquired; all mask work or
similar rights available for the protection of semiconductor chips, now owned
or hereafter acquired; all claims for damages by way of any past, present and
future infringement of any of the foregoing; and

        (g)  Any and all claims, rights and interests in any of the above and
all substitutions for, additions and accessions to and proceeds thereof.


                                      -13-



<PAGE>   1

                                                                    Exhibit 11.1

                         VENTANA MEDICAL SYSTEMS, INC.
                           NET LOSS PER COMMON SHARE

<TABLE>
<CAPTION>
                                                                                                  Three Months Ended
                                                     Year Ended December 31                            March 31
                                         ----------------------------------------------------------------------------------
                                             1993             1994             1995             1995               1996
                                         ----------------------------------------------------------------------------------
                                                                                                      (Unaudited)
<S>                                       <C>              <C>              <C>              <C>              <C>
Historical
- ----------
Net loss                                  (4,979,000)      (5,370,000)      (3,269,000)        (834,000)      (10,307,000)
Less accretion of preferred
  stock redemption requirement            (1,796,000)      (1,983,000)      (2,436,000)        (579,000)         (605,000)
                                         ----------------------------------------------------------------------------------
Net loss applicable to common stock       (6,775,000)      (7,353,000)      (5,705,000)      (1,413,000)      (10,912,000)
                                         ==================================================================================
Weighted average common shares
  outstanding                                857,191          917,179          957,280          903,013         1,119,455
Stock, options and warrants issued 
  within one year of initial
  filing (May 24, 1996)                    1,385,880        1,385,880        1,385,880        1,385,880         1,385,880
Weighted average common shares and
  common share equivalents               ----------------------------------------------------------------------------------
  outstanding during the period            2,243,071        2,303,059        2,343,160        2,288,893         2,505,335
                                         ==================================================================================
Net loss per share                            $(3.02)          $(3.19)          $(2.43)          $(0.62)           $(4.36)
                                         ==================================================================================

<CAPTION>
                                           Year Ended            Three Months Ended
                                           December 31                March 31
                                         --------------------------------------------------
                                               1995             1995               1996
                                         --------------------------------------------------
                                                                      (Unaudited)
<S>                                         <C>              <C>              <C>
Pro Forma                                
- ---------                                
Net loss                                    (3,269,000)        (834,000)      (10,307,000)
                                         ==================================================
Weighted average common shares           
  outstanding                                  957,280          903,013         1,119,455
Assumed conversion of Series A,          
  C, and D preferred shares                  6,579,489        6,499,219         6,648,290
Assumed exercise of Series D             
  warrants                                      49,893           49,893            49,893
Stock, options and warrants issued 
  within one year of initial      
  filing (May 24, 1996)                      1,385,880        1,385,880         1,385,880
                                         --------------------------------------------------
Weighted average common shares and       
  common share equivalents               
  outstanding during the period              8,972,542        8,838,005         9,203,518
                                         ==================================================
Net loss per share                              $(0.36)          $(0.09)           $(1.12)
                                         ==================================================
</TABLE>




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