BOSTON BIOMEDICA INC
S-1/A, 1996-10-08
IN VITRO & IN VIVO DIAGNOSTIC SUBSTANCES
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AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON OCTOBER 8, 1996
                                                      REGISTRATION NO. 333-10759
================================================================================
    

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                   ----------

   
                               AMENDMENT NO. 1 TO
                                    FORM S-1
             REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933
    

                                   ----------

                             BOSTON BIOMEDICA, INC.
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

                                   ----------

          MASSACHUSETTS                       2835                  04-2652826  
(STATE OR OTHER JURISDICTION OF   (PRIMARY STANDARD INDUSTRIAL   I.R.S. EMPLOYER
 INCORPORATION OR ORGANIZATION)   CLASSIFICATION CODE NUMBER)     IDENTIFICATION
                                                                      NUMBER)   
                                   ----------
                                                                 

      375 WEST STREET, WEST BRIDGEWATER, MASSACHUSETTS 02379 (508) 580-1900
   (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE, OF
                    REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)

                                   -----------

                             RICHARD T. SCHUMACHER,
                      PRESIDENT AND CHIEF EXECUTIVE OFFICER
                             BOSTON BIOMEDICA, INC.
                                 375 WEST STREET
                      WEST BRIDGEWATER, MASSACHUSETTS 02379
                                 (508) 580-1900
 (NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE,
                             OF AGENT FOR SERVICE)

                                   ----------

                                   COPIES TO:
    STEVEN R. LONDON, ESQ.                               PAUL JACOBS, ESQ.      
BROWN, RUDNICK, FREED & GESMER                       FULBRIGHT & JAWORSKI L.L.P.
     ONE FINANCIAL CENTER                                 666 FIFTH AVENUE      
 BOSTON, MASSACHUSETTS 02111                          NEW YORK, NEW YORK 10103  
     TEL: (617) 856-8200                                 TEL: (212) 318-3000    
     FAX: (617) 856-8201                                 FAX: (212) 752-5958    
                                                       
                                  -----------
                           


    APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC:  As soon as
practicable  after this  Registration  Statement  is declared  effective  by the
Securities and Exchange Commission.

    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. [x]
       

                                  -----------

    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 SAID SECTION 8(A),
MAY DETERMINE.

================================================================================






   
                  SUBJECT TO COMPLETION, DATED OCTOBER 8, 1996
    

PROSPECTUS
- ----------

                                1,600,000 SHARES

                                     [LOGO]

                             BOSTON BIOMEDICA, INC.
                                  COMMON STOCK


                                  -----------

   
    All of the  1,600,000  shares of Common Stock (the "Common  Stock")  offered
hereby are being sold by Boston Biomedica, Inc. (the "Company").

    Prior to this Offering, there has been no public market for the Common Stock
of the Company. It is currently estimated that the initial public offering price
will be between $8.00 and $10.00 per share. See  "Underwriting"  for information
relating to the  determination  of the initial public offering price. The Common
Stock has been  approved for quotation on the Nasdaq  National  Market under the
symbol "BBII."
    

                                   ----------

SEE "RISK FACTORS"  BEGINNING ON PAGE 6 FOR A DISCUSSION OF CERTAIN FACTORS THAT
SHOULD BE  CONSIDERED  BY  PROSPECTIVE  PURCHASERS  OF THE COMMON STOCK  OFFERED
HEREBY.

                                  -----------

THESE  SECURITIES  HAVE NOT BEEN APPROVED OR  DISAPPROVED  BY THE SECURITIES AND
EXCHANGE  COMMISSION OR ANY STATE  SECURITIES  COMMISSION NOR HAS THE SECURITIES
AND  EXCHANGE  COMMISSION  OR ANY STATE  SECURITIES  COMMISSION  PASSED UPON THE
ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE

================================================================================

                                                UNDERWRITING
                                 PRICE TO      DISCOUNTS AND    PROCEEDS TO
                                  PUBLIC      COMMISSIONS(1)   COMPANY(2)
- --------------------------------------------------------------------------------
Per Share                         $                $               $
- --------------------------------------------------------------------------------
Total(3)                      $                $               $
================================================================================

(1)  Excludes  the value of warrants to be issued to the  Underwriters  and a 1%
     non-accountable  expense allowance  payable to the  Underwriters,  of which
     $40,000  has been paid to date.  The Company  has agreed to  indemnify  the
     Underwriters against certain liabilities,  including  liabilities under the
     Securities Act of 1933, as amended. See "Underwriting."

   
(2)  Before deducting expenses payable by the Company estimated to be $792,000.

(3)  The Company has granted the Underwriters an option,  exercisable  within 30
     days of the date  hereof,  to purchase up to 240,000  additional  shares of
     Common  Stock at the  Price  to  Public  less  Underwriting  Discounts  and
     Commissions to cover over-allotments, if any. If all such additional shares
     are  purchased,  the total  Price to  Public,  Underwriting  Discounts  and
     Commissions  and  Proceeds  to Company  will be $_____,  $ ____ and $_____,
     respectively. See "Underwriting."
    

                                   ----------

    The shares of Common  Stock are offered by the  Underwriters  named  herein,
subject to receipt and  acceptance  by them and subject to their right to reject
any order in whole or in part. It is expected that delivery of the  certificates
representing  such shares will be made against payment therefor at the office of
Oscar Gruss & Son Incorporated in New York, New York on or about_________, 1996.

OSCAR GRUSS & SON INCORPORATED                               KAUFMAN BROS., L.P.

             THE DATE OF THIS PROSPECTUS IS            , 1996.



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.






    Description of photograph:

    Under  the  caption  "Total  Quality  System,"  there  is a  collage  of the
Company's  products which are a part of its Total Quality  System.  In the upper
left corner is a photograph of a TQS Qualification  Panel,  proceeding clockwise
to the upper right  corner is a  photograph  of an Accurun 1(R) vial and pipette
superimposed over a typical  Levey-Jennings  daily quality control chart. In the
lower right corner is a photograph of a lab  technician  operating  equipment in
one of the Company's  laboratories,  and finally, in the lower left corner, is a
photograph  of  Anti-HIV  1  Western  Blots for seven  different  Company  Panel
Products.


    The BBI logo is a trademark  of the  Company.  Accurun  1(R) is a registered
trademark of the Company. Accurun(tm) is a trademark of the Company.

    IN CONNECTION WITH THIS OFFERING,  THE UNDERWRITERS MAY OVER-ALLOT OR EFFECT
TRANSACTIONS WHICH STABILIZE OR MAINTAIN THE MARKET PRICE OF THE COMMON STOCK AT
A LEVEL  ABOVE THAT WHICH  MIGHT  OTHERWISE  PREVAIL  IN THE OPEN  MARKET.  SUCH
STABILIZING, IF COMMENCED, MAY BE DISCONTINUED AT ANY TIME.







    TQS Logo
                                  
                                             o TARGETED TO THE EMERGING
                                               END-USER MARKET FOR
     TOTAL                                     INFECTIOUS DISEASE TEST
    QUALITY                                    KIT QUALITY CONTROL
    SYSTEM                                   o USER-FRIENDLY PRODUCTS
                                               FOR MONITORING
                                               LABORATORY PROFICIENCY,
                                               LOT ACCEPTANCE,
                                               TROUBLESHOOTING AND TRAINING
                                             o DESIGNED TO EVALUATE THE
                                               KEY ELEMENTS IN
                                               THE TESTING PROCESS:
                                               TEST KIT, EQUIPMENT AND PERSONNEL
                                             o ESSENTIAL PRODUCTS IN AN
                                               OVERALL QUALITY ASSURANCE PROGRAM



   
                                                 QUALITY CONTROL         
                                                   PRODUCTS FOR    
                                             INFECTIOUS DISEASE TESTS



o SEROCONVERSION
  PANELS, PERFORMANCE
  PANELS AND SENSITIVITY PANELS
  FOR THE EVALUATION OF
  INFECTIOUS DISEASE
  TEST KITS                                      Photograph of four of the      
o USED BY TEST KIT                      Company's Quality Control Panel Products
  MANUFACTURERS AND                          
  REGULATORS THROUGHOUT
  THE WORLD
o DEVELOPED FROM AN
  EXTENSIVE INVENTORY
  OF HUMAN BLOOD SPECIMENS
o CONTRIBUTING TO THE
  IMPROVED SENSITIVITY
  OF INFECTIOUS DISEASE
  TESTS WORLDWIDE
    




    Inside Front Cover

    Title at top of page reads:  "Serving Our  Customer's  Needs  Throughout the
Entire Product Life Cycle."

    Description  of   Photograph:   Photograph  is  comprised  of  a  pie  chart
superimposed  over photographs of the Company's  products and services.  The pie
chart has four sections and eight  subsections.  The four sections  refer to the
four stages in the test kit life-cycle and are captioned:  "R&D,"  "Regulatory,"
"Production" and "Marketing." Each subsection has a corresponding  photograph of
a Company product or service. The eight subsections are captioned:  "Performance
Panels,"   "Seroconversion   Panels,"  "Highly  Characterized   Specimen  Bank,"
"Clinical  Trials,"  "Characterized  Disease  State  Sera,"  "Basematrix,"  "Run
Controls" and "OEM and Custom Panels."

    Underneath the photograph are the words: "Your Partner in Infectious Disease
Quality Control" and the Company's logo is to the immediate left.




                            PROSPECTUS SUMMARY

   
    The following is qualified in its entirety by the more detailed  information
(including the 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' option to purchase from the Company
up to 240,000  additional  shares of Common Stock to cover  over-allotments,  if
any,  (ii) gives  effect to a 1-for-2  reverse  stock split with  respect to the
Common Stock effected in September  1996,  (iii) gives effect to certain changes
to the Company's  Articles of Organization  effected in September 1996, and (iv)
gives effect to the  termination of certain  redemption  provisions  relating to
117,647  shares of Common Stock upon  completion  of this  Offering.  Unless the
context  indicates  otherwise,  all  references  to the  "Company" are to Boston
Biomedica,  Inc.  and its two  wholly-owned  subsidiaries,  BTRL  Contracts  and
Services,  Inc. ("BTRL"), and BBI -- North American Clinical Laboratories,  Inc.
("BBI -- NACL").  For a discussion of certain  matters that should be considered
by purchasers of the Common Stock offered  hereby,  see "Risk  Factors." For the
definition of certain technical and scientific terms, see "Glossary."
    

                                THE COMPANY

    Boston  Biomedica,  Inc.  is a leading  worldwide  provider  of  proprietary
quality  control  products  for use with in vitro  diagnostic  test kits  ("test
kits") for the  detection,  analysis  and  monitoring  of  infectious  diseases,
including AIDS,  Hepatitis and Lyme Disease.  These products are used to develop
test kits, to permit the monitoring of laboratory  equipment and personnel,  and
to help ensure the accuracy of test results.  The Company's products are derived
from human  plasma and serum  using  proprietary  manufacturing  processes.  The
Company  believes its Quality  Control Panel  products are viewed as the current
industry  standard for the independent  assessment of the performance of HIV and
Hepatitis  test  kits.  The  Company  also  manufactures   diagnostic  test  kit
components  and  provides  specialty  laboratory  services,  including  clinical
trials.

    To  date,  the  Company  has  sold  its  products   primarily  to  test  kit
manufacturers and regulatory agencies, but it has recently begun selling Quality
Control  Products  directly to the emerging  end-user market for quality control
products for  infectious  disease test kits.  In late 1994 the Company  received
United States Food and Drug  Administration  ("FDA") clearance for Accurun 1(R),
its first Quality  Control  Product  designed  specifically  for end-users,  and
subsequently has introduced 24 additional  Accurun(tm) Quality Control Products.
In July 1996,  the  Company  introduced  its Total  Quality  System  ("TQS"),  a
marketing platform that combines Accurun(tm) with other Quality Control Products
to provide test kit  end-users  with the products  needed in an overall  quality
assurance  program.  TQS products  allow  end-users to evaluate  each of the key
elements  of the  testing  process:  the  test  kit,  laboratory  equipment  and
laboratory personnel.

    The Company's  customers include Abbott  Diagnostics,  Boehringer  Mannheim,
Chiron,  Fujirebio,  Hoffman LaRoche,  Ortho Diagnostics (Johnson & Johnson) and
Sanofi  Diagnostics;  regulatory  agencies  such as the United  States FDA,  the
British Public Health  Laboratory  Service,  the French Institut  National de la
Transfusion  Sanguine and the German Paul Ehrlich  Institute;  and  end-users of
diagnostic test kits, such as blood banks, hospitals and clinical laboratories.

    The increased threat of infectious  diseases has created a large and growing
market for  infectious  disease test kits.  Venture  Planning  Group,  a medical
products research firm, estimates that the worldwide infectious disease test kit
market was  approximately  $2.7 billion in 1995 and will grow to $5.0 billion by
2000. The related market for quality  control  products for in vitro  diagnostic
testing for infectious and  non-infectious  disease totaled  approximately  $600
million in 1994,  according to the Genesis Report Dx, a medical products survey.
The Company believes that quality control  products for infectious  disease test
kits currently  represent less than five percent of the overall  quality control
market, primarily as a result of the limited use of such products by end-users.

    The  Company  believes  that the market for  quality  control  products  for
infectious  disease  test kits  will  continue  to  expand,  particularly  among
end-users,  primarily  as  a  result  of  several  key  factors:  (i)  increased
regulatory  scrutiny  due to public  concern  about the  dangers  of  infectious
diseases such as AIDS and  Hepatitis;  (ii) growing  recognition of the value of
using quality  control  products to ensure the greatest  possible  safety of the
blood supply,  to achieve the earliest possible  diagnosis of infection,  and to
minimize the  occurrence of false negative  results;  (iii) the discovery of new
infectious diseases and the development of new treatments for diseases requiring
periodic  monitoring,  such as viral load testing for HIV, Hepatitis B and C and
other  diseases;  and  (iv)  the  emergence  of  new  testing  technologies  and
equipment.


                                       3


    The Company offers three product groups in infectious  disease  diagnostics:
Quality  Control  Panels,  Accurun(tm)  Run Controls and Diagnostic  Components.
These products are used throughout the entire test kit life cycle,  from initial
research and development,  through the regulatory  approval process and test kit
production,  to  training,  troubleshooting  and routine use by  end-users.  The
Company's  Quality  Control  Panels,  which combine human blood  specimens  with
comprehensive  quantitative  data useful for comparative  analysis,  help ensure
that test kits detect the correct analyte (specificity),  detect it the same way
every  time   (reproducibility),   and  detect  it  at  the  appropriate  levels
(sensitivity).  The Company's  Accurun(tm) Run Controls enable end-users of test
kits to confirm the validity of results by monitoring test performance,  thereby
minimizing  false  negative  test  results and  improving  error  detection.  In
addition, the Company provides Diagnostic Components, which are custom processed
human plasma and serum products, to test kit manufacturers.

    The Company's  specialty clinical  laboratory  services include both routine
and  sophisticated  infectious  disease testing in microbiology,  immunology and
molecular biology.  The Company seeks to focus its specialty laboratory services
in advanced areas of infectious disease testing,  and provides contract research
and clinical trials for domestic and foreign test kit manufacturers.

    The  Company's  strategy  is to  leverage  its  scientific  capabilities  in
microbiology,  immunology,  virology, and molecular biology to (i) capitalize on
the emerging  end-user  market,  (ii) develop new products and  services,  (iii)
enhance  technical  leadership,   (iv)  capitalize  on  complementary   business
operations, and (v) pursue strategic acquisitions and alliances.

    The Company  believes that it has several  competitive  advantages that will
help it implement its strategy:

    o an  inventory  of  approximately  50,000  distinct  human blood  specimens
      accumulated  since 1986  through its  worldwide  sources of  blood-supply,
      which enable the Company to quickly respond to market trends;

    o the ability to offer specialty  laboratory  services and conduct  clinical
      trials,  which helps it to maintain  contact and enhance  credibility with
      test kit manufacturers and regulatory authorities,  and allows the Company
      to remain at the forefront of market trends and customer needs;

    o proprietary  manufacturing know-how resulting from ten years of experience
      working with leading  worldwide  manufacturers in the development of their
      infectious disease test kits; and

    o its  reputation  as an authority in  infectious  disease  quality  control
      products among test kit manufacturers and regulatory agencies.

    The Company, a Massachusetts corporation, was organized in 1978, but did not
commence significant  operations until 1986. The Company's principal offices are
located at 375 West Street, West Bridgewater, MA 02379, and its telephone number
is (508) 580-1900.

                                  THE OFFERING

   
Common Stock Offered                    1,600,000 shares(1)

Common Stock to be Outstanding
  after the Offering                    4,290,064 shares(1)(2)
    

Use of Proceeds                         Repayment   of   indebtedness,   capital
                                        expenditures,   and  general   corporate
                                        purposes,  including working capital and
                                        potential  acquisitions.   See  "Use  of
                                        Proceeds."

Proposed Nasdaq National
  Market Symbol                        BBII


   
- -----------
(1) Does not  include up to 240,000  shares of Common  Stock that may be sold by
    the Company pursuant to the Underwriters' over-allotment option.
    See "Underwriting."
    

(2) Does not include  1,161,057 shares of Common Stock issuable upon exercise of
    outstanding  options and warrants and 14,333 shares of Common Stock issuable
    upon  conversion  of  an  outstanding  subordinated  convertible  note.  See
    "Capitalization"  and Notes 6, 10 and 11 of Notes to Consolidated  Financial
    Statements.


                                       4



                    SUMMARY CONSOLIDATED FINANCIAL DATA
                   (In thousands, except per share data)


<TABLE>
<CAPTION>
                                                                            YEAR ENDED DECEMBER 31,        SIX MONTHS ENDED JUNE 30,
                                                                            -----------------------        -------------------------
                                                                          1993(1)    1994      1995            1995          1996
                                                                          -------    ----      ----            ----          ----
<S>                                                                       <C>        <C>       <C>         <C>              <C>
   
STATEMENT OF OPERATIONS DATA:                                           
  Product sales                                                            $3,942    $ 5,982   $ 6,622     $  3,024     $  3,946
  Service revenue                                                           5,215      4,741     5,649        2,540        2,982
    Total revenue                                                           9,157     10,723    12,271        5,564        6,928
                                                                        
  Income from operations                                                      312        405       508          104          307
  Net income (loss)                                                           142         97       103          (36)          83
  Net income (loss) per share(2)(3)                                        $ 0.06    $  0.04   $  0.04     $  (0.01)    $   0.03
  Weighted average common and common equivalent shares                  
   outstanding(2)(3)                                                        2,438      2,587     3,151        2,598        3,253
</TABLE>                                                                
    
                                                        


<TABLE>
<CAPTION>
   
                                                                                                                  JUNE 30, 1996     
                                                                                                                  -------------     
                                                                                                                         PRO FORMA
                                                                                                             ACTUAL   AS ADJUSTED(4)
                                                                                                            ------   --------------
<S>                                                                                                         <C>       <C>
BALANCE SHEET DATA:                                                                                       
  Working capital                                                                                           $ 4,497       $ 14,300
  Total assets                                                                                               10,047         19,360
  Long term debt, less current maturities                                                                     2,798          --
  Redeemable common stock                                                                                       899          --
  Total stockholders' equity                                                                                   3,332        16,831
    
</TABLE>
                                                                                
                                                                                


- ----------
(1)  On June  30,  1993,  the  Company  exercised  its  option  to  pre-pay  the
     acquisition  note issued in connection  with the 1992 purchase of BTRL at a
     discount  from the  balance  due,  resulting  in an  extraordinary  gain of
     $50,000, net of taxes of $33,000. The 1993 net income per share before such
     extraordinary gain was $0.04.

(2)  The effect of the common stock  equivalents  on net income per common share
     has been excluded from the calculation for 1993 and 1994 and the six months
     ended June 30, 1995 as its inclusion was antidilutive.

   
(3)  Pro forma supplementary  earnings per share for the year ended December 31,
     1995  and  the  six  months  ended  June  30,  1996  were  $.09  and  $.06,
     respectively,  based upon an  assumed  weighted  average  common and common
     equivalent shares outstanding of 3,600,007 and 3,701,173,  respectively. In
     accordance with APB Opinion 15, pro forma supplementary  earnings per share
     is presented as if the Company sold on January 1, 1995,  448,530  shares of
     Common Stock, representing the number of shares of Common Stock required to
     be sold at the assumed  initial public offering price of $9.00 per share in
     order for the Company to repay the indebtedness  outstanding during 1995 as
     if the Offering had occurred on January 1, 1995.  See "Use of Proceeds" and
     Note 12 of Notes to Consolidated Financial Statements.

(4)  Adjusted to reflect: (i) application of the estimated net proceeds from the
     sale of 1,600,000  shares of Common Stock offered by the Company  hereby at
     an  assumed  initial  public  offering  price of  $9.00  per  share,  after
     deducting  estimated  underwriting  discounts and  commissions and offering
     expenses,  and (ii) the  termination of redemption  provisions  relating to
     117,647 shares of Common Stock upon completion of this Offering.
    

                                       5


                                  RISK FACTORS

    An investment in the shares of Common Stock offered  hereby  involves a high
degree of risk. In addition to the other  information  in this  Prospectus,  the
following  factors should be considered  carefully in evaluating the Company and
its business before purchasing the shares of Common Stock offered hereby.

UNDEVELOPED END-USER MARKET FOR QUALITY CONTROL PRODUCTS FOR INFECTIOUS
DISEASE TEST KITS

    The Company intends to focus its product development and sales and marketing
efforts on quality  control  products for end-users of  infectious  disease test
kits. Currently,  most quality control products for infectious disease test kits
are sold to test kit  manufacturers  and  regulators.  End-users  of  infectious
disease test kits are currently  using quality  control  products only to a very
limited extent.  See "Business -- Industry  Overview." The Company's strategy is
based primarily upon significant  growth in sales of quality control products to
the end-user market.  See "Business -- Strategy." There can be no assurance that
end-users of  infectious  disease test kits will  increase  their use of quality
control  products,  or that the Company  will be able to  increase  its sales of
quality control products to such end-users.  Clearance or approval by the United
States Food and Drug Administration (the "FDA") will be necessary before quality
control  products  may be sold  for  clinical  laboratory  use  rather  than for
research  purposes  only.  See  "--  Stringent  Government  Regulation."  If the
end-user market for quality control products does not develop, or if the Company
is unable to increase  its sales to this market,  the  Company's  future  growth
could be materially and adversely affected.

COMPETITION

    In sales of both its products and specialty laboratory services, the Company
experiences   substantial   competition  and  the  threat  of  competition  from
established  and potential  competitors,  most of which have greater  financial,
manufacturing  and  marketing  resources  than  the  Company.   Competition  for
customers is intense and depends  principally on the ability to provide products
of the quality and in the quantity required by customers, as well as the ability
to provide  sophisticated  specialty laboratory services, at competitive prices.
The Company  currently  competes  against  independent  reference  laboratories,
integrated plasma collection and processing centers and manufacturers of quality
controls and other Diagnostic  Components.  In addition, the Company understands
that a leading  manufacturer  of quality  control  products  for  non-infectious
diseases recently entered the quality control market for infectious disease test
kits. There can be no assurance that other such manufacturers or other companies
will not enter this  market.  The  entrance of any of these  companies  into the
quality  control market for  infectious  disease test kits could have a material
adverse effect on the Company,  particularly its ability to achieve its strategy
to capitalize on the end-user market for quality control products for infectious
disease test kits. In addition,  certain of the  Company's  products are derived
from donors with rare antibody characteristics.  Competition for blood specimens
from such donors may  increase,  which may increase  the cost of obtaining  such
specimens.  There can be no assurance that such increased  competition  will not
adversely  affect the  Company.  See "--  Difficulty  in  Obtaining  Certain Raw
Materials" and "Business -- Competition."

ABILITY TO MANAGE GROWTH

    The  Company's  future  success will depend in part on its ability to manage
growth as it increases its production capacity and broadens  distribution of its
products.  To compete  effectively and manage future growth, if any, the Company
will be required to continue to implement and improve its operational, financial
and management  information systems,  procedures and controls on a timely basis,
and to  expand,  train,  motivate  and  manage  its  workforce.  There can be no
assurance that the Company's personnel, systems, procedures and controls will be
adequate to support the Company's  future  operations.  The failure to implement
new and improved existing  operational,  financial and management  systems or to
expand, train, motivate or manage employees could have a material adverse effect
on the Company's business,  operating results and financial condition. There can
be no assurance that the Company will continue to grow or, if it does,  that the
Company will manage the growth successfully.


                                       6


FLUCTUATIONS IN QUARTERLY RESULTS OF OPERATIONS

    The  Company's   results  of  operations  have  been  subject  to  quarterly
fluctuations due to a variety of factors, including customer purchasing patterns
and  seasonal  demand  for  laboratory  testing  services.  In  particular,  the
Company's  sales of its  Quality  Control  Products  and  Diagnostic  Components
typically  have been  highest  in the  fourth  quarter  and  lowest in the first
quarter of each fiscal year.  For example,  total revenue for the fourth quarter
ended  December 31, 1994 and 1995 were $3.0  million and $3.8  million  compared
with total  revenue for the first  quarter ended March 31, 1995 and 1996 of $2.7
million and $3.1  million.  The Company  believes  that its customers may expend
end-of-year  budget  surpluses  in  the  fourth  quarter,  thereby  causing  the
Company's  fourth  quarter  product  sales to be higher at the  expense of first
quarter product sales. In addition,  demand for laboratory  services tends to be
somewhat  higher in the third and fourth  quarters of the fiscal year due to the
seasonal  nature of Lyme Disease  testing,  the Company's  highest  volume test.
Moreover,  the Company's  margins for its different  products and services vary,
with Quality Control Products  generally having the highest margins and Contract
Research the lowest.  Therefore,  the Company's  results may vary from period to
period  as a  result  of the mix of  products  and  services  and the mix  among
products. As a result,  quarterly results of operations may not be indicative of
future  results of  operations.  Also,  variations  in the  Company's  quarterly
results of operations may affect the market price of the Common Stock.  See " --
Volatility of Price of Common Stock" and  "Management's  Discussion and Analysis
of Financial Condition and Results of Operations."

RISK OF ACQUISITIONS

   
    The  Company  intends to pursue  strategic  acquisitions  to expand its core
product line, strengthen its base in medical science and technology,  and secure
new sources of blood supply.  The Company is subject to various risks associated
with an acquisition strategy, including the risk that the Company will be unable
to identify and attract  suitable  acquisition  candidates  or to integrate  and
manage  any  acquired  business.   The  Company  will  compete  for  acquisition
candidates  with  companies  which  have  significantly  greater  financial  and
management  resources than the Company.  Acquisitions  could place a significant
burden on the Company's  management and operating  personnel.  Implementing  the
Company's  expansion  strategy may also require  significant  capital resources.
Capital  is  needed  not only  for  acquisitions,  but  also  for the  effective
integration, operation and expansion of such businesses. The Company may need to
raise capital  through the issuance of long-term or short-term  indebtedness  or
the issuance of its  securities in private or public  transactions,  which could
result  in  dilution  of  existing  equity  positions,  increased  interest  and
amortization expense or decreased income to fund future expansion.  There can be
no assurance that acceptable financing for future acquisitions will be available
or that the  integration  of  future  acquisitions  and  expansion  of  existing
business can be achieved. See "-- Ability to Manage Growth."
    

DIFFICULTY IN OBTAINING CERTAIN RAW MATERIALS

    The Company  manufactures its products from human plasma and serum which the
Company  obtains from nonprofit and commercial  blood centers,  primarily in the
United States,  but also from similar sources  throughout the world.  Certain of
the Company's products, including its Seroconversion and Performance Panels, are
comprised of unique and rare plasma specimens  obtained from individuals  during
the short  period of time when the disease  markers of  particular  diseases are
converting  from negative to positive.  See "Business -- Products." As a result,
the  quantity of any such panel is limited,  so the Company  must  replace  such
panels as they sell out with another panel comprised of specimens equally unique
and rare. Competition to obtain such specimens may increase,  which may increase
the cost of obtaining such products.  There can be no assurance that the Company
will continue to be successful in obtaining a steady and adequate  supply of the
unique and rare  specimens  of plasma  and serum  necessary  for  certain of its
products. The inability to continue to obtain such specimens, or any significant
delays in obtaining such specimens,  would have a material adverse effect on the
Company. See "-- Competition."

DEPENDENCE ON KEY PERSONNEL

    The Company's  success depends in large part upon its ability to attract and
retain  highly  qualified  scientific  and  management  personnel.  The  Company
competes  for such  individuals  with other  companies,  academic  institutions,
government entities and other organizations.  There can be no 


                                       7

assurance  that the Company will be successful in hiring or retaining  requisite
personnel. The failure of the Company to recruit and retain qualified scientific
and management  personnel  could have a material  adverse effect on the Company.
None of the  Company's key  management or scientific  personnel is subject to an
employment  agreement with the Company. The loss of the services of any such key
personnel,  including  Richard  T.  Schumacher,  President  and Chief  Executive
Officer of the Company, could have a material adverse effect on the Company. The
Company  maintains  key  person  life  insurance  on  certain  of its  officers,
including Mr. Schumacher, on whose life the Company has $4,750,000 of insurance,
$2,000,000 of which has been pledged to the Company's lender.  See "Management's
Discussion  and Analysis of Financial  Condition  and Results of  Operations  --
Liquidity and Capital  Resources,"  "Business -- Competition" and "Management --
Directors and Executive Officers."

DEPENDENCE ON KEY CUSTOMERS

    The  Company's  three  largest  customers  accounted  for  an  aggregate  of
approximately  20% of the Company's  revenues in 1993, 1994 and 1995 and the six
months ended June 30, 1995 and 1996,  although the customers  were not identical
in each period.  In addition,  the majority of the Company's  revenues are based
upon  purchase  orders.  None  of  the  Company's  customers  are  contractually
committed to make future  product  purchases  from the Company.  The loss of any
major customer or a material  reduction in a major  customer's  purchases  would
have a material adverse effect upon the Company.

    A single U.S.  government services contract accounted for approximately 7.5%
and 7.3% of the  Company's  revenues  in 1995 and the six months  ended June 30,
1996. This contract is due to expire in February 1997. The Company has responded
to a Request for Proposals by the United States  government  for a new four year
contract to replace this contract.  There can be no assurance that the Company's
response  to the  Request for  Proposals  will be accepted by the United  States
government.  Failure to receive the new contract  would have a material  adverse
effect on the Company. See "Business -- Services."

STRINGENT GOVERNMENT REGULATION

   
    The manufacture  and  distribution of medical  devices,  including  products
manufactured  by the Company that are intended for in vitro  diagnostic use, are
subject to extensive  government  regulation  in the United  States and in other
countries.  In the United States,  the Food, Drug, and Cosmetic Act (the "FDCA")
prohibits the  marketing of in vitro  diagnostic  products  until they have been
cleared or approved by the FDA, a process that is time-consuming,  expensive and
uncertain.  Once clearance or approval is obtained,  the FDA requires additional
clearances  or  approvals  for product  changes that could affect the safety and
effectiveness of the device,  including, for example, new indications for use or
changes  in the  design  or  manufacturing  process.  Additional  clearances  or
approvals  may also be  required  for  changes  in  claims  relating  to uses of
products. The Company's Accurun Run Controls,  when marketed for diagnostic use,
have been classified by the FDA as medical devices. The Company has received FDA
clearance  to  market  its  Accurun  1(R)  line  for  diagnostic  purposes.   An
application  for clearance for  diagnostic  use for one  additional  Accurun(tm)
product  has  been  submitted  by  the  Company  to the  FDA,  and  the  Company
anticipates  that  applications  for  approximately  16  additional  Accurun(tm)
products will be prepared and submitted to the FDA by the end of 1997. There can
be no assurance that the Company will obtain regulatory  clearances or approvals
on a timely basis, if at all, for future products,  changes in existing products
or  changes in claims  relating  to uses of  products.  Delays in  obtaining  or
failure to obtain  requisite FDA  clearances or approvals  could have a material
adverse effect on the Company.
    

    All of the Company's  Quality Control Products with the exception of Accurun
1(R) are marketed  "for  research use only," which do not require FDA  premarket
clearance or approval of the product,  and not marketed for diagnostic purposes,
which do require FDA premarket clearance or approval. The Company's labeling for
these products limits their use to research. It is possible,  however, that some
purchasers of these  products may use them for diagnostic  purposes  despite the
Company's intended use. In these circumstances,  the FDA could allege that these
products  should have been cleared or approved by the FDA prior to marketing and
initiate  enforcement  action  against the Company,  which could have a material
adverse effect on the Company.  Failure to obtain,  or delays in obtaining,  FDA
clearances  or  approval  would  adversely  affect  the  Company's  strategy  of
capitalizing on the end-user market.


                                       8


    The Company  believes that its Quality  Control  Panels are not regulated by
the FDA because  they are not  intended  for  diagnostic  purposes.  The Company
believes  that its  Diagnostic  Components,  which  are  components  of in vitro
diagnostic products, may be subject to certain regulatory requirements under the
FDCA and other laws administered by the FDA, but do not require that the Company
obtain a premarket  approval or clearance.  There can be no assurance,  however,
that  the  FDA  would  agree  or  that  the  FDA  will  not  adopt  a  different
interpretation  of the FDCA or other  laws it  administers,  which  could have a
material adverse effect on the Company.

    In addition,  both before and after clearance or approval,  medical devices,
such as Accurun  1(R),  are  subject to certain  export and import  requirements
under the FDCA.

    The  Company  is also  subject to strict  FDA good  manufacturing  practices
("GMP") regulations governing testing,  control and documentation,  and to other
postmarketing  restrictions  with respect to the  manufacture  of the  Company's
medical  device  products.  Ongoing  compliance  with GMP and  other  applicable
regulatory  requirements  is  monitored  through  periodic  inspections  by  the
regulatory  authorities.   Failure  to  comply  with  GMP  or  other  regulatory
requirements  can  result,  among other  consequences,  in the failure to obtain
premarket clearances or approvals,  withdrawal of clearances or approvals, total
or partial  suspension of product  distribution,  injunctions,  civil penalties,
recall or seizures of products,  and criminal  prosecution,  each of which would
have a material adverse effect on the Company.

    Laws and regulations  affecting the Company's products are in effect in many
of the countries, states and other jurisdictions in which the Company markets or
intends to market its products.  There can be no assurance that the Company will
be able to obtain any required  regulatory  clearances  or approvals on a timely
basis,  or at all.  Delays in receipt of or failure to obtain such clearances or
approvals,  or the  failure  to comply  with  regulatory  requirements  in these
countries,  states or other jurisdictions,  could have a material adverse effect
on the Company's business,  financial  condition and results of operations.  See
"Business -- Government Regulation."

    The  Company  is also  subject to other  national,  state and local laws and
regulations,  including those relating to the use and disposal of  biohazardous,
radioactive  and other hazardous  substances and wastes.  Failure to comply with
such laws and regulations  could have a material adverse effect on the Company's
business,  financial  condition  and results of  operations.  See  "Business  --
Government Regulation."

FOREIGN RESTRICTIONS ON IMPORTATION OF BLOOD DERIVATIVES

    Sales  outside  the  United  States  in  1993,  1994  and  1995  represented
approximately  15%, 21% and 25%,  respectively,  of the  Company's  revenues for
those  years,  and 27% in each of the six months  ended June 30,  1995 and 1996.
Foreign  sales are  primarily  to Western  Europe and Japan.  Concern over blood
safety has led to  movements  in a number of  European  and other  countries  to
restrict the importation of blood and blood derivatives,  including  antibodies.
Such  restrictions  continue  to be debated and there can be no  assurance  that
additional  restrictions  will not be imposed in the future.  If  imposed,  such
restrictions could have a material adverse effect on the Company's business.

RISK OF TECHNOLOGICAL CHANGE

    The  infectious  disease  test kit  industry is  characterized  by rapid and
significant  technological  change and  changes in customer  requirements.  As a
result,  the Company's success will be dependent upon its ability to enhance its
existing products and to develop or acquire and introduce in a timely manner new
products that take advantage of  technological  advances and respond to customer
requirements.  There can be no assurance  that the Company will be successful in
developing  and  marketing  such new products or  enhancements  to the Company's
existing  products  on a timely  basis or that  such  products  will  adequately
address the changing needs of the marketplace.  Furthermore, rapid technological
development by the Company or others may result in products or services becoming
obsolete  or  noncompetitive  before the  Company  recovers  its  investment  in
research, development and commercialization.


                                       9


RISK OF BROAD MANAGEMENT DISCRETION IN APPLICATION OF PROCEEDS

   
    A significant  portion of the estimated net proceeds from this Offering will
be  allocated  to working  capital and  general  corporate  purposes,  including
potential acquisitions.  Accordingly,  the Company will have broad discretion as
to the  application  of the net  proceeds  and  may  allocate  portions  of such
proceeds to uses which the Company's  stockholders  may not deem  desirable.  In
October 1996, the Company  entered into a License  Agreement and Preferred Stock
Purchase Agreement ("Purchase Agreement") with BioSeq, Inc. ("BioSeq"), an early
stage  biotechnology  company that is  developing a technology  for  sequencing,
synthesizing  and  characterizing  nucleic acids and proteins.  See "Business --
Strategic  Alliances." Under the Purchase  Agreement,  the Company has agreed to
purchase  approximately  19% of the  outstanding  capital stock of BioSeq for an
aggregate of $1,482,500, to be paid in three installments.  The Company has paid
the  first  installment  of  $210,000  and will pay the  second  installment  of
$522,500 upon  completion of the Offering.  The Company intends to use a portion
of the proceeds of this Offering to fund the second  installment and $210,000 of
such proceeds to repay amounts drawn on the Company's  revolving  line of credit
to fund the first  installment.  The Company  must make the  remaining  $750,000
installment if BioSeq  attains  certain  technical  milestones by July 31, 1997.
There can be no assurance as to the commercial  viability of BioSeq's technology
or that the Company will not lose its entire investment in BioSeq.  Additionally
there can be no assurance that the Company's use of any of the proceeds from the
Offering will yield any return. See "Use of Proceeds."
    

PROTECTION OF INTELLECTUAL PROPERTY AND PROPRIETARY TECHNOLOGY

    None of the Company's Quality Control Products or Diagnostic Components have
been patented and the Company does not intend to seek patent protection for such
products. The Company's ability to compete effectively with other companies will
depend,  in part,  on its  ability to  maintain  the  proprietary  nature of its
technologies  and products and operate  without  infringing  the rights of third
parties.  The Company  relies  primarily on a  combination  of trade secrets and
non-disclosure   and   confidentiality   agreements,   and  in  certain  limited
circumstances,  patents,  to establish and protect its proprietary rights in its
technology  and  products.  There  can be no  assurance  that  others  will  not
independently  develop or otherwise  acquire the same,  similar or more advanced
trade secrets and know-how.

    The Company has two United States  patents and,  jointly with the University
of North  Carolina at Chapel  Hill  ("UNC"),  has filed  three  series of United
States and foreign  patent  applications  relating to compounds,  pharmaceutical
compositions  and  therapeutic  methods in connection  with the  Company's  drug
discovery  program at the  University  of North  Carolina  at Chapel  Hill.  See
"Business -- Services," and " -- Strategic Alliances." There can be no assurance
that patent applications will result in issued patents, that issued patents will
provide  any  competitive  advantage  or that  patents  will not be  challenged,
circumvented or invalidated.

    Third parties may be issued patents to, or may otherwise  acquire the rights
to, technology  necessary or potentially  useful to the Company.  The success of
the  Company  is  dependent  in part upon its not  infringing  patents  or other
intellectual  property  rights  of third  parties.  Litigation  relating  to the
infringement  of the  patents or other  intellectual  property  rights of others
could result in substantial costs to the Company.  Litigation which could result
in  substantial  costs to the  Company  may also be  necessary  to  enforce  the
Company's intellectual property rights or to determine the scope and validity of
the  proprietary  rights of  others.  Any such  substantial  costs  would have a
material adverse effect on the Company.

UNCERTAINTY RELATED TO HEALTHCARE REFORM; NO ASSURANCE OF ADEQUATE REIMBURSEMENT

    Political,  economic and regulatory influences are subjecting the healthcare
industry in the United States to fundamental  change.  Although to date Congress
has failed to pass  comprehensive  health care reform  legislation,  the Company
anticipates  that  Congress and state  legislatures  will continue to review and
assess alternative healthcare delivery and payment systems and may in the future
propose and adopt legislation  effecting  fundamental  changes in the healthcare
delivery system.  Legislative  debate is expected to continue in the future.  In
addition,  the private sector has been changing the healthcare  industry as well
through  consolidations  and alternatives in healthcare  delivery  systems.  The
Company  cannot  predict what impact the adoption of any federal or state health
care reform measures or future private sector reform may have on its industry or
business.



                                       10


    In both domestic and foreign  markets,  sales by the Company's  customers of
products and services  that  incorporate  or affect the demand for the Company's
products  may  depend  in  part  on  the  availability  of  reimbursement   from
third-party payors such as government health administration authorities, private
health insurers and other  organizations.  Third-party  payors are  increasingly
challenging the price and cost-  effectiveness of medical products and services.
There can be no assurance  that pricing  pressures  experienced by the Company's
customers will not adversely affect the Company because of a determination  that
its  products  are not cost  effective  or  because  of  inadequate  third-party
reimbursement  levels to such  customers.  In addition,  where the payor for the
Company's  specialty  laboratory services is the patient rather than third-party
payors, there is a greater risk of non-payment. See "Management's Discussion and
Analysis  of  Financial  Condition  and  Results  of  Operations  --  Results of
Operations."

RISK OF HAZARDOUS WASTE AND PRODUCT LIABILITY; ABSENCE OF INSURANCE

    The  Company's   manufacturing  processes  involve  the  controlled  use  of
biohazardous  materials and chemicals.  The risk of accidental  contamination or
injury from these  materials  cannot be completely  eliminated.  In the event of
such an accident,  the Company could be held liable for any damages that result,
and any such  liability  could exceed the resources of the Company.  The Company
may  incur  substantial  costs to  maintain  safety  in the use of  biohazardous
materials and to comply with  environmental  regulations as the Company  further
develops its manufacturing capacity. See "Business -- Government Regulation."

    Further,  the  Company's  business  exposes it to  liability  risks that are
inherent in the  testing,  manufacturing  and  marketing  of its  products.  The
Company does not currently have product liability  insurance.  Product liability
claims could expose the Company to substantial  liabilities and expenses,  which
could materially and adversely affect the Company.

RISKS ASSOCIATED WITH EXPORT SALES

    The  Company  generated  significant  sales  outside  the United  States and
anticipates  that  foreign  sales will  continue  to account  for a  significant
percentage  of the Company's net  revenues.  The  Company's  foreign  operations
accounted for approximately 15%, 21% and 25% of the Company's total revenues for
the years ended December 31, 1993, 1994 and 1995 and  approximately  27% in each
of the six months  ended  June 30,  1995 and 1996,  and 36%,  38% and 47% of the
Company's product sales for the years ended December 31, 1993, 1994 and 1995 and
50% and 48% for each of the six months ended June 30, 1995 and 1996. The Company
therefore is subject to risks  associated with foreign sales,  including  United
States and foreign  regulatory  requirements  and policy changes,  political and
economic   instability,   difficulties   in  accounts   receivable   collection,
difficulties  in managing  distributors  or  representatives  and seasonality of
sales.  Although the  Company's  sales have been  denominated  in United  States
dollars, the value of the United States dollar in relation to foreign currencies
may also  adversely  affect the  Company's  sales to foreign  customers.  To the
extent that the  Company  expands its  international  operations  or changes its
pricing practices to denominate prices in foreign  currencies,  the Company will
be  exposed  to  increased  risks of  currency  fluctuation.  See  "Management's
Discussion and Analysis of Financial  Condition and Results of  Operations"  and
Note 5 of the Notes to Consolidated Financial Statements.

POSSIBLE ADVERSE EFFECT OF CONTROL BY EXISTING STOCKHOLDERS

   
    Upon  consummation of this Offering,  Richard T.  Schumacher,  President and
Chief Executive  Officer,  his relatives and the existing officers and directors
of the Company  collectively will have voting control over  approximately 39% of
the outstanding shares of Common Stock. Accordingly, these stockholders,  should
they choose to act in concert,  will be in a position to exercise a  significant
degree of control over the Company, and to significantly  influence  stockholder
votes on the  election of the  Company's  directors,  increasing  the  Company's
authorized  capital  stock,  mergers,  and sales of the  Company's  assets.  See
"Principal Stockholders."
    

POSSIBLE ADVERSE EFFECT OF CERTAIN ANTI-TAKEOVER PROVISIONS

    Certain  provisions  of the  Company's  Amended  and  Restated  Articles  of
Organization  and Restated  Bylaws could have the effect of discouraging a third
party from  pursuing a  non-negotiated  takeover of the  Company and  preventing
certain  changes in control.  These  provisions  include a  classified  Board of
Directors,  a fair price provision,  advance notice to the Board of Directors of
stockholder  proposals  and 


                                       11


stockholder  nominees for the Board of Directors,  limitations on the ability of
stockholders to remove directors and call stockholders  meetings,  the provision
that  vacancies  on the  Board of  Directors  be  filled  by a  majority  of the
remaining  directors  and the  ability  of the Board to issue,  without  further
stockholder approval,  preferred stock with rights and privileges which could be
senior to the Common  Stock.  The Company also is subject to Chapter 110F of the
Massachusetts  General Laws which,  subject to certain  exceptions,  prohibits a
Massachusetts  corporation  from  engaging  in any of a broad  range of business
combinations  with any  "interested  stockholder"  for a period  of three  years
following the date that such stockholder became an interested stockholder. These
provisions  could  discourage  a third  party from  pursuing  a takeover  of the
Company  at a price  considered  attractive  by many  stockholders,  since  such
provisions could have the effect of preventing or delaying a potential  acquiror
from  acquiring  control  of  the  Company  and  its  Board  of  Directors.  See
"Description   of  Capital   Stock  --  Preferred   Stock,"  "--   Massachusetts
Anti-Takeover and Related Statutes" and " -- Certain Provisions of the Company's
Articles of Organization and By-laws."

NO ASSURANCE OF PUBLIC MARKET; POSSIBLE VOLATILITY OF PRICE OF COMMON
STOCK

    Prior to this  Offering,  there has been no public  trading  market  for the
Common Stock.  There can be no assurance  that a regular  trading market for the
Common Stock will develop after this Offering or that, if developed,  it will be
sustained.  The  initial  public  offering  price of the  Common  Stock  will be
determined  by  negotiations  between  the Company  and  Representatives  of the
Underwriters  and may not be  indicative  of the price at which the Common Stock
will  trade  after  completion  of  this  Offering.  For  factors  that  will be
considered in determining the initial public offering price, see "Underwriting."
After completion of this Offering, the market price of the Common Stock could be
subject to significant  fluctuations  in response to various factors and events,
including the liquidity of the market for the shares of Common Stock, variations
in the Company's operating results,  changes in earnings estimates by securities
analysts,  publicity  regarding  the Company,  the  infectious  disease test kit
industry or the healthcare  industry  generally,  new statutes or regulations or
changes in the interpretation of existing statutes or regulations  affecting the
healthcare  industry in general or the  infectious  disease test kit industry in
particular.  In addition, the stock market in recent years has experienced broad
price and volume  fluctuations  that often have been  unrelated to the operating
performance  of  particular  companies.   These  market  fluctuations  also  may
adversely affect the market price of the shares of Common Stock.

   
LACK OF UNDERWRITING HISTORY

    Kaufman Bros.,  L.P. became  registered as a broker-dealer  in July 1995 and
has participated in a limited number of public  offerings as an underwriter.  As
part of its due diligence  function,  the  Underwriters  make such  inquiries of
management as they deem  appropriate,  review the accuracy of the Prospectus and
establish the initial public  offering  price for the Common Stock.  Prospective
purchasers of Common Stock offered hereby should consider the limited experience
of Kaufman  Bros.,  L.P. in evaluating  an  investment in the Common Stock.  See
"Underwriting."
    

DILUTION

   
    Purchasers of shares in the Offering will suffer immediate dilution of $5.10
in net tangible book value per share. See "Dilution" and "Underwriting."
    

SHARES ELIGIBLE FOR FUTURE SALE

   
    Sales of substantial  amounts of Common Stock in the public  market,  or the
perception  that such sales may occur,  could  adversely  affect the  prevailing
market price of the Common Stock and the ability of the Company to raise capital
through a public  offering of its equity  securities.  Upon  completion  of this
Offering,  the Company will have  4,290,064  shares of Common Stock  outstanding
(4,530,064  shares if the  Underwriters'  overallotment  option is  exercised in
full). Of those shares,  the 1,600,000  shares sold in this Offering  (1,840,000
shares if the Underwriters'  overallotment  option is exercised in full) will be
freely tradeable without restriction (except as to affiliates of the Company) or
further  registration  under the Securities Act. All of the Company's  directors
and executive officers and certain other stockholders, holding in the
    


                                       12


   
aggregate  2,555,244  shares of Common Stock,  have agreed not to offer to sell,
sell or otherwise  dispose of any shares of Common Stock prior to the expiration
of 180 days from the date of this  Prospectus.  Oscar  Gruss & Son  Incorporated
may, in its sole discretion and at any time without prior notice, release all or
any  portion of the  shares of Common  Stock  subject to the lockup  agreements.
Beginning  91 days  after the date of this  Prospectus,  6,475  shares of Common
Stock will be  eligible  for sale in the  public  market  without  registration,
subject to certain  volume and other  limitations,  pursuant to Rule 144 or Rule
701 under the Securities Act of 1933, as amended (the  "Securities  Act") and an
additional  122,571 shares will be eligible for sale without such  restrictions.
Following the expiration of the 180-day lockup period,  an additional  1,643,197
shares of Common  Stock will be eligible for sale in the public  market  without
registration,  subject to certain volume and other limitations, pursuant to Rule
144 or Rule 701 under the Securities  Act and an additional  734,425 shares will
be eligible for sale without such  restrictions.  The remaining shares of Common
Stock held by existing stockholders,  including shares issuable upon exercise of
options,  will become  eligible  for sale under Rule 144 or otherwise at various
times  thereafter.  All shares of Common Stock  outstanding  on the date of this
Prospectus will be eligible for sale to certain qualified  institutional  buyers
in accordance  with Rule 144A under the Securities  Act. The Company  intends to
register  under  the  Securities  Act,  shortly  after the  consummation  of the
Offering,  shares of Common  Stock  issuable  upon  exercise of  employee  stock
options,  including  934,387  shares  issuable  upon  exercise  of such  options
outstanding on the date of this  Prospectus.  Two of the Company's  stockholders
and the holder of a warrant to purchase Common Stock have the right to cause the
Company to register  their shares under the  Securities Act and to include their
shares in certain  future  registrations  of securities  effected by the Company
under the  Securities  Act.  An  aggregate  of 627,650  shares of Common  Stock,
including  226,670  shares of Common Stock issuable upon exercise of outstanding
warrants,  are  covered  by  such  registration  rights.  If  such  holders,  by
exercising  their  registration  rights,  cause a large  number  of shares to be
registered and sold in the public market,  such sales may have an adverse effect
on the market price of the Common  Stock.  If the Company is required to include
in a Company-initiated  registration shares held by such holders pursuant to the
exercise of their piggyback  registration rights, such sales may have an adverse
effect  on  the  Company's  ability  to  raise  needed  capital.   See  "Certain
Transactions," "Principal Stockholders" and "Shares Eligible for Future Sale."
    


                                       13


                                 USE OF PROCEEDS

   
    The  net  proceeds  to be  received  by the  Company  from  the  sale of the
1,600,000  shares of Common Stock offered hereby are estimated to be $12,600,000
($14,587,200 if the Underwriters over-allotment option is exercised in full), at
an  assumed  public  offering  price of $9.00  per  share  and  after  deducting
estimated  underwriting  discounts and commissions and offering expenses payable
by the Company.

    The Company expects to use approximately $4.1 million of the net proceeds to
repay  outstanding  indebtedness,  as described  below, and  approximately  $1.0
million for capital  expenditures to expand its  manufacturing  capacity in West
Bridgewater, of which approximately $500,000 will be spent on building expansion
and  approximately  $500,000 will be spent on equipment.  The Company intends to
use $522,500 of the net proceeds of this Offering to fund the second installment
of its  investment in BioSeq.  The Company  anticipates  using the remaining net
proceeds for general corporate  purposes,  including working capital, as well as
for potential  acquisitions  and  alliances.  See "Risk Factors -- Risk of Broad
Management  Discretion in  Application  of Proceeds," and "Business -- Strategic
Alliances."

    At October 4, 1996, the  approximately  $4.1 million of  indebtedness  to be
repaid from the proceeds of this  Offering  consists of (i)  approximately  $2.3
million of  indebtedness  under a secured  revolving line of credit due June 30,
1998 that bears  interest at a rate equal to the prime rate plus 0.5% per annum;
(ii) a mortgage note in the principal  amount of  approximately  $685,215 on the
West Bridgewater  property that bears interest at a fixed rate of 8.3% per annum
until December 2000 and  thereafter  bears interest at a rate equal to the prime
rate plus 1% per annum,  and which is due December  2002;  (iii) a term note, in
the principal amount of $442,187,  that bears interest at 9.01% per annum and is
due in October 1998; (iv) a term note, in the principal amount of $137,037, that
bears  interest at the prime rate plus 1% per annum and is due October 1999; (v)
a term note, in the principal amount of $332,549,  that bears interest at a rate
equal to the prime plus 1% per annum and is due August  2000;  (vi) a term note,
in the principal  amount of $86,667,  that bears interest at a rate of 8.22% per
annum and is due December  2000;  and (vii) various  other notes that  aggregate
$78,456 due from June 1997 to August 2000. The proceeds from borrowings incurred
within  the past  year  were  used for  working  capital,  to  acquire  the West
Bridgewater  property,  to purchase capital  equipment and to make the Company's
$210,000 initial investment in BioSeq. See "Management's Discussion and Analysis
of Financial  Condition  and Results of  Operations"  and Note 6 of Notes to the
Consolidated Financial Statements.

    With respect to potential  acquisitions  and  alliances,  in addition to the
investment  in BioSeq,  the  Company  may use a portion of the net  proceeds  to
acquire blood donor centers and other businesses,  products or technologies that
are complementary to the Company's  current business,  although it currently has
no commitments for such acquisitions or alliances. See "Business -- Strategy."
    

    The specific  timing and amount of funds  required for specific  uses by the
Company  cannot be precisely  determined  at this time.  Pending such uses,  the
Company  intends to invest in short-term,  investment  grade,  interest  bearing
obligations.

                              DIVIDEND POLICY

    The Company has never  declared or paid cash  dividends on its capital stock
and does  not plan to pay any cash  dividends  in the  foreseeable  future.  The
Company's  current  policy is to retain all of its  earnings  to finance  future
growth. Any future determination to pay cash dividends will be at the discretion
of the Board of Directors  and will be dependent  upon the  Company's  financial
condition, operating results, capital requirements,  general business conditions
and such other factors as the Board of Directors deems relevant.  The Company is
subject to financial and operating  covenants,  including a prohibition  against
the  payment  of  cash  dividends,  under  its  bank  financing  agreement.  See
"Management's  Discussion  and  Analysis of Financial  Condition  and Results of
Operations -- Liquidity and Capital Resources."


                                       14


                              CAPITALIZATION

   
    The  following  table  sets  forth  as of  June  30,  1996  (i)  the  actual
capitalization of the Company,  (ii) the pro forma capitalization of the Company
after giving effect to the termination of certain redemption provisions relating
to 117,647  shares of Common Stock,  and (iii) as adjusted to give effect to the
sale of  1,600,000  shares of Common Stock  offered by the Company  hereby at an
assumed public  offering  price of $9.00 per share,  after  deducting  estimated
underwriting  discounts and commissions and estimated  offering expenses payable
by the Company.  This table should be read in conjunction  with the Consolidated
Financial  Statements  and related  notes  thereto  appearing  elsewhere in this
Prospectus.
    


<TABLE>
<CAPTION>
   
                                                                      JUNE 30, 1996
                                                                      -------------
                                                                                   PRO FORMA
                                                             ACTUAL   PRO FORMA   AS ADJUSTED
                                                             ------   ---------   -----------
                                                            (IN THOUSANDS, EXCEPT SHARE DATA)
<S>                                                         <C>       <C>         <C>
Current maturities of long term debt                         $  490    $  490       $  --
                                                             ======    ======       =======  
Long-term debt, less current maturities:                    
   Line of credit                                             1,398     1,398          --
   Bank term debt                                               719       719          --
   Mortgage term debt                                           620       620          --
   Other notes payable                                           61        61          --
                                                              -----     -----       -------        
                                                              2,798     2,798          --
                                                              -----     -----       -------        
Redeemable  common stock,  $.01 par value;  authorized
  issued and  outstanding  117,647, and none pro forma
  and pro forma  as adjusted                                    899      --            --
                                                              -----     -----       -------        
Stockholders' equity:
   Common  stock,  $.01 par  value;  authorized 
     15,000,000  shares;  issued and outstanding
     2,572,417 actual, 2,690,064 pro forma and
     4,290,064 pro forma as adjusted(1)                          26        27            43
   Preferred Stock
   Additional paid-in capital                                 2,717     3,615        16,199
   Retained earnings                                            589       589           589
                                                              -----     -----       -------        
     Total stockholders' equity                               3,332     4,231        16,831
                                                              -----     -----       -------        
     Total capitalization                                    $7,029    $7,029       $16,831
                                                             ======    ======       =======
    

</TABLE>


- ----------
(1)  Excludes the following at June 30, 1996: (i) 934,387 shares of Common Stock
     issuable  pursuant  to the  exercise  of  stock  options  outstanding  at a
     weighted  average  exercise  price of $3.15 per share,  of which options to
     purchase  653,684  shares were then  exercisable,  (ii)  226,670  shares of
     Common Stock issuable pursuant to the exercise of warrants outstanding at a
     weighted  average exercise price of $2.50 per share, all of which were then
     exercisable,  and  (iii)  14,333  shares  of  Common  Stock  issuable  upon
     conversion of the subordinated  convertible note at $1.50 per share.  Since
     June  30,  1996,  no  stock  options  were  exercised,  granted  or  became
     exercisable. See "MANAGEMENT -- Stock Plans."


                                       15




                                    DILUTION


   
    At June 30, 1996, the Company had a net tangible book value of $4,137,943 or
$1.54 per share of Common Stock.  "Net tangible book value per share" represents
the  tangible  book  value of the  Company  (total  tangible  assets  less total
liabilities)  divided by the number of shares of Common Stock  outstanding (on a
pro  forma  basis  to give  effect  to the  termination  of  certain  redemption
provisions  relating to 117,647  shares of Common  Stock).  Without  taking into
account any changes in such net tangible  book value as of June 30, 1996,  other
than to give effect to the sale by the Company of the 1,600,000 shares of Common
Stock offered hereby at an assumed  initial  public  offering price of $9.00 and
after  deducting  the  estimated  underwriting  discounts  and  commissions  and
offering expenses payable by the Company,  the pro forma net tangible book value
of the Company at June 30, 1996 would have been $16,737,943, or $3.90 per share.
This  represents an immediate  increase in the net tangible book value per share
of $2.36 to existing  stockholders and an immediate dilution of the net tangible
book value per share of $5.10 to persons  purchasing  the Common  Stock  offered
hereby (the "New  Investors").  The following table  illustrates  this per share
dilution:


Assumed initial public offering price per share                           $ 9.00
Net tangible book value per share before the Offering     $1.54
Increase per share attributable to New Investors           2.36 
                                                           ---- 
Pro forma as adjusted net tangible book value
  per share after the  Offering                                             3.90
                                                                            ----
Dilution per share to New  Investors                                       $5.10
                                                                           =====

    The  following  table sets forth on a pro forma basis,  as of June 30, 1996,
the total number of shares purchased from the Company after giving effect to the
sale of the 1,600,000 shares of Common Stock offered by the Company hereby,  the
total  consideration paid to the Company and the average price per share paid by
existing stockholders and by New Investors at an assumed initial public offering
price of $9.00 per share:
    


<TABLE>
<CAPTION>
   
                                       SHARES PURCHASED      TOTAL CONSIDERATION
                                       ----------------      -------------------
                                                                                     AVERAGE
                                                                                      PRICE
                                       NUMBER     PERCENT     AMOUNT      PERCENT   PER SHARE
                                       ------     -------     ------      -------   ---------
<S>                                   <C>         <C>       <C>           <C>       <C>
Existing Stockholders                 2,690,064     62.7%   $  3,835,373    21.0%     $1.43
New Investors                         1,600,000     37.3%    14,400,000     79.0%     $9.00
                                      ---------     ----     ----------     ----      
  Total                               4,290,064    100.0%   $18,235,373    100.0%
                                      =========    =====    ===========    ===== 
</TABLE>
    

    The above information assumes (i) no exercise of the Underwriters'  warrants
and (ii) no exercise of any other  outstanding  options and warrants  after June
30, 1996. As of June 30, 1996,  there were outstanding  options,  warrants and a
subordinated  convertible  note to purchase an aggregate of 1,175,390  shares of
Common Stock at exercise  prices  ranging  from $0.25 to $8.50 per share.  Since
June 30, 1996, no stock options were exercised,  granted or became  exercisable.
To the extent these  options and warrants are  exercised,  there will be further
dilution  to  New  Investors.   See   "Management  --  Stock  Plans,"   "Certain
Transactions" and Note 10 of Notes to Consolidated Financial Statements.


                                       16



                      SELECTED CONSOLIDATED FINANCIAL DATA

    The following table contains certain selected consolidated financial data of
the Company and is qualified in its entirety by the more  detailed  Consolidated
Financial  Statements and Notes thereto  included  elsewhere in this Prospectus.
The statement of operations  data for the fiscal years 1993,  1994 and 1995, and
the balance sheet data as of December 31, 1994 and 1995,  have been derived from
the Consolidated  Financial Statements of the Company which have been audited by
Coopers & Lybrand L.L.P., independent accountants, and which appear elsewhere in
this Prospectus. The balance sheet data as of December 31, 1993 are derived from
consolidated  financial  statements  that have been audited by Coopers & Lybrand
L.L.P.  The  statement  of  operations  data of the Company for the fiscal years
ending  December 31, 1991 and 1992 and the balance sheet data as of December 31,
1991 and 1992 have been derived from  consolidated  financial  statements of the
Company which have been audited by other  independent  public  accountants.  The
unaudited  consolidated  financial  data as of June  30,  1996,  and for the six
months ended June 30, 1996 and 1995,  have been  prepared on a basis  consistent
with the  audited  consolidated  financial  statements  and,  in the  opinion of
management,  include  all  adjustments  (consisting  only  of  normal  recurring
adjustments)  necessary to present fairly the financial condition and results of
operations for the periods presented.  The results for the six months ended June
30, 1996, are not necessarily indicative of the results that may be expected for
the year ending December 31, 1996. This data should be read in conjunction  with
the   Consolidated   Financial   Statements   and  related   Notes  thereto  and
"Management's  Discussion  and  Analysis of Financial  Condition  and Results of
Operations" appearing elsewhere herein.


<TABLE>
<CAPTION>
                                                                                                          SIX MONTHS ENDED
                                                                                                          ----------------
                                                               YEAR ENDED DECEMBER 31,                   JUNE 30,   JUNE 30,
                                                               -----------------------                   --------   --------
                                                  1991    1992(1)   1993(2)(3)       1994      1995       1995       1996
                                                  ----    -------   ----------       ----      ----       ----       ----
                                                        (IN THOUSANDS, EXCEPT PER SHARE DATA)
<S>                                              <C>      <C>        <C>            <C>       <C>        <C>        <C>
   
CONSOLIDATED STATEMENT OF OPERATIONS DATA:
REVENUE:
   Product sales                                 $2,146    $2,955       $3,942      $ 5,982   $ 6,622    $3,024     $ 3,946
   Services                                         264     1,680        5,215        4,741     5,649     2,540       2,982
                                                    ---     -----        -----        -----     -----     -----       -----
     Total revenue                                2,410     4,635        9,157       10,723    12,271     5,564       6,928
                                                  -----     -----        -----       ------    ------     -----       -----
COSTS AND EXPENSES:
   Cost of product sales                          1,172     1,638        2,088        3,194     3,564     1,646       2,007
   Cost of services                                 191     1,443        3,965        3,416     4,168     1,960       2,250
   Research and development                         104       222          279          469       375       159         362
   Selling and marketing                            372       353          894        1,192     1,340       638         915
   General and administrative                       436       745        1,619        2,047     2,316     1,057       1,088
                                                    ---       ---        -----        -----     -----     -----       -----
     Total operating costs and expenses           2,275     4,401        8,845       10,318    11,763     5,460       6,622
                                                  -----     -----        -----       ------    ------     -----       -----
     Income from operations                         135       234          312          405       508       104         306
Interest expense, net                               101       113          179          244       336       164         168
                                                    ---       ---          ---          ---       ---       ---         ---
   Income (loss) before income taxes and
     extraordinary item                              34       121          133          161       172       (60)        138
Provision for income taxes                           (5)      (45)         (41)         (64)      (69)       24         (55)
                                                  -----     -----       ------      -------    ------    ------      ------ 
   Income (loss) before extraordinary item           29        76           92           97       103       (36)         83
Extraordinary item-gain on elimination of debt,
  net of income taxes                                --        --           50           --        --        --          --
                                                  -----     -----       ------       ------    ------    ------      ------
  Net income (loss)                              $   29    $   76       $  142      $    97   $   103    $  (36)    $    83
                                                 ======    ======       ======      =======   =======    ======     =======
Net income (loss) per share(4)(5)                $ 0.01    $ 0.04       $ 0.06      $  0.04   $  0.04    $(0.01)    $  0.03
Weighted average common and common equivalent
  shares outstanding(4)(5)                        1,948     2,160        2,438        2,587     3,151     2,598      3,253
</TABLE>
    
                                       17


<TABLE>
<CAPTION>
   
                                                                         DECEMBER 31,                       JUNE 30, 1996    
                                                                         ------------                       -------------    
                                                           1991     1992     1993     1994     1995     ACTUAL   PRO FORMA(7)
                                                           ----     ----     ----     ----     ----     ------   ------------
                                                            (IN THOUSANDS, EXCEPT PER SHARE DATA)
<S>                                                       <C>      <C>      <C>      <C>      <C>      <C>       <C>
CONSOLIDATED BALANCE SHEET DATA:                       
Working capital(6)                                        $1,698   $2,457   $3,612   $4,686   $4,829   $ 4,497      $ 4,497
Total assets                                               2,624    4,828    6,870    8,076    9,928    10,047       10,047
Long term debt, less current maturities(6)                   993    1,760    2,381    3,180    4,216     2,798        2,798
Redeemable common stock                                     --       --       --       --       --         899        --
Total stockholders' equity                                   993    1,837    2,762    3,041    3,187     3,332        4,231
Dividends -- None                                      
    
                                              
</TABLE>

- -----------
   
(1) Effective July 1, 1992, the Company acquired through its BTRL subsidiary the
    net assets of a division of Cambridge Biotech Corporation for $762,000 which
    increased 1992 revenues by $1,450,000.
    

(2) On  June  30,  1993,  the  Company  exercised  its  option  to  pre-pay  the
    acquisition  note  in  connection  with  the  1992  purchase  of  BTRL  at a
    substantial  discount  from the balance due,  resulting in an  extraordinary
    gain of $50,000 net taxes of $33,000.  The 1993 net income per share  before
    such extraordinary gain was $0.04.

(3) Effective  January 1, 1993,  the  Company  acquired  the net assets of North
    American  Laboratory  Group Ltd.,  Inc. for $425,000,  which  increased 1993
    revenues by $2,019,000.

(4) The effect of the common stock  equivalents on net income per share has been
    excluded from the calculation for years ended December 31, 1991 through 1994
    and the six months ended June 30, 1995 as its inclusion was antidilutive.

   
(5) Pro forma  supplementary  earnings per share for the year ended December 31,
    1995  and  the  six  months   ended  June  30,  1996  were  $.09  and  $.06,
    respectively,  based  upon an  assumed  weighted  average  common and common
    equivalent shares outstanding of 3,600,007 and 3,701,173,  respectively.  In
    accordance with APB Opinion 15, pro forma  supplementary  earnings per share
    is presented as if the Company  sold on January 1, 1995,  448,530  shares of
    Common Stock,  representing the number of shares of Common Stock required to
    be sold at the assumed  initial public  offering price of $9.00 per share in
    order for the Company to repay the indebtedness  outstanding  during 1995 as
    if the Offering had occurred on January 1, 1995.  See "Use of Proceeds"  and
    Note 12 of Notes to Consolidated Financial Statements.

(6) The Company's  demand line of credit with  outstanding  amounts of $880,000,
    $1,091,000  and  $1,895,000  as  of  December  31,  1991,   1992  and  1993,
    respectively,  has been  presented as part of long-term  debt (and  excluded
    from current  liabilities in calculating  working  capital) for 1991 through
    1993 to be consistent with its  reclassification  to long-term debt in 1994,
    1995 and 1996 due to a modification of its maturity date.

(7) Adjusted to reflect the  reclassification  of  Redeemable  Common Stock into
    117,647  shares of Common Stock upon  completion of this  Offering,  thereby
    terminating the redemption provisions.
    


                                       18


                    MANAGEMENT'S DISCUSSION AND ANALYSIS OF
                  FINANCIAL CONDITION AND RESULTS OF OPERATIONS

    This Prospectus contains forward-looking  statements which involve risks and
uncertainties.  The Company's actual results may differ  significantly  from the
results discussed in the  forward-looking  statements.  Factors that might cause
such a  difference  include,  but are not limited to,  those  discussed in "Risk
Factors."

    The following discussion and analysis should be read in conjunction with the
Company's  Consolidated  Financial  Statements  and the Notes thereto  appearing
elsewhere in this Prospectus.

OVERVIEW

    The Company  generates revenue from products and services provided to the in
vitro diagnostic infectious disease industry.  Products consist of three groups:
Quality  Control  Panels,  Accurun(tm)  Run Controls and Diagnostic  Components.
Services consist of Specialty Clinical  Laboratory  Testing,  Contract Research,
Clinical Trials and Drug Screening.  In the three full years since the Company's
acquisition of BTRL and BBI-NACL, the Company has experienced a shift in revenue
mix towards increased product sales, as product revenue as a percentage of total
revenue  increased  from  43.1% in 1993 to 54.0% in 1995,  with a  corresponding
decrease in the percentage of total revenue provided by services.

    The Company's  gross profit margin  increased from 33.9% in 1993 to 37.0% in
1995  principally  as a result of the  increased  percentage  of  higher  margin
product  revenues.  Within  products,  the Company's  Quality  Control  Products
(Accurun(tm)  Run Controls and Quality  Control Panels) have higher margins than
the Company's Diagnostic  Components.  Within services,  Contract Research gross
margins  are lower than  other  services.  However,  such  contracts  enable the
Company  to  maintain  certain  scientific  staff and  capability  that it might
otherwise not be able to afford.  The Company intends to continue to concentrate
on the growth in sales of its Quality Control Products.

    Historically,  the  Company's  results of  operations  have been  subject to
quarterly  fluctuations  due  to  a  variety  of  factors,   including  customer
purchasing patterns, primarily driven by end-of-year expenditures,  and seasonal
demand  during the summer months for certain  laboratory  testing  services.  In
particular,  the Company's sales of its Quality Control  Products and Diagnostic
Components  typically  have been highest in the fourth quarter and lowest in the
first quarter of each fiscal year, whereas Specialty Clinical Laboratory Testing
has generally reached a seasonal peak during the third quarter,  coinciding with
the peak incidence of Lyme Disease.  Research  Contracts are generally for large
dollar  amounts  spread  over a one or two year  period,  and  upon  completion,
frequently  do not have  renewal  phases.  As a  result  they  can  cause  large
fluctuations  in revenue and net  income.  In  addition  to staff  dedicated  to
internal research and development, certain of the Company's technical staff work
on both  Contract  Research for  customers  and Company  sponsored  research and
development.  The allocation of certain technical staff to such projects depends
on the  volume of  Contract  Research.  As a result,  research  and  development
expenditures  fluctuate due to increases or decreases in Contract Research.  See
"Risk Factors -- Fluctuations in Quarterly Results of Operations."

    To develop new Quality Control  Products and support  increased  sales,  the
Company hired  additional  research and development  staff in the second half of
1995 and sales and marketing  staff in 1996. The Company  intends to continue to
add staff to these departments.  This should cause both research and development
and selling and  marketing  expenses to increase as a  percentage  of revenue in
1996 and 1997,  compared to 1995.  General and  administrative  expenses are not
expected  to increase  at the same rate,  as the  Company  has already  incurred
significant infrastructure expenses.

    The Company does not have any foreign operations.  However, the Company does
have significant export sales to agents under distribution  agreements,  as well
as  directly  to test kit  manufacturers.  All  sales  are  denominated  in U.S.
dollars. Export sales for the years ended December 31, 1993, 1994, and 1995 were
$1.4 million,  $2.3 million,  and $3.1  million,  respectively,  and for the six
months  ended  June 30,  1995 and  1996  were  $1.5  million  and $1.9  million,
respectively.  The  Company  expects  that  export  sales will  continue to be a
significant  source of revenue and operating income.  See "Risk Factors -- Risks
Associated with Export Sales."



                                       19


    The Company's cash flow from  operations  over the last three years has been
negative as it funded  investment in research and  development,  increased sales
and marketing  expenditures,  and supported growth-driven working capital needs.
The Company funded the shortfall  through a combination of sales of common stock
and bank financing.  The Company anticipates using a portion of the net proceeds
of this Offering for working  capital  requirements  until such time as its cash
flow from operations becomes sufficient.

RESULTS OF OPERATIONS

    The following  table sets forth for the periods  indicated the percentage of
total  revenue   represented  by  certain  items   reflected  in  the  Company's
consolidated statements of operations:

<TABLE>
<CAPTION>
                                               YEAR ENDED           SIX MONTHS
                                              DECEMBER 31,        ENDED JUNE 30,
                                              ------------        --------------
                                         1993     1994     1995    1995     1996
                                         ----     ----     ----    ----     ----
<S>                                     <C>      <C>      <C>      <C>     <C>
Revenue:
  Products                               43.1%    55.8%   54.0%    54.4%   57.0%
  Services                               56.9     44.2    46.0     45.6    43.0
    Total revenue                       100.0    100.0   100.0    100.0   100.0
Gross profit                             33.9     38.4    37.0     35.2    38.6
Operating expenses:
   Research and development               3.0      4.4     3.1      2.9     5.2
   Selling and marketing                  9.8     11.1    10.9     11.4    13.2
   General and administrative            17.7     19.1    18.9     19.0    15.7
     Total operating expenses            30.5     34.6    32.9     33.3    34.1
   Income from operations                 3.4      3.8     4.1      1.9     4.4
Interest expense                          2.0      2.3     2.7      3.0     2.4
  Income (loss) before income taxes       1.5      1.5     1.4     (1.1)    2.0
  Net income (loss)                       1.6      0.9     0.8     (0.6)    1.2
Product gross profit                     47.0%    46.6%   46.2%    45.6%   49.1%
Services gross profit                    24.0%    28.0%   26.2%    22.8%   24.6%
</TABLE>

 SIX MONTHS ENDED JUNE 30, 1996 AND 1995

    Total revenue  increased  24.5%,  or  $1,364,000,  to $6,928,000 for the six
months  ended  June 30,  1996 from  $5,564,000  in the prior year  period.  This
increase was the result of an increase in product  sales of 30.4%,  or $921,000,
to $3,946,000 from $3,025,000 and an increase in specialty  laboratory  services
of 17.4%, or $443,000, to $2,983,000 from $2,540,000.  Product revenue increased
primarily  as a result  of an  overall  increase  of 34.5%  in  Quality  Control
Products,  due to  sales  of new  products  and  increased  volume  of  existing
products,  including  an  increase  of 132.5% in the sales of  Accurun(tm).  The
increase in service  revenue was primarily  attributable  to a 19.0% increase in
Specialty  Clinical  Laboratory  Testing revenue,  particularly  molecular (PCR)
testing,  and the  addition  of two new  research  contracts  with the  National
Institutes of Health in the fourth quarter of 1995.

    Gross profit increased 36.5%, or $714,000,  to $2,672,000 for the six months
ended June 30, 1996 from  $1,958,000 in the prior year period.  The gross profit
margin  increased to 38.6% in the six months ended June 30, 1996 versus 35.2% in
the prior year  period.  Gross  margins  improved  in both  products,  (45.6% to
49.1%), and services (22.8% to 24.6%), as the Company benefited from an improved
revenue mix at the higher volume level.

    Research and development expenses increased 127.4%, or $203,000, to $362,000
for the six months  ended June 30, 1996 from  $159,000 in the prior year period.
Research and development costs as a percentage of revenues increased to 5.2% for
the six months ended June 30, 1996 from 2.9% in the comparable 1995 period. This
increase was primarily the result of increased  costs of personnel  hired in the
second half of 1995 which enabled the Company to introduce  over 30 new products
in the first half of 1996 compared with 15 new  introductions  in the prior year
period.


                                       20


    Selling and marketing expenses increased 43.6%, or $278,000, to $915,000 for
the six months ended June 30, 1996 from $638,000 in the prior year period.  This
increase was primarily attributable to increased personnel costs associated with
the addition of  tele-sales  staff for Quality  Control  Products,  particularly
Accurun(tm),  and increased  advertising  costs due to the  commencement  of the
Company's "Total Quality System" (TQS) marketing campaign.

    General  and  administrative   expenses  increased  3.0%,  or  $31,000,   to
$1,088,000  for the six months ended June 30, 1996 from  $1,057,000 in the prior
year period. As a result,  general and  administrative  expenses  decreased as a
percentage  of revenues to 15.7% for 1996 from 19.0% in the prior year period as
management maintained close control of expense levels.

    Interest expense was essentially  unchanged in the six months ended June 30,
1996 versus the prior year period as the prime rate  increases in late 1995 were
offset by reduced borrowing due to both additional equity raised and prepayments
from certain customers for contract research services.

 YEARS ENDED DECEMBER 31, 1995 AND 1994

    Total revenue  increased  14.4%, or $1,548,000,  to $12,271,000 in 1995 from
$10,723,000 in 1994. The increase in revenues was the result of a 10.7% increase
in product  revenues of  $640,000 to  $6,622,000  from  $5,981,000,  and a 19.1%
increase in service  revenues of $908,000 to $5,649,000  from $4,741,000 in 1995
compared  to 1994.  The  increase  in product  revenue  was  attributable  to an
increase  in prices at the  beginning  of 1995 and an  increase in the volume of
sales of  Quality  Control  Products  and  Basematrix  (part  of the  Diagnostic
Components  group),  which  increase  was  partially  offset by the  absence  of
revenues  in 1995  from two OEM  Quality  Control  Panel  contracts  which  were
completed in 1994.  The Company also  reduced  emphasis on certain  lower margin
Diagnostic  Components  as it focused  more  effort on sales of its  proprietary
Basematrix  product,  which carries a higher  margin.  During 1995,  the Company
reorganized  its sales and  marketing  department  and believes that this had an
adverse effect on sales growth for the period.  The increase in service  revenue
was primarily the result of increased specialty clinical laboratory testing, two
new research  contracts and increased  clinical trial services,  particularly in
the area of HIV.

    Gross profit  increased  10.4%,  or $426,000,  to  $4,539,000  for 1995 from
$4,113,000  in 1994.  Products  gross profit  increased  9.7%,  or $270,000,  to
$3,057,000 in 1995 from  $2,787,000 in 1994 as the products  sales  increase was
offset by a small  decrease in products  gross  profit  margin (to 46.2% in 1995
from 46.6%). The products gross margin decrease was a result of a small increase
in material handling personnel costs.  Services gross profit increased 11.8%, or
$156,000,  to $1,481,000 in 1995 from  $1,326,000 in 1994 as the sales  increase
was offset by a decrease in services  gross profit  margin to 26.2% in 1995 from
28.0% in 1994. Services gross margin declined primarily as a result of increased
personnel costs in the specialty clinical laboratory and an increase in contract
research activities, which carry a lower margin.

    Research  and  development  expenditures  decreased  20.0%,  or $94,000,  to
$376,000 in 1995 from  $469,000 in 1994.  The  decrease  resulted  from  certain
technical staff being utilized for Company sponsored research and development in
1994 and Contract  Research in 1995.  See "-- Years Ended  December 31, 1994 and
1993." Development  projects included  Accurun(tm),  molecular and immunological
Run Controls,  specialized  molecular  assays,  and the  development of a second
generation  Lyme Disease western blot test kit for internal use by the Company's
specialty testing laboratory.

    Selling and marketing expenses  increased 12.4%, or $148,000,  to $1,340,000
in 1995 from  $1,192,000  in 1994.  The increase was primarily  attributable  to
additional  sales and marketing  staff and overhead,  partially  offset by lower
trade show and travel expenses as the Company realized greater benefits from its
distributor network.

    General and administrative costs increased 13.1%, or $269,000, to $2,316,000
in 1995 from  $2,047,000 in 1994.  This increase was primarily  attributable  to
additional  staffing in support of revenue growth and higher reserve  provisions
for doubtful accounts associated with the increased volume of revenue related to
testing in situations  where payment to the Company  depends on collecting  from
the


                                       21

patient  rather than a healthcare  institution.  These  increases were partially
offset by lower  professional  fees. Also included in general and administrative
expense was approximately $60,000 of nonrecurring costs associated with the move
of the specialty testing laboratory into a larger, custom-designed facility.

    Interest  expense  increased  37.8%,  or  $92,000,  to $336,000 in 1995 from
$244,000 in 1994,  as the Company  funded its working  capital  needs  primarily
through increased borrowings.

 YEARS ENDED DECEMBER 31, 1994 AND 1993

    Total revenue  increased  17.1%, or $1,566,000,  to $10,723,000 in 1994 from
$9,157,000  in 1993.  This  increase  was a result  of a 51.7%,  or  $2,039,000,
increase in product sales, partially offset by a 9.1%, or $473,000,  decrease in
service revenue.  The product sales increase was primarily  attributable to unit
volume growth of both existing and new Quality  Control  Panels for HIV and HCV,
and, to a lesser extent, to sales of the Company's first molecular-based Quality
Control Panel targeted for end-user PCR training.  The service  revenue  decline
was primarily  attributable  to the  completion in February 1994 of a government
contract  with the United  States Army for  retrovirology  research that reduced
contract  research  revenue by  approximately  $1,100,000  in 1994 compared with
1993. This decrease was partially  offset by a $676,000,  or 36.5%,  increase in
specialty laboratory testing services.

    Gross profit  increased  32.5%,  or $1,009,000,  to $4,113,000 for 1994 from
$3,104,000 in 1993.  Products  gross profit  increased  50.3%,  or $933,000,  to
$2,787,000 in 1994 from  $1,855,000 in 1993 as the products  sales  increase was
partially  offset by a small decrease in products gross margin (to 46.6% in 1994
from  47.0%).  The products  gross margin  decrease was a result of higher costs
associated  with pilot  manufacturing  of  Accurun(tm).  Services  gross  profit
increased 6.1%, or $76,000, to $1,326,000 in 1994 from $1,250,000 in 1993 as the
sales  decrease was more than offset by an increase in services gross margin (to
28.0% in 1994 from 24.0%). Services gross margin increased primarily as a result
of improved economies of scale at its specialty clinical  laboratory afforded by
higher test volume,  and redeployment of staff into Company  sponsored  research
and development projects.

    Research and development  expenditures  increased by 68.3%, or $190,000,  to
$469,000 in 1994 from $279,000 in 1993 as the Company commenced several research
and development  projects,  including  development of Quality Control Panels for
molecular  diagnostics,  increased  expenditures related to the development of a
PCR test for Lyme Disease,  and a second  generation  Lyme Disease  western blot
test kit for internal use by the Company's specialty clinical laboratory.

    Selling and marketing expenses  increased 33.3%, or $297,000,  to $1,192,000
in 1994 from $894,000 in 1993. This increase was primarily attributable to staff
additions in sales and customer  service  support for the products  business and
also higher travel costs.

    General  and  administrative  expenses  increased  26.4%,  or  $428,000,  to
$2,047,000  in 1994  from  $1,619,000  in  1993.  This  increase  was  primarily
attributable  to a full year impact of staff  additions in information  systems,
regulatory  affairs and accounting in support of the Company's  sales growth and
growth  expectations  in both the Quality  Control  Products  and the  Specialty
Clinical Laboratory Services business.

    Interest  expense  increased  36.4%,  or  $65,000,  to $244,000 in 1994 from
$179,000  in 1993 as the  Company  funded its  increased  equipment  and working
capital needs primarily from borrowings.

LIQUIDITY AND CAPITAL RESOURCES

    The Company has  financed  its  operations  to date  through  cash flow from
operations, borrowings from banks and sales of equity.

   
    At June 30, 1996 the Company had  $1,398,000  outstanding  and $2,028,000 of
availability  under its $3.5 million Revolving Line of Credit Agreement due June
30, 1998 (the  "Revolver").  The Revolver  bears interest at a rate equal to the
prime rate plus 0.5% per annum,  currently  8.75%.  Prior to June 30, 1996,  the
Revolver  bore  interest  at a rate  equal to the prime  rate plus 1% per annum.
Under the terms of the  Revolver,  the  Company  operates  under a zero  balance
account  arrangement  whereby cash

                                       22



receipts are received into a lockbox at the bank and reduce the Revolver,  while
disbursements  for payroll and accounts  payable items increase the  outstanding
balance of the  Revolver.  Borrowings  under the  Revolver are limited to 80% of
eligible  accounts  receivable  plus  the  lesser  of 40% of  inventory  or $1.5
million.  The Revolver  contains  various  covenants  and  restrictions  and the
amounts  outstanding are secured by all of the Company's assets and a $2 million
life  insurance  policy  on an  officer/stockholder.  See Note 6 to Notes to the
Consolidated  Financial Statements.  The Company expects to use a portion of the
proceeds of the Offering to repay the  outstanding  amount  under the  Revolver,
which at October 4, 1996 was  approximately  $2,300,000.  See "Use of Proceeds."
Amounts repaid on the Revolver will be available for reborrowing.
    

    Net cash provided by  operations  for the six months ended June 30, 1996 was
$685,000 as compared to $105,000 in the prior year period. This increase in cash
flow was primarily  attributable to an increase in net income and an increase in
deferred revenue from a payment of $308,000 under a research contract for future
clinical  trial  services.  Cash flow used in operations in 1995,  1994 and 1993
amounted to $29,000, $554,000 and $427,000,  respectively.  The decrease in cash
used in operations in 1995 from 1994 was primarily  attributable  to an increase
in deferred revenue.

    Cash used in investing activities for the six months ended June 30, 1996 was
$283,000 as compared to  $216,000  in the prior year  period.  This  increase in
investing  activities  was the  result of  increased  capital  expenditures  for
production  equipment  associated  with  Accurun(tm)  and other Quality  Control
Products.  Cash used in investing activities for 1995, 1994 and 1993 amounted to
$1,320,000,  $405,000 and $850,000,  respectively.  The increased use of cash in
1995  versus  1994  was  the  result  of  the  purchase  of the  Company's  West
Bridgewater facility and in 1993 related to the acquisition of the net assets of
North American Laboratory Group Limited, Inc.

   
    Cash used in financing activities for the six months ended June 30, 1996 was
$403,000 as compared to $151,000  provided by financing  activities in the prior
comparable year period. Net cash was used in financing activities primarily as a
result of the repayment of $1,591,000 of the Revolver  offset by $899,000 raised
through the sale of 117,647 shares of Common Stock to Kyowa Medex,  Co., Ltd. in
April 1996.  Cash  provided by  borrowings  for 1995,  1994 and 1993 amounted to
$1,240,000, $846,000 and $494,000,  respectively, and net proceeds from the sale
of  Common  Stock for the same  periods  amounted  to  $176,000,  $170,000,  and
$765,000, respectively. The proceeds of such debt were used for working capital,
to acquire the West Bridgewater property and to purchase capital equipment.  The
Company  expects to use a portion of the  proceeds of the  Offering to repay the
outstanding  balances on these notes  payable,  which  aggregated  approximately
$1,829,000 at August 1, 1996. See "Use of Proceeds."

    Capital  expenditures  relate  primarily  to the  Company's  facilities  and
related  equipment.  For the six months  ended June 30,  1996 and 1995,  capital
expenditures  totaled  $283,000 and $216,000  respectively.  This  represents an
increase  of $67,000  in the six months  ended  June 30,  1996,  as the  Company
continues to invest in manufacturing  equipment and information  systems related
to both  operations  and finance.  In 1995,  1994 and 1993 capital  expenditures
amounted to $1,316,000,  $405,000 and $461,000,  respectively. In 1995, $806,000
of the  Company's  capital  expenditures  related  to the  purchase  of the West
Bridgewater  facility.  As of October 4, 1996, the Company has available to it a
$250,000  five  year term  facility  to  finance  equipment  purchases,  bearing
interest at prime plus 1%.

    The Company anticipates capital  expenditures to increase over the near term
as it  expects to use  approximately  $1.0  million  from the  proceeds  of this
Offering to expand its manufacturing  capacity in West Bridgewater over the next
12 months, of which  approximately  $500,000 will be spent on building expansion
and approximately $500,000 will be spent on equipment.  The Company also expects
to use  $522,500 to fund the  Company's  purchase of its second  installment  of
capital stock of BioSeq  following the completion of this Offering.  See "Use of
Proceeds."  The Company must make the remaining  $750,000  installment if BioSeq
attains certain technical milestones by July 31, 1997. If the milestones are not
achieved,  the Company will have the option to purchase the additional  $750,000
of BioSeq  capital  stock until  December 31, 1997.  The Company  believes  that
existing cash balances,  the borrowing  capacity  available  under the Revolver,
cash generated from  operations and the proceeds of this Offering are sufficient
to fund  operations and  anticipated  capital  expenditures  for the foreseeable
future. There were no material financial commitments for capital expenditures as
of June 30, 1996, and currently there are no material commitments for capital or
investment expenditures other than the BioSeq investment.
    


                                       23


   
    On April 26,  1996 the  Company  entered  into a new five year  distribution
agreement with Kyowa Medex,  Co., Ltd., a foreign  distributor,  extending a six
year old relationship.  Simultaneously, Kyowa Medex, Co., Ltd. purchased 117,647
shares of the Company's Common Stock at a price of $8.50 per share. The Purchase
Agreement includes a redemption right that may require the Company to repurchase
the  stock  at  $8.50  per  share  in  the  event  the  Company  terminates  the
distribution  agreement or it expires prior to the Company completing an initial
public  offering of its Common  Stock.  These shares have been  presented in the
Company's  balance sheet  separately as redeemable  Common Stock.  Completion of
this initial public offering will terminate the redemption  provisions and cause
the reclassification of these shares into stockholders' equity.
    

RECENT ACCOUNTING PRONOUNCEMENTS

   
    In March 1995, the Financial  Accounting Standards Board issued Statement of
Financial  Accounting  Standards  No. 121,  "Accounting  for the  Impairment  of
Long-Lived  Assets and for  Long-Lived  Assets to Be Disposed Of" ("SFAS  121").
SFAS 121 requires that an impairment  loss be recognized for  long-lived  assets
and certain identified  intangibles when the carrying amount of these assets may
not be  recoverable.  The Company has adopted SFAS 121 effective in 1996 and the
adoption did not have a material impact on the financial statements.
    

    In October 1995, the FASB issued Statement of Financial Accounting Standards
No. 123 ("SFAS 123")  "Accounting for Stock-Based  Compensation,"  which becomes
effective  for  fiscal  years  beginning  after  December  15,  1995.  SFAS  123
establishes  new financial  accounting and reporting  standards for  stock-based
compensation  plans.  However,  entities are allowed to elect whether to measure
compensation expense for stock-based  compensation under SFAS 123 or APB No. 25,
"Accounting  for Stock Issued to Employees." The Company has elected to continue
to account under APB No. 25 and will make the required pro forma  disclosures of
net  income and  earnings  per share as if the  provisions  of SFAS 123 had been
applied in its December 31, 1996 financial  statements.  The potential impact of
adopting this standard on the Company's pro forma  disclosures of net income and
earnings per share has not been quantified at this time.


                                       24




                                    BUSINESS

GENERAL

    The Company is a leading worldwide  provider of proprietary  quality control
products  for use with in vitro  diagnostic  test  kits  ("test  kits")  for the
detection,  analysis and  monitoring of  infectious  diseases,  including  AIDS,
Hepatitis  and Lyme  Disease.  These  products are used to develop test kits, to
permit the monitoring of laboratory equipment and personnel,  and to help ensure
the  accuracy of test  results.  The  Company's  products are derived from human
plasma and serum using proprietary manufacturing processes. The Company believes
its Quality Control Panel products are viewed as the current  industry  standard
for the  independent  assessment of the  performance  of HIV and Hepatitis  test
kits. The Company also manufactures  diagnostic test kit components and provides
specialty  laboratory   services,   including  clinical  trials.  The  Company's
customers include test kit manufacturers,  regulatory  agencies and end-users of
test kits such as blood banks,  hospital  laboratories  and  clinical  reference
laboratories.  Currently the Company's  products are used in connection with the
detection of more than 15  infectious  diseases,  and its  specialty  laboratory
services are used in connection with the detection of over 100 such diseases.

INDUSTRY OVERVIEW

    According to the World Health Organization ("WHO"),  infectious diseases are
now the leading  cause of  premature  death  around the world and the third most
common  cause of premature  death in the United  States.  In 1995,  more than 17
million people died from exposure to infectious  diseases,  constituting  nearly
one-third of the  approximately  52 million  people  worldwide who died from all
causes.  Currently,  the  Company  focuses  on two  infectious  diseases,  Viral
Hepatitis and AIDS,  which are among the largest  killers and are also a primary
focus of blood testing efforts worldwide.

    WHO estimates that  approximately  20 million people  worldwide are infected
with HIV,  and that  approximately  one million  people  died from  AIDS-related
illnesses  during  1995.  WHO  also  estimates  that  up to 350  million  people
worldwide  are infected  with  Hepatitis  Type B, one of several  types of Viral
Hepatitis, and that over one million people died of Viral Hepatitis during 1995.
In developed countries,  blood products are routinely screened for HIV and Viral
Hepatitis by use of infectious disease test kits.

   
    The  increased  threat  from  infectious  diseases  has  created a large and
growing  market  for test  kits.  Venture  Planning  Group,  a medical  products
research firm,  estimates that the worldwide  infectious disease test kit market
was  approximately  $2.7 billion in 1995,  and will grow to $5.0 billion by 2000
and $8.0 billion by 2005.
    

    Infectious  Disease Test Kits and Testing Methods.  Test kits contain in one
compact  package all of the materials  necessary to run a test for an infectious
disease. These include the disposable diagnostic components,  instructions,  and
reaction  mixing  vessels  (generally  96-well  plates or test tubes)  which are
coated  with the  relevant  infectious  disease  antigens,  antibodies  or other
materials.  To perform the test,  either a  technician  or a specially  designed
instrument  typically  mixes the  solutions  from the test kit with human  blood
specimens in a specific  sequence  according to the test kit  instructions.  The
mixture must then  "incubate" for up to 18 hours,  during which time a series of
biochemical  reactions trigger signals  (including color,  light and radioactive
count) which indicate the presence or absence and amount of specific  markers of
the particular disease in the specimen.

    Test kits  generally  employ one of three  methods  for  infectious  disease
testing: microbiology, immunology or molecular biology. Traditional microbiology
tests use a growth medium that enables an organism, if present, to replicate and
be detected visually.  Immunology tests detect the antigen or antibody, which is
an  indicator  (marker)  of the  pathogen  (e.g.,  virus,  bacterium,  fungus or
parasite).  Molecular diagnostic methods,  such as the polymerase chain reaction
("PCR"),  test for the presence of nucleic acids (DNA or RNA) which are specific
to a particular pathogen.

                                       25



    Most infectious disease tests currently use microbiological or immunological
methods.  However,  molecular  diagnostic methods are increasingly being used in
research laboratories  worldwide and the Company believes that soon they will be
accepted  for  routine  use in the  clinical  laboratory  setting.  The  Company
believes that the advent of molecular  diagnostic methods will complement rather
than diminish the need to test by microbiological and immunological  procedures,
because  different test methods  reveal  different  information  about a disease
state. The Company  anticipates that as new test methods become more widespread,
they will account for a larger portion of the Company's business.

   
    Quality Control for In Vitro Diagnostic Test Kits.  Customers employ quality
control  products  in order to develop  and use test kits (both  infectious  and
non-infectious).  Quality control products help ensure that test kits detect the
correct   analyte   (specificity),   detect   it  the   same  way   every   time
(reproducibility  or  precision),  and  detect  it  at  the  appropriate  levels
(sensitivity).  The  major  element  of  this  quality  control  process  is the
continuous  evaluation  of test kits by the testing of  carefully  characterized
samples that resemble the donor or patient samples routinely used with the test.
Quality  control  is used in both  the  infectious  and  non-infectious  disease
markets, although currently it is not as prevalent among end-users of infectious
disease test kits.
    

    The market for quality  control  products  consists  of three main  customer
segments:  (i) manufacturers of test kits, (ii) regulatory agencies that oversee
the  manufacture  and use of test kits and (iii) end-users of test kits, such as
hospitals, clinical reference laboratories and blood banks.

    According to the Genesis  Report Dx (May 1994), a medical  products  survey,
the quality  control market for in vitro  diagnostic  testing for infectious and
non-infectious  disease in 1994 totaled  approximately $600 million. The Company
believes that the market for quality  control  products for  infectious  disease
testing  currently  represents  less than five  percent of the  overall  quality
control  market.  At  the  present  time,  most  quality  control  products  for
non-infectious  disease test kits are sold to  end-users,  who have used quality
control  products as part of standard  laboratory  practice for several decades.
Conversely,  most quality control  products for the infectious  disease test kit
segment of the market are sold to test kit manufacturers and regulators, and not
to end-users,  who have  historically  used quality  control  products only on a
limited  basis.  The  Company  believes  that this  lower  level of usage  among
end-users  of  infectious  disease  test  kits is  primarily  due to  laboratory
practices  that have evolved from earlier  testing  methods that did not require
routine  and  extensive  use of  external  quality  controls as part of standard
laboratory practice. However, the Company also believes that this lower level of
usage among end-users of test kits represents a major market  opportunity  since
current testing methods have been improving test kit performance to increasingly
higher  levels of  sensitivity,  specificity  and  reproducibility.  The Company
believes  that these  three key  criteria  of test kit  performance  can be best
monitored through the use of quality control products, such as those sold by the
Company.

MARKET TRENDS

    The  Company  believes  that  end-users  of test kits will  become  the most
significant  users of quality control products in the infectious  disease market
and that the market for infectious disease test kits and related quality control
products  will continue to expand,  primarily as a result of the following  four
trends.

    Increased Regulatory Scrutiny.  Due to the high level of public concern with
the dangers of infectious diseases, particularly AIDS, Viral Hepatitis, and Lyme
Disease,  governmental  regulatory  agencies are requiring  additional  tests to
improve the safety of the blood  supply,  and are  requiring  manufacturers  and
end-users of test kits to adopt  quality  assurance  programs  applicable to the
entire test kit product life-cycle,  from initial product design and development
through  manufacture  and  end-use.  The  passage  of  the  Clinical  Laboratory
Improvement  Amendments  of  1988  ("CLIA")  and its  regulatory  implementation
beginning in 1992 have resulted in a set of  recommended  laboratory  practices,
including more stringent quality control programs, as well as regular government
inspections  aimed at improving the overall  standard of proficiency in clinical
laboratories.  As a result,  the Company believes that blood bank,  hospital and
clinical laboratory personnel are adopting more comprehensive  quality assurance
programs,  especially in  infectious  disease  testing,  to minimize the risk of
errors and to comply with CLIA and other regulations.

                                       26



    Growing  Recognition  of the Value of Using  Quality  Control  Products.  To
ensure the greatest possible safety of the blood supply, to achieve the earliest
possible  diagnosis  of  infection,  and to  minimize  the  occurrence  of false
negative results, sensitivity of tests (i.e., their ability to accurately detect
very small  amounts of the disease  marker) is a critical  element.  The Company
believes  there  is  increasing  recognition  of  the  benefit  of  continuously
monitoring test  sensitivity  using quality control  products to help ensure the
accuracy of each test run.

    New Diseases and the  Development  of New Therapies.  In recent years,  HIV,
Hepatitis C Virus ("HCV"),  Borrelia burgdorferi ("Lyme Disease") and Ehrlichia,
among  others,  have  emerged  as  significant  human  pathogens.  New and  drug
resistant strains of known pathogens, such as those causing tuberculosis, escape
mutants of  Hepatitis B Virus  ("HBV"),  and Group O and other  variants of HIV,
have also emerged. In response,  new and improved tests are being developed.  In
addition, as new drug therapies are introduced to treat infectious diseases, new
tests are needed to monitor the  effectiveness of these therapies.  For example,
the recent  advances in AIDS drug therapy,  which use a  combination  of several
drugs to treat infected patients, have prompted the creation of a new viral load
test used to  periodically  measure the precise amount of virus in the patient's
blood to evaluate the  effectiveness  of the drug therapy.  The Company believes
that  viral load  testing  will be applied  to  additional  areas of  infectious
disease, including Hepatitis B and C and Lyme Disease.

    Advanced  Test  Technologies  and  Equipment.  Test  kit  manufacturers  are
continuing to enhance the sensitivity,  specificity and reproducibility of their
tests.  Molecular  diagnostics  now permit the direct  detection  of the nucleic
acids (DNA and RNA)  specific to viruses and other  pathogens and are being used
to complement traditional microbiological and immunological tests for infectious
disease.  New tests  for  urine  and  saliva  have  been  developed  that  offer
advantages  in some settings over blood tests and may be more widely used in the
future.  Test kit  manufacturers  are also  developing  assays on silicon chips,
laser-read microspot arrays, and are using electrochemi- luminescence detection,
among other  technologies.  The different types of information  obtained through
the  complementary use of various  diagnostic  methods can provide the physician
with a broader  perspective  on the diagnosis  and prognosis of the disease,  as
well as on the effectiveness of drug therapy.

THE BOSTON BIOMEDICA ADVANTAGE

   
    The  Company  offers  a broad,  integrated  range of  products  for  quality
assurance  throughout the entire  infectious  disease test kit life-cycle,  from
initial  research and development,  through the regulatory  approval process and
test kit production, to training,  troubleshooting and routine use by end-users.
To directly  address  the  emerging  end-user  market  opportunity,  the Company
introduced its TQS marketing  platform based around its  Accurun(tm) Run Control
products.  The Company believes that TQS is the first  comprehensive  package of
quality control products designed  specifically for infectious  disease test kit
end-users,  providing them with a customized approach to evaluate all of the key
elements of the testing process.
    

    The Company believes that it has several  competitive  advantages which have
enabled  it to achieve  its  current  leadership  position  in  quality  control
products for infectious diseases:

    Valuable  Inventory.  The Company has an inventory of  approximately  50,000
distinct  human blood  specimens  accumulated  since 1986 through its  worldwide
sources of blood-supply.  This inventory cannot be easily or rapidly acquired on
the open market, and enables the Company to respond quickly to market trends and
customer needs.

    Specialty  Laboratory  Services and Clinical  Trials.  The knowledge  gained
through the Company's specialty laboratory services allows the Company to remain
at the  forefront of emerging  market trends and customer  needs.  By conducting
clinical  trials of new test kits  under  development,  the  Company  is able to
maintain  close  contact  with  manufacturers  and to  release  Quality  Control
Products for test kits soon after the test kits are introduced to the market. In
addition,  by operating a specialty clinical laboratory,  the Company is able to
better understand the requirements of the end-user.

                                       27



    Proprietary  Manufacturing  Know-How. As a result of ten years of experience
working with leading  worldwide  manufacturers  in the development of their test
kits and with regulators to help in the evaluation of test kits, the Company has
developed proprietary know-how in manufacturing its Quality Control Products.

    Reputation.  The Company  believes  that it has developed a reputation as an
authority in quality control products for infectious disease among manufacturers
and regulators of infectious  disease test kits.  The Company  believes that its
reputation,  established over the past ten years,  will assist it in penetrating
the emerging end-user market.

STRATEGY

    The  Company's  strategy  is to  enhance  its  leadership  position  in  the
infectious diseases quality control market and to take advantage of the emerging
opportunities  in the end-user  market for quality control  products.  There are
five key elements to this strategy:

    Capitalize on Emerging  End-User Market.  In 1996 the Company  introduced an
expanded line of Quality Control Products that are specifically designed for the
end-users  of  test  kits,   such  as  blood  banks,   hospitals   and  clinical
laboratories.  The  Company  plans to  continue  to expand  its line of  Quality
Control Products,  particularly its Accurun(tm) line of Run Controls, to cover a
wider range of immunological  and molecular  markers.  The Company also recently
introduced its Total Quality System ("TQS") marketing  platform,  which combines
Accurun(tm)  with other Quality  Control  Products to provide test kit end-users
with the products needed in an overall quality  assurance  program.  The Company
intends to continue to expand its sales,  marketing and distribution  activities
to support its product  development  program for the emerging  end-user  quality
control market.

    Develop New Products and Services.  The Company intends to capitalize on its
reputation  with  manufacturers  and  regulators by developing  Quality  Control
Products  and  Diagnostic  Components  for use with  test kits for both new test
methodologies and new diseases.  For example,  in response to a 1996 FDA mandate
that all blood collected for transfusion  must be tested for the presence of the
HIV antigen,  the Company recently  introduced on an OEM basis the first quality
control  training panels for use with the two FDA-licensed HIV antigen test kits
available in the United  States.  In addition,  the Company has also  provided a
training panel for end-users of the only  FDA-licensed  molecular  amplification
test for HIV RNA, and has  introduced a new line of HIV RNA controls to meet the
demand of the newly emerging viral load test market. In the future,  the Company
expects to provide  Quality  Control Panels for use with tests that  distinguish
among the  subtypes of HIV, the  serotypes  of HCV,  and the various  strains of
Mycobacteria causing tuberculosis.

    Enhance  Technical  Leadership.  The Company  seeks to expand its  technical
capabilities  by  continually   enhancing  its  strong   scientific   staff  and
collaborating with other scientists worldwide, thus strengthening its reputation
in the area of quality  control  for  infectious  disease  testing.  The Company
maintains and enhances its technical  leadership by  participating in scientific
studies  relevant to its products and services,  and by making  presentations at
scientific  meetings on blood  banking and  infectious  diseases.  The Company's
scientists also publish articles in peer reviewed journals.

    Capitalize on  Complementary  Business  Operations.  The Company  intends to
capitalize  on  operational  and marketing  opportunities  that arise out of its
activities in both  infectious  disease  products and laboratory  services.  For
example,  the Company  conducts  clinical trials for  manufacturers  of in vitro
diagnostic  products,  which allows the Company to maintain  close  contact with
test kit manufacturers  and regulators,  and enables the Company to evaluate new
technologies  in various stages of  development.  The Company  believes that the
reputation and experience of its  laboratory  and  scientific  staff,  its large
number of unique  Quality  Control  Panels,  and its inventory of  characterized
serum and plasma  specimens  assist the Company in marketing its clinical  trial
services to its customers.  Finally, the Company's specialty clinical laboratory
also affords the Company  access to materials  needed in the  production  of its
Quality Control Products and Diagnostic Components.

                                       28



   
    Pursue Strategic  Acquisitions and Alliances.  The Company intends to pursue
strategic  acquisitions  and  alliances  to expand its core  product  lines,  to
strengthen its base in medical science and technology,  and to secure sources of
blood supply. To date, the Company has acquired BTRL, a research and development
laboratory  with a strong  capability  in molecular  and cellular  biology,  and
BBI-NACL,  formerly North American  Laboratory  Group Ltd., Inc., a microbiology
and immunology clinical  laboratory  specializing in the diagnosis of infectious
diseases,   including  tick-borne  diseases.   These  acquisitions  led  to  the
introduction  in  1994 of the  Company's  first  Quality  Control  Products  for
molecular  diagnostics.  In October 1996,  the Company  entered into a strategic
alliance with BioSeq.  Under the License Agreement,  upon the earlier of payment
of the final installment of the Company's  aggregate  $1,482,500  investment and
December  31,  1997,  the  Company  will be granted the  worldwide  right to use
technology  which is being developed for DNA sequencing and analysis,  a process
which may allow for more precise  identification  of infectious  disease agents.
The Company  believes  that there may be  additional  acquisition  and  alliance
opportunities,  such as blood donor centers in strategic locations and companies
with  complementary   technology  or  synergistic   product  lines,  that  would
strengthen its existing business.
    

PRODUCTS

    The Company designs,  develops and markets diagnostic  products used for the
quality control, quality assurance and technical evaluation of test kits for the
laboratory  diagnosis of infectious  disease.  The Company  offers three product
groups: Quality Control Panels, Run Controls and Diagnostic Components.

   
     The Company manufactures its products from human plasma and serum which are
obtained from  nonprofit and commercial  blood centers,  primarily in the United
States.  The Company has  acquired and  developed an inventory of  approximately
50,000  individual  blood units and specimens (with volumes ranging from 1 ml to
800 ml) which provides most of the raw material for its products.
    

QUALITY CONTROL PANELS

    Quality  Control  Panels  consist  of blood  products  characterized  by the
presence or absence of  specific  disease  markers  and a Data Sheet  containing
comprehensive  quantitative data useful for comparative analysis.  These Quality
Control  Products are designed for measuring  overall test kit  performance  and
laboratory proficiency,  as well as for training laboratory  professionals.  The
Company's  Data Sheets are an integral  part of its  Quality  Control  Products.
These Data  Sheets are  created as the result of  extensive  testing of proposed
panel  components  in both  the  Company's  laboratories  and at  major  testing
laboratories on behalf of the Company in the United States and Europe, including
national  public health  laboratories,  research and clinical  laboratories  and
regulatory agencies. These laboratories are selected based on their expertise in
performing the appropriate tests on a large scale in an actual clinical setting;
this testing process provides the Company's  customers with the benefit that the
Quality  Control Panels they purchase from the Company have  undergone  rigorous
testing  in  actual  clinical  settings.  In  addition,   the  Company  provides
information on its Data Sheets on the reactivity of panel  components in all FDA
licensed test kits and all leading  European test kits for the target  pathogen,
as well as for all other appropriate markers of this pathogen.  For example, the
Company's HIV panel Data Sheets include anti-HIV by IFA, ELISA and western blot;
HIV antigen by ELISA; and HIV RNA by several  molecular  diagnostic  procedures.
The Company's Data Sheets require  significant time and scientific  expertise to
prepare.

    The Company first  introduced  Quality  Control  Panels in 1987. The Company
currently  offers a broad range of Quality Control Panels that address a variety
of needs of  manufacturers  and  regulators of test kits as well as blood banks,
hospitals,  clinical laboratories and other end-users.  Prices for the Company's
quality control  seroconversion,  performance and sensitivity  panels range from
$450 to $2,000  each,  and its  qualification  and OEM panels range from $100 to
$200 per panel. The following table describes the types of Quality Control Panel
products currently offered by the Company.

                                       29
  

                         QUALITY CONTROL PANEL PRODUCTS

<TABLE>
<CAPTION>
     PRODUCT LINE            DESCRIPTION                USE                 CUSTOMERS
     ------------            -----------                ---                 ---------
  <S>                    <C>                    <C>                   <C>
  Seroconversion         Plasma samples         Compare the           Test kit
   Panels                collected from a       clinical              manufacturers and
                         single individual      sensitivity of        regulators
                         over a specific        competing
                         time period showing    manufacturers' test
                         conversion from        kits, enabling the
                         negative to            user to assess the
                         positive for           sensitivity of a
                         markers of an          test in detecting a
                         infectious disease     developing
                                                antigen/antibody

  Performance            A set of 10 to 50      Determine test kit    Test kit
   Panels                serum and plasma       performance against   manufacturers and
                         samples collected      all expected levels   regulators
                         from many different    of reactivities in
                         individuals and        the evaluation of
                         characterized for      new, modified and
                         the presence or        improved test
                         absence of a           methods
                         particular disease
                         marker

  Sensitivity Panels     Precise dilutions      Evaluate the          Test kit
                         of human plasma or     low-end analytical    manufacturers
                         serum containing a     sensitivity of a
                         known amount of an     test kit
                         infectious disease
                         marker as
                         calibrated against
                         international
                         standards

  Qualification          Dilutions of human     Demonstrate the       Clinical reference
   Panels                plasma or serum        consistent            laboratories, blood
                         manifesting a full     lot-to-lot            banks, and hospital
                         range of               performance of test   laboratories
                         reactivities in        kits, troubleshoot
                         test kits for a        problems, evaluate
                         specific marker        proficiency, and
                                                train laboratory
                                                technicians

  OEM Panels             Custom-designed        Train laboratory      Custom designed
                         Qualification          personnel on new      with test kit
                         Panels for             test kits or          manufacturers and
                         regulators and test    equipment             regulators as an
                         kit manufacturers                            end-user product or
                         for distribution to                          for internal use
                         customers or for
                         internal use
</TABLE>

    Seroconversion  and  Performance  Panels  are  comprised  of unique and rare
plasma specimens  obtained from individuals during the short period of time when
the markers for a particular  disease are converting  from negative to positive.
As a result, the quantity of any such panel is limited, so that the Company must
replace these panels as they sell out with another panel  comprised of different
specimens  equally unique and rare. The Company  believes that its inventory and
relationships with blood centers affords it a competitive advantage in acquiring
such plasma for  replacement  panels and  developing new products to meet market
demand.  There can be no assurance  that the Company will be able to continue to
obtain  such  specimens.  See "Risk  Factors  --  Difficulty  in  Obtaining  Raw
Materials."

    The Company  believes  that it offers its customers a broad range of Quality
Control Panel products to address the requirements of the complete life-cycle of
a test kit,  from  initial  research  and  development,  through the  regulatory
approval process, test kit production, training, troubleshooting and routine use
by end-users.  The Company  further  believes that its Data Sheets,  an integral
part of all  panel  products,  offer its  customers  in-depth  information  on a
particular test kit of interest. Quality

                                       30



Control Panels  currently  span the  immunologic  markers for AIDS (i.e.,  HIV),
Hepatitis B and C, Lyme Disease and ToRCH (Toxoplasma,  rubella, cytomegalovirus
and  herpes  simplex  virus).  New  introductions  this year  include  molecular
Performance Panels for HBV and HCV,  qualification  panels for HIV, HBV and HCV,
and additional Seroconversion Panels for HIV, HBV, and HCV.

ACCURUN(TM) RUN CONTROLS

    End-users  of test kits  utilize Run  Controls  to confirm  the  validity of
results by monitoring test performance,  thereby  minimizing false negative test
results and  improving  error  detection.  Run  controls  consist of one or more
specimens of known  reactivity  that are tested  together  with donor or patient
samples in an assay to  determine  whether  the assay is  performing  within the
manufacturer's  specifications.  Clinical  laboratories  generally process their
patient  specimens in a batch processing  mode, and typically  include 25 to 100
specimens to be tested in each batch (a "run").  Large  laboratories may perform
several runs per day, while smaller  laboratories  may perform only a single run
each day, or sometimes only several runs per week. A clinical laboratory using a
Run Control will place the Run Control  product in a testing well or  test-tube,
normally used for a specimen,  and will test it in the same manner that it tests
the donor or patient specimens. It will then compare the results generated to an
acceptable range, determined by the user, to measure whether the other specimens
are  being  accurately  tested.  The  Run  Control  result  must be  within  the
acceptable range to be considered  valid. This is often tracked visually using a
Levey-Jennings chart.  Depending upon a particular  laboratory's quality control
practices,  it may use several  Run  Controls on each run or it may simply use a
Run Control in a single run at the beginning and end of the day.

    The Company  believes its  Accurun(tm)  product line  provides the following
benefits to end-users:

    * Helps to satisfy the requirements of Good Laboratory Practice.

    * Tracks the accuracy and precision of test runs.

    * Detects  laboratory  errors and  identifies  trends  before  they become a
      problem.

    * Monitors test kit performance, equipment and personnel.

    * Helps  to  meet  National  Committee  For  Clinical  Laboratory  Standards
      ("NCCLS")  for  molecular  and   immunological   diagnostic   methods  for
      infectious disease quality control.

    * Documents the validity of test results, day to day, week to week.

    The Company  introduced its first four  Accurun(tm) Run Control  products in
the fourth  quarter of 1993 and has since  developed  and  released  for sale an
additional  24  Accurun(tm)  products.  A limited  number of these  products are
available for diagnostic purposes;  the others currently are limited to research
use. See " -- Government  Regulation."  Current Accurun(tm) Run Control products
range in price from $15 to $45 per milliliter and are described in the following
table.

                         ACCURUN(TM) RUN CONTROLS
<TABLE>
<CAPTION>
                                                             CURRENT
                                                            NUMBER OF               PRIMARY
     PRODUCT LINE                 DESCRIPTION                PRODUCTS             CUSTOMER(S)
     ------------                 -----------                --------             -----------
  <S>                    <C>                                 <C>           <C>
  Accurun(tm) 1-99       Multi-marker Run Control for           4          Blood Banks
                         immunological tests
  Accurun(tm) 100-199    Single-marker Run Control              17         Hospitals and clinical
                         for immunological tests                           reference laboratories
  Accurun(tm) 200-299    Multi-marker Run Control for           1          Research and specialty
                         molecular tests                                   laboratories
  Accurun(tm) 300-399    Single-marker Run Control              3          Research and specialty
                         for molecular tests                               laboratories
  Accurun(tm) 800-899    Negative Run Control for               3          All laboratories
                         immunological and molecular
                         tests
</TABLE>

                                       31



    The  Company's  Accurun(tm)  family of products is targeted at the  emerging
market of end-users of infectious  disease test kits. The Company  believes that
it offers the most comprehensive line of Run Controls in the industry,  and that
its  Accurun(tm)  products,  in  combination  with  its  Quality  Control  Panel
products,  provide an  extensive  line of  products  for  quality  assurance  in
infectious disease testing. See "-- Sales and Marketing." The Company intends to
continue  to expand its line of  Accurun(tm)  products,  thereby  providing  its
customers with the convenience and cost  effectiveness  of a single supplier for
independent run controls.  See "Risk Factors -- Undeveloped  End-User Market For
Quality Control Products for Infectious Disease Test Kits."

   
    The Company has received 510(k) clearance from the FDA to market its Accurun
1(R) line, for diagnostic purposes,  and intends to apply for such clearance for
the remainder of its  Accurun(tm)  products.  All of the  Company's  Accurun Run
Controls  will  require  FDA  premarket  clearance  or  approval  prior to being
marketed for diagnostic use. An application for clearance for diagnostic use for
one additional Accurun(tm) product has been submitted by the Company to the FDA,
and the Company  anticipates that  applications for  approximately 16 additional
Accurun(tm)  products  will be prepared  and  submitted to the FDA by the end of
1997.  Failure to obtain,  or delays in  obtaining,  such  clearance or approval
would  adversely  affect the Company's  strategy of capitalizing on the end-user
market. See "Risk Factors -- Stringent Government Regulation" and "-- Government
Regulation."
    

DIAGNOSTIC COMPONENTS

    Diagnostic  Components are the individual  materials  supplied to infectious
disease test kit manufacturers  and combined (often after further  processing by
the manufacturer) with other materials to become the various fluid components of
the manufacturer's test kit. The Company supplies Diagnostic  Components in four
product  lines:  Normal  Human  Plasma,  Normal  Human  Serum,  Basematrix,  and
Characterized  Disease State Serum and Plasma. Normal Human Plasma and Serum are
both the clear  liquid  portion of blood which  contains  proteins,  antibodies,
hormones  and  other  substances,  except  that the  Serum  product  has had the
clotting factors removed.  Basematrix, the Company's proprietary processed serum
product that has been  chemically  converted  from  plasma,  is designed to be a
highly-stable,  lower cost  substitute  for most  Normal  Human Serum and Plasma
applications.  Characterized  Disease State Serum and Plasma are collected  from
specific  blood  donors  pre-selected  because of the  presence  or absence of a
particular   disease  marker.   The  Company  often  customizes  its  Diagnostic
Components by further  processing the raw material to meet the specifications of
the test kit manufacturer.  The Company's  Diagnostic  Components range in price
from $0.25 to $60 per milliliter, with the majority selling between $0.50 and $5
per milliliter.

    The  Company  believes  that  it  has  several  competitive   advantages  in
Diagnostic Components. Through its trained and experienced laboratory staff, the
Company  is able to  perform  comprehensive  in-house  testing  for a number  of
markers in a  particular  material,  and  consequently  is able to  address  the
demands of its customers.  The Company's large inventory of approximately 50,000
specimens  provides it with the  flexibility  to produce  Diagnostic  Components
efficiently and rapidly in response to customer  requests.  The Company believes
that its proprietary  manufacturing  knowledge enables it to manufacture stable,
high quality products to meet the demands of its worldwide customer base.

SERVICES

    The Company  seeks to focus its  specialty  laboratory  services in both the
clinical  reference  laboratory testing and advanced research areas. The Company
concentrates its services in those areas of infectious disease testing which are
complementary to its quality control and diagnostic products businesses.

    Specialty Clinical Laboratory  Testing.  The Company operates an independent
specialty  clinical  laboratory  which  performs both routine and  sophisticated
infectious  disease testing in microbiology,  immunology and molecular  biology,
with special emphasis in AIDS,  Viral Hepatitis and Lyme Disease.  The Company's
specialty  clinical  laboratory  combines  traditional  microbiology,   advanced
immunology, and current molecular diagnostic techniques,  such as PCR, to detect
and identify  microorganisms,  their antigens and related antibodies,  and their
nucleic  acids  (i.e.,  DNA and RNA).  Customers  include  physicians,  clinics,
hospitals and other clinical/research laboratories.

                                       32



   
    Contract  Research.  The  Company  offers a  variety  of  contract  research
services in molecular  biology,  cell  biology and  immunology  to  governmental
agencies,   diagnostic  test  kit  manufacturers  and  biomedical   researchers.
Molecular  biology  services  include DNA  sequencing,  recombinant DNA support,
probe  labeling  and custom PCR assays.  Cell  biology and  immunology  services
include sterility testing,  virus infectivity  assays,  cultivations of virus or
bacteria from clinical specimens,  preparation of viral or bacterial antigens or
nucleic acids, and production of antibodies.  The Company is currently providing
research  services for assessment of the efficiency of candidate HIV vaccines in
a monkey model system under two separate  contracts with the National  Institute
for Allergy and Infectious Disease ("NIAID"),  a part of the National Institutes
of Health ("NIH").  Each of these contracts has a two year term which expires in
September  1997.  In  addition,  since  1983,  the  Company,  through  its  BTRL
subsidiary,  has  provided  blood  processing  and  repository  services for the
National Cancer Institute ("NCI"), also a part of the NIH. The repository stores
over 2,000,000 specimens and processes or ships up to several thousand specimens
per week in support of various NIH cancer and virus research programs. While the
current NCI  repository  contract  terminates in February  1997, the Company has
responded to a Request for Proposals by the United States  government  for a new
four year contract to replace this contract.  There can be no assurance that any
of these  contracts  will be replaced with new  contracts.  See "Risk Factors --
Dependence on Key Customers."
    

    Small Business  Innovation  Research  ("SBIR")  grants and other  government
contracts  similar to the ones  described  have  enabled  the Company to develop
technologies  applicable to new product  development and its specialty  clinical
laboratory.  For example, recent SBIR grants have enabled the Company to develop
PCR based  assays for the  detection  of the nucleic  acids of HIV, HCV and Lyme
Disease.  Although the Company does not currently  have any SBIR grants,  it has
two  pending  applications  for such  grants  and  intends to  continue  to seek
government  grants and contracts that further the Company's core  technology and
commercial business. There can be no assurance that the Company will receive any
government research grants in the future.

    Clinical  Trials.  The Company  conducts  clinical  trials for  domestic and
foreign test kit manufacturers.  Test kit manufacturers must conduct such trials
to collect data for  submission  to the United  States FDA and other  regulatory
agencies.  By  providing  this  service,  the Company is able to maintain  close
contact with test kit manufacturers and regulators,  and is able to evaluate new
technologies  in various stages of  development.  The Company  believes that the
reputation of its laboratory and scientific  staff,  its large number of Quality
Control Panels,  and its inventory of  characterized  serum and plasma specimens
assist the Company in marketing its clinical  trial  services to its  customers.
The  Company has  performed  clinical  trials for a number of United  States and
foreign  test kit  manufacturers  seeking  to  obtain  FDA  approval  for  their
infectious disease test kits.

    Drug Screening Program. As a subcontractor for an NIH AIDS grant held by the
University  of North  Carolina at Chapel Hill,  the Company has  established  an
anti-HIV  drug  screening  program to test a large  number of  natural  products
(largely plant derivatives) to determine whether they inhibit HIV replication in
an in vitro assay system. These in vitro assays are also offered as a service to
researchers  and  pharmaceutical  companies  who wish to test various  candidate
anti-viral agents for anti-HIV activity.

RESEARCH AND DEVELOPMENT

    The Company's  research and development effort is focused on the development
of (i) new and improved  Quality  Control  Products  for the  emerging  end-user
market,  (ii) new products for existing customers,  (iii) Diagnostic  Components
for use with test kits for both new test  methodologies  and new  diseases,  and
(iv)  infectious  disease  testing  services  using PCR and other  amplification
assays for AIDS, Viral Hepatitis, Lyme Disease and Chlamydia,  among others. The
Company  has  approximately  20 full or  part-time  employees  dedicated  to its
research  and  development  effort.  For the six months  ended June 30, 1996 the
Company  increased  spending on research  and  development  as a  percentage  of
revenues compared to the same period ended June 30, 1995 and expects to continue
to increase such  expenditures  as a percentage of revenues for the next several
years.  See  "Management's  Discussion  and Analysis of Financial  Condition and
Results  of  Operations  --  Results  of  Operations."  The  Company's  research
scientists  work closely with sales,  marketing and  manufacturing  personnel to
identify and prioritize the development of new products and services.

                                       33



    The Company's product  development  activities center on the  identification
and  characterization  of materials for the  manufacture of new Quality  Control
Products and the replacement of sold-out products. For example, during 1996, the
Company has introduced 10 new Seroconversion,  Performance and Sensitivity Panel
products as well as 14 new  Accurun(tm) Run Controls;  in addition,  during July
1996, the Company released its first Qualification  Panel products.  The Company
is developing new Quality  Control  Products for use with  molecular  diagnostic
tests for HIV, HCV and HBV.  Recently the Company  expanded its Quality  Control
Product  line beyond the  retrovirus  and Viral  Hepatitis  diagnostics  area to
include sexually  transmitted  diseases (e.g.,  Syphilis),  tick-borne  diseases
(e.g., Lyme Disease), and respiratory and other infections (e.g.,  Tuberculosis)
and is  continuing to develop new Quality  Control  Products for these and other
diseases.  The Company has increased the number of Quality  Control  Products it
offers from approximately 20 in 1990 to approximately 150 products in 1996.

    The Company is also developing new and improved infectious disease specialty
tests for Lyme Disease and other  tick-borne  diseases for use in its  specialty
laboratory  business.  For  example,  the Company was among the first to develop
enzyme  immunoassays  and Western Blot assays for Lyme  Disease.  The Company is
also  pursuing  new  applications  of  PCR  technology  to  infectious   disease
diagnostics,  such as  amplification  assays for the  pathogens  of AIDS,  Viral
Hepatitis,  Lyme Disease and  Chlamydia,  and for the direct  detection of other
infectious agents in blood, tissues and other body fluids.

    From time to time in the  past,  the  Company  has  funded a portion  of its
research and development activities from grants provided by various agencies and
departments of the U.S. government. See "-- Services."

STRATEGIC ALLIANCES

   
    University  of North  Carolina  at Chapel  Hill.  The  Company  is  directly
supporting  a drug  discovery  program  at UNC,  in which a  full-time  research
scientist is working to develop synthetic derivatives of anti-HIV compounds that
have been  discovered  pursuant to the Company's joint  collaboration  with UNC.
This  research  scientist is also working to  introduce  modifications  to these
derivatives that would make them more soluble,  less toxic, or otherwise enhance
their anti-viral properties. UNC has licensed to the Company exclusive worldwide
rights to three series of patent  applications filed by the Company and UNC with
respect  to  three  classes  of  anti-HIV  compounds.  Two such  compounds  have
exhibited  therapeutic indices in in vitro test model systems in excess of those
recorded  for AZT under  comparable  test  conditions.  The Company is expending
approximately  $100,000 per year for research and development  relating to these
compounds.  In  addition,  under this  license,  the Company  will also have the
rights to any new anti-HIV  compounds or derivatives  developed in the course of
this  sponsored  research,  provided  the  Company  obtains  certain  regulatory
approvals from the FDA. See "-- Services."

    Ajinomoto  Co., Inc. The Company  entered into an agreement  with  Ajinomoto
Co., Inc. in October 1995  pursuant to which the Company is performing  research
regarding  among other  things,  whether tests for certain amino acids in plasma
can be used to  determine  a person's  immune  status,  particularly  in chronic
fatigue  syndrome.  This  project  is funded by  Ajinomoto  and has a three year
budget of approximately $1,000,000.  Discoveries and inventions arising from the
research  will be owned by  Ajinomoto,  but the  Company  has the right of first
refusal to obtain  certain  exclusive  licenses  from  Ajinomoto of any patented
technology  arising  from the  research.  The  Company  is  entitled  to certain
royalties  based  upon a  percentage  of sales of  products  arising  out of the
research. This agreement expires in September 1998.

    BioSeq,  Inc. In October 1996, the Company entered into a strategic alliance
with  BioSeq,  an  early  stage  biotechnology  company  that  is  developing  a
technology  that may,  through the use of  pressure,  be able to more  precisely
control  chemical  reactions.  The Company  believes that this technology may be
useful  for  sequencing,  synthesizing  and  characterizing  nucleic  acids  and
proteins, which may then allow for the more precise identification of infectious
disease agents.

    The Company has agreed to purchase approximately 19% of the capital stock of
BioSeq for an aggregate of $1,482,500 in three installments.  Of the $1,482,500,
$210,000 has been invested and $522,500 will be invested upon  completion of the
Offering.  The Company must make the remaining  $750,000  installment  if BioSeq
attains  certain  technical  milestones by July 31, 1997. If such milestones are
not  attained by BioSeq by July 31,  1997,  the Company  will have the option to
make the remaining  $750,000  investment  until  December 31, 1997.  See "Use of
Proceeds." The Company has price  anti-dilution  protection,  pre-emptive rights
and the  right to board  representation,  the  last of which  terminates  if the
Company fails to make the second installment

                                       34



under the Purchase Agreement.  In addition, the Company was granted the right to
acquire additional shares of common stock of BioSeq for additional consideration
under certain  conditions,  provided that this right is not  exercisable  to the
extent it would cause the Company's  ownership of BioSeq to equal or exceed 20%.
BioSeq has also  agreed to engage the  Company to perform a minimum of  $100,000
and $150,000 of research and development  services  following the payment of the
second and third installments, respectively.

    Under the  License  Agreement,  upon the  earlier  of  payment  of the final
installment of the Company's  investment and December 31, 1997, the Company will
be granted a worldwide right to use the BioSeq technology relating to sequencing
and analysis  services.  The License will be  exclusive  until BioSeq  commences
selling on a  commercial  basis the  equipment  used in the DNA  sequencing  and
analysis  process,  at which time the  License  will become  non-exclusive.  The
License  provides that the Company will pay BioSeq certain  royalties based upon
net  revenues  arising out of the  services  performed  by the Company  with the
licensed technology.
    

SALES AND MARKETING

    The  Company's  sales and  marketing  efforts are  directed by a Senior Vice
President of Sales and Marketing  who  supervises 15 sales people and four other
full-time sales and marketing employees.

   
    The Company's marketing strategy is focused upon addressing the needs of its
customers in the infectious  disease  testing market  throughout the entire test
kit life-cycle,  from initial research and  development,  through the regulatory
approval  process and test kit  production,  to  training,  troubleshooting  and
routine use by  end-users  such as clinical  laboratories,  hospitals  and blood
banks.  By serving its  customers at all stages of the product  life-cycle,  the
Company  expects  to stay at the  forefront  of  trends  in  infectious  disease
testing,  which in turn  enables  the Company to  anticipate  and respond to the
needs of the marketplace.
    

    The Company  recently has begun to focus its sales and marketing  efforts on
the emerging end-user market for quality control products for infectious disease
test kits.  To promote  this  objective,  the  Company is  implementing  a major
marketing platform, known as "Total Quality System" ("TQS"). TQS is a package of
Quality  Control  Products,  including the Company's  Accurun(tm)  Run Controls,
which is designed to provide test kit end-users  with the products  needed in an
overall  quality  assurance  program.  These  products  enable  laboratories  to
evaluate each of the key elements involved in the testing process: the test kit,
laboratory  equipment and laboratory  personnel.  The Company  believes that TQS
effectively  addresses  the need for  end-users  to ensure the accuracy of their
test results.  The Company intends to continue to expand its sales and marketing
activities with respect to its Accurun(tm) line of Run Control  products.  Since
the beginning of 1996, the Company has hired two new employees for the sales and
marketing of its Accurun(tm) line of products and expects to add six more direct
salespeople by the end of 1997.

    The  Company's   products  are  currently  sold  through  a  combination  of
telephone,  mail,  third party  distributors  and limited  direct sales efforts.
Domestically,  products are sold through an in-house tele-sales group consisting
of five sales  representatives,  two sales  managers  and one  customer  service
representative.  Internationally,  the Company  distributes  its  products  both
directly and through 17 independent  distributors  located in Japan,  Australia,
South America,  Southeast Asia, Israel and Europe.  The Company's  international
sales manager  oversees the Company's  foreign  distributors.  During the fiscal
years  1993,  1994,  1995 and the six months  ended  June 30,  1995 and 1996 the
Company's  distributors  accounted for 1.9%,  3.5%,  6.2%,  2.8% and 8.8% of the
Company's  total revenue,  respectively.  The Company  intends to further expand
sales through  international  distributors,  although there can be no assurances
that it will be able to do so. See "Risk Factors -- Risks Associated with Export
Sales."

    The Company's  Specialty  Clinical  Laboratory Testing services are marketed
primarily  through a direct  domestic  sales  force  consisting  of seven  sales
representatives  managed  by a sales  director.  The sales  representatives  are
located throughout the eastern and mid-western United States. They are supported
internally by a client services representative.

    The  Company  emphasizes  high  quality  products  and  services,  technical
knowledge,  and responsiveness to customer needs in its marketing activities for
both products and services. The Company educates its distributors, customers and
prospective  customers about its products through a series of detailed marketing
brochures,  technical  bulletins and  pamphlets,  press releases and direct mail
pieces.  These  materials are  supplemented  by  advertising  campaigns in major
industry  publications,  technical  presentations,  and  exhibitions  at  local,
national and international trade shows and expositions.

                                       35



CUSTOMERS

   
    The  Company's   customers  for  Quality  Control  Products  and  Diagnostic
Components  comprise  three major  groups:  (i)  international  diagnostics  and
pharmaceutical  manufacturing  companies,  such as Abbott Diagnostics,  Behring,
Boehringer  Mannheim,  Chiron,  Fujirebio,  Hoffman LaRoche,  Ortho  Diagnostics
(Johnson and Johnson),  Sanofi Diagnostics and Sorin Biomedica;  (ii) regulatory
agencies  such as the United States FDA, the British  Public  Health  Laboratory
Service, the French Institut National de la Transfusion Sanguine, and the German
Paul Ehrlich  Institute;  and (iii)  end-users of diagnostic  test kits, such as
hospital  clinical  laboratories,  public health  laboratories  and blood banks,
including the Swiss Red Cross,  United Blood Services and Kaiser Permanente.  In
1995,  the  Company  sold  products  to   approximately   100   diagnostics  and
pharmaceutical  manufacturers,  15 regulatory agencies,  and 250 end-users.  The
Company's  Specialty  Clinical  Laboratory Testing services are sold to hospital
and  clinical  laboratories,  blood  banks,  researchers  and other  health care
providers.  The Company's Contract Research services are typically offered under
contracts  to  governmental  agencies,  diagnostic  test kit  manufacturers  and
biomedical researchers.  See "Management's  Discussion and Analysis of Financial
Condition and Results of Operations -- Overview."

    The Company does not have long-term contracts with its customers for Quality
Control Products and Diagnostic  Components.  The Company's products are sold to
its customers pursuant to purchase orders for discrete  purchases.  Although the
Company believes that its  relationships  with these customers are satisfactory,
termination of the Company's  relationship  with any one of such customers could
have a material  adverse effect on the Company.  See "Risk Factors -- Dependence
on Key Customers."
    

    During the fiscal years 1993,  1994 and 1995,  and the six months ended June
30, 1995 and 1996, sales to the Company's three largest customers  accounted for
an aggregate  of  approximately  20% of the  Company's  net sales,  although the
customers  were not  identical in each period and no one customer  accounted for
more than 10% of net sales.

MANUFACTURING AND OPERATIONS

    The Company manufactures and assembles  substantially all of its products at
its facility in West  Bridgewater,  Massachusetts.  The Company has computerized
purchasing,  inventory,  and test result and  materials  tracking  systems in an
integrated  operations  management  system,  and believes that these systems are
adequate  for its  current  level  of  production,  but  would  require  further
enhancements if the Company  experiences  substantial future growth. The Company
acquires raw materials  from a variety of vendors and through a program of donor
recruitment,  donor screening, product collection,  product characterization and
donor management. All important materials have multiple sources of supply.

    The Company's West Bridgewater facility contains  environmentally-controlled
freezers and cold rooms, which are used to store raw materials for manufacturing
and  finished  products.  More  than  3,000  square  feet of  space  in the West
Bridgewater  facility is dedicated to freezers and cold rooms.  The freezers and
cold rooms are monitored  continuously  and the Company  maintains a natural gas
fired emergency generator in the event of a power outage.

    The Company also  operates a specialty  clinical  laboratory in New Britain,
Connecticut  and a research and development  laboratory in Rockville,  Maryland.
See "-- Properties."

COMPETITION

    The market for the  Company's  products and services is highly  competitive.
Many of the Company's  competitors  are larger than the Company and have greater
financial,   research,   manufacturing,   and  marketing  resources.   Important
competitive  factors for the Company's products include product quality,  price,
ease of use,  customer  service and  reputation.  In a broader  sense,  industry
competition  is based upon  scientific  and  technical  capability,  proprietary
know-how, access to adequate capital, the ability to develop and market products
and processes,  the ability to attract and retain qualified  personnel,  and the
availability of patent protection. To the extent that the Company's products and
services do not reflect technological advances, the Company's ability to compete
in those products and services could be adversely affected. See "Risk Factors --
Risk of Technological Change" and "-- Competition."

    In the area of Quality Control Products,  the Company competes in the United
States  primarily with NABI (formerly North American  Biologicals,  Inc.) in Run
Controls and Quality Control Panel products and Blackhawk Biosystems Inc. in Run
Controls.  In Europe,  the  Netherlands  Red Cross has recently

                                       36



begun offering several Run Control and panel products. The Company believes that
all three of these  competitors  currently offer a more limited line of products
than the Company,  although there can be no assurance  these  companies will not
expand their product lines.

    In the Diagnostic  Components area, the Company competes against  integrated
plasma collection and processing companies such as Serologicals,  Inc. and NABI,
as well as smaller,  independent plasma collection centers and brokers of plasma
products.  In the Diagnostic  Components area, the Company competes on the basis
of quality, breadth of product line, technical expertise and reputation.

    The  Company  believes  that it has  competitive  advantages  in the quality
control products and diagnostic components industry. These include its access to
raw materials, technical know-how, broad product line and established reputation
among large diagnostics and pharmaceutical manufacturers,  as well as regulatory
agencies.

    In  the  Specialty  Clinical  Laboratory  Testing  services  portion  of the
Company's business, it competes with large national reference laboratories, such
as LabCorp of America,  Corning  Clinical  Laboratories  and SmithKline  Beecham
Clinical  Laboratories,  as well as several independent  regional  laboratories,
hospital  laboratories,  government  contract  laboratories  and large  research
institutions.  The Company  believes that by focusing on the specialty  clinical
laboratory  market,  it is able to offer  its  customers  a  higher  value-added
service on the more complex  diagnostic tests than the larger national reference
laboratories.

GOVERNMENT REGULATION

    The manufacture  and  distribution of medical  devices,  including  products
manufactured  by the Company that are intended for in vitro  diagnostic use, are
subject to extensive  government  regulation  in the United  States and in other
countries. See "Risk Factors -- Stringent Government Regulation."

    In the United States,  the Food,  Drug, and Cosmetic Act ("FDCA")  prohibits
the marketing of in vitro  diagnostic  products  until they have been cleared or
approved by the FDA, a process that is time-consuming, expensive, and uncertain.
In  vitro  diagnostic  products  must  be the  subject  of  either  a  premarket
notification   clearance  (a  "510(k)")  or  an  approved   premarket   approval
application  ("PMA").  With  respect  to  devices  reviewed  through  the 510(k)
process,  a Company may not market a device for diagnostic use until an order is
issued by FDA finding the product to be  substantially  equivalent  to a legally
marketed  device.  A  510(k)  submission  may  involve  the  presentation  of  a
substantial  volume  of  data,  including  clinical  data,  and  may  require  a
substantial  period of review.  With respect to devices reviewed through the PMA
process,  a  Company  may not  market  a device  until  FDA has  approved  a PMA
application,  which must be supported by extensive data,  including  preclinical
and clinical trial data, literature,  and manufacturing information to prove the
safety and effectiveness of the device.

    The Company's  Accurun Run Controls,  when marketed for diagnostic use, have
been classified by the FDA as medical devices. The Accurun 1(R) Multi-Marker Run
Control,  which  include  eight  analytes,  has been cleared  through the 510(k)
process. The Company expects that, in the future, most of its products that need
FDA premarket review also will be reviewed  through the 510(k) process.  The FDA
could, however,  require that some products be reviewed through the PMA process,
which  generally  involves a longer  review  period and the  submission  of more
information  to FDA.  There can be no  assurance  that the  Company  will obtain
regulatory  approvals on a timely basis, if at all. Failure to obtain regulatory
approvals in a timely fashion or at all could have a material  adverse effect on
the Company.

    All of the Company's Quality Control Products, with the exception of Accurun
1(R),  are marketed  "for research use only," which do not require FDA premarket
clearance  or  approval,  and not for  diagnostic  uses,  which do  require  FDA
premarket clearance or approval. The labeling of these products limits their use
to research. It is possible, however, that some purchasers of these products may
use them for diagnostic  purposes  despite the Company's  intended use. In these
circumstances, the FDA could allege that these products should have been cleared
or approved  by the FDA prior to  marketing,  and  initiate  enforcement  action
against the Company, which could have a material adverse effect on the Company.

    Once  cleared or  approved,  medical  devices are subject to  pervasive  and
continuing  regulation  by  the  FDA,  including,   but  not  limited  to,  good
manufacturing  practices ("GMP")  regulations  governing testing,  control,  and
documentation;  and reporting of adverse experiences with the use of the device.

                                       37



Ongoing  compliance  with GMP and other  applicable  regulatory  requirements is
monitored through periodic inspections. FDA regulations require agency clearance
or  approval  for  certain  changes  if they do or could  affect  the safety and
effectiveness of the device,  including,  for example,  new indications for use,
labeling  changes or changes in design or  manufacturing  methods.  In addition,
both before and after  clearance  or  approval,  medical  devices are subject to
certain  export and import  requirements  under the FDCA.  Product  labeling and
promotional  activities  are  subject  to  scrutiny  by the FDA and,  in certain
instances,  by the Federal  Trade  Commission.  Products  may be promoted by the
Company  only for their  approved  use.  Failure to comply  with these and other
regulatory  requirements  can result,  among other  consequences,  in failure to
obtain premarket approvals, withdrawal of approvals, total or partial suspension
of product  distribution,  injunctions,  civil penalties,  recall or seizures of
products and criminal prosecution.

    The Company  believes that its Quality  Control  Panels are not regulated by
the FDA because  they are not  intended  for  diagnostic  purposes.  The Company
believes  that its  Diagnostic  Components,  which  are  components  of in vitro
diagnostic products, may be subject to certain regulatory requirements under the
FDCA and other laws administered by the FDA, but do not require that the Company
obtain a premarket  approval or clearance.  There can be no assurance,  however,
that  the  FDA  would  agree  or  that  the  FDA  will  not  adopt  a  different
interpretation  of the FDCA or other  laws it  administers,  which  could have a
material adverse effect on the Company.

    Laws and regulations  affecting some of the Company's products are in effect
in many of the  countries in which the Company  markets or intends to market its
products.  These requirements vary from country to country. Member states of the
European  Economic Area (which is composed of the European Union members and the
European Free Trade Association  members) are in the process of adopting various
product and services  "Directives"  to address  essential  health,  safety,  and
environmental  requirements  associated with the subject  products and services.
The  "Directives"  cover both  quality  system  requirements  (ISO  Series  9000
Standards) and product and marketing  related  requirements.  In addition,  some
jurisdictions have requirements  related to marketing of the Company's products.
There can be no assurance that the Company will be able to obtain any regulatory
approvals  required to market its products on a timely basis,  or at all. Delays
in receipt of, or failure to receive  such  approvals,  or the failure to comply
with  regulatory  requirements  in  these  countries  or  states  could  lead to
compliance  action,  which could have a material adverse effect on the Company's
business, financial condition, or results of operations.

    The Company's  service-related business (clinical trials, infectious disease
testing,  and  contract  research)  is  subject  to  other  national  and  local
requirements.  The  Company's  facilities  are  subject to  review,  inspection,
licensure or accreditation by some states,  national professional  organizations
(College of  American  Pathologists),  and other  national  regulatory  agencies
(Health  Care  Financing  Administration).  Studies  to  evaluate  the safety or
effectiveness  of FDA regulated  products  (primarily  human and animal drugs or
biologics) must also be conducted in conformance with relevant FDA requirements,
including Good Laboratory Practice ("GLP") regulations, investigational new drug
or device  regulations,  Institutional  Review  Board  ("IRB")  regulations  and
informed consent regulations.

    CLIA prohibits  laboratories  from performing in vitro tests for the purpose
of  providing  information  for the  diagnosis,  prevention  or treatment of any
disease or  impairment  of, or the  assessment  of,  the health of human  beings
unless there is in effect for such laboratories a certificate issued by the U.S.
Department of Health and Human  Services  ("HHS")  applicable to the category of
examination or procedure performed.

    The Company  currently holds permits issued by HHS (CLIA  license),  Centers
for Disease Control and Prevention (Importation of Etiological Agents or Vectors
of  Human  Diseases),  the  U.S.  Department  of  Agriculture  (Importation  and
Transportation  of Controlled  Materials and Organisms and Vectors) and the U.S.
Nuclear  Regulatory  Commission (in vitro testing with byproduct  material under
general license, covering the use of certain radioimmunoassay test methods).

    The Company is also subject to government  regulation  under the Clean Water
Act, the Toxic  Substances  Control Act, the Resource  Conservation and Recovery
Act, the Atomic  Energy Act, and other  national,  state and local  restrictions
relating  to the  use  and  disposal  of  biohazardous,  radioactive  and  other
hazardous  substances  and  wastes.  The  Company  is an exempt  small  quantity
generator  of hazardous  waste

                                       38



and  has a U.S.  Environmental  Protection  Agency  identification  number.  The
Company is also registered with the U.S. Nuclear  Regulatory  Commission for use
of certain radioactive materials. All hazardous waste is manifested and disposed
of  properly.   The  Company  is  also  subject  to  various  state   regulatory
requirements governing the handling of and disposal of biohazardous, radioactive
and hazardous  wastes.  The Company has never been a party to any  environmental
proceeding.

    Internationally,  some of the  Company's  products are subject to additional
regulatory requirements,  which vary significantly from country to country. Each
country  in which the  Company's  products  and  services  are  offered  must be
evaluated independently to determine the country's particular  requirements.  In
foreign  countries,  the Company's  distributors  are generally  responsible for
obtaining any required government consents.

INTELLECTUAL PROPERTY

    None of the Company's Quality Control Products or Diagnostic Components have
been  patented.  The  Company  has  decided  to hold as  trade  secrets  current
technology  used to  prepare  Basematrix  and other  blood-based  products.  The
Company relies  primarily on a combination  of trade secrets and  non-disclosure
and confidentiality  agreements, and in certain limited circumstances,  patents,
to establish and protect its proprietary  rights in its technology and products.
There  can be no  assurance  that  others  will  not  independently  develop  or
otherwise acquire the same, similar or more advanced trade secrets and know-how.

    The Company has two United States  patents and,  jointly with UNC, has filed
three  series of United  States and  foreign  patent  applications  relating  to
compounds,  pharmaceutical  compositions  and therapeutic  methods in connection
with the Company's  drug  discovery  program at UNC. See "-- Services," and " --
Research and Development."

    The  Company  has no reason to believe  that its  products  and  proprietary
methods  infringe the  proprietary  rights of any other  party.  There can be no
assurance,  however,  that other parties will not assert  infringement claims in
the  future.  See "Risk  Factors --  Protection  of  Intellectual  Property  and
Proprietary Technology."

PROPERTIES

    The Company's corporate offices and manufacturing  facilities are located in
a two story, 22,500 square foot building in West Bridgewater, Massachusetts. The
Company  owns  and  operates  this   building.   The  Company   intends  to  use
approximately  $1  million  of the  proceeds  of this  Offering  to  expand  its
manufacturing   capacity  and  to  purchase  necessary  equipment  at  its  West
Bridgewater  site,  and  has  submitted  plans  to  local  authorities  for  the
development  of an additional  7,500 square feet,  primarily  for  manufacturing
purposes.  The Company  anticipates that these renovations will begin this year.
The Company  believes that  following  these  renovations,  its facility in West
Bridgewater  will be  sufficient  to meet  its  foreseeable  needs.  See "Use of
Proceeds."

    The Company leases its laboratory facilities in Rockville,  Maryland and New
Britain,  Connecticut. The Rockville facility contains 21,000 square feet and is
occupied  under a five-year  lease that is due to expire on June 30,  1997.  The
Company is currently  considering the exercise of its option to extend the lease
for an additional five years, as well as relocating its laboratory.  The Company
believes that there is sufficient space available in the Rockville  facility for
its current  needs.  The New Britain  facility has 15,000  square feet,  most of
which is dedicated to laboratory  space.  The lease is for five years and is due
to expire on July 30, 2000; the Company has an option to renew for an additional
five years.

EMPLOYEES

    As of August 1, 1996 the  Company  employed  184  persons,  all of whom were
located in the United  States.  Seventy-seven  of these persons were employed in
West Bridgewater,  Massachusetts,  58 in New Britain, Connecticut, and 49 at the
Rockville,  Maryland  site.  None of the  Company's  employees  is  covered by a
collective bargaining agreement. The Company believes that it has a satisfactory
relationship with its employees.

                                       39



                                   MANAGEMENT

DIRECTORS AND EXECUTIVE OFFICERS

    The directors  and  executive  officers of the Company and their ages are as
follows:

<TABLE>
<CAPTION>
                  NAME                        AGE                       POSITION
                  ----                        ---                       --------
<S>                                           <C>     <C>
Richard T. Schumacher(1)                      46      President; Chief Executive Officer and
                                                        Chairman of the Board
Kevin W. Quinlan(2)                           46      Senior Vice President, Finance; Chief
                                                        Financial Officer; Treasurer and Director
Patricia E. Garrett, Ph.D.                    53      Senior Vice President, Regulatory Affairs &
                                                        Strategic Programs
Mark M. Manak, Ph.D.                          45      Senior Vice President, Research and
                                                        Development
Richard C. Tilton, Ph.D.                      60      Senior Vice President, Specialty Laboratory
                                                        Services
Barry M. Warren                               49      Senior Vice President, Sales & Marketing

Ronald V. DiPaolo, Ph.D.                      52      Vice President of Operations

Francis E. Capitanio(2)                       52      Director

Henry A. Malkasian(1)                         79      Director

Calvin A. Saravis(1)(2)                       66      Director

- ---------------
(1)  Member of the Compensation Committee.

(2)  Member of the Audit Committee.
</TABLE>

    Mr.  Schumacher,  the founder of the Company,  has been the President  since
1986, and Chief Executive Officer and Chairman since 1992. Mr. Schumacher served
as the Director of Infectious Disease Services for Clinical Science  Laboratory,
a New England-based medical reference  laboratory,  from 1986 to 1988. From 1972
to 1985,  Mr.  Schumacher  was  employed  by the  Center for Blood  Research,  a
nonprofit medical research institute associated with Harvard Medical School. Mr.
Schumacher received a B.S. in zoology from the University of New Hampshire.

    Mr. Quinlan,  a Director of the Company since its founding,  has been Senior
Vice President,  Finance,  Treasurer,  and Chief Financial Officer since January
1993. From 1990 to December 1992, he was the Chief Financial Officer of ParcTec,
Inc. a New York-based leasing company.  Mr. Quinlan served as Vice President and
Assistant  Treasurer of American  Finance Group,  Inc. from 1981 to 1989 and was
employed  by Coopers & Lybrand  from 1975 to 1980.  Mr.  Quinlan is a  certified
public accountant and received a M.S. in accounting from Northeastern University
and a B.S. in economics from the University of New Hampshire.

    Dr. Garrett has been Senior Vice President,  Regulatory  Affairs & Strategic
Programs  since 1988.  From 1980 to 1987,  Dr.  Garrett  served as the Technical
Director of the Chemistry  Laboratory,  Department of Laboratory Medicine at the
Lahey Clinic Medical Center. Dr. Garrett earned her Ph.D. from the University of
Colorado and was a postdoctoral research associate at Harvard University, Oregon
State  University,  Massachusetts  Institute of Technology and the University of
British Columbia.

    Dr.  Manak has served as Senior Vice  President,  Research  and  Development
since 1992. From 1980 to 1992, he served as Senior Research Scientist, Molecular
Biology,  of Biotech  Research  Laboratories.  Dr. Manak  received his Ph.D.  in
biochemistry  from the  University of  Connecticut  and  completed  postdoctoral
research work in biochemistry/virology at Johns Hopkins University.

                                       40



    Dr.  Tilton  has  served  as Senior  Vice  President,  Specialty  Laboratory
Services  since  the  Company's   acquisition  of  BBI-North  American  Clinical
Laboratories,  Inc. in 1993 and was one of the  founders of  BBI-NACL,  where he
served as President  from 1989 to 1993. Dr. Tilton has 25 years of experience in
university hospital clinical microbiology laboratories and is board certified in
medical  and public  health  microbiology.  Dr.  Tilton  received  his Ph.D.  in
microbiology from the University of Massachusetts.

    Mr.  Warren has served as Senior Vice  President,  Sales &  Marketing  since
1993.  From 1985 to 1993,  Mr. Warren  served as Group  Director of Marketing of
Organon  Teknika,  a manufacturer  of infectious  disease  reagents.  Mr. Warren
received an M.A. in political  science from Loyola  University  of Chicago and a
B.A. from Loyola University.

    Dr.  DiPaolo has been Vice  President  of  Operations  since 1993.  Prior to
joining the Company, Dr. DiPaolo served as Vice President and General Manager of
the Biomedical Products Division of Collaborative  Research,  a medical research
products  company.  From  1975 to 1986 he was  employed  by DuPont  New  England
Nuclear,  an in vitro test kit  manufacturer.  Dr. DiPaolo received his Ph.D. in
biochemistry  from  Massachusetts  Institute of Technology  and later  completed
postdoctoral research at the Eunice Shriver Center in Waltham, Massachusetts.

    Mr.  Capitanio  has served as a Director  since  January  1986.  He has been
President,   Treasurer  and  Director  of  Diatech  Diagnostics  Inc.  (formerly
Immunotech  Corporation),  an in vitro  diagnostics  company and a wholly  owned
subsidiary of Healthcare  Technologies  Ltd., since 1980. Mr. Capitanio received
an  M.B.A.  from the Sloan  School of  Management,  Massachusetts  Institute  of
Technology and a B.S. in metallurgy from Massachusetts Institute of Technology.

    Mr.  Malkasian has served as a Director since the Company's  organization in
1978.  Mr.  Malkasian is a practicing  attorney-at-law  and a member of the firm
Malkasian & Budge in  Massachusetts.  He received  his J.D.  degree from Harvard
University School of Law and a B.A. degree from Clark University.

    Dr. Saravis has served as a Director since 1978. Since 1971, Dr. Saravis has
been a Senior Research Associate at the Mallory Institute of Pathology and since
1979 he has been a Senior Research Associate at the Cancer Research Institute --
New England Deaconess  Hospital.  Since 1984, Dr. Saravis has had an appointment
as an Associate  Professor of Surgery  (biochemistry)  at Harvard Medical School
and an Associate  Research Professor of Pathology at Boston University School of
Medicine. Dr. Saravis received his Ph.D. in immunology and serology from Rutgers
University.

    In August 1990 the Board of Directors  established a Compensation  Committee
currently composed of Messrs.  Schumacher,  Saravis and Malkasian. The functions
of the Compensation  Committee include  presentation and  recommendations to the
Board of  Directors  on  compensation  levels for  officers  and  directors  and
issuance of stock options to the Board of Directors, employees and affiliates.

    In  August  1990  the  Board of  Directors  established  an Audit  Committee
currently composed of Messrs.  Capitanio,  Quinlan and Saravis. The functions of
the  Audit  Committee  include  recommending  to  the  Board  of  Directors  the
engagement  of the  independent  accountants,  reviewing  the scope of  internal
controls and reviewing the implementation by management of recommendations  made
by the independent accountants.

    The  Company's  Board of Directors is divided into three  classes,  with the
classes being elected for staggered  three-year terms. At each annual meeting of
stockholders, directors will be elected to succeed those in the class whose term
then expires,  and each elected  director shall serve for a term expiring at the
third succeeding annual meeting of stockholders after such director's  election,
and until the  director's  successor is elected and qualified.  Thus,  directors
stand for election  only once in three years.  Executive  officers  serve at the
discretion of the Board of Directors.

DIRECTOR COMPENSATION

   
    Directors  of the  Company  do  not  receive  cash  compensation  for  their
services.  Each director is eligible to receive options to purchase Common Stock
under the Company's 1987 Non-Qualified Stock Option Plan. As of October 4, 1996,
options  to  purchase  an  aggregate  of  249,750  shares  have been  granted to
directors  of the  Company  under  this Plan.  During  fiscal  1995,  options to
purchase  an  aggregate  of 15,000  shares of Common  Stock were  granted to the
Directors  as  follows:  5,000  shares  to Mr.  Capitanio,  5,000  shares to Mr.
Malkasian,  and  5,000  shares  to Dr.  Saravis  and no  shares  to  either  Mr.
Schumacher or Mr. Quinlan.
    

                                       41


EXECUTIVE COMPENSATION

    The following  table sets forth the  compensation  for the fiscal year ended
December 31, 1995 of each of the Chief Executive Officer and the six most highly
compensated  officers of the Company (the "Named Executive  Officers"),  none of
whom received any bonuses during the fiscal year ended December 31, 1995:

   
                           SUMMARY COMPENSATION TABLE
<TABLE>
<CAPTION>
                                                                                    ANNUAL COMPENSATION
                                                                                      FOR FISCAL 1995
                                                                                             OTHER ANNUAL
                         NAME AND PRINCIPAL POSITION                           SALARY($)    COMPENSATION($)
                         ---------------------------                           ---------    ---------------
<S>                                                                            <C>          <C>
Richard T. Schumacher.......................................................    $166,676      $ 2,008(1)
  President and Chief Executive Officer
Kevin W. Quinlan............................................................     120,615        1,650(2)
  Senior Vice President, Finance and Chief Financial Officer
Patricia E. Garrett, Ph.D. .................................................      92,353        1,650(2)
  Senior Vice President, Regulatory Affairs & Strategic Programs
Mark M. Manak, Ph.D. .......................................................     102,753          --
  Senior Vice President, Research & Development
Richard C. Tilton, Ph.D. ...................................................     111,924        6,000(3)
  Senior Vice President, Specialty Laboratory Services
Barry M. Warren.............................................................     113,454        1,500(2)
  Senior Vice President, Sales & Marketing
Ronald V. DiPaolo, Ph.D. ...................................................      86,614        1,500(2)
  Vice President of Operations
    

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

(1) Consists of personal  usage of Company  vehicle,  and includes the value of
     premiums paid for a term life insurance policy.

(2) Consists of automobile allowance, discontinued as of March 31, 1995.

(3) Consists of automobile allowance.
</TABLE>

    The  following  table sets forth the  aggregate  number and value of options
exercisable  and  unexercisable  by the Named  Executive  Officers during fiscal
1995.  No stock  options  were  granted  to, or  exercised  by, any of the Named
Executive Officers in fiscal 1995.

   
                          FISCAL YEAR-END OPTION VALUES
<TABLE>
<CAPTION>
                                                       
                                                       NUMBER OF SECURITIES      VALUE OF UNEXERCISED
                                                      UNDERLYING UNEXERCISED     IN-THE-MONEY OPTIONS
                                                      OPTIONS AT 12/31/95(#)      AT 12/31/95($)(1)
            NAME AND PRINCIPAL POSITION             EXERCISABLE/UNEXERCISABLE EXERCISABLE/UNEXERCISABLE
            ---------------------------             ---------------------------------------------------
<S>                                                  <C>                     <C>
Richard T. Schumacher ..............................   127,500         2,500  $ 988,500     $ 16,250
  President and Chief Executive Officer
Kevin W. Quinlan ...................................    58,000        10,000    403,750       65,000
  Senior Vice President, Finance and Chief
  Financial Officer
Patricia E. Garrett, Ph.D. .........................    41,250         1,250    334,125        5,625
  Senior Vice President, Regulatory Affairs &
  Strategic Programs
Mark M. Manak, Ph.D. ...............................    26,250         8,750    170,625       56,875
  Senior Vice President, Research & Development
Richard C. Tilton, Ph.D. ...........................    17,500        17,500    105,000      105,000
  Senior Vice President, Specialty Laboratory
  Services
Barry M. Warren ....................................     7,500         7,500     33,750       33,750
  Senior Vice President, Sales & Marketing
Ronald V. DiPaolo, Ph.D. ...........................    25,000         1,000    183,900        4,500
  Vice President of Operations

- -----------------------
</TABLE>
(1)  There was no public  trading market for the Common Stock as of December 31,
     1995.  Accordingly,  these values have been  calculated on the basis of the
     assumed  initial  public  offering  price  of  $9.00  per  share,  less the
     applicable exercise price.
    
                                       42



EMPLOYMENT AGREEMENTS

    None of the Company's  employees are subject to employment  agreements  with
the Company.

STOCK PLANS

   
    1987  Non-Qualified   Stock  Option  Plan:  The  Company  adopted  the  1987
Non-Qualified  Stock  Option  Plan  (the  "Non-Qualified  Plan") to  provide  an
opportunity to employees,  officers,  directors and  consultants  employed by or
affiliated  with the Company or any of its  subsidiaries to acquire stock in the
Company, to provide increased  incentives to such persons to promote the success
of the  Company's  business and to encourage  such persons to become  affiliated
with the Company  through the granting of options to acquire its capital  stock.
Any  employee  of the  Company  or of a  subsidiary  of the  Company,  including
officers,  as well as directors of the Company and  consultants  or providers of
services to the Company,  are  eligible to receive  nonqualified  stock  options
under the Non-Qualified Plan. A total of 897,600 shares of Common Stock has been
reserved for issuance under the Non-Qualified Plan.

    The  Non-Qualified  Plan  is  required  to be  administered  by a  Committee
consisting of at least one member appointed by the Board of Directors, and after
the completion of this Offering,  consisting of at least two independent members
of  the  Board  of  Directors.  The  Committee  currently  consists  of  Richard
Schumacher,  Kevin Quinlan and Henry Malkasian.  The Committee has the authority
and discretion to determine those persons to whom options shall be granted under
the  Non-Qualified  Plan,  to determine  the number of shares to be granted,  to
establish  the terms and  conditions  upon which  options  may be  exercised  or
transferred,  to alter any restrictions or conditions on the options and to make
all other  determinations  necessary or desirable for the  administration of the
Non-Qualified   Plan.  The  exercise   price  for  options   granted  under  the
Non-Qualified Plan is determined by the Committee,  but is in no event less than
the par value of the Common Stock.  Options granted under the Non-Qualified Plan
continue  in  effect  for  such  period  as  the   Committee   determines.   The
Non-Qualified Plan terminates as of December 16, 1997.

    As of October 4, 1996,  options to purchase 749,850 had been issued pursuant
to the  Non-Qualified  Plan at  exercise  prices  ranging  from  $.25 to  $6.00,
including an aggregate of 249,750  shares to the  Company's  directors,  Richard
Schumacher,  Kevin  Quinlan,  Francis  Capitanio,  Henry  Malkasian,  and Calvin
Saravis.

    Employee  Stock Option Plan:  The purpose of the Employee  Stock Option Plan
(the  "Employee  Plan") is to provide  increased  incentives  to  employees,  to
encourage new employees to become  affiliated  with the Company and to associate
more  closely the  interests  of such  persons  with those of the  Company.  The
Employee  Plan permits the issuance of options to purchase up to 750,000  shares
of Common Stock in the form of incentive stock options as defined in Section 422
of the  Internal  Revenue  Code of 1986,  as amended,  and  non-qualified  stock
options.  The Employee Plan is currently  administered by a Committee consisting
of at least  one  member  appointed  by the  Board of  Directors,  and after the
completion of this Offering,  shall consist of at least two independent  members
of the Board of Directors.  The exercise price of stock options is determined by
the Committee, but is in no event less than par value, and the exercise price of
incentive stock options may not be less than the fair market value of the Common
Stock on the date of grant  (or,  in the case of  holders  of 10% or more of the
outstanding  Common  Stock,  110% of the fair market  value on such  date).  The
Committee also determines the vesting schedule, number of shares and other terms
of the options.  As of October 4, 1996,  options to purchase  184,537  shares of
Common  Stock at  exercise  prices  ranging  from  $6.00 to $8.50 per share were
outstanding under the Employee Plan.
    

COMPENSATION COMMITTEE INTERLOCKS AND INSIDER PARTICIPATION

    The  Compensation  Committee  currently  consists of Messrs.  Schumacher and
Malkasian and Dr. Saravis,  each of whom has received options to purchase shares
of Common Stock. See "-- Director Compensation" and "-- Stock Plans."

LIMITATION OF OFFICERS' AND DIRECTORS' LIABILITY; INDEMNIFICATION AGREEMENTS

    The  Company's  Amended and  Restated  Articles of  Organization  eliminate,
subject to certain  exceptions,  the  personal  liability  of  directors  to the
Company or its  stockholders  for  monetary  damages for  breaches of  fiduciary
duties as directors. The Restated Articles do not provide for the elimination of
or any limitation on the personal  liability of a director for (i) any breach of
the director's duty of loyalty

                                       43



to the Company or its stockholders,  (ii) acts or omissions not in good faith or
which  involve  intentional  misconduct  or a knowing  violation  of law,  (iii)
certain unauthorized  dividends,  redemptions or distributions as provided under
Section 61 of the Massachusetts  Business Corporation Law, (iv) certain loans of
assets of the Company to any of its  officers  or  directors  as provided  under
Section 62 of the Massachusetts  Business Corporation Law or (v) any transaction
from which the director derived an improper personal benefit.  This provision of
the  Amended  and  Restated  Articles of  Organization  will limit the  remedies
available to a stockholder in the event of breaches of any director's  duties to
such stockholder or the Company.

    The Company's Amended and Restated Articles of Organization provide that the
Company  may,   either  in  its  By-laws  or  by   contract,   provide  for  the
indemnification  of  directors,  officers,  employees  and  agents,  by whomever
elected or appointed,  to the full extent permitted by law, as it may be amended
from time to time.

   
    The Company  intends to enter into  indemnification  agreements with each of
the directors and officers. The indemnification agreements will provide that the
Company will pay certain amounts incurred by a director or officer in connection
with any civil or  criminal  action or  proceeding  and  specifically  including
actions  by or  in  the  name  of  the  Company  (derivative  suits)  where  the
individual's  involvement  is by reason of the fact that he is or was a director
or officer.  Such  amounts  include,  to the maximum  extent  permitted  by law,
attorney's  fees,  judgments,  civil or criminal fines,  settlement  amounts and
other expenses customarily incurred in connection with legal proceedings.  Under
the  indemnification   agreements,  a  director  or  officer  will  not  receive
indemnification if he is found not to have acted in good faith in the reasonable
belief that his action was in the best interests of the Company.

                              CERTAIN TRANSACTIONS

    Registration  Rights.  The  Company  is a  party  to a  Registration  Rights
Agreement dated June 5, 1990, as amended (the "Registration Agreement"),  with G
& G Diagnostics  Limited Partnership I and G & G Diagnostics Limited Partnership
II  (together,  "G & G") pursuant to which G & G has certain  rights to have its
shares of Common Stock  registered  by the Company under the  Securities  Act. A
total of 366,670 shares of Common Stock (the "Registrable Shares") held by G & G
or subject to warrants  held by G & G may be registered  under the  Registration
Agreement.  If the Company  proposes to register any of its securities under the
Securities  Act,  either  for  its  own  account  or for the  account  of  other
securityholders, G & G is entitled to notice of the registration and is entitled
to include, at the Company's expense, the Registrable Shares therein,  provided,
among other conditions, that the underwriters have the right to limit the number
of such shares included in the registration.  In addition, G & G may require the
Company at its  expense on no more than two  occasions,  to file a  registration
statement under the Securities Act with respect to its Registrable  Shares,  and
the  Company  is  required  to use its best  efforts  to effect a  registration,
subject to certain  conditions and limitations.  Further,  G & G may require the
Company at its expense to register the Registrable  Shares on Form S-3 when such
form  becomes  available  to the  Company,  subject  to certain  conditions  and
limitations.  G & G waived its respective registration rights for this Offering.
See "Principal Stockholders."
    

    Warrant  Exercise.  In May 1995, G & G Diagnostics  Limited  Partnership  II
exercised  warrants to purchase 40,000 shares of the Company's  Common Stock for
an exercise price of $2.50 per share or an aggregate amount of $100,000.

    Indemnification Contracts. The Company intends to enter into indemnification
agreements  with  each  of  its  directors  and  officers.  See  "Management  --
Limitation of Officers' and Directors' Liability; Indemnification Agreements."

                                       44



                             PRINCIPAL STOCKHOLDERS

   
    The  following  table sets forth certain  information  as of October 4, 1996
concerning  the beneficial  ownership of Common Stock by each director,  certain
executive  officers,  all executive  officers and directors as a group, and each
person  known by the  Company  to be the  beneficial  owner of 5% or more of the
Company's Common Stock. This information is based upon information received from
or on behalf of the named  individuals.  Unless  otherwise noted, the beneficial
owners listed have sole voting and investment power over the shares listed.
<TABLE>
<CAPTION>
                                                                               PERCENTAGE OF OUTSTANDING SHARES
                                                                                    BENEFICIALLY OWNED(1)
                                                                                    ---------------------
                                                           NUMBER OF SHARES      BEFORE THE        AFTER THE
         NAME AND ADDRESS OF BENEFICIAL OWNER             BENEFICIALLY OWNED      OFFERING          OFFERING
         ------------------------------------             ------------------      --------          --------
<S>                                                       <C>                     <C>               <C>
5% Stockholders
  Irwin J. Gruverman(2)                                         412,920             14.71%             9.37%
   c/o G & G Diagnostics Limited Partnership I
   30 Ossipee Road
   Newton, MA 02164
  G & G Diagnostics Limited Partnership II(3)                   153,333              5.69              3.57
Directors and Senior Executives
  Richard T. Schumacher(4)(5)                                 1,013,957             35.89             22.91
  Henry A. Malkasian(4)(6)                                      311,510             11.54              7.24
  Kevin W. Quinlan(4)                                            93,100              3.37              2.13
  Patricia E. Garrett(4)                                         55,000              2.01              1.27
  Richard C. Tilton(4)                                           62,500              2.29              1.44
  Mark M. Manak(4)                                               55,500              2.03              1.28
  Barry M. Warren(4)                                             37,500              1.37                 *
  Ronald V. DiPaolo(4)                                           28,000              1.03                 *
  Calvin A. Saravis(4)                                           23,000                 *                 *
  Francis E. Capitanio(4)                                         8,750                 *                 *
  All Executive Officers and Directors as a group
   (10 Persons)(4)(5)(6)(7)                                   1,688,817             54.04             35.74
    
- -------------------
  *  Less than 1% of the outstanding Common Stock.

(1)  The number of shares of Common Stock  outstanding  used in calculating  the
     percentage  for each  listed  person  includes  the shares of Common  Stock
     underlying options or warrants held by such person.

(2)  Includes  283,333  shares  held of  record  by three  limited  partnerships
     (including  G &  G  Diagnostics  Limited  Partnership  II),  of  which  Mr.
     Gruverman is the general partner,  10,000 shares subject to options held by
     Mr.  Gruverman and 106,670  shares subject to warrants held by one of three
     limited partnerships.

(3)  The address for G & G  Diagnostics  Limited  Partnership  II is the same as
     that for Mr. Gruverman. Mr. Gruverman is the beneficial owner of the shares
     of Common Stock held of record by G & G Limited Partnership II.

   
(4)  Includes the following  shares subject to options:  Mr. Capitanio -- 8,750,
     all of which are  exercisable  within 60 days after  October  4, 1996;  Dr.
     DiPaolo --  28,000,  25,000 of which are  exercisable  within 60 days after
     October 4, 1996;  Dr.  Garrett -- 45,000,  41,250 of which are  exercisable
     within 60 days  after  October 4, 1996;  Mr.  Quinlan -- 73,000,  58,000 of
     which are exercisable  within 60 days after October 4, 1996; Mr.  Malkasian
     -- 10,000,  all of which are  exercisable  within 60 days after  October 4,
     1996; Dr. Manak -- 37,500,  26,250 of which are exercisable  within 60 days
     after October 4, 1996; Dr. Saravis -- 23,000,  all of which are exercisable
     within 60 days after October 4, 1996; Mr. Schumacher --135,000,  127,500 of
     which are  exercisable  within 60 days after October 4, 1996; Dr. Tilton --
     37,500,  26,250 of which are  exercisable  within 60 days after  October 4,
     1996; and Mr. Warren -- 37,500,  7,500 of which are  exercisable  within 60
     days after October 4, 1996.

(5)  Includes 50,000 shares held of record by Mr. Schumacher's spouse and 20,000
     shares held of record by Mr.  Schumacher  as  custodian  for his  daughter.
     Excludes an  aggregate  of 144,067  shares held by other  relatives  of Mr.
     Schumacher as to which Mr. Schumacher disclaims beneficial ownership.
    

(6)  Includes 12,000 shares held of record by Mr.  Malkasian's son, 5,000 shares
     held by Mr.  Malkasian's  daughter,  53,850 shares held by Mr.  Malkasian's
     spouse and 30,000 shares held by Mr. Malkasian as trustee in trust for each
     of his son and his daughter.

(7)  Includes  4,000  shares held of record by Mr.  Manak as  custodian  for his
     daughter.
</TABLE>
                                       45
                          DESCRIPTION OF CAPITAL STOCK

    The authorized capital stock of the Company consists of 20,000,000 shares of
Common  Stock,  $0.01 par value  (referred  to herein  as  "Common  Stock")  and
1,000,000  shares of  Preferred  Stock,  $.01 par value  (referred  to herein as
"Preferred Stock").

COMMON STOCK

   
    As of  October  4,  1996,  there  were  2,690,064  shares  of  Common  Stock
outstanding, held of record by approximately 130 stockholders.
    

    The  holders  of  Common  Stock  are  entitled  to one vote per share on all
matters  to be  voted  on by  stockholders  and are  entitled  to  receive  such
dividends,  if any,  as may be  declared  from  time to  time  by the  Board  of
Directors from funds legally available therefor.  The holders of Common Stock do
not have cumulative voting rights in the election of directors. Upon liquidation
or  dissolution  of the  Company,  the holders of Common  Stock are  entitled to
receive all assets  available for distribution to the  stockholders.  The Common
Stock  has  no  preemptive  or  other  subscription  rights,  and  there  are no
conversion  rights or redemption or sinking fund provisions with respect to such
shares. All of the shares of Common Stock are, and the shares to be sold in this
Offering will be, fully paid and nonassessable.

PREFERRED STOCK

    The  Company is  authorized  to issue up to  1,000,000  shares of  Preferred
Stock, none of which are outstanding. The Board of Directors may, without future
action of the  stockholders of the Company,  issue the Preferred Stock in one or
more classes or series and fix the rights and preferences thereof, including the
dividend rights,  dividend rates,  conversion  rights,  voting rights,  terms of
redemption  (including  sinking fund  provisions),  redemption  price or prices,
liquidation  preferences  and the  number  of shares  constituting  any class or
series, or the designations of such class or series. The voting and other rights
of the holders of Common Stock may be subject to and adversely  affected by, the
rights of holders of any Preferred Stock that may be issued in the future.

MASSACHUSETTS ANTI-TAKEOVER AND RELATED STATUTES

    Control  Share  Acquisition  Law.  Under  Chapter 110D of the  Massachusetts
General Laws governing "control share  acquisitions," any stockholder of certain
publicly-held  Massachusetts  corporations who acquires certain ranges of voting
power  --  one-fifth  or more but  less  than  one-third  of all  voting  power,
one-third or more but less than a majority of all voting power, or a majority or
more of all voting power -- may not (except in certain  transactions)  vote such
stock  unless the  stockholders  (excluding  the shares  held by the  interested
stockholders) of the corporation so authorize. As permitted by Chapter 110D, the
Company's  Amended and Restated  By-laws  include a provision which excludes the
Company from the applicability of that statute upon completion of the Offering.

    Business  Combination  Statute.  Chapter 110F of the  Massachusetts  General
Laws, entitled "Business Combinations with Interested  Shareholders," applies to
publicly-held  Massachusetts  corporations  with  200 or  more  stockholders  of
record. Generally,  this statute prohibits such Massachusetts  corporations from
engaging in a "business  combination"  with an  "interested  stockholder"  for a
period of three years  following the date of the transaction in which the person
becomes an interested  stockholder unless (a) the interested stockholder obtains
the  approval  of the  corporation's  board of  directors  prior to  becoming an
interested stockholder;  (b) the interested stockholder acquires at least 90% of
the voting stock of the corporation (excluding shares held by certain affiliates
of  the   corporation)   outstanding  at  the  time  he  becomes  an  interested
stockholder;  or (c) the business  combination  is both approved by the board of
directors and authorized at an annual or special  meeting of stockholders by the
holders  of  at  least  two-thirds  of  the  outstanding  voting  stock  of  the
corporation   (excluding  shares  held  by  the  interested   stockholder).   An
"interested   stockholder"  is  a  person  who,  together  with 

                                       46



affiliates and associates, owns (or at any time within the prior three years did
own) 5% or more of the outstanding voting stock of the Corporation.  A "business
combination" includes,  among other transactions,  a merger, stock or asset sale
and other transactions resulting in a financial benefit to the stockholder.  The
Amended  and  Restated  Articles of  Organization  and  Restated  By-laws of the
Company do not  expressly  provide for opting out of the  provisions  of Chapter
110F.  As a  result,  the  application  of this  statute  to the  Company  after
completion of this Offering  could  discourage or make it more difficult for any
person or group of  persons to attempt  to obtain  control of the  Company.  The
Company may at any time amend its Amended and Restated  Articles of Organization
or Restated  By-laws to elect not to be governed by Chapter  110F,  by a vote of
the holders of a majority of its voting stock,  but such an amendment  would not
be  effective  for twelve  months and would not apply to a business  combination
with any person who became an  interested  stockholder  prior to the date of the
amendment.


CERTAIN PROVISIONS OF THE COMPANY'S AMENDED AND RESTATED ARTICLES OF
ORGANIZATION AND AMENDED AND RESTATED BY-LAWS

    The Company's Amended and Restated Articles of Organization  include several
provisions  which may render more  difficult an unfriendly  tender offer,  proxy
contest,  merger or other change in control of the Company. See "Risk Factors --
Possible Adverse Effect of Certain Anti-takeover Provisions."

    Preferred  Stock. The Amended and Restated  Articles of Organization  permit
the Board of Directors to issue preferred stock in one or more series and to fix
the rights,  preferences,  privileges and restrictions thereof,  without further
vote or action by the stockholders. The issuance of preferred stock may have the
effect of delaying,  deferring or  preventing a change in control of the Company
and may  adversely  affect the voting and other  rights of the holders of Common
Stock. The Company currently has no plans to issue any preferred stock.

   
    Classification  of Board of Directors.  The Amended and Restated Articles of
Organization  provide for the classification of the Company's Board of Directors
into three  classes,  with the classes being  elected for  staggered  three-year
terms.  At each annual  meeting of  stockholders,  directors  will be elected to
succeed  those in the class whose term then expires,  and each elected  director
shall  serve for a term  expiring  at the third  succeeding  annual  meeting  of
stockholders after such director's election,  and until the director's successor
is elected and qualified.  Thus, directors stand for election only once in three
years.  This provision also restricts the ability of stockholders to enlarge the
Board of Directors. Changes in the number of Directors may be effected by a vote
of a  majority  of the  Continuing  Directors  (as  defined in the  Amended  and
Restated  Articles of  Organization)  or by the stockholders by vote of at least
80% of the shares of the Company's voting stock outstanding,  voting as a single
class. Under this provision, Directors may only be removed with or without cause
by the affirmative vote of the holders at least 80% of the combined voting power
of the outstanding  shares of the Company's  voting stock,  voting together as a
single class, or upon the vote of a majority of the Continuing Directors.
    

    Fair Price  Provision.  The Amended and  Restated  Articles of  Organization
contain a "Fair Price Provision" that is intended to protect stockholders who do
not tender their shares in a takeover bid by  guaranteeing  them a minimum price
for their shares in any subsequent  attempt to purchase such remaining shares at
a price lower than the acquiror's  original  acquisition  price.  The Fair Price
Provision  requires the  affirmative  vote of the holders of at least 80% of the
Company's  outstanding  voting stock for certain  business  combinations  with a
Related Person, unless specified price criteria and procedural  requirements are
met or the  business  combination  is approved  by a majority of the  Continuing
Directors.

    Indemnification Provision. The Amended and Restated Articles of Organization
provide that the Company may, either in its By-laws or by contract,  provide for
the  indemnification of directors,  officers,  employees and agents, by whomever
elected or appointed,  to the full extent permitted by applicable law, as it may
be amended from time to time.  See "--  Limitation of Officers'  and  Directors'
Liability; Indemnification Agreements."

TRANSFER AGENT AND REGISTRAR

   
    The Transfer Agent and Registrar for the Common Stock is American Securities
Transfer & Trust, Inc.
    

                                       47



                         SHARES ELIGIBLE FOR FUTURE SALE

    Prior to this  Offering,  there has been no  public  market  for the  Common
Stock.  Future sales of substantial amounts of Common Stock in the public market
could adversely affect the market price of the Common Stock.

   
    Upon completion of this Offering,  the Company will have 4,290,064 shares of
Common Stock outstanding  (4,530,064  shares if the Underwriters'  overallotment
option is exercised in full). Of those shares, the 1,600,000 shares sold in this
Offering  (1,840,000  shares  if  the  Underwriters'   overallotment  option  is
exercised in full) will be freely tradeable  without  restriction  (except as to
affiliates of the Company) or further registration under the Securities Act. The
remaining  2,690,064 shares of Common Stock were sold by the Company in reliance
on exemptions from the  registration  requirements of the Securities Act and are
"restricted securities" within the meaning of Rule 144 under the Securities Act.
All  of the  Company's  directors  and  executive  officers  and  certain  other
stockholders,  holding in the aggregate  2,555,244 shares of Common Stock,  have
agreed not to offer to sell,  sell or otherwise  dispose of any shares of Common
Stock  prior to the  expiration  of 180 days  from the date of this  Prospectus.
Oscar  Gruss & Son  Incorporated  may,  in its sole  discretion  and at any time
without prior  notice,  release all or any portion of the shares of Common Stock
subject to the lockup agreements.

    Beginning 91 days after the date of this Prospectus,  6,475 shares of Common
Stock will be  eligible  for sale in the  public  market  without  registration,
subject to certain  volume and other  limitations,  pursuant to Rule 144 or Rule
701 under the Securities Act of 1933, as amended (the  "Securities  Act") and an
additional  122,571 shares will be eligible for sale without such  restrictions.
Following the expiration of the 180-day lockup period,  an additional  1,643,197
shares of Common  Stock will be eligible for sale in the public  market  without
registration,  subject to certain volume and other limitations, pursuant to Rule
144 or Rule 701 under the Securities  Act and an additional  734,425 shares will
be eligible for sale without such  restrictions.  The remaining shares of Common
Stock held by existing stockholders will become eligible for sale under Rule 144
or otherwise at various times thereafter. All shares of Common Stock outstanding
on the date of this  Prospectus  will be eligible for sale to certain  qualified
institutional buyers in accordance with Rule 144A under the Securities Act.
    

    In  general,  under Rule 144 as  currently  in effect,  a person (or persons
whose shares are aggregated), including an affiliate of the Company, may sell in
the open market within any  three-month  period a number of shares that does not
exceed the  greater of (i) 1% of the  then-outstanding  shares of the  Company's
Common Stock or (ii) the average weekly  trading volume in the  over-the-counter
market  during the four  calendar  weeks  preceding  such sale,  provided that a
minimum of two years has elapsed between the later of the date of acquisition of
the securities  from the issuer or from an affiliate of the issuer.  The holding
period of shares of a non-affiliate for this purpose includes the holding period
of all prior non-affiliate holders,  provided that if an affiliate has held such
shares  at any  time,  the  holding  period  shall  commence  upon the sale to a
non-affiliate by the last affiliate to hold the shares. Sales under Rule 144 are
also subject to certain  limitations on the manner of sale,  notice  requirement
and  availability of current public  information  about the Company.  Under Rule
144(k),  a non-affiliate  who holds  restricted  securities and who has not been
affiliated with the Company during the three-month period preceding the proposed
sale thereof may sell such  securities  without regard to conditions  imposed by
Rule 144 if at least three years have elapsed  from the sale of such  securities
by the Company or any  affiliate.  The  Securities  and Exchange  Commission has
proposed  amendments to Rule 144,  including an amendment which would reduce the
waiting period to one year.

    Under Rule 701 of the Securities Act,  persons who purchased shares pursuant
to an employee stock purchase  program or upon exercise of options granted prior
to the  effective  date  of this  Offering  are  entitled,  subject  to  certain
conditions  and  limitations  of Rule 701, to sell such shares 90 days after the
effective date of this Offering in reliance upon Rule 144, without regard to the
holding  period  requirement  of Rule  144 and,  in the case of  non-affiliates,
without  compliance  with the public  information,  volume  limitation or notice
provisions of Rule 144.

   
    The Company  intends to register  under the Securities Act shortly after the
consummation  of the offering an  aggregate of 1,647,600  shares of Common Stock
issued or issuable  upon exercise of employee  stock  options  granted under the
Non-Qualified Plan and the Employee Plan, including 934,387 shares issuable upon
exercise of such options outstanding on the date of this Prospectus.  Two of the
Company's stockholders and the holder of a warrant to purchase Common Stock have
the right to cause the Company to register their shares under the Securities Act
and to  include  their  shares in certain  future  registrations  of  securities
effected by the Company under the Securities Act. An aggregate of 627,650 shares
of Common Stock, including 226,670 shares of Common Stock issuable upon exercise
of  outstanding  warrants  are covered by such  registration  rights.  See "Risk
Factors  --  Shares  Eligible  for  Future  Sale,"   "Certain   Transactions  --
Registration Rights" and "Principal Stockholders."
    

                                       48

                                  UNDERWRITING

    The  Underwriters  named below,  for whom Oscar Gruss & Son Incorporated and
Kaufman Bros., L.P. are acting as the Representatives  (the  "Representatives"),
have  severally  agreed,  subject to the terms and  conditions  contained in the
Underwriting  Agreement,  to  purchase  from the Company the number of shares of
Common Stock set forth opposite their respective names below.

<TABLE>
<CAPTION>
   
                                                                        NUMBER OF
                                NAME                                     SHARES
                                ----                                     ------
<S>                                                                    <C>
Oscar Gruss & Son Incorporated
Kaufman Bros., L.P.
                                                                       ---------
  TOTAL                                                                1,600,000
                                                                       =========
</TABLE>

    The  Underwriting  Agreement  provides  that the  several  Underwriters  are
obligated to purchase all of the 1,600,000 shares of Common Stock offered by the
Underwriters  hereby  (other  than  shares  which  may be  purchased  under  the
over-allotment  option) if any are purchased.  The Representatives  have advised
the  Company  that the  Underwriters  propose  to offer the shares to the public
initially  at the  public  offering  price set  forth on the cover  page of this
Prospectus,  that the Underwriters may allow to selected dealers a concession of
$_____ per share and that such  dealers may reallow a  concession  of $_____ per
share to certain other dealers.  After the initial public offering, the offering
price  and  the  concessions  may  be  changed  by  the   Representatives.   The
Representatives have informed the Company that the Underwriters do not intend to
confirm sales to any accounts over which they exercise discretionary authority.

    The Company has granted to the Underwriters an option, expiring at the close
of business  on the 30th day after the date of the  Underwriting  Agreement,  to
purchase up to 240,000  additional shares of Common Stock at the public offering
price less underwriting discounts and commissions, all as set forth on the cover
page of this Prospectus.  The Underwriters may exercise the option only to cover
over-allotments, if any, in the sale of shares of Common Stock in this Offering.
To the extent that the Underwriters  exercise the option,  each Underwriter will
become obligated,  subject to certain conditions,  to purchase approximately the
same  percentage  thereof  that the number of shares to be  purchased by each of
them as shown in the  foregoing  table bears to the  1,600,000  shares of Common
Stock offered hereby.

    The  Company  has  agreed to pay to the  Representatives  a  non-accountable
expense allowance of one percent of the gross proceeds of the Offering ($144,000
if the Underwriters'  over-allotment option is not exercised and $165,600 if the
Underwriters'  overallotment  option is exercised in full, at an assumed  public
offering  price of $9.00 per share),  of which $40,000 has been paid to date. If
the Offering is not consummated,  the Representatives will return to the Company
any unused  portion of the  pre-paid  expense  allowance.  The  Company has also
agreed to pay all expenses in connection  with  registering  or  qualifying  the
Common Stock  offered  hereby for sale under the laws of the states in which the
Common Stock is sold by the Underwriters (including expenses of counsel retained
for such purposes by the  Underwriters) as well as certain  expenses  associated
with information meetings.

    The Company has agreed to sell to the  Representatives,  or their designees,
warrants  (the  "Underwriters'  Warrants")  to  purchase  160,000  shares of the
Company's Common Stock at an aggregate  purchase price of $______.  The exercise
price per Underwriters' Warrant, subject to anti-dilution  adjustment,  is equal
to 135% of the public  offering price per share of Common Stock offered  hereby.
The  Underwriters'  Warrants expire on the fifth anniversary of the closing date
of the Offering.  The Underwriters' Warrants may not be transferred or exercised
for one year from the date of this Prospectus,  except for transfers to officers
of the  Representatives  or members of the  underwriting or selling group and/or
their  officers  or 

                                       49



partners,  if any. The  Underwriters'  Warrants  become  exercisable  during the
four-year  period  commencing  one year  from the date of this  Prospectus  (the
"Warrant  Exercise Term").  During the Warrant Exercise Term, the holders of the
Underwriters'  Warrants are given,  at nominal cost,  the  opportunity to profit
from an increase in the market price of the Company's  Common Stock. The Company
has granted the Representatives  certain registration rights with respect to the
Underwriters'  Warrants. All registration rights will terminate seven years from
the closing date of the Offering.

    Except as set forth below,  the Company,  its  officers and  directors,  and
certain of its  stockholders,  who will hold an aggregate  of  2,555,244  shares
after this  Offering,  have agreed that they will not,  directly or  indirectly,
offer,  sell,  offer to sell,  contract to sell, grant any option to purchase or
otherwise  sell or dispose of any shares of Common Stock or other  capital stock
of  the  Company  or  any  securities   convertible   into,  or  exercisable  or
exchangeable  for,  any  shares of Common  Stock or other  capital  stock of the
Company for a period of 180 days after the date of this  Prospectus  without the
prior  written  consent  of Oscar  Gruss & Son  Incorporated  on  behalf  of the
Underwriters.  Oscar Gruss & Son Incorporated may, in its sole discretion and at
any time  without  prior  notice,  release  all or any  portion of the shares of
Common Stock subject to these "lock-up" agreements.
    

    Prior to this Offering,  there has not been any public market for the Common
Stock.  Consequently,  the initial  public  offering  price of the Common  Stock
offered hereby will be determined through  negotiations  between the Company and
the  Representatives.  Among  the  factors  to  be  considered  in  making  such
determination will be the prevailing market conditions, the Company's fiscal and
operating  history and condition,  the Company's  prospects and the prospects of
its industry, the management of the Company, the market price for securities for
companies in  businesses  similar to that of the Company and the recent  trading
activity and prices of shares of common stock on the Nasdaq National Market. The
estimated  initial  public  offering  price range set forth on the cover page of
this Prospectus is subject to change as a result of market  conditions and other
factors. See "Risk Factors -- No Assurance of Public Market; Volatility of Stock
Price."

   
    Kaufman Bros.,  L.P. became  registered as a broker-dealer  in July 1995 and
has participated in a limited number of public offerings as an underwriter.  See
"Risk Factors -- Lack of Underwriting History."
    

    The  Company  has  agreed to  indemnify  the  Underwriters  against  certain
liabilities, including liabilities under the Securities Act.

                                  LEGAL MATTERS

    Certain legal  matters in connection  with this Offering will be passed upon
for the  Company  by  Brown,  Rudnick,  Freed & Gesmer,  Boston,  Massachusetts.
Certain legal matters in connection with the Common Stock offered hereby will be
passed upon for the Underwriters by Fulbright & Jaworski  L.L.P.,  New York, New
York. A member of Brown,  Rudnick,  Freed & Gesmer,  counsel to the Company,  is
Clerk and is the owner of 12,000 shares of the Company's Common Stock.

                                     EXPERTS

    The consolidated  balance sheets of Boston Biomedica,  Inc. and Subsidiaries
as of December 31, 1994 and 1995 and the consolidated  statements of operations,
stockholders'  equity,  and cash flows for each of the three years in the period
ended December 31, 1995, included in this prospectus,  have been included herein
in reliance on the report of Coopers & Lybrand L.L.P.,  independent accountants,
given on the authority of that 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 (the
"Registration  Statement")  under the  Securities Act with respect to the Common
Stock offered  hereby.  This  Prospectus does not contain all of the information
set forth in the Registration  Statement and the exhibits and schedules thereto.
For


                                       50


further information with respect to the Company and the Common Stock,  reference
is made to the  Registration  Statement and the exhibits and schedules  thereto.
Statements  contained in this  Prospectus  as to the contents of any contract or
other  document are not  necessarily  complete and, in each instance  where such
contract  or  document  is filed as an  exhibit to the  Registration  Statement,
reference is made to the copy of such  contract or 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 offices of the Commission at 450 Fifth Street,
N.W.,  Washington,  D.C. 20549, and at the Commission's regional offices located
at Seven World Trade Center,  13th Floor,  New York, New York 10048,  and at 500
West Madison Street,  Northwestern Atrium Center, Suite 1400, Chicago,  Illinois
60661-2511.  Copies of materials can also be obtained at  prescribed  rates from
the  Public  Reference  Section of the  Commission  at 450 Fifth  Street,  N.W.,
Washington,  D.C. 20549.  The Commission  maintains a World Wide Web site on the
Internet at http://www.sec.gov that contains registration  statements,  reports,
proxy and information  statements and other  information  regarding  registrants
that file electronically with the Commission.

    The  Company  intends  to  distribute  to its  stockholders  annual  reports
containing   consolidated   financial  statements  audited  by  its  independent
accountants  and will make available  copies of quarterly  reports for the first
three quarters of each fiscal year containing unaudited  consolidated  financial
information.



                                       51







                    BOSTON BIOMEDICA, INC. AND SUBSIDIARIES
                       INDEX TO FINANCIAL STATEMENTS


<TABLE>
<CAPTION>
                                                                                             PAGE
                                                                                             ----
 <S>                                                                                        <C> 
 Report of Coopers & Lybrand L.L.P., Independent Accountants                                  F-2

 Consolidated  Balance  Sheets as of December 31, 1994 and 1995 and June
  30, 1996 (unaudited)                                                                        F-3 

 Consolidated  Statements of Operations  for the years ended  December 31, 1993,
  1994, and 1995 and for the six months ended June 30, 1995 (unaudited) and June
  30, 1996 (unaudited)                                                                        F-4

 Consolidated  Statements  of  Stockholders'  Equity for the years ended
   December 31, 1993,  1994,  and 1995 and for the six months ended June
   30, 1996 (unaudited)                                                                       F-5

 Consolidated  Statements of Cash Flows for the years ended December 31,
   1993,  1994,  and 1995 and for the six  months  ended  June 30,  1995
   (unaudited) and June 30, 1996 (unaudited)                                                  F-6

 Notes to Consolidated Financial Statements                                                   F-7
</TABLE>

                                      F-1





   
                     REPORT OF INDEPENDENT ACCOUNTANTS
    

To the Board of Directors and Stockholders of
 BOSTON BIOMEDICA, INC.:

    We have  audited  the  accompanying  consolidated  balance  sheets of Boston
Biomedica,  Inc.  and  Subsidiaries  as of  December  31,  1994 and 1995 and the
related  consolidated  statements of operations,  stockholders'  equity and cash
flows for each of the three years in the period ended  December 31, 1995.  These
consolidated  financial  statements  are  the  responsibility  of the  Company's
management.  Our  responsibility is to express an opinion on these  consolidated
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  financial  position of Boston
Biomedica,  Inc.  and  Subsidiaries  as of  December  31,  1994 and 1995 and the
results of their  operations and their cash flows for each of the three years in
the period  ended  December  31,  1995 in  conformity  with  generally  accepted
accounting principles.



                                            COOPERS & LYBRAND L.L.P.


   
Boston, Massachusetts
March 12, 1996,  except as to the information
 in the first paragraph of Note 11,
 for which the date is September 10, 1996
    

                                    F-2





                    BOSTON BIOMEDICA, INC. AND SUBSIDIARIES
                        CONSOLIDATED BALANCE SHEETS

   
<TABLE>
<CAPTION>
                                                                     DECEMBER 31,               JUNE 30, 1996
                                                                     ------------               -------------
                                                                   1994         1995         ACTUAL      PRO FORMA
                                                                   ----         ----         ------      ---------
                                                                                                 (UNAUDITED)
<S>                                                            <C>           <C>          <C>           <C>
                                                       ASSETS
CURRENT ASSETS:
   Cash                                                        $    89,129   $   11,463   $    10,548   $    10,548
   Accounts receivable, less allowances of $94,723 in 1994,
     $142,372 in 1995 and $133,579 in 1996                       2,259,842    3,075,870     2,866,401     2,866,401
   Inventories (Notes 1 & 3)                                     3,609,516    3,676,851     3,865,219     3,865,219
   Prepaid expense and other                                       156,117      254,199       294,646       294,646
   Deferred income taxes (Note 7)                                  101,880      110,766       213,538       213,538
                                                                ----------    ---------    ----------    ----------
     Total current assets                                        6,216,484    7,129,149     7,250,352     7,250,352
                                                                ----------    ---------    ----------    ----------
Property and equipment, net (Notes 1 & 4)                        1,724,420    2,614,982     2,625,117     2,625,117

OTHER ASSETS:
   Notes receivable and other                                       22,079       83,422        79,037        79,037
   Goodwill and other intangibles, net (Notes 1 & 2)               112,521      100,820        92,777        92,777
                                                                ----------    ---------    ----------    ----------
                                                                   134,600      184,242       171,814       171,814
                                                                ----------    ---------    ----------    ----------
     TOTAL ASSETS                                              $ 8,075,504   $9,928,373   $10,047,283   $10,047,283
                                                               ===========   ==========   ===========   ===========

                                         LIABILITIES AND STOCKHOLDERS' EQUITY
CURRENT LIABILITIES:
   Current maturities of long term debt (Note 6)               $   242,006   $  436,509   $   490,126   $   490,126
   Accounts payable                                                787,406      745,216       815,946       815,946
   Accrued compensation                                            361,911      395,755       488,223       488,223
   Other accrued expenses                                          139,052      199,334       127,712       127,712
   Deferred revenue                                                --           523,401       831,244       831,244
                                                                ----------    ---------    ----------    ----------
     Total current liabilities                                   1,530,375    2,300,215     2,753,251     2,753,251
                                                                ----------    ---------    ----------    ----------
LONG-TERM LIABILITIES:
   Long-term debt, less current maturities (Note 6)              3,179,526    4,215,501     2,797,581     2,797,581
   Deferred rent                                                   186,860      141,068       107,832       107,832
   Deferred income taxes (Note 7)                                  137,520       84,641       157,899       157,899

COMMITMENTS AND CONTINGENCIES (Note 8)

REDEEMABLE COMMON STOCK (Note 11)
   $.01 par value; 117,647 shares authorized, issued and
     outstanding                                                   --            --           898,503       --

STOCKHOLDERS' EQUITY (Note 10):

    Common stock, $.01 par value; authorized 15,000,000 
     shares in 1994, 1995 and 1996;  issued and outstanding
     2,578,865 in 1994; issued 2,640,417 in 1995;
     issued and outstanding 2,572,417 in 1996 actual and
     2,690,064 pro forma                                            25,789       26,404        25,724        26,901
   Additional paid-in capital                                    2,612,500    2,798,620     2,717,700     3,615,026
   Retained earnings                                               402,934      505,924       588,793       588,793
                                                                ----------    ---------    ----------    ----------
                                                                 3,041,223    3,330,948     3,332,217     4,230,720
   Less treasury stock, at cost -- 80,000 shares                   --          (144,000)      --            --
                                                                ----------    ---------    ----------    ----------
     Total stockholders' equity                                  3,041,223    3,186,948     3,332,217     4,230,720
                                                                ----------    ---------    ----------    ----------
     TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY                $ 8,075,504   $9,928,373   $10,047,283   $10,047,283
                                                               ===========   ==========   ===========   ===========
</TABLE>
    

       The accompanying notes are an integral part of these consolidated
                              financial statements

                                       F-3



                     BOSTON BIOMEDICA, INC. AND SUBSIDIARIES
                      CONSOLIDATED STATEMENTS OF OPERATIONS


   
<TABLE>
<CAPTION>
                                                         YEARS ENDED DECEMBER 31,           SIX MONTHS ENDED JUNE 30,
                                                         ------------------------           -------------------------
                                                     1993          1994          1995          1995          1996
                                                     ----          ----          ----          ----          ----
                                                                                                   (UNAUDITED)
<S>                                              <C>            <C>           <C>           <C>           <C>
REVENUE:
   Product sales                                 $ 3,942,328    $ 5,981,378   $ 6,621,631   $ 3,024,629   $ 3,945,759
   Services                                        5,214,688      4,741,376     5,649,099     2,539,851     2,982,624
                                                  ----------      ---------    ----------    ----------    ----------
     Total revenue                                 9,157,016     10,722,754    12,270,730     5,564,480     6,928,383

COSTS AND EXPENSES:
   Cost of product sales                           2,087,771      3,194,217     3,564,241     1,646,594     2,006,833
   Cost of services                                3,965,154      3,415,777     4,167,625     1,960,315     2,249,610
   Research and development                          278,859        469,358       375,712       159,035       361,619
   Selling and marketing                             894,202      1,191,573     1,339,792       637,567       915,289
   General and administrative                      1,619,331      2,047,256     2,315,814     1,056,590     1,088,448
                                                  ----------      ---------    ----------    ----------    ----------
       Total operating costs and expenses          8,845,317     10,318,181    11,763,184     5,460,101     6,621,799
                                                  ----------      ---------    ----------    ----------    ----------
       Income from operations                        311,699        404,573       507,546       104,379       306,584
Interest expense, net                                178,640        243,694       335,899       164,569       168,469
                                                  ----------      ---------    ----------    ----------    ----------
       Income (loss) before income taxes and
        extraordinary item                           133,059        160,879       171,647       (60,190)      138,115
(Provision) benefit (for) from income taxes
  (Notes 1 & 7)                                      (40,473)       (64,351)      (68,657)       24,034       (55,246)
                                                  ----------      ---------    ----------    ----------    ----------
       Income (loss) before extraordinary item        92,586         96,528       102,990       (36,156)       82,869
                                                  ----------      ---------    ----------    ----------    ----------
Extraordinary item-gain on elimination of debt
  (Notes 6 & 7), net of income taxes of $33,157       49,736        --            --            --            --
                                                  ----------      ---------    ----------    ----------    ----------
       Net income (loss)                         $    142,322   $     96,528  $    102,990  $   (36,156)  $     82,869
                                                 ============   ============  ============  ============   ===========
Income (loss) per share:
       Before extraordinary gain                 $      0.04    $      0.04   $      0.04   $     (0.01)  $      0.03
       Extraordinary gain                               0.02        --            --            --            --
                                                  ----------      ---------    ----------    ----------    ----------
       Net income (loss)                         $      0.06    $      0.04   $      0.04   $     (0.01)  $      0.03
                                                 ============   ===========   ===========   ============   ==========
Weighted average common and common equivalent
  shares outstanding                               2,437,725      2,587,137     3,151,477     2,597,590     3,252,643
                                                 ============   ===========   ===========   ===========    ==========
</TABLE>
    

       The accompanying notes are an integral part of these consolidated
                              financial statements

                                       F-4



                    BOSTON BIOMEDICA, INC. AND SUBSIDIARIES
           CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY


   
<TABLE>
<CAPTION>
                                                    COMMON STOCK
                                                    ------------
                                                                         ADDITIONAL                                  TOTAL
                                                             $.01 PAR      PAID-IN       RETAINED     TREASURY   STOCKHOLDERS'
                                                 SHARES       VALUE        CAPITAL       EARNINGS      STOCK         EQUITY
                                                 ------       -----        -------       --------      -----         ------
<S>                                            <C>          <C>          <C>           <C>            <C>         <C>
BALANCE, December 31, 1992                      2,280,040   $   22,800   $ 1,635,830   $   164,084      --        $ 1,822,714
  Issuance of common stock                        201,298        2,013       711,318       --           --            713,331
  Stock options and warrants exercised             33,000          330        65,420       --           --             65,750
  Conversion of note payable                       10,690          107        17,532       --           --             17,639
  Net income                                       --           --           --            142,322      --            142,322
                                               ----------    ---------    ----------    ----------    --------     ----------
BALANCE, December 31, 1993                      2,525,028       25,250     2,430,100       306,406      --          2,761,756
  Issuance of common stock                         29,862          299       139,403       --           --            139,702
  Stock options and warrants exercised             23,975          240        30,197       --           --             30,437
  Tax benefit of stock options exercised           --           --            12,800       --           --             12,800
  Net income                                       --           --           --             96,528      --             96,528
                                               ----------    ---------    ----------    ----------    --------     ----------
BALANCE, December 31, 1994                      2,578,865       25,789     2,612,500       402,934      --          3,041,223
  Issuance of common stock                          8,535           85        58,160       --           --             58,245
  Stock options and warrants exercised             47,200          472       117,068       --           --            117,540
  Conversion of note payable                        5,817           58         9,542       --           --              9,600
  Treasury stock purchased -- 80,000 shares        --           --           --            --        $ (144,000)     (144,000)
  Tax benefit of stock options exercised           --           --             1,350       --           --              1,350
  Net income                                       --           --           --            102,990      --            102,990
                                               ----------    ---------    ----------    ----------    --------     ----------
BALANCE, December 31, 1995                      2,640,417       26,404     2,798,620       505,924    (144,000)     3,186,948
  Stock options and warrants exercised
   (unaudited)                                     12,000          120        62,280       --           --             62,400
  Issuance of treasury stock -- 80,000 shares
   (unaudited)                                    (80,000)        (800)     (143,200)      --          144,000        --
  Net income (unaudited)                           --           --           --             82,869      --             82,869
                                               ----------    ---------    ----------    ----------    --------     ----------
BALANCE, June 30, 1996 (unaudited)              2,572,417   $   25,724   $ 2,717,700   $   588,793      --        $ 3,332,217
                                               ==========   ==========   ===========   ===========    ========    ===========
</TABLE>
    

       The accompanying notes are an integral part of these consolidated
                              financial statements

                                       F-5




                     BOSTON BIOMEDICA, INC. AND SUBSIDIARIES
                      CONSOLIDATED STATEMENTS OF CASH FLOWS


<TABLE>
<CAPTION>
                                                           YEARS ENDED DECEMBER 31,          SIX MONTHS ENDED JUNE 30,
                                                           ------------------------          -------------------------
                                                        1993         1994          1995          1995          1996
                                                        ----         ----          ----          ----          ----
                                                                                                     (UNAUDITED)
<S>                                                 <C>           <C>          <C>           <C>            <C>
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)                                   $   142,322   $   96,528  $    102,990  $    (36,156)  $     82,869
Adjustments  to  reconcile  net income  (loss)
 to net cash (used in) provided by
  operating activities:
   Depreciation and amortization                        301,004      360,512       441,356       202,693        280,426
   Provision for doubtful accounts                       22,956      102,099       181,084        53,643         77,145
   Deferred rent                                         99,708        5,908       (45,792)      (12,556)       (33,236)
   Deferred income taxes                                 42,323      (42,798)      (61,765)      (74,809)       (29,514)
   Tax benefit of stock options exercised               --            12,800         1,350       --             --
   Extraordinary item-gain on elimination of debt       (49,736)      --           --            --             --

Changes in operating assets and liabilities:
   Accounts receivable                                 (215,270)    (529,157)     (997,112)       11,403        132,324
   Note receivable and other assets                     (17,002)      (3,720)      (61,343)      (12,962)         4,385
   Inventories                                         (950,715)    (567,420)      (67,335)       77,857       (188,368)
   Prepaid expenses                                      25,410       (3,500)      (98,082)      (79,496)       (40,447)
   Accounts payable                                      11,875      (86,130)      (42,190)       35,834         70,730
   Accrued expenses                                     160,021      100,767        94,126       (60,639)        20,846
   Deferred revenue                                     --            --           523,401       --             307,843
                                                     ----------    ---------    ----------    ----------     ----------
       Net cash (used in) provided by operating
        activities                                     (427,104)    (554,111)      (29,312)      104,812        685,003
                                                     ----------    ---------    ----------    ----------     ----------
CASH FLOWS FOR INVESTING ACTIVITIES:
   Additions to property and equipment                 (460,591)    (404,639)   (1,316,217)     (215,542)      (282,518)
   Purchase of intangible assets                        --            --            (4,000)      --             --
   Net assets of acquisitions (net of cash
     acquired)                                         (389,703)      --           --            --             --
                                                     ----------    ---------    ----------    ----------     ----------
       Net cash used in investing activities           (850,294)    (404,639)   (1,320,217)     (215,542)      (282,518)
                                                     ----------    ---------    ----------    ----------     ----------
CASH FLOWS FOR FINANCING ACTIVITIES:
   Proceeds from notes payable                        1,107,392    1,734,425     1,517,867       191,990        226,300
   Proceeds from redeemable common stock, net           --            --           --            --             898,503
   Proceeds of common stock issued, net                 765,081      170,139       175,785       103,126         62,400
   Repayments of long-term debt                        (613,199)    (887,989)     (277,789)      --          (1,590,603)
   Purchase of treasury stock                           --            --          (144,000)     (144,000)       --
                                                     ----------    ---------    ----------    ----------     ----------
       Net cash (used in) provided by financing
        activities                                    1,259,274    1,016,575     1,271,863       151,116       (403,400)
                                                     ----------    ---------    ----------    ----------     ----------
(DECREASE) INCREASE IN CASH:                            (18,124)      57,825       (77,666)       40,386           (915)
   Cash, beginning of period                             49,428       31,304        89,129        89,129         11,463
                                                     ----------    ---------    ----------    ----------     ----------
   Cash, end of period                              $    31,304  $    89,129  $     11,463  $    129,515   $     10,548
                                                    ===========   ==========   ===========  ============    ===========

SUPPLEMENTAL DISCLOSURES OF NONCASH
  ACTIVITIES:
   Conversion of note payable to common stock       $    17,639      --       $      9,600  $      9,600       --

SUPPLEMENTAL INFORMATION:
   Income taxes paid                                $    10,689  $    33,718  $    168,994  $    129,100    $     85,000
   Interest paid                                    $   163,831  $   254,133  $    331,495  $    163,735    $   178,328
</TABLE> 

       The accompanying notes are an integral part of these consolidated
                              financial statements

                                       F-6



                    BOSTON BIOMEDICA, INC. AND SUBSIDIARIES
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
     (INFORMATION AS OF JUNE 30, 1996 AND FOR THE SIX MONTHS ENDED JUNE 30,
                          1996 AND 1995 IS UNAUDITED.)

(1) BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES

    Boston Biomedica,  Inc. ("BBI") and Subsidiaries  (together,  the "Company")
provide infectious disease diagnostic products,  contract research and specialty
infectious  disease  testing  services  to  the  in-vitro  diagnostic  industry,
government  agencies,  blood banks,  hospitals  and other health care  providers
worldwide.

    Significant  accounting  policies  followed  in  the  preparation  of  these
consolidated financial statements are as follows:

 (i) Principles of Consolidation

    The consolidated  financial  statements  include the accounts of BBI and its
wholly-owned  subsidiaries,  Biotech Research  Laboratories,  Inc.  ("BTRL") and
BBI-North American Clinical  Laboratories,  Inc.  ("BBI-NACL").  All significant
intercompany   accounts   and   transactions   have  been   eliminated   in  the
consolidation.

 (ii) Reclassification

    Certain amounts included in the prior year's financial  statements have been
reclassified to conform to the current presentation.

 (iii) Use of Significant Estimates

    To prepare the financial  statements in conformity  with generally  accepted
accounting principles,  management is required 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.  In
particular,   the  Company   records   reserves  for  estimates   regarding  the
collectability  of accounts  receivable.  Actual  results  could differ from the
estimates and assumptions used by management.

 (iv) Revenue Recognition

    Product  revenues are  recognized as sales upon shipment of the products or,
for  specific  orders at the request of the  customer,  on a bill and hold basis
after completion of manufacture.  All bill and hold  transactions meet specified
revenue  recognition  criteria which include normal billing,  credit and payment
terms,  and  transfer to the  customers  of all risks and rewards of  ownership.
Accounts  receivable  as of December 31, 1995 and June 30, 1996 include bill and
hold  receivables  of $179,000  and  $85,000,  respectively.  There were no such
receivables as of December 31, 1993 and 1994.

    The Company periodically enters into barter transactions whereby the Company
exchanges  inventory for testing  services.  Revenue on these  transactions  are
recognized  when both the products  have been  shipped and the testing  services
have been  completed and are recorded at the estimated  fair market value of the
inventory based upon standard  Company prices.  The revenue  recognized on these
transactions  for the years ended  December 31, 1993,  1994 and 1995 and for the
six  months  ended  June 30,  1995 and 1996  was  $30,000,  $192,000,  $213,000,
$126,000 and $191,000, respectively.

    Services are  recognized  as revenue upon  completion of tests for specialty
laboratory services.

   
    Revenue under long-term contracts, including funded research and development
contracts,  is recorded under the percentage of completion method, wherein costs
plus  profit is recorded  as service  revenue and billed  monthly as the work is
performed.  Certain  customers  make advance  payments  that are deferred  until
revenue  recognition  is  appropriate.  Unbilled  amounts for fee  retainage are
included in accounts receivable at
    

                                    F-7


                  BOSTON BIOMEDICA, INC. AND SUBSIDIARIES
         NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - (CONTINUED)
  (INFORMATION AS OF JUNE 30, 1996 AND FOR THE SIX MONTHS ENDED JUNE 30,
                       1996 AND 1995 IS UNAUDITED.)

(1) BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES -- (CONTINUED)

   
December 31, 1994, 1995, and June 30, 1996, and are immaterial. When the current
contract estimates indicate a loss,  provision is made for the total anticipated
loss. The Company does not believe there are any material  collectability issues
associated with these receivables.

    Total  revenue  related to funded  research and  development  contracts  was
approximately  $1,721,000,  $660,000,  $728,000,  $278,000  and $598,000 for the
years ended  December 31, 1993,  1994 and 1995 and for the six months ended June
30, 1995 and 1996,  respectively.  Total  contract costs  associated  with these
agreements  were  approximately  $1,392,000,  $511,000,  $575,000,  $219,000 and
$553,000 for the years ended December 1993, 1994 and 1995 and for the six months
ended June 30, 1995 and 1996, respectively.
    

 (v) Research and Development Costs

    Research and development costs are expensed as incurred.

 (vi) Inventories

    Inventories are stated at the lower of average cost or net realizable  value
and include material, labor and manufacturing overhead.

 (vii) Property and Equipment

    Property and equipment are stated at cost. For financial reporting purposes,
depreciation  is  recognized  using  accelerated  and   straight-line   methods,
allocating the cost of the assets over their estimated useful lives ranging from
five years to ten years for certain manufacturing and laboratory equipment,  and
fifteen years for the building.  Upon  retirement or sale,  the cost and related
accumulated  depreciation of the asset are removed from the books. Any resulting
gain or loss is credited or charged to income.

 (viii) Goodwill and Intangibles

    Goodwill  results from excess of the purchase  prices over the net assets of
BTRL and BBI-NACL  acquired  and is amortized on a straight  line basis over ten
years.   Other  intangibles   primarily  consist  of  patents,   licenses,   and
intellectual property rights and are amortized over five to ten years.

 (ix) Income Taxes

    The Company  utilizes the liability  method of accounting  for income taxes.
Under the liability  method,  deferred  taxes arise from  temporary  differences
between the financial  statement and tax bases of assets and  liabilities  using
enacted tax rates in effect in the years in which the  differences  are expected
to reverse.  A valuation  allowance  is provided for net deferred tax assets if,
based on the weighted available  evidence,  it is more likely than not that some
or all of the  deferred  tax  assets  will  not be  realized.  Tax  credits  are
recognized when realized using the flow through method of accounting.

 (x) Concentration of Credit Risk

    Financial   instruments   which   potentially   subject   the   Company   to
concentrations of credit risk are principally cash and accounts receivable.  The
Company places its cash in federally  chartered banks,  each of which is insured
up to $100,000 by the Federal Deposit  Insurance  Corporation.  Concentration of
credit risk with respect to accounts  receivable is limited to certain customers
to whom the Company

                                    F-8



                     BOSTON BIOMEDICA, INC. AND SUBSIDIARIES
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - (CONTINUED)
     (INFORMATION AS OF JUNE 30, 1996 AND FOR THE SIX MONTHS ENDED JUNE 30,
                          1996 AND 1995 IS UNAUDITED.)

(1) BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES -- (CONTINUED)

makes  substantial  sales.  The  Company  does not require  collateral  from its
customers. To reduce risk, the Company routinely assesses the financial strength
of its  customers  and,  as a  consequence,  believes  that its  trade  accounts
receivable credit risk exposure is limited.

 (xi) Interim Consolidated Financial Statements

   
    The  consolidated  financial  statements as of June 30, 1996 and for the six
months  ended  June  30,  1995 and 1996 and  related  footnote  information  are
unaudited and have been prepared on a basis  substantially  consistent  with the
audited consolidated  financial  statements,  and, in the opinion of management,
include  all  adjustments  (consisting  of only  normal  recurring  adjustments)
necessary for fair  presentation  of the results of these interim  periods.  The
results of the six months ended June 30, 1996 are not necessarily  indicative of
the results to be expected for the entire year.
    

 (xii) Deferred Revenue

    Deferred revenue consists of payments  received from customers in advance of
services performed.

 (xiii) Computation of Income (Loss) Per Share

   
    Net income  (loss)  per common  share is  computed  based upon the  weighted
average number of common shares and common equivalent shares (using the treasury
stock method)  outstanding  after certain  adjustments  described below.  Common
equivalent shares consist of common stock options and warrants  outstanding.  In
accordance with Securities and Exchange Commission Staff Accounting Bulletin No.
83, all common,  redeemable  common,  and common equivalent shares issued during
the twelve month period prior to the proposed date of the initial  filing of the
Registration  Statement  have been included in the  calculation  as if they were
outstanding  for all periods  using the  treasury  stock  method and assuming an
initial  public  offering  price of $9.00 per share.  Fully  diluted  net income
(loss) per common  share is not  presented  as it does not differ  from  primary
earnings per share.

 (xiv) Recent Accounting Pronouncements

    In March 1995, the Financial  Accounting Standards Board issued Statement of
Financial  Accounting  Standards  No. 121,  "Accounting  for the  Impairment  of
Long-Lived  Assets and for  Long-Lived  Assets to Be Disposed Of" ("SFAS  121").
SFAS 121 requires that an impairment  loss be recognized for  long-lived  assets
and certain identified  intangibles when the carrying amount of these assets may
not be  recoverable.  The Company has adopted SFAS 121 effective in 1996 and the
adoption did not have a material impact on the financial statements.

    In October 1995, the FASB issued Statement of Financial Accounting Standards
No. 123 ("SFAS 123")  "Accounting for Stock-Based  Compensation,"  which becomes
effective  for  fiscal  years  beginning  after  December  15,  1995.  SFAS  123
establishes  new financial  accounting and reporting  standards for  stock-based
compensation  plans.  However,  entities are allowed to elect whether to measure
compensation expense for stock-based  compensation under SFAS 123 or APB No. 25,
"Accounting  for Stock Issued to Employees." The Company has elected to continue
to account under APB No. 25 and will make the required pro forma  disclosures of
net  income and  earnings  per share as if the  provisions  of SFAS 123 had been
applied in its December 31, 1996 financial  statements.  The potential impact of
adopting this standard on the Company's pro forma  disclosures of net income and
earnings per share has not been quantified at this time.

 (xv) Pro Forma Presentation (Unaudited)

    As  discussed  further  in Note 11,  completion  of a public  offering  will
terminate the redemption  feature of the  Redeemable  Common Stock and cause its
reclassification  into 117,647  shares of common stock.  The unaudited pro forma
balance sheet has been prepared assuming the  reclassification of the Redeemable
Common Stock into common stock as of June 30, 1996.
    


                                    F-9



                     BOSTON BIOMEDICA, INC. AND SUBSIDIARIES
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - (CONTINUED)
     (INFORMATION AS OF JUNE 30, 1996 AND FOR THE SIX MONTHS ENDED JUNE 30,
                          1996 AND 1995 IS UNAUDITED.)


(2) ACQUISITION

    Effective January 1, 1993, North American Laboratory,  Inc., a Massachusetts
corporation and wholly-owned subsidiary of BBI, acquired the net assets of North
American  Laboratory  Group,  Ltd.,  Inc. from its founder and chief  scientific
officer, who remains in this same capacity. During 1995, the name was changed to
BBI-North  American  Clinical   Laboratories,   Inc.  BBI-NACL  is  a  specialty
infectious  disease testing  laboratory  providing testing services to hospitals
and other  health  care  providers.  The  purchase  price was  $425,000  in cash
representing  $375,038 of net tangible  assets  (including  cash of $35,297) and
$49,962 of goodwill and other intangibles.

(3) INVENTORIES

    The  Company  purchases  human  plasma and serum from  various  private  and
commercial  blood  banks.  Upon  receipt,   such  purchases   generally  undergo
comprehensive  testing,  and  associated  costs are included in the value of raw
materials.  Most plasma is  manufactured  into  Basematrix and other  diagnostic
components  to  customer  specifications.  Plasma  and  serum  with the  desired
antibodies or antigens are sold or  manufactured  into Quality  Control  Panels,
Accurun(tm) run controls,  and reagents ("Finished Goods").  Panels and reagents
are unique to specific donors and/or collection periods, and require substantial
time to characterize and manufacture due to stringent technical  specifications.
Panels play an important role in diagnostic test kit development,  licensure and
quality  control.  Panels are  manufactured  in  quantities  sufficient  to meet
expected user demand which may exceed one year.

Inventories consist of the following:


<TABLE>
<CAPTION>
                                DECEMBER 31,
                                ------------
                             1994          1995       JUNE 30, 1996
                             ----          ----       -------------
                                                       (UNAUDITED)
<S>                       <C>           <C>           <C>
Raw materials             $ 1,548,560   $ 1,298,131    $ 1,272,687
Work-in-process               551,280       565,667        597,922
Finished goods              1,509,676     1,813,053      1,994,610
                           ----------    ----------     ----------
                          $ 3,609,516   $ 3,676,851    $ 3,865,219
                          ===========   ===========    ===========
</TABLE>

(4) PROPERTY AND EQUIPMENT

    Property  and  equipment  at  December  31,  1994  and 1995  consist  of the
following:


<TABLE>
<CAPTION>
                                           1994         1995
                                           ----         ----
<S>                                     <C>          <C>
Laboratory equipment                    $1,442,349   $1,630,872
Management information systems             609,923      834,768
Office equipment                           249,544      332,496
Automobiles                                176,315      178,465
Leasehold improvements                     300,341      108,892
Land, building and improvements             --          941,175
                                         ---------    ---------
                                         2,778,472    4,026,668
Less accumulated depreciation            1,054,052    1,411,686
                                         ---------    ---------

Net book value                          $1,724,420   $2,614,982
                                        ==========   ==========  
</TABLE>

    Depreciation  expense for the years ended  December 31, 1993,  1994 and 1995
and the six  months  ended  June  30,  1995 and  1996  was  $286,456,  $345,228,
$425,655, $194,236 and $272,383, respectively.

                                      F-10




                     BOSTON BIOMEDICA, INC. AND SUBSIDIARIES
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - (CONTINUED)
     (INFORMATION AS OF JUNE 30, 1996 AND FOR THE SIX MONTHS ENDED JUNE 30,
                          1996 AND 1995 IS UNAUDITED.)

(5) REVENUE FROM SIGNIFICANT CUSTOMERS AND EXPORT SALES

    The Company performs contract research and certain services under contracts,
subcontracts and grants from United States  Government  Agencies,  primarily the
National Institutes of Health ("NIH"). Revenue from such contracts, subcontracts
and  grants  was  approximately  $2,707,000  in 1993,  $1,677,000  in 1994,  and
$1,628,000 in 1995.

    Export sales accounted for approximately  $1,411,000, or 15% of consolidated
revenue in 1993;  $2,279,000,  or 21% in 1994;  $3,104,000,  or 25% in 1995; and
$1,523,000,  or 27%,  and  $1,877,000,  or 27% for the six months ended June 30,
1995 and 1996, respectively.

(6) LONG TERM DEBT

    In August 1995,  the Company's  revolving  line of credit  ("Revolver")  was
increased to  $3,500,000  and the due date  extended to June 30,  1997.  In July
1996, the due date of the Company's  Revolver was extended to June 30, 1998, and
the interest rate reduced to prime plus 1/2 %. In addition, the Company borrowed
$200,000 under a five-year  term loan approved in 1994 ($170,370  outstanding at
December 31, 1995),  $100,000  under a five-year term loan, and $123,700 under a
$350,000  five year term loan facility for  equipment  acquisitions  approved in
1995 ("New Term"). As of December 31, 1995, the Company had additional borrowing
capacity  available  under the New Term facility equal to $226,300.  The Company
borrowed  this amount prior to the facility  expiration  date of May 2, 1996. In
July 1996,  the Company  received  approval for a $250,000,  five year equipment
facility loan from its bank due July 31, 2001 at a rate of prime plus 1%.

    Borrowings  under the  Revolver  are  limited  to 80% of  eligible  accounts
receivable  plus the lesser of 40% of inventory or  $1,500,000.  The Company had
approximately  $657,000  and  $2,028,000  available  under it's  Revolver  as of
December 31, 1995 and June 30, 1996, respectively. Amounts outstanding under the
Revolver  bear interest at the lender's base rate plus 1% (9.75% at December 31,
1995 and 9.25% at June 30, 1996) and are  collateralized by all of the Company's
assets and a $2 million life insurance policy of an officer/stockholder.

    The Revolver contains covenants regarding the Company's debt-to-equity ratio
and certain minimum debt service coverage ratios.  The Revolver further provides
for restrictions on the payment of dividends,  limitations on the acquisition of
property  and  equipment,  limitations  on  additional  borrowings,  and certain
minimum stock ownership levels by the officer/stockholder referred to above.

    In December  1995,  the Company  purchased  its corporate  headquarters  and
manufacturing  facility in West  Bridgewater,  MA from its former  landlord at a
price of $806,800  including  closing costs, and borrowed $750,000 from its bank
to finance the purchase. See also Note 4.

    On  June  30,  1993,  the  Company  exercised  its  option  to  pre-pay  the
acquisition  note in connection  with the 1992 purchase of BTRL at a substantial
discount  from the balance due,  resulting in an  extraordinary  gain of $49,736
($82,893 minus taxes of $33,157).

    During 1993,  convertible  debt in the amount of $17,639 was converted  into
10,690  shares  of  common  stock at a price of $1.65 per  share.  During  1995,
convertible  debt in the amount of $9,600  was  converted  into 5,817  shares of
common stock at a price of $1.65 per share.

                                      F-11



                     BOSTON BIOMEDICA, INC. AND SUBSIDIARIES
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - (CONTINUED)
     (INFORMATION AS OF JUNE 30, 1996 AND FOR THE SIX MONTHS ENDED JUNE 30,
                          1996 AND 1995 IS UNAUDITED.)

(6) LONG TERM DEBT -- (CONTINUED)

At December 31, 1994 and 1995,  and June 30, 1996, the Company had the following
debt outstanding:

<TABLE>
<CAPTION> 
                                                                                             JUNE 30,
                                                                     1994         1995         1996
                                                                     ----         ----         ----
                                                                                            (UNAUDITED)
<S>                                                               <C>          <C>          <C>
Revolving Line of Credit Agreement due June 30, 1998              $2,533,860   $2,784,307   $1,397,884

Note payable to a bank,  due in monthly  principal 
  payments of $17,687  through October 1998 with
  interest fixed at 9.01%. Collateralized by all of the
  assets of the Company                                             813,625       601,375      495,250

Note payable to a bank, due in monthly principal payments
  of $3,704 through October 1999 with interest at prime
  rate plus 1.0%. Collateralized by all of the assets of
  the Company                                                         --          170,370      148,148

Note payable to a bank, due in monthly principal payments
  of $1,667 through December 2000 with interest at 8.22%.
  Collateralized by all of the assets of the Company                  --          100,000       91,667

Note payable to a bank, with interest only due until May
  2, 1996, and thereafter 54 consecutive equal monthly
  principal payments of $6,863 commencing June 18, 1996.
  Interest is at prime rate plus 1.0%. Collateralized by
  all of the assets of the Company                                    --          123,700      343,137

Note payable to a bank, due in 84 fixed payments of principal
  and interest of $11,729, bearing interest fixed at 8.30%
  for the first five years, and floating at prime plus 1.0%
  for the remaining term. Collateralized by a mortgage and
  all of the assets of the Company                                    --          750,000      705,580

Subordinated convertible note payable, at 12.5% interest
  rate, due December 31, 1996, interest payable monthly.
  Convertible into common stock at $1.50 per share at the
  option of the holder                                               31,100        21,500       21,500

Other installment notes payable with interest rates ranging
  from 7.25% to 10.99% at December 31, 1995, collateralized
  by office equipment and vehicles due at various maturity
  dates from April 1996 to August 2001                               42,947       100,758       84,541
                                                                   ---------    ---------    ---------
  Total long term debt                                            3,421,532     4,652,010    3,287,707
Less: current maturities                                           (242,006)     (436,509)    (490,126)
                                                                   ---------    ---------    ---------
                                                                 $3,179,526    $4,215,501   $2,797,581
                                                                 ==========     =========   ==========
</TABLE> 

                                      F-12




                    BOSTON BIOMEDICA, INC. AND SUBSIDIARIES
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - (CONTINUED)
     (INFORMATION AS OF JUNE 30, 1996 AND FOR THE SIX MONTHS ENDED JUNE 30,
                          1996 AND 1995 IS UNAUDITED.)

(6) LONG TERM DEBT -- (CONTINUED)

    At December 31, 1995, debt maturities are as follows:


<TABLE>
<CAPTION>
 YEAR ENDED                                                             AMOUNT
 ----------                                                             ------
  <S>                                                                 <C>
  1996                                                                $  436,509
  1997                                                                 3,199,875
  1998                                                                   386,723
  1999                                                                   207,300
  2000                                                                   161,382
  Thereafter                                                             260,221
                                                                       ---------
                                                                      $4,652,010
                                                                      ==========
</TABLE>

(7) INCOME TAXES

    The  Company's  effective  tax rate does not  significantly  differ from the
federal and state income tax statutory  rates.  The  components of the provision
for income taxes are as follows:


<TABLE>
<CAPTION>
                                                    1993        1994        1995
                                                    ----        ----        ----
<S>                                              <C>          <C>         <C>
Current expense: federal and state               $  23,700    $  91,242   $ 130,422
Deferred (benefit) expense: federal and state       49,930      (26,891)    (61,765)
                                                  --------     --------    --------
  Total                                          $  73,630    $  64,351   $  68,657
                                                 =========    =========   =========
</TABLE>

    The  provision  for 1993  includes  $33,157 of income taxes which was offset
against the  extraordinary  gain on elimination of debt of $82,893 and presented
net in the Statement of Operations. See also Notes 2 and 6.

    Significant items making up deferred tax liabilities and deferred tax assets
are as follows:


<TABLE>
<CAPTION>
                                                             1994        1995
                                                             ----        ----
<S>                                                       <C>          <C>
Current deferred taxes:
   Inventory                                              $  47,318        --
   Allowances and other accruals                             54,562    $ 110,766
                                                            -------      -------
     Total deferred tax assets                              101,880      110,766

Long term deferred taxes:
   Accelerated tax depreciation                            (163,139)    (207,361)
   Cash basis benefit of subsidiary                         (47,818)       --
   Goodwill                                                 (26,859)     (22,795)
   Tax credits                                              100,296      106,710
   State net operating loss carryforwards                    --           38,805
                                                            -------      -------
     Total deferred tax liabilities                        (137,520)     (84,641)
                                                            -------      -------
     Total net deferred tax (liabilities) assets          $ (35,640)   $  26,125
                                                          ===========  =========
</TABLE>

    As of December 31, 1995,  the net  operating  loss  carryforwards  expire at
various  dates  beginning in 1998 through  2000.  Tax credits  expire at various
dates beginning in 2006 through 2009.

                                      F-13



                    BOSTON BIOMEDICA, INC. AND SUBSIDIARIES
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - (CONTINUED)
     (INFORMATION AS OF JUNE 30, 1996 AND FOR THE SIX MONTHS ENDED JUNE 30,
                          1996 AND 1995 IS UNAUDITED.)

(8) COMMITMENTS AND CONTINGENCIES

    The Company leases certain office space, laboratory, and research facilities
under operating leases with various terms through July 2000. All the real estate
leases include renewal options at increasing levels of rent.

    One of the facility leases  includes  scheduled base rent increases over the
term of the lease.  The amount of base rent payments is being charged to expense
on the straight-line method over the term of the lease. As of December 31, 1995,
the Company has recorded a $141,068  noncurrent  liability to reflect the excess
of rent expense over cash payments since  inception of the lease. In addition to
base rent, the Company pays a monthly  allocation of the operating  expenses and
real estate taxes for the above facilities.

    Rent expense for the years ended  December  31, 1993,  1994 and 1995 and six
months ended June 30, 1995 and 1996 was $479,697,  $549,713,  $477,580, $225,109
and $181,816,  respectively.  At December 31, 1995,  the  remaining  fixed lease
commitment was as follows:


<TABLE>
<CAPTION>
 YEAR ENDED                                                              AMOUNT
 ----------                                                              ------
<S>                                                                     <C>

1996                                                                    $371,200
1997                                                                     254,600
1998                                                                     117,300
1999                                                                     124,800
2000                                                                      79,700
                                                                         -------
                                                                        $947,600
                                                                        ========
</TABLE>

   
    Commencing  in  February  1995,  the  Company  committed  under a  sponsored
research  agreement with a university to fund a research  scientist at a cost of
$13,125 per  quarter  for three  years  which costs are charged to research  and
development expense. In return, the Company has exclusive rights to any anti-HIV
compounds or derivatives developed in the course of this research,  provided the
Company obtains certain regulatory approvals from the FDA.
    

(9) RETIREMENT PLAN

    In January,  1993,  the Company  adopted a  retirement  savings plan for its
employees,  which has been qualified under Section 401(k) of the Code.  Eligible
employees are permitted to  contribute  to the plan through  payroll  deductions
within  statutory  limitations  and subject to any  limitations  included in the
plan. To date, the Company has made no contributions to the plan.

(10) COMMON STOCK

    The Company has two stock option plans which are administered by a committee
of the Board of Directors who determines the employees and affiliated persons to
receive  options and the number and option price of shares  covered by each such
option.

    Options  granted under both plans may be either  incentive  stock options or
non-qualified stock options. In general, for incentive stock options, the option
price  shall not be less than the fair  market  value at the time the  option is
granted. Generally,  options become exercisable at the rate of 25% at the end of
each of the four years  following the  anniversary of the grant.  Options issued
expire ten years from the date of grant, or 30 days from the date of termination
or affiliation.

    At December 31, 1995,  897,600  shares have been reserved for  non-qualified
stock options,  of which 97,125 are available for future grants. At December 31,
1995,  750,000 shares have been reserved for incentive  stock options,  of which
696,812 are available for future grants.

                                      F-14



                     BOSTON BIOMEDICA, INC. AND SUBSIDIARIES
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - (CONTINUED)
     (INFORMATION AS OF JUNE 30, 1996 AND FOR THE SIX MONTHS ENDED JUNE 30,
                          1996 AND 1995 IS UNAUDITED.)

(10) COMMON STOCK -- (CONTINUED)

    The Company has issued  warrants in connection  with certain equity and debt
financings.  As of June 30,  1996,  226,670  shares  of Common  Stock  have been
reserved  for issuance  pursuant to the exercise of such  warrants at a weighted
average exercise price of $2.50 per share.

    The Company has reserved  shares of its authorized but unissued common stock
for the following:


<TABLE>
<CAPTION>
                                                    STOCK OPTIONS               WARRANTS
                                                    -------------               --------
                                                              PRICE                    PRICE         TOTAL
                                                 SHARES     PER SHARE     SHARES     PER SHARE      SHARES
                                                 ------     ---------     ------     ---------      ------
<S>                                              <C>        <C>           <C>       <C>            <C>
Balance outstanding, December 31, 1992            747,600   $.25-$4.50    266,670   $2.00-$2.50    1,014,270
   Granted                                        166,250         4.50     59,468     3.75-5.20      225,718
   Exercised                                      (13,000)    .25-1.50    (20,000)         2.50      (33,000)
   Expired                                        (19,000)        2.50      --                       (19,000)
                                                  -------                 -------                   --------
Balance outstanding, December 31, 1993            881,850     .25-4.50    306,138     2.00-5.20    1,187,988
   Granted                                         --           --          --          --            --
   Exercised                                      (19,375)    .25-4.50     (4,600)         3.75      (23,975)
   Expired                                        (81,525)    .25-4.50      --          --           (81,525)
                                                  -------                 -------                   --------
Balance outstanding, December 31, 1994            780,950     .25-4.50    301,538     2.00-5.20    1,082,488
   Granted                                         73,187         6.00      --          --            73,187
   Exercised                                       (6,000)   1.50-2.50    (41,200)    2.50-5.20      (47,200)
   Expired                                        (47,850)   1.50-4.50      --          --           (47,850)
                                                  -------                 -------                   --------
Balance outstanding, December 31, 1995            800,287     .25-6.00    260,338     2.00-5.20    1,060,625
   Granted (unaudited)                            140,600    7.00-8.50      --          --           140,600
   Exercised (unaudited)                           --           --        (12,000)         5.20      (12,000)
   Expired (unaudited)                             (6,500)   6.00-7.00    (21,668)         5.20      (28,168)
                                                  -------                 -------                   --------
Balance outstanding, June 30, 1996
  (unaudited)                                     934,387     .25-8.50    226,670     2.00-5.00    1,161,057
                                                 ========                 =======                 ==========

Exercisable at June 30, 1996 (unaudited)          359,500     .25-1.65      --          --           359,500
                                                  262,200    2.50-4.50    206,670     2.00-2.50      468,870
                                                   31,984         6.00     20,000          5.00       51,984
                                                  -------                 -------                   --------
Total exercisable at June 30, 1996
  (unaudited)                                     653,684   $.25-$6.00    226,670   $2.00-$5.00      880,354
                                                 ========                 =======                 ==========
Proceeds of exercisable at June 30, 1996
  (unaudited)                                  $1,356,655                $566,675                 $1,923,330
                                               ==========                ========                 ==========
</TABLE>

                                      F-15



                     BOSTON BIOMEDICA, INC. AND SUBSIDIARIES
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - (CONTINUED)
     (INFORMATION AS OF JUNE 30, 1996 AND FOR THE SIX MONTHS ENDED JUNE 30
                          1996 AND 1995 IS UNAUDITED.)

   
(11) SUBSEQUENT EVENTS
    

 Stock Split

   
    On August 8, 1996 the Board of Directors  approved a 1-for-2  reverse  stock
split and an increase in authorized common shares to 20,000,000,  and authorized
1,000,000 shares of preferred stock (par value $.01), which were approved by the
stockholders  on  September  10,  1996.  The stock split has been  retroactively
reflected in the  accompanying  financial  statements  and notes for all periods
presented.

STOCK PURCHASE AGREEMENT (UNAUDITED)

    On April 26, 1996, the Company  entered into a Stock Purchase  Agreement and
Exclusive  Distributor  Agreement  for five  years  with a foreign  distributor.
Pursuant to the Stock Purchase  Agreement,  the Company issued 117,647 shares of
redeemable common stock at a price per share of $8.50, for which it received net
proceeds of $898,503. Issuance costs were $101,497.  Furthermore,  the agreement
may  require  the  Company  to  repurchase  the  stock  at  the  issuance  price
($1,000,000  in  total)  in  three  equal  installments  in the  event  that the
Distribution Agreement is terminated by the Company prior to the completion of a
public  offering.  Completion of a public offering will terminate the redemption
feature  and cause  the  reclassification  of these  shares  into  stockholders'
equity. In addition, the distributor is restricted from selling these securities
for a one-year period after  completion of such Offering.  The Company  utilized
the 80,000 shares of Treasury Stock in connection with this transaction.

BioSeq, Inc. (Unaudited)

    In October  1996,  the Company  entered into a License  Agreement,  Purchase
Agreement,   Stockholders'  Agreement  and  Warrant  Agreement  with  BioSeq,  a
privately held, technology based development stage company.

    The Company has agreed to purchase convertible preferred stock of BioSeq for
an aggregate of $1,482,500 in three  installments.  Of the $1,482,500,  $210,000
was  invested  at the date of the  agreements  and  $522,500  is  required to be
invested  within ten business days of the closing of the initial public offering
of the Company's  common stock provided the closing  occurs before  December 31,
1996. The Company must make the remaining $750,000 installment if BioSeq attains
certain  technical  milestones  by July 31,  1997.  If such  milestones  are not
attained by BioSeq by July 31,  1997,  the Company will still have the option to
make the  remaining  $750,000  investment  until  December 31,  1997.  Under the
operative documents, the Company has price anti-dilution protection, pre-emptive
rights and the right to board  representation,  the last of which  terminates if
the Company fails to make the second  installment under the Purchase  Agreement.
In addition,  the Company was granted warrants to acquire  additional  shares of
common stock of BioSeq for additional  consideration  under certain  conditions,
provided  that this right is not  exercisable  to the extent it would  cause the
Company's  ownership to equal or exceed 20%. The Company is  accounting  for its
investment in BioSeq on the cost basis in accordance  with the provisions of APB
18 since  the  cumulative  investment  is and must  remain  less than 20% of the
equity  of  BioSeq  and the  Company  does not exert  significant  influence  or
control.   Due  to  the  uncertainty  of  technology  based   development  stage
enterprises  and in accordance with the provisions of SFAS 121, the Company will
perform a periodic  analysis of the investment to determine whether the carrying
value of its  investment  in BioSeq has been  impaired.  If so  determined,  the
Company would adjust the carrying  value of its investment by taking a charge to
earnings.

    Upon the  earlier  of  payment  of the final  installment  of the  Company's
aggregate  $1,482,500  investment  and December  31,  1997,  the Company will be
granted a worldwide  right to use the BioSeq  technology  relating to sequencing
and analysis  services.  The License will be  exclusive  until BioSeq  commences
selling on a  commercial  basis the  equipment  used in the DNA  sequencing  and
analysis  process,  at which time the  License  will become  non-exclusive.  The
License  provides that the Company will pay BioSeq  royalties  ranging from five
percent to ten percent of net revenues arising out of the services  performed by
the Company  with the  licensed  technology.  The Company  will  account for the
royalty as a cost of revenue as the revenues are earned.
    

                                      F-16



                     BOSTON BIOMEDICA, INC. AND SUBSIDIARIES
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - (CONTINUED)
     (INFORMATION AS OF JUNE 30, 1996 AND FOR THE SIX MONTHS ENDED JUNE 30,
                          1996 AND 1995 IS UNAUDITED.)

   
(11) SUBSEQUENT EVENTS -- (CONTINUED)

Initial Public Offering (Unaudited)

    The Company  has filed a  registration  statement  for the sale of shares of
common  stock.  Accordingly,  the  unaudited  pro forma  balance  sheet has been
prepared  assuming  the  reclassification  of the  redeemable  common stock into
common stock as of June 30, 1996.  There can be no  assurances  that the initial
public offering of common stock will be successfully completed.

(12) SUPPLEMENTARY PRO FORMA EARNINGS PER SHARE -- (UNAUDITED)

    If the  Offering  had been  completed  on January 1, 1995,  a portion of the
proceeds  would have been used to retire all debt  outstanding at that time, and
all debt  incurred  in 1995 and 1996  would not have been  needed.  Based on the
foregoing,  supplemental  pro forma net earnings per share of common stock would
have been $.09 and $.06 for the year ended  December 31, 1995 and the six months
ended June 30, 1996,  respectively.  Such net earnings per share of common stock
are based on  3,600,007  and  3,701,173  shares of  common  stock  respectively,
consisting of 3,151,477  and  3,252,643  shares of common stock and common stock
equivalents  plus 448,530  shares  assumed to be issued at $9.00 per share as if
the Offering had occurred on January 1, 1995 to retire indebtedness  outstanding
during 1995.
    

                                   F-17





                                    GLOSSARY

AIDS                          Acquired  Immune  Deficiency  Syndrome.   AIDS  is
                              caused    by    infection     with    the    Human
                              Immunodeficiency Virus, HIV.

Antibodies                    Binding proteins naturally produced by the body in
                              response to exposure  to  non-self  agents  (e.g.,
                              bacteria,  viruses, cancer cells). Antibodies form
                              part of the immunological defense system.

Antigens                      Foreign  non-self  agents (such as the proteins or
                              the  nucleic  acids  of  infectious  agents)  that
                              stimulate  an  immune   response,   including  the
                              production of antibodies.

Assay                         Synonym  for  test:  qualitative  or  quantitative
                              measurement of some component of a material.

Chlamydia                     A  sexually  transmitted  pathogen  that can cause
                              Trachoma  (an  eye  disease  which  culminates  in
                              blindness),  chronic  infection of genitals (which
                              can  result  in   infertility),   and   pneumonia,
                              especially in the newborn.

CLIA                          The Clinical  Laboratory  Improvement  Amendments,
                              passed by Congress in October 1988, and formulated
                              into  regulations  and  implemented  by the Health
                              Care Financing  Administration  beginning in 1992.
                              CLIA refers to a set of  regulations  which govern
                              the staffing and function of all U.S. laboratories
                              that  perform  in  vitro   diagnostic   tests  for
                              clinical use,  except for blood bank  laboratories
                              and     Veterans'      Administration     hospital
                              laboratories, which are regulated separately using
                              similar rules.

Cytomegalovirus               A virus  responsible for several diseases that are
                              especially prevalent in immunocompromised patients
                              such as those infected with HIV,  receiving  organ
                              transplants or receiving cancer chemotherapy.

Diagnostic Components         The solutions  and  materials  that are  combined,
                              sometimes after further manufacture, to make an in
                              vitro diagnostic test kit.

DNA                           Deoxyribonucleic  Acid, together with RNA, a class
                              of molecules  called "nucleic  acids." DNA carries
                              the genetic  information in most living organisms.
                              The DNA of each cell contains the  information for
                              "building"  a whole  organism  (e.g.,  a virus,  a
                              plant,  or a whole human  being).  DNA testing can
                              identify   microscopic   amounts  of  the  genetic
                              material of a virus or bacterium,  thus indicating
                              its  presence in  quantities  undetectable  in the
                              bloodstream by immunoassay techniques.

ELISA                         Enzyme-Linked  Immunosorbent  Assay, a biochemical
                              procedure in which  interactions among antibodies,
                              antigens  and  enzymes  are  used  to  detect  and
                              quantify  various  diseases and other materials of
                              interest through the measurement of color released
                              at the end of the assay.

End-User                      The   purchaser   and  consumer  of  an  in  vitro
                              diagnostic    test    kit;     usually    clinical
                              laboratories,  but may also be other  health  care
                              providers or members of the general public.


                                      G-1



Hepatitis                     A disease that causes  inflammation  of and damage
                              to the liver, often caused by a virus. In advanced
                              stages,  hepatitis can result in life  threatening
                              liver   dysfunction,   liver  cirrhosis  or  liver
                              cancer.  The most common causes of viral hepatitis
                              are the Hepatitis A, B and C viruses (HAV, HBV and
                              HCV).

HIV                           Human  Immunodeficiency  Virus. HIV, a retrovirus,
                              causes   AIDS.   HIV   infection   leads   to  the
                              destruction of the immune system.

Immunology                    Narrowly  defined  as  the  study  of  the  immune
                              system,  but  often  used to  describe  tests  for
                              infectious diseases which rely on the principle of
                              the binding of antigens and antibodies.

Immunoassay                   A  test  that  relies  on the  specificity  of the
                              reaction between antibodies and antigens to detect
                              and  measure  the   concentration   of  biological
                              molecules.

In Vitro                      Laboratory  procedures  that  occur  "in the  test
                              tube," or outside  the body.  In vitro  diagnostic
                              testing is the process of analyzing blood,  urine,
                              saliva  and other  specimens  outside  the body to
                              screen for, monitor or diagnose diseases and other
                              medical conditions.

Infectious Agent              Any  microorganism,  such  as  bacteria,  viruses,
                              fungi  or other  parasites,  capable  of  invading
                              another  organism,  with or  without  pathological
                              manifestations.

Levey-Jennings Chart          A  chart  on  which  the  test  results  for a Run
                              Control  are  plotted  over  time,   so  that  the
                              reproducibility of a test method can be monitored.
                              The  acceptable  range  for  the Run  Control,  as
                              determined by each  individual  test kit end-user,
                              is also indicated on the chart.

Lyme Disease                  A  bacterial  infection  caused  by  a  spirochete
                              called Borrelia burgdorferi (B. burgdorferi). This
                              spirochete  usually  infects  the deer tick  which
                              then bites a person or animal,  thus  transmitting
                              the infection.

Marker                        A substance which, when detected in blood or other
                              study sample by an in vitro  diagnostic  test,  is
                              indicative  of the  presence  of  disease or other
                              medical condition.

Microbiology                  The  clinical   laboratory  testing  segment  that
                              specializes  in the  detection of  organisms  that
                              cause infectious  disease.  Often used to refer to
                              traditional  tests that use a growth  medium which
                              enables an organism,  if present, to replicate and
                              be detected visually.  Newer methods for detection
                              and  monitoring  of  infectious  diseases  such as
                              immunology  and  molecular   biology  methods  are
                              sometimes  performed in separate  laboratories and
                              sometimes     incorporated    into    microbiology
                              laboratories.

Molecular Biology             The clinical laboratory testing segment which uses
                              newer methods such as PCR to detect  nucleic acids
                              (i.e.,   DNA  and  RNA)  for  infectious   disease
                              diagnosis and other purposes.



                                      G-2


Multi-Marker Run Control      A run  control  designed  to be used with  several
                              tests for  different  analytes or  markers.  These
                              controls  are  designed to cover groups of markers
                              that are  tested in the same  laboratory  section,
                              e.g.,  Accurun 1(R) is a multi-marker  run control
                              for blood bank tests.

Nucleic Acids                 Two families of compounds called  deoxyribonucleic
                              acid (DNA) and  ribonucleic  acid (RNA) that carry
                              the  coded   information  from  which  all  living
                              organisms are made.

Pathogen                      An  organism  that  causes  disease  in the  study
                              subjects  (e.g.,  a virus which causes  disease in
                              humans is human  pathogen;  an insect  that causes
                              disease in a plant is a plant pathogen).

PCR                           Polymerase Chain Reaction,  a sequence of chemical
                              steps using DNA primers  (short  pieces of nucleic
                              acids)  to  locate  and  copy  (amplify)  specific
                              sequences of DNA, if present,  to a  concentration
                              high enough for chemical detection.

Performance Panels            A set of serum and plasma  samples  collected from
                              many different  individuals and  characterized for
                              the  presence or absence of a  particular  disease
                              marker.

Plasma                        The clear liquid  portion of blood which  contains
                              clotting factors, proteins, antibodies,  hormones,
                              electrolytes  and other  components  dissolved  in
                              water.  Plasma  differs  from  serum  only in that
                              plasma  contains  clotting  factors in addition to
                              its other components, and serum does not.

Qualification Panels          Dilutions of human plasma or serum  manifesting  a
                              full  range  of  reactivities  in test  kits for a
                              specific marker.

Qualitative Test              An assay  for  which the  reportable  results  are
                              positive,    negative   or    indeterminate.    An
                              alternative set of terms sometimes used to express
                              qualitative test results is reactive, non-reactive
                              or gray zone.

Quality Control Products      Materials  including   characterized   samples  of
                              various  kinds,  data  sheets  and  software,  all
                              designed for use in the performance  evaluation of
                              in   vitro    diagnostic    tests   during   their
                              development, manufacture or use.

Quantitative Test             An assay  for  which the  reportable  results  are
                              numeric.

Reactivity                    Test result for a qualitative  test;  can take one
                              of   three    forms:    positive,    negative   or
                              indeterminate.

Reagent                       A substance,  usually a chemical solution, used as
                              a component of an in vitro diagnostic test.



                                      G-3



Retrovirus                    A virus with its  genetic  information  encoded in
                              RNA rather than DNA. HIV is a retrovirus.

RNA                           Ribonucleic  acid,  with DNA, a class of molecules
                              called  nucleic  acids.  RNA functions with DNA in
                              most  organisms  to  translate  the coded  genetic
                              information  into  the  organism  itself.  In some
                              viruses,  RNA  substitutes for DNA in carrying the
                              coded information from which the organism is made.
                              HIV and HCV are RNA viruses.

Run Controls                  Well-characterized  samples  designed  to resemble
                              the donor and  patient  samples  routinely  tested
                              with a  given  method,  manufactured  to  specific
                              levels of  reactivity  and provided in  quantities
                              sufficient  to be used  each time the test is run,
                              over a period of time,  so that  test  performance
                              can be continuously monitored.

Sensitivity                   The ability of a test to detect  accurately  small
                              quantities of a substance of interest. The greater
                              the  sensitivity,  the smaller the quantity of the
                              substance the test can detect, and the fewer false
                              negatives  will  be  reported.   Sensitivity   and
                              specificity  are  two  important  measures  of the
                              quality of a test.

Sensitivity Panels            Precise   dilutions   of  human  plasma  or  serum
                              containing a known amount of an infectious disease
                              marker   as   calibrated   against   international
                              standards.

Seroconversion Panels         Plasma samples  collected from a single individual
                              over a specific  time  period  showing  conversion
                              from  negative  to  positive  for  markers  of  an
                              infectious disease.

Serum                         The clear liquid  portion of blood which  contains
                              proteins, antibodies,  hormones,  electrolytes and
                              other components dissolved in water. Serum differs
                              from  plasma  only in that serum does not  contain
                              clotting factors.

Single Analyte Run Control    A run control designed to be used with tests for a
                              single analyte or marker,  e.g.,  Accurun 106 is a
                              positive   control  for  HIV  antigen  tests  from
                              several manufacturers.

Specificity                   The  ability  of a  test  to  distinguish  between
                              similar  materials.  The greater the  specificity,
                              the better a test is at identifying a substance in
                              the presence of substances of similar makeup,  and
                              the  fewer  false   positives  will  be  reported.
                              Sensitivity  and  specificity  are  two  important
                              measures of the quality of a test.

Therapeutic Index             A   mathematical   description  of  the  potential
                              usefulness  of a  candidate  drug,  based  on  its
                              toxicity   to   the   host   system   versus   its
                              effectiveness    against   the    pathogen.    The
                              Therapeutic  Index of a candidate drug is compared
                              to the  Therapeutic  Index in the same test system
                              of a drug  already  in use for the  disease  being
                              studied.


                                      G-4




Titer                         An  approximation of the quantity of a marker in a
                              qualitative  test,  arrived  at  by  diluting  the
                              sample  repeatedly and testing the dilutions until
                              the  marker  is no  longer  detected  by the  test
                              method.

Toxoplasma                    A   protozoan   parasite,    ubiquitous   in   the
                              environment,   and  which  causes   Toxoplasmosis.
                              Toxoplasmosis is commonly  acquired by eating food
                              contaminated  by cysts.  Pregnant  women may be at
                              risk of acquiring  Toxoplasmosis  from cats,  with
                              subsequent infection of the baby.

Virus                         A  microorganism  dependent on host cells in order
                              to grow and reproduce.

Western Blot Method           The standard diagnostic method for confirmation of
                              the presence of an infectious disease marker (e.g.
                              HIV,  Borrelia  burgdorferi),  in which  lysate (a
                              mixture  of  proteins)  is  separated  on a gel by
                              electrochemical  means and then  transferred  to a
                              nitrocellulose  filter.  The filter is then tested
                              against a blood sample to identify  antibodies  to
                              the proteins.



                                      G-5









Photograph  showing  certain of the Company's  Quality  Control Panel  Products,
including Seroconversion and Performance Panels.













================================================================================

NO  DEALER,  SALESMAN  OR ANY  OTHER  PERSON  HAS  BEEN  AUTHORIZED  TO GIVE ANY
INFORMATION  OR MAKE ANY  REPRESENTATIONS  OTHER  THAN THOSE  CONTAINED  IN THIS
PROSPECTUS IN CONNECTION WITH THE OFFERING  DESCRIBED  HEREIN,  AND, IF GIVEN OR
MADE,  SUCH OTHER  INFORMATION  OR  REPRESENTATIONS  MUST NOT BE RELIED  UPON AS
HAVING BEEN AUTHORIZED BY THE COMPANY, OR THE UNDERWRITERS. NEITHER THE DELIVERY
OF THIS PROSPECTUS NOR ANY SALE MADE HEREUNDER SHALL,  UNDER ANY  CIRCUMSTANCES,
CREATE ANY IMPLICATION  THAT THE INFORMATION  CONTAINED  HEREIN IS CORRECT AS OF
ANY TIME SUBSEQUENT TO ITS DATE. THIS PROSPECTUS DOES NOT CONSTITUTE AN OFFER TO
SELL OR A  SOLICITATION  OF AN  OFFER TO BUY ANY  SECURITIES  OTHER  THAN  THOSE
SPECIFICALLY  OFFERED  HEREBY  OR  OF  ANY  SECURITIES  OFFERED  HEREBY  IN  ANY
JURISDICTION  TO ANY  PERSON  TO  WHOM  IT IS  UNLAWFUL  TO  MAKE  AN  OFFER  OR
SOLICITATION IN SUCH JURISDICTION.  THIS PROSPECTUS DOES NOT CONSTITUTE AN OFFER
TO  SELL  OR  A  SOLICITATION  OF  AN  OFFER  TO  BUY  SUCH  SECURITIES  IN  ANY
CIRCUMSTANCES IN WHICH SUCH OFFER OR SOLICITATION IS UNLAWFUL.


                                   ----------


                             TABLE OF CONTENTS


   
                                                                            PAGE
                                                                            ----
Prospectus Summary                                                             3
Risk Factors                                                                   6
Use of Proceeds                                                               14
Dividend Policy                                                               14
Capitalization                                                                15
Dilution                                                                      16
Selected Consolidated Financial Data                                          17
Management's Discussion and Analysis of
  Financial Condition and Results of
  Operations                                                                  19
Business                                                                      25
Management                                                                    40
Certain Transactions                                                          44
Principal Stockholders                                                        45
Description of Capital Stock                                                  46
Shares Eligible for Future Sale                                               48
Underwriting                                                                  49
Legal Matters                                                                 50
Experts                                                                       50
Additional Information                                                        50
Index to Consolidated Financial Statements                                   F-1
Glossary                                                                     G-1
    

    UNTIL        , 1996 (25 DAYS AFTER THE DATE OF THIS PROSPECTUS) ALL  DEALERS
EFFECTING   TRANSACTIONS  IN  THE  SHARES  OF  COMMON  STOCK,   WHETHER  OR  NOT
PARTICIPATING  IN THIS  DISTRIBUTION,  MAY BE REQUIRED TO DELIVER A  PROSPECTUS.
THIS IS IN ADDITION TO THE  OBLIGATIONS OF DEALERS TO DELIVER A PROSPECTUS  WHEN
ACTING  AS  UNDERWRITERS  AND  WITH  RESPECT  TO  THEIR  UNSOLD   ALLOTMENTS  OR
SUBSCRIPTIONS.

================================================================================



   
                                1,600,000 SHARES
    


                                     [LOGO]


                             BOSTON BIOMEDICA, INC.


                                  COMMON STOCK





                                   ----------
                                   PROSPECTUS
                                   ----------





                         OSCAR GRUSS & SON INCORPORATED

                              KAUFMAN BROS., L.P.





                                      , 1996





================================================================================



                                    PART II
                     INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 13. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION

                                                              TOTAL
                                                             EXPENSES
                                                             --------

   
SEC Registration Fee                                         $  8,508
NASD Filing Fee                                                 2,708
Nasdaq National Market Listing Fee                             30,000*
Blue Sky Fees and Expenses                                     15,000*
Underwriters' Non-Accountable Expense
Allowance                                                     144,000*
Transfer Agent and Registrar Fees                               2,500*
Accounting Fees and Expenses                                  150,000*
Legal Fees and Expenses                                       300,000*
Printing and Engraving                                         60,000*
Miscellaneous                                                  79,284*
                                                             ---------
  TOTAL                                                      $792,000*
                                                             =========
    


- ---------
* Estimate



ITEM 14. INDEMNIFICATION OF DIRECTORS AND OFFICERS


    The Company's Amended and Restated By-Laws include  provisions to permit the
indemnification of officers and directors of the Company for damages arising out
of the  performance  of  their  duties  unless  such  damages  arise  out of the
officer's or  director's  failure to exercise  his duties and to  discharge  the
duties of his office in good faith and in the reasonable  belief that his action
was in, or not opposed to, the best interest of the Company, and with respect to
any criminal action or proceeding,  had no reasonable  cause to believe that his
conduct  was  unlawful.  The  Company  intends  to  enter  into  indemnification
contracts  with each of its directors and officers.  Reference is hereby made to
the caption  "Management  -- Limitation of Officers' and  Directors'  Liability;
Indemnification Agreements."

    Reference  is hereby made to the caption  "Description  of Capital  Stock --
Limitation of Directors'  Liability" in the Prospectus,  which is a part of this
Registration Statement.

   
    Reference is hereby made to Section 6 of the Underwriting  Agreement between
the  Company  and the  Underwriter,  filed as Exhibit  1.1 to this  Registration
Statement, for a description of indemnification arrangements between the Company
and the Underwriter.
    

ITEM 15. RECENT SALES OF UNREGISTERED SECURITIES

    The following  information is furnished with regard to all securities issued
by the Registrant  within the past three years which were not  registered  under
the Securities Act.

    In August  1996,  the  stockholders  of the  Registrant  voted to approve an
amendment to the  Registrant's  Articles of Organization to effect a one-for-two
reverse stock split of the Registrant's  Common Stock, $.01 par value per share.
All  references  to number of shares of Common  Stock give  effect to this stock
split.

                                   II-1




    (1) In August 1993, the  Registrant  sold to eight  individual  investors an
aggregate  of 45,000  shares of Common  Stock for total  cash  consideration  of
$202,500, at a price per share of $4.50, and to another investor 1,958 shares of
Common  Stock  in  exchange  for  services  rendered  valued  at  $8,811,  which
securities were not registered under the Securities Act.

    (2) In April 1994,  the  Registrant  sold to eight  individual  investors an
aggregate of 21,200 shares of Common Stock, for total  consideration of $127,200
at a price per share of $6.00,  which  securities were not registered  under the
Securities Act.

    (3) From June through  December 1994,  the Registrant  sold the following at
$6.00  per  share:  to one  investor  5,000  shares  of  Common  Stock  for cash
consideration of $30,000,  to a second investor 1,167 shares of Common Stock for
cash  consideration  of $3,501 and in exchange for services  rendered  valued at
$3,501,  and to a third investor 2,494 shares in exchange for services  rendered
valued at $14,964,  which  securities  were not registered  under the Securities
Act.

    (4) In November and December 1995,  the Registrant  sold to two investors an
aggregate  of 7,800  shares of Common  Stock for  total  cash  consideration  of
$54,600 at a price of $7.00,  and to another investor 734 shares of Common Stock
in exchange for services  rendered valued at $5,138,  which  securities were not
registered under the Securities Act.

    (5) On April 26, 1996, the Registrant sold 117,647 shares of Common Stock to
Kyowa  Medex,  Co.,  Ltd.  for total cash  consideration  of  $1,000,000,  which
securities were not registered under the Securities Act.

    (6) For the  period  August  1,  1993 to date,  the  Registrant  granted  to
directors, officers, employees and consultants, 15,000 ($6.00 per share), 63,000
($4.50 to $7.00 per share), 244,037 ($4.50 to $8.50 per share), and 8,000 ($6.00
per share),  respectively,  options to purchase shares of Common Stock under the
Registrant's 1987 Non-Qualified Stock Option Plan or Employee Stock Option Plan,
which securities were not registered under the Securities Act.

    (7) During the period  from March 1994  through  June 1996,  the  Registrant
issued an aggregate of 88,993 shares to fifteen persons pursuant to the exercise
of options,  warrants or convertible notes of the Registrant for exercise prices
ranging  from  $0.25  to  $5.20  per  share  (an  aggregate  exercise  price  of
$219,977.50), which securities were not registered under the Securities Act.

    To the extent that the foregoing transactions constituted "sales" within the
meaning of the Securities Act, the securities  issued in such  transactions were
not  registered  under the  Securities  Act,  as amended,  in reliance  upon the
exemptions  from  registration  set  forth  in  Section  3(b)  and  4(2)  of the
Securities  Act,  relating  to sales  by an  issuer  not  involving  any  public
offering,  or in reliance upon  Regulation S of the  Securities  Act relating to
sales  by an  issuer  of  securities  outside  the  United  States.  None of the
foregoing  transactions,  either  individually  or in the aggregate,  involved a
public offering.

ITEM 16. FINANCIAL STATEMENT SCHEDULE AND EXHIBITS


<TABLE>
<CAPTION>
 SCHEDULE
    NO.
    ---
    <S>          <C>
    II           -- Valuation and Qualifying Accounts

</TABLE>

<TABLE>
<CAPTION>
   
  EXHIBIT
    NO.
    ---
  <S>            <C>
    1.1          -- Form of Underwriting Agreement***
    3.1          -- Amended and Restated Articles of Organization of the Registrant
    3.2          -- Amended and Restated By-Laws of the Registrant
    4.1          -- Description of Certificate for Shares of the Registrant's Common Stock
</TABLE>
    
                                      II-2




<TABLE>
<CAPTION>
   
  EXHIBIT
    NO.
    ---
  <S>            <C>

   5.1           -- Legal Opinion of Brown, Rudnick, Freed & Gesmer***
  10.1           -- Agreement, dated January 17, 1994, between Roche Molecular Systems, Inc. and the
                    Registrant*
  10.2           -- Exclusive License Agreement, dated December 6, 1994, between the University of
                    North Carolina at Chapel Hill and the Registrant**
  10.3           -- Contract, dated September 30, 1995, between the National Institutes of Health
                    and the Registrant (No. 1-AI-55273)**
  10.4           -- Contract, dated September 30, 1995, between the National Institutes of Health
                    and the Registrant (No. 1-AI-55277)**
  10.5           -- Contract, dated March 1, 1993, between the National Cancer Institute and the
                    Registrant**
  10.6           -- Agreement, dated October 1, 1995, between Ajinomoto Co., Inc. and the Registrant**
  10.7           -- Lease Agreement, dated June 30, 1992, for Rockville, Maryland Facility between
                    Cambridge Biotech Corporation and the Registrant**
  10.8           -- Lease Agreement, dated July 28, 1995, for New Britain, Connecticut Facility between
                    MB Associates and the Registrant**
  10.9           -- Worcester County Institution for Savings Warrant dated December 1, 1995 (No. 1)*
  10.10          -- Worcester County Institution for Savings Warrant dated July 26, 1993 (No. 2)*
  10.11          -- Stock Purchase Agreement, dated June 5, 1990, between G&G Diagnostics Limited
                    Partnership I and the Registrant, as amended*
  10.12          -- Purchase and Sale Agreement, dated December 11, 1995, for 375 West Street Property
                    between James Leonard, Trustee, C.W.B. Trust and the Registrant*
  10.13          -- Purchase and Sale Agreement, dated December 20, 1995, for 80 Manley Street Property
                    between the Registrant and Donald M. Leonard, Trustee, Live Oak Realty Trust*
  10.14          -- Stock Purchase Agreement, dated April 26, 1996, between Kyowa Medex Co., Ltd.
                    and the Registrant*
  10.15          -- 1987 Non-Qualified Stock Option Plan*
  10.16          -- Employee Stock Option Plan*
  10.17          -- Form of  Underwriters  Warrant  (contained in Exhibit 1.1)***
  10.18.1        -- Second  Amended and  Restated  Loan and  Security  Agreement,
                    dated August 2, 1995,  between the First National Bank of Boston
                    and the Registrant, as amended*
  10.18.2        -- Note  Payable to The First  National  Bank of  Boston,  dated
                    October 1994, in the amount of $200,000
  10.18.3        -- Note Payable to The First National Bank of Boston, dated October 1994, in the
                    amount of $849,000
  10.18.4        -- Note Payable to The First National Bank of Boston, dated August 1995, in the amount
                    of $350,000
  10.18.5        -- Note Payable to The First National Bank of Boston, dated December 1995, in the
                    amount of $100,000
  10.18.6        -- Mortgage Note to The First National Bank of Boston, dated December 1995, in the
                    amount of $750,000
  10.18.7        -- Note Payable to The First National Bank of Boston, dated July 1996, in the amount
                    of $250,000
  10.19          -- Form of Indemnification Agreement with Officers and Directors*
</TABLE>
    

                                      II-3



<TABLE>
<CAPTION>
   
  EXHIBIT
    NO.
    ---
  <S>            <C>
  10.20          -- Purchase Agreement, dated October 7, 1996, between BioSeq, Inc. and the Registrant
  10.21          -- Warrant Agreement, dated October 7, 1996, between BioSeq, Inc. and the Registrant
  10.22          -- Stockholders' Agreement, dated October 7, 1996, between BioSeq, Inc. and the Registrant
  10.23          -- License Agreement, dated October 7, 1996, between BioSeq, Inc. and the Registrant
  11             -- Statement re Computation of Per Share Earnings
  21             -- Subsidiaries of the Registrant*
  23.1           -- Consent of Brown, Rudnick, Freed & Gesmer (contained in Exhibit 5.1)***
  23.2           -- Consent of Coopers & Lybrand L.L.P., independent accountants
  24             -- Power of Attorney*
  27             -- Financial Data Schedule*

</TABLE>

*   Previously filed.
**  Confidential Treatment requested for certain portions of this document which
    has been previously filed.
*** To be filed by amendment.

    

ITEM 17. UNDERTAKINGS

    (a) The undersigned Registrant hereby undertakes:

       (1) To file, during any period in which offers or sales are being made, a
    post-effective amendment to this registration statement;

       (i) To include any prospectus required by Section 10(a)(3) of the
    Securities Act of 1933;

       (ii) To reflect in the  prospectus  any facts or events arising after the
    effective   date  of  the   registration   statement  (or  the  most  recent
    post-effective  amendment thereof) which,  individually or in the aggregate,
    represent  a  fundamental  change  in  the  information  set  forth  in  the
    registration  statement.  Notwithstanding  the  foregoing,  any  increase or
    decrease  in volume of  securities  offered  (if the total  dollar  value of
    securities  offered  would not  exceed  that which was  registered)  and any
    deviation from the low or high end of the estimated  maximum  offering range
    may be  reflected  in the  form of  prospectus  filed  with  the  Commission
    pursuant  to Rule  424(b) if, in the  aggregate,  the  changes in volume and
    price  represent no more than a 20 percent  change in the maximum  aggregate
    offering price set forth in the  "Calculation of Registration  Fee" table in
    the effective registration statement;

       (iii) To include any  material  information  with  respect to the plan of
    distribution not previously  disclosed in the registration  statement or any
    material change to such information in the registration statement;

       (2)  That,  for the  purpose  of  determining  any  liability  under  the
    Securities Act of 1933, each such  post-effective  amendment 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.

       (3) To remove from  registration by means of a  post-effective  amendment
    any  of  the  securities   being  registered  which  remain  unsold  at  the
    termination of the Offering.

    (b)  The  undersigned   Registrant  hereby  undertakes  to  provide  to  the
underwriter at the closing specified in the underwriting agreements certificates
in  such  denominations  and  registered  in  such  names  as  required  by  the
underwriter to permit prompt delivery to each purchaser.

    (c) 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 Registrant's By-Laws, the Underwriting  Agreement
relating to this Offering, or otherwise, the Registrant has been 


                                      II-4






advised  that in the opinion of the  Securities  and  Exchange  Commission  such
indemnification  is  against  public  policy  as  expressed  in the  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 Act and will be governed by the final adjudication of
such issue.

    (d) The undersigned Registrant hereby further 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-5





                                   SIGNATURES

   
    Pursuant to the  requirements  of the Securities Act of 1933, the Registrant
has duly caused this Amendment No. 1 to the Registration  Statement to be signed
on its behalf by the undersigned, thereunto duly authorized, in the City of West
Bridgewater, Commonwealth of Massachusetts, on October 8, 1996.

                                            BOSTON BIOMEDICA, INC.

                                            By: /s/ RICHARD T. SCHUMACHER
                                            -----------------------------
                                               RICHARD T. SCHUMACHER
                                                    PRESIDENT

    PURSUANT TO THE  REQUIREMENTS  OF THE SECURITIES ACT OF 1933, THIS AMENDMENT
NO. 1 TO THE 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/ RICHARD T. SCHUMACHER               Principal Executive Officer          October 8, 1996
           ----------------------               and Director
           RICHARD T. SCHUMACHER       


        /s/ KEVIN W. QUINLAN                  Principal Financial and Accounting    October 8, 1996
           -------------------                 Officer and Director
            KEVIN W. QUINLAN   

                    *                         Director                              October 8, 1996
           -------------------
           HENRY A. MALKASIAN  

                   *                          Director                              October 8, 1996
           -------------------
          FRANCIS E. CAPITANIO

                    *                         Director                              October 8, 1996
          --------------------
             CALVIN A. SARAVIS

    *By /s/ RICHARD T. SCHUMACHER
           ----------------------
            RICHARD T. SCHUMACHER
              ATTORNEY-IN-FACT
     

</TABLE>



                                   II-6




                       REPORT OF INDEPENDENT ACCOUNTANTS

To the Board of Directors and Stockholders of 
BOSTON BIOMEDICA, INC.:

   
    In connection with our audits of the  consolidated  financial  statements of
Boston Biomedica,  Inc. and Subsidiaries,  as of December 31, 1994 and 1995, and
for each of the  three  years in the  period  ended  December  31,  1995,  which
financial  statements are included in this  Amendment No. 1 to the  Registration
Statement  on  Form  S-1  (File  No.  333-10759),   we  have  also  audited  the
consolidated financial statement schedule listed in Item 16 herein.
    

    In  our  opinion,  this  consolidated  financial  statement  schedule,  when
considered  in  relation  to the basic  financial  statements  taken as a whole,
presents  fairly,  in all  material  respects,  the  information  required to be
included therein.

                                            COOPERS & LYBRAND L.L.P.

Boston, Massachusetts
March 12, 1996





                                    S-1






                                   SCHEDULE II

                  BOSTON BIOMEDICA, INC. AND SUBSIDIARIES
                     VALUATION AND QUALIFYING ACCOUNTS


<TABLE>
<CAPTION>
                                                                          RECOVERIES
                                            BALANCE AT                   FOR ACCOUNTS   UNCOLLECTIBLE   BALANCE AT
                                             BEGINNING   PROVISION FOR    PREVIOUSLY       ACCOUNTS       END OF
     ALLOWANCE FOR DOUBTFUL ACCOUNTS         OF PERIOD      BAD DEBT      WRITTEN OFF    WRITTEN OFF      PERIOD
     -------------------------------         ---------      --------      -----------    -----------      ------
<S>                                          <C>            <C>           <C>            <C>             <C>
   
Six months ended June 30, 1996               $142,372       $ 77,145           --         $ (85,938)     $133,579
1995                                           94,723        181,084           --          (133,435)      142,372
1994                                           43,956        102,099           --           (51,332)       94,723
1993                                           21,000         22,956           --            --            43,956
</TABLE>
    

                                    S-2





                             INDEX TO EXHIBITS


<TABLE>
<CAPTION>
                                                                                             SEQUENTIALLY
  EXHIBIT                                                                                      NUMBERED
  NUMBER                                      DESCRIPTION                                        PAGE
  ------                                      -----------                                        ----
  <S>         <C>                                                                                <C>         
   
   1.1        -- Form of Underwriting Agreement***
   3.1        -- Amended and Restated Articles of Organization of the Registrant
   3.2        -- Amended and Restated By-Laws of the Registrant
   4.1        -- Description of Certificate for Shares of the Registrant's Common Stock
   5.1        -- Legal Opinion of Brown, Rudnick, Freed & Gesmer***
  10.1        -- Agreement, dated January 17, 1994, between Roche Molecular Systems, Inc. and
                 the Registrant*
  10.2        -- Exclusive License Agreement, dated December 6, 1994, between the University
                 of North Carolina at Chapel Hill and the Registrant**
  10.3        -- Contract, dated September 30, 1995, between the National Institutes of Health
                 and the Registrant (No. 1-AI-55273)**
  10.4        -- Contract, dated September 30, 1995, between the National Institutes of Health
                 and the Registrant (No. 1-AI-55277)**
  10.5        -- Contract, dated March 1, 1993, between the National Cancer Institute and the
                 Registrant**
  10.6        -- Agreement, dated October 1, 1995, between Ajinomoto Co., Inc. and the Registrant**
  10.7        -- Lease Agreement, dated June 30, 1992, for Rockville, Maryland Facility between
                 Cambridge Biotech Corporation and the Registrant**
  10.8        -- Lease Agreement, dated July 28, 1995, for New Britain, Connecticut Facility
                 between MB Associates and the Registrant**
  10.9        -- Worcester County Institution for Savings Warrant dated December 1, 1995 (No.
                 1)*
  10.10       -- Worcester County Institution for Savings Warrant dated July 26, 1993
                 (No. 2)*
  10.11          -- Stock Purchase  Agreement,  dated June 5, 1990,  between G&G
                 Diagnostics  Limited  Partnership  I  and  the  Registrant,  as
                 amended*
  10.12       -- Purchase and Sale Agreement, dated December 11, 1995, for 375 West Street
                 Property between James Leonard, Trustee, C.W.B. Trust and the Registrant*
  10.13       -- Purchase and Sale Agreement, dated December 20, 1995, for 80 Manley Street
                 Property between the Registrant and Donald M. Leonard, Trustee, Live Oak Realty
                 Trust*
  10.14       -- Stock Purchase Agreement, dated April 26, 1996, between Kyowa Medex Co., Ltd.
                 and the Registrant*
  10.15       -- 1987 Non-Qualified Stock Option Plan*
  10.16       -- Employee Stock Option Plan*
  10.17       -- Form of  Underwriters  Warrant  (contained  in Exhibit  1.1)***
  10.18.1     -- Second Amended and Restated Loan and Security Agreement,  dated
                 August 2, 1995,  between the First National Bank of Boston and the
                 Registrant, as amended*
  10.18.2     -- Note  Payable  to The  First  National  Bank of  Boston,  dated
                 October 1994, in the amount of $200,000
  10.18.3     -- Note Payable to The First National Bank of Boston, dated October 1994, in
                 the amount of $849,000
</TABLE>
    






                       INDEX TO EXHIBITS (CONTINUED)



<TABLE>
<CAPTION>
                                                                                             SEQUENTIALLY
  EXHIBIT                                                                                      NUMBERED
  NUMBER                                      DESCRIPTION                                        PAGE
  ------                                      -----------                                        ----
<S>           <C>                                                                                <C>         
   
10.18.4       -- Note Payable to The First National Bank of Boston, dated August 1995, in the
                 amount of $350,000
10.18.5       -- Note Payable to The First National Bank of Boston, dated December 1995, in
                 the amount of $100,000
10.18.6       -- Mortgage Note to The First National Bank of Boston, dated December 1995, in
                 the amount of $750,000
10.18.7       -- Note Payable to The First National Bank of Boston, dated July 1996, in the
                 amount of $250,000
10.19         -- Form of Indemnification Agreement with Officers and Directors*
10.20         -- Purchase Agreement, dated October 7, 1996, between BioSeq, Inc. and the Registrant
10.21         -- Warrant Agreement, dated October 7, 1996, between BioSeq, Inc. and the Registrant
10.22         -- Stockholders' Agreement, dated October 7, 1996, between BioSeq, Inc. and the
                 Registrant
10.23         -- License Agreement, dated October 7, 1996, between BioSeq, Inc. and the Registrant
11            -- Statement re Computation of Per Share Earnings
21            -- Subsidiaries of the Registrant*
23.1          -- Consent of Brown, Rudnick, Freed & Gesmer (contained in Exhibit 5.1)***
23.2          -- Consent of Coopers & Lybrand L.L.P., independent accountants
24            -- Power of Attorney*
27            -- Financial Data Schedule*
</TABLE>


- -----------
*   Previously filed.

**  Confidential Treatment requested for certain portions of this document which
    has been previously filed.

*** To be filed by amendment.
    

                                                                     EXHIBIT 3.1

                       
                       THE COMMONWEALTH OF MASSACHUSETTS


                           MICHAEL JOSEPH CONNOLLY        FEDERAL IDENTIFICATION
- -------------               Secretary of State                                  
Examiner            ONE ASHBURTON PLACE, BOSTON, MASS: 02108     NO. 04-2652826 
                                                                     -----------
                                                             
                                                             

                         RESTATED ARTICLES OF ORGANIZATION
                     General Laws, Chapter 156B, Section 74

This certificate  must be submitted to the Secretary of the Commonwealth  within
sixty  days after the date of the vote of  stockholders  adopting  the  restated
articles of  organization.  The fee for filing this certificate is prescribed by
General Laws,  Chapter 156B, Section 114. Make check payable to the Commonwealth
of Massachusetts.

                                  -----------

  We, Richard T. Schumacher                                      , President and
      Howard L. Levin                                                 , Clerk of


                              Boston Biomedica Inc.
- --------------------------------------------------------------------------------
                              (Name of Corporation)

located at   375 West Street, West Bridgewater
          ----------------------------------------------------------------------
do hereby certify that the following restatement of the articles of organization
of the corporation was duly adopted at a meeting held on September 5     , 1996,
by vote of

4,812,307   shares of     common stock    out of  5,380,130  shares outstanding,
- ------------         --------------------       ------------
                       (Class of Stock)

           shares of                      out of         shares outstanding, and
- ------------         -------------------        ---------
                       (Class of Stock)

            shares of                    out of              shares outstanding,
- ------------         -------------------        -------------
                       (Class of Stock)

being at least  two-thirds  of each class of stock  outstanding  and entitled to
vote and of each class or series of stock adversely affected thereby: -

         1. The name by which the corporation  shall be known is: -

                Boston Biomedica, Inc.

         2. The purposes for which the corporation is formed are as follows: -

C  [ ]   To engage generally in the clinical laboratory business relating to the
P  [ ]   testing of blood and doing all other types of medical  testing,  and in
M  [ ]   connection  there with,  obtaining  blood,  doing research  therein and
RA [ ]   supplying  same  to other institutions  for research  purposes,  and to
         carry on any other  business,  and to do and perform  any other  lawful
         acts  and  businesses  necessary  or  incidental  to  the  above-stated
         purposes.  To have in  furtherance of the corporate  purposes,  all the
         powers conferred upon  corporations  organized under the Business corp-
         oration  Law  subject to the  limitations  thereof  contained  in these
         Restated Articles of Organization  or in the Laws of the  Commonwealth
         of Massachusetts. To carry on any business or activity permitted by the
         laws of the Commonwealth of  Massachusetts  to a corporation  organized
         under the  provisions of Chapter 156B of the General  Laws,  whether or
         not related to those in the foregoing.

- --------
  P.C.

     Note:  If the  space  provided  under any  article  or item on this form is
     insufficient,  additions shall be set forth on separate 81/2 x 11 sheets of
     paper leaving a left hand margin of at least 1 inch for binding.  Additions
     to more than one article may be continued on a single sheet so long as each
     article requiring each such addition is clearly indicated.

                                                             




     3. The total  number of shares and the par value,  if any, of each class of
        stock which the corporation is authorized to issue is as follows:



                     WITHOUT PAR VALUE                   WITH PAR VALUE
                     -----------------                   --------------
CLASS OF STOCK        NUMBER OF SHARES         NUMBER OF SHARES        PAR VALUE
- --------------        ----------------         ----------------        ---------

 PREFERRED                                       1,000,000               $.01

 COMMON                                         20,000,000               $.01

                               Please see Contination Pages marked Article 3(a)

     *4.If more  than one  class is  authorized,  a  description  of each of the
        different classes of stock with, if any, the preferences, voting powers,
        qualifications,  special or  relative  rights or  privileges  as to each
        class thereof and any series now established:


          Please see Continuation Pages marked Article 4








     *5.The  restrictions,  if any, imposed by the artcles of organization  upon
        the transfer of shares of stock of any class are as follow:


          None








     *6.Other lawful  provisions,  if any, for the conduct and regulation of the
        business and affairs of the corporation,  for its voluntary dissolution,
        or for limiting,  defining, or regulating the powers of the corporation,
        or of its directors or stockholders or of any class of stockholders:

          Please see Continuation Pages marked Article 6




     *If there are no such provisions, state "None".






                             BOSTON BIOMEDICA, INC.

                        RESTATED ARTICLES OF ORGANIZATION

                               CONTINUATION PAGES

                                  ARTICLE 3(a)

         Simultaneously   with  the  effective   date  of  this  amendment  (the
"Effective Date"), each share of the Corporation's  Common Stock, $.01 par value
per share,  issued and outstanding  immediately prior to the Effective Date (the
"Old  Shares")  shall  automatically  and  without any action on the part of the
holder  thereof be  reclassified  as and changed into one-half of a share of the
Corporation's Common Stock, $.01 par value per share (the "New Shares"), subject
to the treatment of fractional share interests as described  below.  Each holder
of a certificate or certificates  which  immediately prior to the Effective Date
represented outstanding Old Shares (the "Old Certificates," whether one or more)
shall be entitled to receive  upon  surrender  of such Old  Certificates  to the
Corporation  for   cancellation,   a  certificate  or  certificates   (the  "New
Certificates,"  whether one or more) representing the number of whole New Shares
into  which  and for  which  the Old  Shares  formerly  represented  by such Old
Certificates so surrendered are  reclassified  under the terms hereof.  From and
after the Effective  Date, Old  Certificates  shall  represent only the right to
receive  New  Certificates  (and,  where  applicable,  one New  Share in lieu of
fractional  shares,  as provided  below) pursuant to the provisions  hereto.  No
certificates or scrip representing fractional share interests in New Shares will
be issued, and no such fractional share interest will entitle the holder thereof
to vote, or to any rights of a shareholder of the  Corporation.  A holder of Old
Certificates shall receive,  in lieu of any fraction of a share of New Shares to
which the holder would otherwise be entitled,  one additional New Share. If more
than one Old Certificate shall be surrendered at one time for the account of the
same stockholder, the number of full New Shares for which New Certificates shall
be  issued  shall be  computed  on the basis of the  aggregate  number of shares
represented  by the Old  Certificates  so  surrendered.  In the  event  that the
Corporation  determines that a holder of Old  Certificates  has not tendered all
his  certificates  for  exchange,   the  Corporation  shall  carry  forward  any
fractional  shares until all certificates of that holder have been presented for
exchange  such that  payment for  fractional  shares to any one person shall not
exceed the number of New Shares to which the holder would have been  entitled if
all  certificates of that holder had been presented for exchange at one time. If
any New  Certificate  is to be issued in a name other than that in which the Old
Certificates  surrendered  for  exchange  are issued,  the Old  Certificates  so
surrendered  shall be properly  endorsed and otherwise  delivered in proper form
for transfer, and the person or persons requesting such exchange shall affix any
requisite  stock  transfer tax stamps to the Old  Certificates  surrendered,  or
provide  funds for their  purchase,  or  establish  to the  satisfaction  of the
Corporation  that such taxes are not payable.  From and after the Effective Date
the amount of capital represented by the New Shares into which and for which Old
Shares are  reclassified  under the terms hereof shall be the same as the amount
of capital  represented  by the Old  Shares so  reclassified,  until  thereafter
reduced or increased in accordance with applicable law.





                             BOSTON BIOMEDICA, INC.

                        RESTATED ARTICLES OF ORGANIZATION

                               CONTINUATION PAGES

                                    ARTICLE 4

        The classes of stock of the  Corporation  authorized  by this  Article 4
shall  have the  preferences,  voting  powers,  qualifications,  and  special or
relative  rights or  privileges  as to each  class  thereof  and any  series now
established  as set  forth  in this  Article  4.  Stock of any  class or  series
authorized  pursuant  hereto may be issued from time to time by authority of the
Board of Directors for such  consideration  as from time to time may be fixed by
vote of the Board of Directors.

                              PART I - COMMON STOCK

        The holders of the Common  Stock shall be entitled to one vote per share
and, subject to the rights and preferences of the holders of the Preferred Stock
and any other  class of stock  ranking  senior to or on a parity with the Common
Stock,  shall be entitled to dividends  when, as and if declared and paid to the
holders of Common Stock, and upon liquidation,  dissolution or winding up of the
Corporation,  to share ratably in the assets  available for  distribution to the
holders of the Common Stock.

                            PART II - PREFERRED STOCK


        Preferred Stock may be issued by the Board of Directors,  in one or more
series and with such rights, powers, preferences and terms and at such times and
for such  consideration  as the  Board of  Directors  shall  determine,  without
further  stockholder  action.  With respect to each series of  Preferred  Stock,
prior to issuance,  the Board of Directors by resolution  shall  designate  that
series  to  distinguish  it from  other  series  and  classes  of  stock  of the
Corporation,  shall  specify  the number of shares to be included in the series,
and shall fix the  rights,  powers,  preferences  and terms of the shares of the
series,  including, but without limitation:  (i) the dividend rate, which may be
fixed or  variable,  its  preference  as to any other class or series of capital
stock, and whether dividends will be cumulative or non-cumulative;  (ii) whether
the  shares are to be  redeemable  and,  if so, at what times and prices  (which
price or prices may, but need not, vary  according to the time or  circumstances
of such redemption) and on what other terms and conditions;  (iii) the terms and
amount of any  sinking  fund  provided  for the  purchase or  redemption  of the
shares; (iv) whether the shares shall be convertible or exchangeable and, if so,
the times,  prices,  rates,  adjustments  and other terms of such  conversion or
exchange; (v) the voting rights, if any, applicable to the shares in addition to
those prescribed by law; (vi) the  restrictions  and conditions,  if any, on the
issue or reissue of any additional  shares of such series or of any other series
of  Preferred  Stock  ranking  on a parity  with or prior to the  shares of such
series;  (vii)  whether,  and the extent to which,  any of the  rights,  powers,
preferences  and  terms of any such  series  may be made  dependent  upon  facts
ascertainable  outside of the Articles of 





Organization or outside the resolution or resolutions providing for the issuance
of such series by the Board of Directors, provided that the manner in which such
facts  shall  operate  is clearly  set forth in the  resolution  or  resolutions
providing for the issuance of such series adopted by the Board of Directors; and
(viii) the rights of the holders of such shares upon  voluntary  or  involuntary
liquidation, dissolution or winding up of the Corporation.







                             BOSTON BIOMEDICA, INC.

                        RESTATED ARTICLES OF ORGANIZATION

                               CONTINUATION PAGES

                                    ARTICLE 6

        The other lawful  provisions  for the conduct and regulation of business
and affairs of the corporation,  for its voluntary dissolution, or for limiting,
defining or  regulating  the powers of the  corporation,  or of its directors or
stockholders, or any class of stockholders, are set forth in this Article 6.

A.      DEFINITIONS

        The following definitions shall apply for the purpose of this Article 6:

        (a)"Affiliate"  shall have the meaning  given such term Rule 12b-2 under
the Exchange Act.

        (b) "Announcement Date" shall mean the date of first public announcement
of the proposal of a Business Combination.

        (c)  "Associate"  shall have the  meaning  given such term in Rule 12b-2
under the Exchange Act.

        (d) "Business Combination" shall mean:

        (i)    any merger or  consolidation of the Corporation or any Subsidiary
               with (a) any Related Person,  or (b) any other Person (whether or
               not itself a Related  Person)  which is, or after such  merger or
               consolidation would be, an Affiliate of a Related Person; or

        (ii)   any sale, lease, exchange, mortgage,  pledge,  transfer or  other
               disposition (in one transaction or a series of  transactions)  to
               or with any Related Person or any Affiliate of any Related Person
               of any  assets of the  Corporation  or any  Subsidiary  having an
               aggregate Fair Market Value in excess of ten percent (10%) of the
               Corporation's  total  stockholder's  equity as  reflected  on the
               Corporation's most recent audited financial statements; or

        (iii)  the issuance or transfer by the Corporation or any Subsidiary (in
               one transaction or a series of transactions) of any securities of
               the  Corporation  or any  Subsidiary to any Related Person or any
               Affiliate of any Related Person in exchange for cash,  securities
               or other property (or a combination  thereof) having an aggregate
               Fair  Market  Value  in  excess  of  ten  percent  (10%)  of  the
               Corporation's  total  stockholders'  equity as  reflected  on the
               Corporation's most recent audited financial statements; or






        (iv)   the  adoption  of any plan or  proposal  for the  liquidation  or
               dissolution  of the  Corporation  proposed by or on behalf of any
               Related Person or any Affiliate of any Related Person; or

        (v)    any  reclassification of securities  (including any reverse stock
               split), or recapitalization of the Corporation,  or any merger or
               consolidation  of the Corporation with any of its Subsidiaries or
               any other  transaction  (whether or not with or into or otherwise
               involving the Related  Person) which has the effect,  directly or
               indirectly,  of increasing the proportionate  share of securities
               of the  Corporation  or  any  Subsidiary  which  is  directly  or
               indirectly  owned by any Related  Person or any  Affiliate of any
               Related Person.

        (e)  "Continuing  Director"  shall  mean  any  member  of the  Board  of
Directors who is not an Affiliate of any Related  Person and who was a member of
the Board of Directors  prior to the time that any such Related  Person became a
Related Person,  and any successor of a Continuing  Director who is unaffiliated
with any Related Person and is recommended to succeed a Continuing Director by a
majority  of  the   Continuing   Directors  then  on  the  Board  of  Directors.
Notwithstanding the above, a majority of the then existing Continuing  Directors
can deem a new director to be a Continuing Director,  even though such person is
Affiliated with a Related Person.

        (f)  "Determination  Date"  shall mean the date upon which the  Business
Combination is consummated.

        (g) "Exchange  Act" shall mean the  Securities  Exchange Act of 1934, as
amended, from time to time.

        (h) "Fair  Market  Value"  shall  mean:  (i) in the case of  stock,  the
highest  closing sale price during the 30-day period  immediately  preceding the
date in  question  of a share  of such  stock  on the  principal  United  States
securities exchange or quotation system on which such stock is listed or quoted,
or, if no such price or quotations are available,  the highest closing bid price
of a share of such stock  during  such period on the  quotation  system on which
such stock is then quoted,  or, if no such  quotations are  available,  the fair
market value on the date in question of a share of such stock as  determined  by
the Board of  Directors  in good faith;  and (ii) in the case of property  other
than  cash or  stock,  the fair  market  value of such  property  on the date in
question as determined by the Board of Directors in good faith.

        (i)  "Person"  shall  mean  any  individual,  firm,  partnership,  joint
venture,  joint stock  company,  trust,  business  trust,  corporation,  limited
liability partnership, limited liability corporation, unincorporated association
or other entity of whatsoever nature.

        (j) "Related  Person" shall mean any Person (other than the Corporation,
any Subsidiary or any  individual  who was a stockholder  of the  Corporation on
July 31, 1996) which,  together with such Person's Affiliates and Associates and
with any other  Person  (other  than the  Corporation,  any  Subsidiary,  or any
individual who was a stockholder of the Corporation on July


                                      -2-



31,  1996) with  which  such  Person or they have  entered  into any  agreement,
arrangements or understanding with respect to acquiring, holding or disposing of
voting  stock,  acquires  beneficial  ownership (as defined in Rule 13d-3 of the
Exchange  Act,  except that such term shall  include any voting stock which such
person has the right to  acquire,  whether  or not such  right may be  exercised
within 60 days),  directly or  indirectly  of more than five percent (5%) of the
voting power of the outstanding voting stock after July 31, 1996.

        (k)  "Subsidiary"  shall mean any corporation in which a majority of the
capital stock  entitled to vote generally in the election of directors is owned,
directly or indirectly, by the Corporation.

        (l) "Voting Stock" shall mean all the then outstanding shares of capital
stock entitled to vote generally in the election of directors.

B.       CLASSIFICATION OF BOARD OF DIRECTORS AND RELATED MATTERS.

        (a) Number, Election and Terms of Directors

        1.  Subject to the rights of the holders of any class or series of stock
having a preference over the Corporation's  voting stock as to dividends or upon
liquidation to elect  additional  directors  under specific  circumstances,  the
number of directors shall be fixed from time to time exclusively by the Board of
Directors  pursuant  to a  resolution  adopted by a majority  of the  Continuing
Directors or by the  affirmative  vote of the holders of at least eighty percent
(80%) of the  shares  of voting  stock  outstanding,  voting  as a single  class
(whether or not there exist any vacancies in previously authorized directorships
at the time any such  resolution  is  presented  to the Board of  Directors  for
adoption). After the 1996 annual meeting of stockholders, the Board of Directors
shall  vote to cause the  directors,  other than those who may be elected by the
holder of any class or series of stock having a preference over the voting stock
as to dividends or upon liquidation, to be divided into three classes, as nearly
equal in number  as  possible,  with the term of  office  of the first  class to
expire at the 1997  annual  meeting of  stockholders,  the term of office of the
second class to expire at the 1998 annual meeting of  stockholders  and the term
of  office  of  the  third  class  to  expire  at the  1999  annual  meeting  of
stockholders.  At each annual  meeting of  stockholders  following  such initial
classification  and  election,  the  successors of those  directors  whose terms
expire at that meeting shall be elected by a plurality vote of all votes cast at
such  meeting  for a term of office to  expire  at the third  succeeding  annual
meeting  of  stockholders  after  their  election,   unless  by  reason  of  any
intervening  changes  in the  authorized  number  of  directors,  the  Board  of
Directors  shall  designate  one or more of the then  expired  directorships  as
directorships  of another  class in order more  nearly to  achieve  equality  of
number of directors among the classes.

        2. The  number of the Board of  Directors  may be changed by a vote of a
majority of the Continuing  Directors then in office or by the  stockholders  by
vote of eighty percent (80%) of the shares of voting stock  outstanding,  voting
as a single class.

        3.  Notwithstanding  the rule that the three  classes shall be as nearly
equal in number of  directors  as  possible,  in the event of any  change in the
authorized number of directors,  each 


                                      -3- 


director then  continuing  to serve as such,  shall  nevertheless  continue as a
director  of the  class  of which he is a member  until  the  expiration  of his
current term, or his prior death,  resignation or removal.  If any newly created
directorship  may,  consistent  with the rule that the three classes shall be as
nearly equal in number of  directors as possible,  be allocated to one of two or
more classes,  the Board of Directors shall allocate it to that of the available
classes  whose term of office is due to expire at the  earliest  date  following
such allocation.

        (b)     Newly Created Directorships and Vacancies

        Except  as  otherwise  provided  for  or  fixed  by or  pursuant  to the
provisions  of these  Articles  of  Organization  relating  to the rights of the
holders  of any class or series of stock  having a  preference  over the  voting
stock as to dividends or upon  liquidation to elect  directors  under  specified
circumstances,  newly created  directorships  resulting from any increase in the
number of directors and any vacancies on the Board of Directors  resulting  from
death,  resignation,  disqualification,  removal or other  cause shall be filled
only by the  affirmative  vote of a  majority  of a majority  of the  Continuing
Directors,  even  though  less  than a quorum  of the  Board of  Directors.  Any
director elected in accordance with the preceding sentence shall hold office for
the  remainder  of the full  term of the  class of  directors  in which  the new
directorship  was  created or the  vacancy  occurred  and until such  director's
successor  shall have been elected and  qualified.  No decrease in the number of
directors shall shorten the term of an incumbent director.

        (c)     Removal

        Subject  to the  rights of the  holders  of any class or series of stock
having a preference over the voting stock as to dividends or upon liquidation to
elect additional  directors under specified  circumstances,  any director may be
removed from office with or without  cause only by the  affirmative  vote of the
holders of at least eighty  percent  (80%) of the  combined  voting power of the
outstanding shares of voting stock, voting together as a single class.

        (d)     Amendment, Repeal or Alteration

        Notwithstanding  anything contained in these Articles of Organization to
the contrary,  the  affirmative  vote of the holders of at least eighty  percent
(80%) of the  outstanding  shares of voting stock,  voting  together as a single
class,  shall be required to alter,  change,  amend or repeal this  Section B of
Article 6 or to adopt any provision  inconsistent with this Section B of Article
6.

C.       FAIR PRICE PROVISION.

         1. In addition to the affirmative vote otherwise required by law or any
provision of these  Articles of  Organization,  except as otherwise  provided in
Section 2 of this Section C of Article 6, any Business Combination shall require
the  affirmative  vote of the holders of eighty  percent  (80%) of the  combined
voting power of all Voting Stock voting together as a single class.

         Such  affirmative  vote  shall be  required  notwithstanding  any other
provisions of these Articles of Organization,  or any provision of law or of any
agreement with any national 


                                      -4-


securities  exchange which might otherwise  permit a lesser vote or no vote, and
such  affirmative  vote of the  holders  of the  combined  voting  power  of the
outstanding  shares of any  particular  class or series of the  Voting  Stock or
other capital stock required by law or by these Articles of Organization.

         2.  The  provisions  of  Section  1 of  this  Section  C  shall  not be
applicable in respect of a Business Combination if, in the case of such Business
Combination that does not involve any consideration received by the stockholders
of the Corporation, solely in their respective capacities as stockholders of the
Corporation,  the condition  specified in paragraph (a) below is met, or, in the
case of any other Business  Combination,  the conditions  specified in either of
paragraphs (a) or (b) below are met; in which event,  such Business  Combination
shall  require  only such  affirmative  vote as is  required  by law,  any other
provision of these Articles of Organization,  or any agreement with any national
securities exchange, as the case may be:

         (a) The Business  Combination shall have been approved by a majority of
the Continuing  Directors,  it being understood that this condition shall not be
capable of satisfaction unless there is at least one Continuing Director.

         (b) All of the following conditions shall have been met:

             (i) The form of the consideration  received by holders of shares of
a particular  class of outstanding  Voting Stock shall be in cash or in the same
form as the  Related  Person has paid for  shares of such class of Voting  Stock
within the two-year period ending on and including the  Determination  Date. If,
within such two-year period, the Related Person has paid for shares of any class
of Voting Stock with varying forms of  consideration,  the form of consideration
received  per share by holders of shares of such class of voting  stock shall be
either  cash or the form used to acquire  the  largest  number of shares of such
class of Voting  Stock  acquired by the  Related  Person  within  such  two-year
period.

             (ii) The aggregate  amount of  consideration  received per share by
holders of each class of Voting Stock in such Business  Combination  shall be at
least  equal  to the  higher  of the  following  (it  being  intended  that  the
requirements  of this paragraph  (b)(ii) shall be met with respect to every such
class of  Voting  Stock  outstanding,  whether  or not the  Related  Person  has
previously acquired any shares of that particular class of Voting Stock):

                  (a) (if applicable) the highest per share price (including any
                  brokerage  commission,  transfer taxes and soliciting dealers'
                  fees) paid by the Related  Person for any shares of that class
                  of Voting  Stock  acquired  by it within the  two-year  period
                  immediately   prior  to  the  Announcement   Date  or  in  the
                  transaction in which it became a Related Person,  whichever is
                  higher; or

                  (b) the Fair Market  Value per share of such  Voting  Stock on
                  the Announcement Date; or

                  (c) in the case of any class of Preferred  Stock,  the highest
                  preferential  amount per share to which the  holders of shares
                  of such class of Voting Stock are entitled 


                                      -5-

                  in the  event of any  voluntary  or  involuntary  liquidation,
                  dissolution or winding up of the Corporation;

             (iii)  After such  Related  Person has become a Related  Person and
prior to the consummation of such Business Combination:

                  (a)  except  as  approved  by a  majority  of  the  Continuing
                  Directors, there shall have been no failure to declare and pay
                  at the regular  date  therefor  any full  quarterly  dividends
                  (whether  or  not  cumulative)  on any  outstanding  Preferred
                  Stock;

                  (b) there shall have been (I) no  reduction in the annual rate
                  of dividends  paid on the Common Stock (except as necessary to
                  reflect  any  subdivision  of the  Common  Stock),  except  as
                  approved by a majority of the Continuing  Directors,  and (II)
                  an increase in such annual rate of  dividends  as necessary to
                  reflect any  reclassification  (including  any  reverse  stock
                  split,   recapitalization,   reorganization   or  any  similar
                  transaction  which has the  effect of  reducing  the number of
                  outstanding shares of the Common Stock), unless the failure so
                  to increase  such annual  rate of  dividends  is approved by a
                  majority of the Continuing Directors;

                  (c) such Related  Person shall not have become the  beneficial
                  owner of any newly issued  shares of Voting Stock  directly or
                  indirectly  from  the  Corporation   except  as  part  of  the
                  transaction  which results in such Related  Person  becoming a
                  Related Person;

                  (d) after such  Related  Person  has become a Related  Person,
                  such  Related  Person  shall not have  received  the  benefit,
                  directly or indirectly (except proportionately, solely in such
                  Related   Person's   capacity   as  a   stockholder   of   the
                  Corporation), of any loans, advances,  guarantees,  pledges or
                  other  financial  assistance  or any tax  credits or other tax
                  advantages   provided   by   the   Corporation,   whether   in
                  anticipation   of  or  in   connection   with  such   Business
                  Combination or otherwise; and

                  (e) a proxy or information  statement  describing the proposed
                  Business  Combination  and complying with the  requirements of
                  the Exchange Act and the rules and regulations  thereunder (or
                  any  subsequent   provisions  replacing  such  Act,  rules  or
                  regulations)  shall  be  mailed  to  all  stockholders  of the
                  Corporation at least 30 days prior to the consummation of such
                  Business Combination (whether or not such proxy or information
                  statement  is required to be mailed  pursuant to the  Exchange
                  Act or  subsequent  provisions).  Such  proxy  or  information
                  statement  shall  contain  on the front  thereof,  prominently
                  displayed,  any  recommendation  as  to  the  advisability  or
                  inadvisability   of  the   Business   Combination   which  the
                  Continuing  Directors,  or any of them,  may have furnished in
                  writing  to the Board of  Directors  and/or  shall  contain an
                  opinion by an investment banking firm,  selected by a majority
                  of  the   Continuing   Directors,   as  to


                                      -6-

                  the fairness (or  unfairness)  of the Business  Combination to
                  the  stockholders of the  Corporation,  other than the Related
                  Person.

         3. A majority of the total number of  Continuing  Directors  shall have
the power and duty to  determine,  on the  basis of  information  known to them,
after reasonable inquiry,  all facts necessary to determine compliance with this
Section E of Article 6 including,  without limitation, (i) whether a person is a
Related Person,  (ii) the number of shares of voting stock beneficially owned by
any person,  (iii) whether the applicable  conditions set forth in paragraph (b)
of subsection 2 have been met with respect to any Business Combination, and (iv)
whether the assets  which are the  subject of any  Business  Combination  or the
consideration  received  for the  issuance  or  transfer  of  securities  by the
Corporation or any Subsidiary in any Business Combination have an aggregate Fair
Market  Value  in  excess  of  ten  percent  (10%)  of the  Corporation's  total
stockholders'  equity as  reflected  on the  Corporation's  most recent  audited
financial statements.

         4. Nothing  contained in this Section E of Article 6 shall be construed
to relieve any Related Person from any fiduciary obligation imposed by law.

         5. Notwithstanding anything contained in these Articles of Organization
to the contrary,  the affirmative vote of the holders of at least eighty percent
(80%) of the combined  voting power of all Voting  Stock,  voting  together as a
single  class,  shall be required to amend or repeal this Section C, or to adopt
any provision inconsistent herewith.

         6. In the  event of any  inconsistencies  between  this  Section  C and
Chapter 110 F of the Massachusetts  General Laws, the provisions of this Section
C shall control.

D.      BY-LAWS.

        The By-laws may provide that the directors may make, amend or repeal the
By-laws in whole or in part,  except with respect to any provision thereof which
by law or the By-laws requires action by the stockholders.

E.      MEETINGS.

        Meetings of the  stockholders of the corporation may be held anywhere in
the United States.

F.      ACTING AS PARTNER.

        The  corporation  may be a general  or limited  partner in any  business
enterprise it would have power to conduct by itself.

G.      INDEMNIFICATION.

        The corporation may provide,  either in the corporation's  By-laws or by
contract, for the indemnification of directors,  officers, employees and agents,
by whomever elected or appointed, 


                                      -7-



to the full  extent  presently  permitted  by law;  provided,  however,  that if
applicable  law is hereafter  modified to permit  indemnification  in situations
where  it  was  not  theretofor  permitted,  then  such  indemnification  may be
permitted to the full extent permitted by such law as amended.

H.      TRANSACTIONS WITH INTERESTED PERSONS.

        The  By-laws  may  contain  provisions  providing  that no  contract  or
transaction of the  corporation  shall be void or voidable by reason of the fact
that any officer,  director or stockholder of the  corporation  may have held an
interest therein.

I.      REPURCHASES BY CORPORATION.

        The  corporation  may from time to time offer to purchase  and  purchase
shares from any  stockholder of the corporation  upon fair and reasonable  terms
and at a fair  and  reasonable  price,  whether  or not the  stockholder  owns a
controlling  interest  in  the  corporation,   without  offering  to  any  other
stockholder an equal opportunity to sell a ratable number, or any, of his shares
of stock in the  corporation to the corporation  upon  comparable  terms or at a
comparable  price,  or to  make  any  offer  to  purchase  whatsoever  to  other
stockholders of the corporation.

J.      ELIMINATION OF DIRECTORS' PERSONAL LIABILITY.

        No  director  shall  be  personally  liable  to the  corporation  or its
stockholders  for monetary  damages for breach of  fiduciary  duty as a director
notwithstanding any provision of law imposing such liability; provided, however,
that this provision 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
sixty-one or sixty-two of Chapter 156B of the  Massachusetts  General  Laws,  or
(iv) for any transaction  from which the director  derived an improper  personal
benefit.  No amendment to or repeal of this paragraph shall apply to or have any
effect on the liability or alleged  liability of any director of the Corporation
for or with respect to any acts or omissions of such director occurring prior to
the date of such amendment or repeal.



                                      -8-



*We further certify that the foregoing restated articles of organization  effect
no amendments to the articles of organization  of the corporation  as heretofore
amended, except amendments to the following articles
                                                    ----------------------------
                             3, 4 and 6
- --------------------------------------------------------------------------------
    (*If there are no such amendments, state "None".)




                              Briefly describe amendments in space below:


          Article 3 is amended to increase and change the authorized capital and
          Article 4 is amended to describe the new classes of stock.

          Article 6 is  amended to change the other  lawful  provisions  for the
          conduct and regulation of the business and affairs of the Corporation.










IN WITNESS WHEREOF AND UNDER THE PENALTIES OF PERJURY, we have hereto signed our
names this    5th     day of      September        in the year 1996


Richard T. Schumacher     /s/ Richard T. Schumacher                    President
- -----------------------------------------------------------------------
Howard L. Levin           /s/ Howard L. Levin                             Clerk 
- -----------------------------------------------------------------------








                        THE COMMONWEALTH OF MASSACHUSETTS

                        RESTATED ARTICLES OF ORGANIZATION
                    (GENERAL LAWS, CHAPTER 156B, SECTION 74)

                    I hereby  approve  the  within  restated
                    articles of organization and, the filing
                    fee in the  amount of  $________  having
                    been   paid,  said  articles are  deemed
                    to have  been  filed  with  me this__day
                    of_________ , 19__.





                                      MICHAEL JOSEPH CONNOLLY
                                         Secretary of State














                         TO BE FILLED IN BY CORPORATION
           PHOTO COPY OF RESTATED ARTICLES OF ORGANIZATION TO BE SENT

                    TO:
                         Howard L. Levin, Esquire
                    -------------------------------------------------
                         Brown, Rudnick, Freed & Gesmer, P.C.
                    -------------------------------------------------
                          One Financial Center, Boston, MA 0211l
                    -------------------------------------------------
                    Telephone   (617) 856-8200
                             ----------------------------------------

                                                          Copy Mailed



                                                                     EXHIBIT 3.2




                                     BY-LAWS

                                       OF

                             BOSTON BIOMEDICA, INC.

                           A MASSACHUSETTS CORPORATION
















                           Adopted:       May 5, 1986
   
                           -------------------------------------
                           Howard L. Levin, Clerk

                           Amended:       December 5, 1990
                           Amended and Restated:  September 5, 1996
 
                                                       









                                     BY-LAWS
                                TABLE OF CONTENTS

ARTICLE I.  STOCKHOLDERS....................................................1

         Section 1.1. Annual Meeting........................................1
         Section 1.2. Special Meetings......................................1
         Section 1.3. Notice of Meeting.....................................1
         Section 1.4. Quorum................................................2
         Section 1.5. Voting and Proxies....................................2
         Section 1.6. Action at Meeting.....................................2
         Section 1.7. Action Without Meeting................................2
         Section 1.8. Voting of Shares of Certain Holders...................2
         Section 1.9. Meetings..............................................3

ARTICLE II.  BOARD OF DIRECTORS.............................................3

         Section 2.1. Powers................................................3
         Section 2.2. Enumeration, Election and Term of Office..............3
         Section 2.3. Nomination of Directors...............................4
         Section 2.4. Election of Directors.................................5
         Section 2.5. Vacancies; Reduction of the Board.....................5
         Section 2.6. Enlargement of the Board..............................5
         Section 2.7. Tenure and Resignation................................5
         Section 2.8. Removal...............................................5
         Section 2.9. Meetings..............................................5
         Section 2.10. Notice of Meeting....................................6
         Section 2.11. Agenda...............................................6
         Section 2.12. Quorum...............................................6
         Section 2.13. Action at Meeting....................................6
         Section 2.14. Action Without Meeting...............................6
         Section 2.15. Committees...........................................6

ARTICLE III.  OFFICERS......................................................7

         Section 3.1. Enumeration...........................................7
         Section 3.2. Election..............................................7
         Section 3.3. Qualification.........................................7
         Section 3.4. Tenure................................................7
         Section 3.5. Removal...............................................7
         Section 3.6. Resignation...........................................7
         Section 3.7. Vacancies.............................................8
         Section 3.8. President.............................................8
         Section 3.9. Vice-Presidents.......................................8
         Section 3.10. Treasurer and Assistant Treasurers...................8
         Section 3.11. Clerk and Assistant Clerks...........................8
         Section 3.12. Other Powers and Duties..............................9

                                       -i-





ARTICLE IV.  STOCK CERTIFICATES.............................................9

         Section 4.1. Stock Certificates....................................9
         Section 4.2. Transfer of Shares....................................9
         Section 4.3. Record Holders........................................9
         Section 4.4. Record Date..........................................10
         Section 4.5. Transfer Agent and Registrar for Shares of 
                      Corporation..........................................10
         Section 4.6. Loss of Certificates.................................11
         Section 4.7. Restrictions on Transfer.............................11
         Section 4.8. Multiple Classes of Stock............................11

ARTICLE V.  DIVIDENDS......................................................11

         Section 5.1. Declaration of Dividends.............................11
         Section 5.2. Reserves.............................................11

ARTICLE VI.  POWERS OF OFFICERS TO CONTRACT WITH THE CORPORATION...........12


ARTICLE VII.  INDEMNIFICATION..............................................12

         Section 7.1. Definitions..........................................12
         Section 7.2. Actions in Name of the Corporation or Stockholder....13
         Section 7.3. Other Actions........................................13
         Section 7.4. Advances of Expenses.................................14
         Section 7.5. Presumptions upon Termination of Proceeding..........14
         Section 7.6. Indemnification Not Exclusive........................14
         Section 7.7. Insurance............................................14
         Section 7.8. Employee Benefit Plans...............................14

ARTICLE VIII.  MISCELLANEOUS PROVISIONS....................................14

         Section 8.1. Articles of Organization.............................15
         Section 8.2. Fiscal Year..........................................15
         Section 8.3. Corporate Seal.......................................15
         Section 8.4. Execution of Instruments.............................15
         Section 8.5. Voting of Securities.................................15
         Section 8.6. Evidence of Authority................................15
         Section 8.7. Corporate Records....................................15
         Section 8.8. Charitable Contributions.............................15
         Section 8.9. Election in Respect of Control Share Acquisitions....16

ARTICLE IX.  AMENDMENTS....................................................16

         Section 9.1. Amendment by Stockholders............................16
         Section 9.2. Amendment by Board of Directors......................17


                                      -ii-




                                     BY-LAWS

                                       OF

                             BOSTON BIOMEDICA, INC.
                          (A Massachusetts Corporation)

                                   ARTICLE I.

                                  Stockholders

         Section 1.1. Annual Meeting.  The annual meeting of the stockholders of
the  corporation  shall be held on the first  Tuesday of April in each year,  at
such time and place within the United  States as may be designated in the notice
of  meeting.  If the day  fixed for the  annual  meeting  shall  fall on a legal
holiday,  the  meeting  shall  be held on the  next  succeeding  day not a legal
holiday. If the annual meeting is omitted on the day herein provided,  a special
meeting  may be held in  place  thereof,  and any  business  transacted  at such
special  meeting  in lieu of annual  meeting  shall  have the same  effect as if
transacted or held at the annual meeting.

         Section 1.2. Special Meetings. Special meetings of the stockholders may
be called at any time by the president or by the board of directors and shall be
called by the clerk upon written  application  of one or more  stockholders  who
hold  shares  representing  at least  ten  percent  (10%) of the  capital  stock
entitled to vote at such meeting.  Special meetings of the stockholders shall be
held at such time,  date and place within or without the United States as may be
designated in the notice of such meeting.

         Section 1.3.  Notice of Meeting.  A written  notice  stating the place,
date,  and  hour of each  meeting  of the  stockholders,  and,  in the case of a
special meeting, the purposes for which the meeting is called, shall be given to
each stockholder  entitled to vote at such meeting, and to each stockholder who,
under the Articles of Organization or these By-laws, is entitled to such notice,
by  delivering  such notice to such person or leaving it at their  residence  or
usual place of business,  or by mailing it,  postage  prepaid,  and addressed to
such stockholder at his address as it appears upon the books of the corporation,
at least  seven (7) days and not more than sixty (60) before the  meeting.  Such
notice shall be given by the clerk, an assistant  clerk, or any other officer or
person  designated  either by the clerk or by the person or persons  calling the
meeting.

         The requirement of notice to any stockholder may be waived by a written
waiver of notice, executed before or after the meeting by the stockholder or his
attorney  thereunto duly authorized,  and filed with the records of the meeting,
or if communication  with such stockholder is unlawful,  or by attendance at the
meeting  without  protesting  prior thereto or at its  commencement  the lack of
notice. Except as otherwise provided herein, the notice to the stockholders need
not specify the purposes of the meeting.

                                      -1-


         If a meeting is adjourned to another time or place,  notice need not be
given of the  adjourned  meeting  if the time and  place  are  announced  at the
meeting at which the adjournment is taken, except that if the adjournment is for
more than thirty days,  or if after the  adjournment  a new record date is fixed
for the adjourned  meeting,  notice of the  adjourned  meeting shall be given to
each stockholder of record entitled to vote at the meeting.

         Section 1.4. Quorum. The holders of a majority in interest of all stock
issued, outstanding and entitled to vote at a meeting shall constitute a quorum.
Any  meeting  may be  adjourned  from  time to time by a  majority  of the votes
properly cast upon the question, whether or not a quorum is present.

         Section 1.5. Voting and Proxies.  Each stockholder  shall have one vote
for each share of stock  entitled  to vote owned by such  stockholder  of record
according to the books of the corporation,  unless otherwise  provided by law or
by the Articles of  Organization.  Stockholders  may vote either in person or by
written  proxy.  No proxy  dated more than six  months  prior to the date of the
meeting shall be valid although, unless otherwise limited therein, proxies shall
entitle  the  persons  authorized  thereby  to vote at any  adjournment  of such
meeting.  Proxies  shall be  filed  with the  clerk  of the  meeting,  or of any
adjournment  thereof.  A proxy  purporting  to be  executed by or on behalf of a
stockholder  shall be deemed valid unless challenged at or prior to its exercise
and the burden of proving invalidity shall rest on the challenger.  A proxy with
respect  to  stock  held in the  name of two or more  persons  shall be valid if
executed  by one of them  unless  at or  prior  to  exercise  of the  proxy  the
corporation  receives a specific  written notice to the contrary from any one of
them.

         Section  1.6.  Action  at  Meeting.  When a quorum  is  present  at any
meeting, a plurality of the votes properly cast for election to any office shall
elect to such  office,  and a  majority  of the  votes  properly  cast  upon any
question  other than  election to an office shall decide such  question,  except
where a larger vote is required by law,  the Articles of  Organization  or these
by-laws.  No ballot  shall be required for any  election  unless  requested by a
stockholder  present or  represented  at the meeting and entitled to vote in the
election.

         Section 1.7. Action Without  Meeting.  Any action required or permitted
to be taken at any meeting of the stockholders may be taken without a meeting if
all stockholders entitled to vote on the matter consent to the action in writing
and the consent shall be treated for all purposes as a vote at a meeting.

         Section 1.8.  Voting of Shares of Certain  Holders.  Shares of stock of
the  corporation  standing  in the  name of  another  corporation,  domestic  or
foreign,  may be voted by such officer,  agent,  or proxy as the by-laws of such
corporation may prescribe, or, in the absence of such provision, as the board of
directors of such corporation may determine.

         Shares of stock of the  corporation  standing in the name of a deceased
person,  a  minor  ward  or  an  incompetent   person,   may  be  voted  by  his
administrator,  executor,  court-appointed  guardian  or  conservator  without a
transfer  of such shares into the name of such  administrator,  executor,  court
appointed  guardian or  conservator.  Shares of capital stock of the corporation
standing in the name of a trustee may be voted by him.

                                      -2-


         Shares of stock of the  corporation  standing in the name of a receiver
may be voted by such  receiver,  and  shares  held by or under the  control of a
receiver may be voted by such  receiver  without the  transfer  thereof into his
name if authority so to do be contained in an appropriate  order of the court by
which such receiver was appointed.

         A  stockholder  whose shares are pledged shall be entitled to vote such
shares until the shares have been transferred into the name of the pledgee,  and
thereafter the pledgee shall be entitled to vote the shares so transferred.

         Shares  of its own stock  belonging  to this  corporation  shall not be
voted,  directly  or  indirectly,  at any  meeting  and shall not be  counted in
determining the total number of outstanding shares at any given time, but shares
of its own stock held by the  corporation  in a fiduciary  capacity may be voted
and shall be counted in determining the total number of outstanding shares.

         Section 1.9.  Meetings.  Special  meetings of the  stockholders  may be
called  at any  time by the  President  or by the  Board of  Directors.  Special
meetings of the stockholders shall be called by the Clerk, or in the case of the
death,  absence,  incapacity or refusal of the Clerk, by any other officer, upon
written  application by one or more  stockholders  who hold at least 50% of each
class of stock outstanding and entitled to vote at such meeting. Such call shall
state the time, place and purposes of the meeting.

                                   ARTICLE II.

                               Board of Directors

         Section 2.1. Powers.  Except as reserved to the stockholders by law, by
the  Articles  of  Organization  or  by  these  By-laws,  the  business  of  the
corporation shall be managed under the direction of the board of directors,  who
shall have and may exercise all of the powers of the corporation. In particular,
and without limiting the foregoing,  the board of directors shall have the power
to issue or reserve for issuance  from time to time the whole or any part of the
capital stock of the  corporation  which may be authorized  from time to time to
such person,  for such  consideration and upon such terms and conditions as they
shall  determine,  including the granting of options,  warrants or conversion or
other rights to stock.

         Section 2.2.  Enumeration,  Election and Term of Office.  The number of
Directors  on the Board of  Directors  shall be  determined  as  provided in the
Articles of Organization of the Corporation. No Director need be a Stockholder.

         The Directors of the  Corporation  shall be divided into three classes:
Class I, Class II and Class III.  Each class  shall  consist as nearly as may be
possible,  of one-third of the whole  number of the Board of  Directors.  In the
election of Directors at the 1996 Annual  Meeting of  Stockholders,  the Class I
Directors  shall be  elected  to hold  office  for a term to expire at the first
Annual  Meeting of  Stockholders  thereafter;  the Class II  Directors  shall be
elected  to hold  office for a term to expire at the  second  Annual  Meeting of
Stockholders  thereafter;  and the Class III Directors  shall be elected to hold
office  for a term  to  expire  at the  third  Annual  Meeting  of 


                                      -3-




Stockholders  thereafter;  and in the case of each class, until their respective
successors  are duly elected and qualified.  At each annual  election held after
the 1996 Annual Meeting of Stockholders,  the Directors elected to succeed those
whose terms expire shall be  identified as being the same class as the Directors
they  succeed  and shall be elected  to hold  office for a term to expire at the
third  Annual  Meeting of  Stockholders  after their  election,  and until their
respective successors are duly elected and qualified. If the number of Directors
changes,  any increase or decrease in Directors  shall be apportioned  among the
classes so as to maintain all classes as nearly equal in number as possible, and
any additional  Director elected to any class shall hold office for a term which
shall coincide with the terms of the other Directors in such class and until his
successor is duly elected and qualified.

         Any vacancy in the Board of Directors,  however occurring,  including a
vacancy  resulting  from the  enlargement  of the Board of  Directors,  shall be
filled as provided in the Articles of Organization of the Corporation. The Board
of Directors may be enlarged as provided in the Articles of  Organization of the
Corporation.  A Director,  whether elected by the stockholders or Directors, may
be removed from office in the manner provided by the Articles of Organization of
the Corporation.

         Section 2.3.  Nomination of Directors.  Nominations for the election of
directors at an annual meeting of the  stockholders,  or special meeting in lieu
of the annual  meeting,  may be made by the Board of  Directors  or a  committee
appointed by the Board of Directors  or by any  stockholder  entitled to vote in
the election of directors at the meeting.  Stockholders entitled to vote in such
election may  nominate  one or more  persons for  election as directors  only if
written  notice  of  such  stockholder's  intent  to  make  such  nomination  or
nominations has been given either by personal  delivery,  overnight  (receipted)
courier  or by  United  States  mail,  postage  prepaid,  to  the  Clerk  of the
Corporation  not later than  ninety  days prior to the  anniversary  date of the
immediately  preceding  annual meeting or special meeting in lieu thereof.  Such
notice shall set forth:  (a) the name and address of the stockholder who intends
to make the  nomination  and of the  persons  or person to be  nominated;  (b) a
representation  that the  stockholder  is a  holder  of  record  of stock of the
Corporation  entitled to vote at such meeting and intends to appear in person or
by proxy at the  meeting to  nominate  the person or  persons  specified  in the
notice;  (c) 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;  (d) such other information  regarding each nominee 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;  and (e)
the  consent of each  nominee to serve as a director  of the  Corporation  if so
elected.  The  presiding  officer of the meeting may refuse to  acknowledge  the
nomination of any person not made in compliance with the foregoing procedure

         Section  2.4.  Election of  Directors.  The initial  board of directors
shall be  elected  by the  incorporator(s)  at the  first  meeting  thereof  and
thereafter by the stockholders at their annual meeting or at any special meeting
the notice of which  specifies  the election of directors as an item of business
for such meeting.

                                      -4-




         Section  2.5.  Vacancies;  Reduction  of the Board.  Any vacancy in the
board of directors,  however  occurring,  including a vacancy resulting from the
enlargement of the board of directors,  may be filled by the  stockholders or by
the directors then in office or by a sole remaining director. In lieu of filling
any such vacancy the stockholders or board of directors may reduce the number of
directors,  but not to a number less than the minimum number required by Section
2.2.  When one or more  directors  shall  resign  from the  board of  directors,
effective  at a  future  date,  a  majority  of the  directors  then in  office,
including  those who have so resigned,  shall have power to fill such vacancy or
vacancies, the vote thereon to take effect when such resignation or resignations
shall become effective.

         Section 2.6.  Enlargement  of the Board.  The board of directors may be
enlarged  by the  stockholders  at any  meeting or by vote of a majority  of the
directors then in office.

         Section 2.7. Tenure and  Resignation.  Except as otherwise  provided by
law, by the Articles of Organization  or by these By-laws,  directors shall hold
office until the next annual meeting of stockholders  and thereafter until their
successors  are chosen and  qualified.  Any director may resign by delivering or
mailing  postage  prepaid  a  written  resignation  to  the  corporation  at its
principal  office or to the president,  clerk or assistant  clerk,  if any. Such
resignation  shall be  effective  upon  receipt  unless  it is  specified  to be
effective at some other time or upon the happening of some other event.

         Section 2.8. Removal.  A director,  whether elected by the stockholders
or directors,  may be removed from office with or without cause at any annual or
special  meeting  of  stockholders  by vote of a  majority  of the  stockholders
entitled to vote in the election of such  director,  or for cause by a vote of a
majority of the directors then in office; provided, however, that a director may
be removed for cause only after  reasonable  notice and  opportunity to be heard
before the body proposing to remove him.

         Section 2.9.  Meetings.  Regular meetings of the board of directors may
be held without  call or notice at such times and such places  within or without
the  Commonwealth  of  Massachusetts  as the  board  may,  from  time  to  time,
determine,  provided that notice of the first regular meeting following any such
determination  shall be given to  directors  absent from such  determination.  A
regular  meeting  of the  board  of  directors  shall  be  held  without  notice
immediately  after,  and at  the  same  place  as,  the  annual  meeting  of the
stockholders  or the special meeting of the  stockholders  held in place of such
annual  meeting,  unless a quorum of the directors is not then present.  Special
meetings  of the  board of  directors  may be held at any time and at any  place
designated in the call of the meeting when called by the  president,  treasurer,
or one or more  directors.  Members of the board of directors  or any  committee
elected thereby may participate in a meeting of (amended such board or committee
by means of a conference telephone or 12/5/90) similar communications  equipment
by means of which all persons  participating  in the meeting can hear each other
at the same time, and  participation by such means shall constitute  presence in
person at the meeting.

         Section 2.10.  Notice of Meeting.  It shall be  sufficient  notice to a
director  to send  notice by mail at least  seventy-two  (72)  hours  before the
meeting  addressed  to such  person  at his  usual

                                      -5-



or last known business or residence  address or to give notice to such person in
person or by  telephone  at least  twenty-four  (24) hours  before the  meeting.
Notice shall be given by the clerk,  assistant  clerk, if any, or by the officer
or directors calling the meeting.  The requirement of notice to any director may
be waived by a written waiver of notice, executed by such person before or after
the  meeting or  meetings,  and filed with the  records  of the  meeting,  or by
attendance  at  the  meeting  without   protesting   prior  thereto  or  at  its
commencement  the lack of notice.  A notice or waiver of notice of a  directors'
meeting need not specify the purposes of the meeting.

         Section  2.11.  Agenda.  Any lawful  business  may be  transacted  at a
meeting of the board of directors,  notwithstanding  the fact that the nature of
the  business  may not have been  specified in the notice or waiver of notice of
the meeting.

         Section  2.12.  Quorum.  At any  meeting of the board of  directors,  a
majority  of the  directors  then in office  shall  constitute  a quorum for the
transaction of business. Any meeting may be adjourned by a majority of the votes
cast upon the question,  whether or not a quorum is present, and the meeting may
be held as adjourned without further notice.

         Section  2.13.  Action at  Meeting.  Any motion  adopted by vote of the
majority  of the  directors  present  at a meeting  at which a quorum is present
shall be the act of the board of  directors,  except  where a different  vote is
required by law, by the Articles of Organization or by these By-laws. The assent
in writing of any director to any vote or action of the  directors  taken at any
meeting, whether or not a quorum was present and whether or not the director had
or waived  notice of the meeting,  shall have the same effect as if the director
so  assenting  was  present at such  meeting  and voted in favor of such vote or
action.

         Section 2.14.  Action Without Meeting.  Any action by the directors may
be taken  without a meeting  if all of the  directors  consent  to the action in
writing and the consents are filed with the records of the directors'  meetings.
Such consent  shall be treated for all purposes as a vote of the  directors at a
meeting.

         Section  2.15.   Committees.   The  board  of  directors  may,  by  the
affirmative  vote of a majority  of the  directors  then in  office,  appoint an
executive committee or other committees  consisting of one or more directors and
may by vote  delegate to any such  committee  some or all of their powers except
those which by law, the Articles of  Organization  or these By-laws they may not
delegate.  Unless  the board of  directors  shall  otherwise  provide,  any such
committee may make rules for the conduct of its business,  but unless  otherwise
provided by the board of directors or such rules,  its meetings shall be called,
notice given or waived,  its business conducted or its action taken as nearly as
may be in the same  manner as is  provided  in these  By-laws  with  respect  to
meetings or for the conduct of business or the taking of actions by the board of
directors. The board of directors shall have power at any time to fill vacancies
in, change the  membership  of, or discharge any such committee at any time. The
board of directors shall have power to rescind any action of any committee,  but
no such rescission shall have retroactive effect.

                                  ARTICLE III.

                                      -6-


                                    Officers

         Section 3.1. Enumeration.  The officers shall consist of a president, a
treasurer,  a clerk and such other  officers and agents  (including  one or more
vice-presidents,   assistant  treasurers,   assistant  clerks,  secretaries  and
assistant  secretaries),  with such duties and powers, as the board of directors
may, in their discretion, determine.

         Section 3.2.  Election.  The  president,  treasurer  and clerk shall be
elected  annually by the directors at their first  meeting  following the annual
meeting of the  stockholders.  Other  officers may be chosen by the directors at
such meeting or at any other meeting.

         Section 3.3. Qualification. An officer may, but need not, be a director
or stockholder  and no officer shall be a director  solely by virtue of being an
officer. Any two or more offices may be held by the same person. The clerk shall
be a resident  of  Massachusetts  unless the  corporation  has a resident  agent
appointed for the purpose of service of process.  Any officer may be required by
the  directors  to give bond for the faithful  performance  of his duties to the
corporation  in  such  amount  and  with  such  sureties  as the  directors  may
determine. The premiums for such bonds may be paid by the corporation.

         Section 3.4.  Tenure.  Except as otherwise  provided by the Articles of
Organization  or these By-laws,  the term of office of each officer shall be for
one year or until his successor is qualified or until his earlier resignation or
removal.

         Section 3.5. Removal.  Any officer may be removed from office,  with or
without cause,  by the  affirmative  vote of a majority of the directors then in
office;  provided,  however, that an officer may be removed for cause only after
reasonable notice and opportunity to be heard by the board of directors prior to
action thereon.

         Section  3.6.  Resignation.  Any  officer may resign by  delivering  or
mailing  postage  prepaid  a  written  resignation  to  the  corporation  at its
principal  office or to the president,  clerk,  or assistant  clerk, if any, and
such  resignation  shall be effective  upon receipt unless it is specified to be
effective at some other time or upon the happening of some event.

         Section 3.7. Vacancies.  A vacancy in any office arising from any cause
may be filled for the unexpired portion of the term by the board of directors.

         Section 3.8.  President.  The  president  shall be the chief  executive
officer of the corporation. Except as otherwise voted by the board or directors,
the president shall preside at all meetings of the stockholders and of the board
of directors at which present.  The president  shall have such duties and powers
as are  commonly  incident to the office and such duties and powers as the board
of directors shall from time to time designate.

         Section 3.9. Vice-Presidents.  Vice-presidents, if any, shall have such
powers and perform such duties as the board of  directors  may from time to time
determine.

                                      -7-



         Section  3.10.  Treasurer  and  Assistant  Treasurers.  The  treasurer,
subject to the direction and under the  supervision  and control of the board of
directors,   shall  have  general  charge  of  the  financial   affairs  of  the
corporation.  The  treasurer  shall have  custody of all funds,  securities  and
valuable  papers  of the  corporation,  except  as the  board of  directors  may
otherwise  provide.  The  treasurer  shall  keep or  cause  to be kept  full and
accurate records of account which shall be the property of the corporation,  and
which  shall be  always  open to the  inspection  of each  elected  officer  and
director  of the  corporation.  The  treasurer  shall  deposit  or  cause  to be
deposited all funds of the corporation in such depository or depositories as may
be authorized by the board of directors.  The treasurer  shall have the power to
endorse  for  deposit  or  collection  all  notes,  checks,  drafts,  and  other
negotiable instruments payable to the corporation.  The treasurer shall have the
power to borrow  money and enter into and execute  arrangements  as to advances,
loans and credits to the  corporation.  The  treasurer  shall perform such other
duties as are incidental to the office, and such other duties as may be assigned
by the board of directors.

         Assistant  treasurers,  if any, shall have such powers and perform such
duties as the board of directors may from time to time determine.

         Section 3.11. Clerk and Assistant  Clerks.  The clerk shall record,  or
cause to be recorded,  all proceedings of the meetings of the  stockholders  and
directors  (including  committees  thereof)  in the  book  of  records  of  this
corporation.  The  record  books  shall  be  open  at  reasonable  times  to the
inspection of any stockholder,  director, or officer. The clerk shall notify the
stockholders and directors,  when required by law or by these By-laws,  of their
respective  meetings,  and shall  perform such other duties as the directors and
stockholders  may from time to time prescribe.  The clerk shall have the custody
and charge of the corporate seal, and shall affix the seal of the corporation to
all instruments  requiring such seal, and shall certify under the corporate seal
the proceedings of the directors and of the stockholders,  when required. In the
absence of the clerk at any such meeting,  a temporary clerk shall be chosen who
shall record the proceedings of the meeting in the aforesaid books.

         Assistant clerk, if any, shall have such powers and perform such duties
as the board of directors may from time to time designate.

         Section 3.12. Other Powers and Duties.  Subject to these By-laws and to
such limitations as the board of directors may from time to time prescribe,  the
officers of the corporation  shall each have such powers and duties as generally
pertain to their respective  offices,  as well as such powers and duties as from
time to time may be conferred by the board of directors.

                                   ARTICLE IV.

                                  Capital Stock

         Section 4.1. Stock Certificates.  Each stockholder shall be entitled to
a  certificate  representing  the number of shares of the  capital  stock of the
corporation owned by such person in such form as shall, in conformity to law, be
prescribed from time to time by the board of directors.  Each certificate  shall
be  signed  by the  president  or  vice-president  and  treasurer  or 

                                      -8-



assistant  treasurer or such other officers designated by the board of directors
from time to time as permitted by law,  shall bear the seal of the  corporation,
and shall express on its face its number,  date of issue,  class,  the number of
shares  for  which,  and the name of the  person  to  whom,  it is  issued.  The
corporate seal and any or all of the  signatures of corporation  officers may be
facsimile if the stock  certificate is manually  counter-signed by an authorized
person on behalf of a transfer agent or registrar  other than the corporation or
its employee.

         If an officer,  transfer  agent or registrar  who has signed,  or whose
facsimile  signature has been placed on, a  certificate  shall have ceased to be
such before the certificate is issued,  it may be issued by the corporation with
the same effect as if he were such officer,  transfer  agent or registrar at the
time of its issue.

         Section 4.2. Transfer of Shares. Title to a certificate of stock and to
the shares  represented  thereby shall be  transferred  only on the books of the
corporation  by  delivery  to the  corporation  or  its  transfer  agent  of the
certificate properly endorsed, or by delivery of the certificate  accompanied by
a written  assignment  of the same,  or a  properly  executed  written  power of
attorney to sell, assign or transfer the same or the shares represented thereby.
Upon  surrender  of a  certificate  for  the  shares  being  transferred,  a new
certificate or  certificates  shall be issued  according to the interests of the
parties.

         Section 4.3.  Record  Holders.  Except as otherwise  may be required by
law, by the Articles of Organization or by these By-laws,  the corporation shall
be  entitled  to treat the  record  holder of stock as shown on its books as the
owner of such stock for all purposes, including the payment of dividends and the
right to vote with respect thereto,  regardless of any transfer, pledge or other
disposition of such stock,  until the shares have been  transferred on the books
of the corporation in accordance with the requirements of these By-laws.

         It shall be the duty of each  stockholder to notify the  corporation of
his post office address.

         Section 4.4.  Record Date. In order that the  corporation may determine
the  stockholders  entitled  to receive  notice of or to vote at any  meeting of
stockholders  or any  adjournments  thereof,  or to express consent to corporate
action in  writing  without a meeting,  or  entitled  to receive  payment of any
dividend  or other  distribution  or  allotment  of any  rights,  or 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 be more than sixty (60) days prior to
any other action.  In such case only  stockholders of record on such record date
shall be so entitled,  notwithstanding any transfer of stock on the books of the
corporation after the record date.

         If no  record  date is  fixed:  (i) the  record  date  for  determining
stockholders  entitled  to  receive  notice  of  or  to  vote  at a  meeting  of
stockholders shall be at the close of business on the day next preceding the day
on which notice is given,  or, if notice is waived,  at the close of business on
the day next  preceding  the day on which the  meeting is held;  (ii) the record
date for  determining  stockholders  entitled  to express  consent to  corporate
action  in  writing  without  a  meeting,  when no prior  action by the board of
directors is necessary,  shall be the day on which the first written  consent is
expressed;  and (iii) the record date for determining stockholders for


                                      -9-


any  other  purpose  shall be at the close of  business  on the day on which the
board of directors adopts the resolution relating thereto.

         Section 4.5.  Transfer  Agent and Registrar for Shares of  Corporation.
The board of  directors  may  appoint a transfer  agent and a  registrar  of the
certificates of stock of the corporation.  Any transfer agent so appointed shall
maintain,  among other records, a stockholders' ledger,  setting forth the names
and addresses of the holders of all issued  shares of stock of the  corporation,
the number of shares held by each, the  certificate  numbers  representing  such
shares, and the date of issue of the certificates  representing such shares. Any
registrar so appointed  shall maintain,  among other records,  a share register,
setting  forth the total  number  of  shares of each  class of shares  which the
corporation  is  authorized  to issue  and the total  number of shares  actually
issued. The stockholders' ledger and the share register are hereby identified as
the stock transfer books of the  corporation;  but as between the  stockholders'
ledger and the share register, the names and addresses of stockholders,  as they
appear on the stockholders' ledger maintained by the transfer agent shall be the
official list of stockholders of record of the corporation. The name and address
of each  stockholder of record,  as they appear upon the  stockholders'  ledger,
shall be  conclusive  evidence of who are the  stockholders  entitled to receive
notice of the meetings of stockholders,  to vote at such meetings,  to examine a
complete  list of the  stockholders  entitled to vote at  meetings,  and to own,
enjoy and  exercise  any other  property  or rights  deriving  from such  shares
against the corporation.  Stockholders,  but not the corporation, its directors,
officers,  agents or attorneys,  shall be responsible for notifying the transfer
agent, in writing, of any changes in their names or addresses from time to time,
and  failure to do so will  relieve  the  corporation,  its other  stockholders,
directors, officers, agents and attorneys, and its transfer agent and registrar,
of liability for failure to direct  notices or other  documents,  or pay over or
transfer  dividends or other property or rights, to a name or address other than
the name and address  appearing in the  stockholders'  ledger  maintained by the
transfer agent.

         Section 4.6. Loss of Certificates.  In case of the loss, destruction or
mutilation of a certificate of stock, a replacement certificate may be issued in
place  thereof  upon  such  terms  as the  board  of  directors  may  prescribe,
including,  in the  discretion of the board of directors,  a requirement of bond
and indemnity to the corporation.

         Section 4.7. Restrictions on Transfer.  Every certificate for shares of
stock which are subject to any restriction on transfer,  whether pursuant to the
Articles of  Organization  the By-laws or any agreement to which the corporation
is a party,  shall have the fact of the restriction  noted  conspicuously on the
certificate and shall also set forth on the face or back either the full text of
the restriction or a statement that the  corporation  will furnish a copy to the
holder of such certificate upon written request and without charge.

         Section 4.8.  Multiple  Classes of Stock. The amount and classes of the
capital stock and the pal value, if any, of the shares, shall be as fixed in the
Articles  of  Organization.  At all times when there are two or more  classes of
stock,  the several  classes of stock shall conform to the  description  and the
terms and have the  respective  preferences,  voting  powers,  restrictions  and
qualifications  set forth in the  Articles of  Organization  and these  By-laws.
Every  certificate  issued when the corporation is authorized to issue more than
one class or series of stock  shall set


                                      -10-




forth on its face or back  either (i) the full text of the  preferences,  voting
powers,  qualifications  and special and  relative  rights of the shares of each
class and series  authorized to be issued,  or (ii) a statement of the existence
of such preferences, powers, qualifications and rights, and a statement that the
corporation  will furnish a copy thereof to the holder of such  certificate upon
written request and without charge.

                                   ARTICLE V.

                                    Dividends

         Section 5.1. Declaration of Dividends.  Except as otherwise required by
law or by the  Articles  of  Organization  the board of  directors  may,  in its
discretion,  declare what, if any,  dividends  shall be paid from the surplus or
from the net  profits  of the  corporation  upon the  stock of the  corporation;
provided,  however,  that no  dividend  shall be declared or paid the payment of
which  would  diminish  the amount of the  paid-in  capital of the  corporation.
Dividends  may be paid in cash,  in  property,  in shares  of the  corporation's
stock, or in any combination thereof. Dividends shall be payable upon such dates
as the board of directors may designate.

         Section  5.2.  Reserves.  Before the payment of any dividend and before
making any  distribution of profits,  the board of directors,  from time to time
and in its absolute discretion, shall have power to set aside out of the surplus
or net  profits of the  corporation  such sum or sums as the board of  directors
deems proper and sufficient as a reserve fund to meet  contingencies or for such
other purpose as the board of directors  shall deem to be in the best  interests
of the  corporation,  and the board of directors  may modify or abolish any such
reserve.

                                   ARTICLE VI.

                         Powers of Officers to Contract

                              With the Corporation

         Any  and  all  of  the  directors  and  officers  of  the  corporation,
notwithstanding  their official  relations to it, may enter into and perform any
contract or agreement of any nature between the corporation  and themselves,  or
any and all of the  individuals  from  time to time  constituting  the  board of
directors  of the  corporation,  or any firm or  corporation  in which  any such
director may be  interested,  directly or indirectly,  whether such  individual,
firm or corporation thus  contracting with the corporation  shall thereby derive
personal or corporate profits or benefits or otherwise;  provided,  that (i) the
material  facts of such  interest  are  disclosed  or are  known to the board of
directors or committee thereof which authorizes such contract or agreement; (ii)
if the material facts as to such person's relationship or interest are disclosed
or are known to the stockholders  entitled to vote thereon,  and the contract is
specifically approved in good faith by a vote of the stockholders;  or (iii) the
contract  or  agreement  is  fair  as to the  corporation  as of the  time it is
authorized, approved or ratified by the board of directors, a committee thereof,
or the  stockholders.  Any director of the  corporation who is interested in any
transaction  as  aforesaid  may  nevertheless  be  counted  in  determining  the
existence  of a quorum at any  meeting  of the board of  directors  which  shall
authorize or ratify any such transaction. This Article shall not be


                                      -11-



construed to invalidate any contract or other  transaction which would otherwise
be valid under the common or statutory law applicable thereto.

                                  ARTICLE VII.

                                 Indemnification

         Section 7.1.      Definitions.  For purposes of this Article VII:

         (a)  "Covered  Person"  means an  individual:  (i) who is a present  or
former director,  officer, agent or employee of the corporation or who serves or
served another corporation,  partnership, joint venture, trust, employee benefit
plan or other  enterprise in one of those  capacities or as trustee,  partner or
fiduciary  at the  request  of the  corporation;  and (ii) who by  reason of his
position was, is, or is threatened to be made a party to a proceeding.  It shall
also include such person's heirs, executors and administrators.

         (b) "Proceeding" includes any threatened, pending, or completed action,
suit, or proceeding, whether civil, criminal,  administrative, or investigative,
and any claim which could be the subject of such a proceeding.

         (c) "Disinterested Director" means a director who is not a party to the
Proceeding(s) in question.

         (d) "Expenses" means liabilities,  including but not limited to amounts
paid in satisfaction of judgments, in compromises or as fines or penalties,  and
expenses, including reasonable legal and accounting fees.

         Section 7.2.  Actions in Name of the  Corporation or  Stockholder.  The
corporation  may indemnify any Covered Person to the extent legally  permissible
against all Expenses  incurred in connection  with the defense or disposition of
any Proceeding by or in the name of the  corporation  or any  stockholder in his
capacity as such if a reasonable determination is made, based on a review of the
readily  available  facts but without  special  investigation,  that the Covered
Person acted in good faith, and in the reasonable belief that his action was in,
or not opposed to, the best interest of the corporation, and with respect to any
criminal  action or  proceeding,  had no  reasonable  cause to believe  that his
conduct was unlawful. Such determination shall be made by:

         (a)      the vote of a majority of a quorum of Disinterested Directors;

         (b)      a special litigation/indemnification committee of the board of
                  directors appointed by the board;

         (c)      independent legal counsel in a written opinion; or

         (d) the vote of the holders of a majority of the  outstanding  stock at
the time entitled to vote for directors,  voting as a single class, exclusive of
any stock owned by any interested director or officer.

                                      -12-



         No indemnification shall be made with respect to any matter as to which
such Covered Person has been adjudicated  liable for negligence or misconduct in
the performance of his duty to the corporation,  unless,  and only to the extent
that,  the court  deciding the action  determines  that such  Covered  Person is
entitled to indemnification.

         Such indemnification may be provided in connection with a Proceeding in
which it is claimed  that an officer or director  received an improper  personal
benefit by reason of his position,  regardless of whether the claim involves his
service  in such  capacity,  subject  to the  foregoing  limitations  and to the
additional  limitation  that it shall not have been finally  determined  that an
improper personal benefit was received by the director or officer.

         Section 7.3. Other Actions.  The  corporation may indemnify any Covered
Person  against  any  Expenses  incurred  in  connection  with  the  defense  or
disposition of any  Proceeding  other than a Proceeding of the type described in
Section 7.2,  except with  respect to any matter as to which the Covered  Person
shall have been finally  adjudicated  in the Proceeding (i) not to have acted in
good faith and in a manner he  reasonably  believed to be in, or not opposed to,
the best  interests  of the  corporation  or, (ii) with  respect to any criminal
Proceeding, to have had reasonable cause to believe his conduct was unlawful.

         Section  7.4.  Advances  of  Expenses.   The  corporation  may  advance
attorneys'  fees or other  Expenses  incurred by a Covered Person in defending a
Proceeding, upon receipt of an undertaking by or on behalf of the Covered Person
to repay the amount advanced,  which undertaking may be accepted by the board of
directors  without  reference to the financial ability of such Covered Person to
make repayment.

         Section  7.5.   Presumptions   upon  Termination  of  Proceeding.   The
termination of any Proceeding by judgment,  order,  settlement,  conviction,  or
upon a plea of nolo contendere or its equivalent, shall not, of itself, create a
presumption  that a person  did not act in good  faith and in a manner  which he
reasonably  believed  to be in, or not  opposed,  to the best  interests  of the
corporation,  or, with respect to any criminal proceeding,  had reasonable cause
to believe that his conduct was unlawful.

         Section   7.6.    Indemnification   Not   Exclusive.   The   right   of
indemnification provided by this Article VII shall not be exclusive of or affect
any other rights to which any such Covered Person may be entitled.

         Section  7.7.  Insurance.  The  corporation  may  purchase and maintain
insurance  on its  behalf  and on  behalf  of any  Covered  Person  against  any
liability  asserted  against such Covered Person and incurred by him in any such
capacity,  or arising out of his status as such,  whether or not the corporation
would  have the  power  to  indemnify  him  against  such  liability  under  the
provisions of this Article VII.

         Section 7.8.  Employee  Benefit Plans. If the corporation or any of its
subsidiaries or affiliates  sponsors any employee  benefit plan, and any Covered
Person  undertakes  or incurs any  responsibility  as a fiduciary  with  respect
thereto then, for purposes of  indemnification of such Covered Person under this
Article VII, (i) such Covered  Person shall be deemed not to have

                                      -13-


failed to have acted in good faith and in the reasonable  belief that his action
was in or not opposed to the best  interests of the  corporation  if he acted in
good faith and in the reasonable belief that his action was in or not opposed to
the best interests of the  participants or  beneficiaries of said plan, and (ii)
"Expenses"  shall be deemed to include any taxes or  penalties  assessed on such
Covered Person with respect to said plan under applicable law.

                                  ARTICLE VIII.

                            Miscellaneous Provisions

         Section 8.1. Articles of Organization.  All references in these By-laws
to the  Articles  of  Organization  shall be deemed to refer to the  Articles of
Organization of the corporation, as amended and in effect from time to time.

         Section  8.2.  Fiscal  Year.  Except  as from  time  to time  otherwise
provided by the board of directors, the fiscal year of the corporation shall end
on the 31st day in December of each year.

         Section 8.3.  Corporate  Seal.  The board of  directors  shall have the
power to adopt and alter the seal of the corporation.

         Section 8.4. Execution of Instruments.  All deeds,  leases,  transfers,
contracts,  bonds, notes, and other obligations  authorized to be executed by an
officer of the corporation on its behalf shall be signed by the president or the
treasurer  except as the board of directors may generally or in particular cases
otherwise determine.

         Section  8.5.  Voting of  Securities.  Unless  the  board of  directors
otherwise  provides,  the president or the treasurer may waive notice of and act
on behalf of this  corporation,  or appoint  another person or persons to act as
proxy or attorney  in fact for this  corporation  with or without  discretionary
power  and/or  power  of  substitution,   at  any  meeting  of  stockholders  or
shareholders of any other  corporation or organization,  any of whose securities
are held by this corporation.

         Section 8.6.  Evidence of Authority.  A certificate by the clerk or any
assistant  clerk as to any action  taken by the  stockholders,  directors or any
officer or representative  of the corporation  shall, as to all persons who rely
thereon in good faith,  be conclusive  evidence of such action.  The exercise of
any power which by law, by the Articles of Organization or by these By-laws,  or
under any vote of the  stockholders or the board of directors,  may be exercised
by an officer of the corporation only in the event of absence of another officer
or any other  contingency  shall bind the corporation in favor of anyone relying
thereon in good faith, whether or not such absence or contingency existed.

         Section 8.7.  Corporate Records.  The original,  or attested copies, of
the  Articles  of  Organization,   By-laws,  records  of  all  meetings  of  the
incorporators  and  stockholders,  and the stock  transfer  books  (which  shall
contain the names of all  stockholders  and the record address and the amount of
stock held by each) shall be kept in  Massachusetts  at the principal  office of
the corporation, or at an office of its resident agent, transfer agent or of the
clerk or of the assistant clerk, if any. Said copies and records need not all be
kept in the same  office.  They shall be

                                      -14-



available at all  reasonable  times to  inspection  of any  stockholder  for any
purpose but not to secure a list of stockholders for the purpose of selling said
list or copies  thereof  or of using the same for a  purpose  other  than in the
interest  of the  applicant,  as a  stockholder,  relative to the affairs of the
corporation.

         Section 8.8. Charitable Contributions. The board of directors from time
to time  may  authorize  contributions  to be made  by the  corporation  in such
amounts as it may determine to be reasonable to corporations,  trusts,  funds or
foundations  organized and operated  exclusively for  charitable,  scientific or
educational  purposes, no part of the net earning of which inures to the private
benefit of any stockholder or individual.

         Section  8.9.  Election in Respect of Control  Share  Acquisitions.  In
accordance  with the  provisions  of Chapter 110D of the  Massachusetts  general
Laws,  the  provisions  of such  Chapter  shall  not  apply  to  "control  share
acquisitions"  (as  such  term  is  defined  under  said  Chapter  110D)  of the
corporation.

                                  ARTICLE IX.

                                   Amendments

         Section 9.1. Amendment by Stockholders. Prior to the issuance of stock,
these  By-laws may be amended,  altered or  repealed by the  incorporator(s)  by
majority  vote.  After  stock has been  issued,  these  By-laws  may be amended,
altered or repealed by the stockholders at any annual or special meeting by vote
of a majority of all shares  outstanding and entitled to vote, except that where
the effect of the amendment would be to reduce any voting requirement  otherwise
required by law, the Articles of Organization  or these By-laws,  such amendment
shall  require the vote that would have been  required by such other  provision.
Notice and a copy of any proposal to amend these By-laws must be included in the
notice of meeting of stockholders at which action is taken upon such amendment.


                                      -15-




         Section 9.2.      Amendment by Board of Directors.

         (a) These  By-laws may be amended,  altered or repealed by the board of
directors  at a meeting  duly  called for the  purpose by  majority  vote of the
directors then in office, except that directors shall not amend the By-laws in a
manner which:

         (i) changes the stockholder voting requirements for any action;

         (ii) alters or abolishes any preferential  right or right of redemption
applicable to a class or series of stock with shares already outstanding;

         (iii) alters the provisions of Articles VII or IX hereof; or

         (iv) permits the board of directors to take any action which under law,
the  Articles of  Organization  or these  By-laws is required to be taken by the
stockholders.

         (b) If the By-laws  are  amended or altered by the board of  directors,
notice of the amendment, alteration or repeal shall be given to all stockholders
entitled to vote not later than the time of giving notice of the next meeting of
stockholders following such amendment, alteration or repeal.

         (c) Any  amendment of these  By-laws by the board of  directors  may be
altered or  repealed  by the  stockholders  at any annual or special  meeting of
stockholders.

                                      -16-

                                                                     EXHIBIT 4.1
                                      BBI

                             BOSTON BIOMEDICA, INC.
                        WEST BRIDGEWATER, MASSACHUSETTS

NUMBER                                                                    SHARES
FBU
                                  COMMON STOCK
        INCORPORATED UNDER THE LAWS OF THE COMMONWEALTH OF MASSACHUSETTS

THIS STOCK IS TRANSFERABLE IN BOSTON, MASSACHUSETTS              CUSIP 100560101
           OR NEW YORK, NEW YORK

THIS CERTIFIES THAT                                              SEE REVERSE FOR
                                                             CERTAIN DEFINITIONS




Is the owner of

  fully-paid and non-assessable shares of the COMMON STOCK, $.01 par value, of
                             BOSTON BIOMEDICA, INC.


(herein called the "Corporation"),  transferable 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 and the shares represented
hereby are subject to the laws of the Commonwealth of  Massachusetts  and to the
Articles of Organization and the By-laws of the Corporation as from time to time
amended.  This  Certificate  is not valid unless  countersigned  by the Transfer
Agent and Registrar.

     WITNESS the facsimile seal of the Corporation and the facsimile  signatures
of its duly authorized officers.

Dated


                             BOSTON BIOMEDICA, INC.
                              CORPORATE SEAL 1978
                                 MASSACHUSETTS


_______________________                               __________________________
President                                             Treasurer

COUNTERSIGNED AND REGISTERED:

American Securities Transfer & Trust, Inc.
____________________________
BY                         TRANSFER AGENT
                           AND REGISTRAR

     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 tennants in common              UNIF GIFT MIN ACT --     Custodian
TEN ENT - as tennants by the entireties           (Cust)               (Minor)
JT TEN  - as joint tennants with right of      under Uniform Gifts to Minors
          survivorship and not as tennants      Act _____________
          in common                                   (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  common  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 __________________________

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

Signature(s) Guaranteed:

____________________________________________
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.

The  Corporation  is authorized to issue more than one class of stock. A copy of
the full text of the preferences,  voting powers,  qualifications and special or
relative  rights of the shares of each class of stock  will be  provided  to the
holder hereof upon written request and without charge.


                                                                 EXHIBIT 10.18.2

                                                                       EXECUTION



                              TERM PROMISSORY NOTE


$200,000.00                                                Boston, Massachusetts
Due:  October 18, 1999                                   Dated: October 11, 1994


     FOR VALUE RECEIVED, the undersigned,  BOSTON BIOMEDICA, INC., ("BBI"), BTRL
CONTRACTS AND SERVICES,  INC. ("BTRL") and NORTH AMERICAN LABORATORY GROUP, INC.
("NALG"), each of which is a Massachusetts  corporation validly created, legally
existing  and  in  good  standing  under  the  laws  of  the   Commonwealth   of
Massachusetts  and each of which has its "Notice  Address"  at 375 West  Street,
West Bridgewater,  Massachusetts  02379 (BBI, BTRL and NALG, together with their
successors and assigns,  are collectively  referred to herein as the "Borrower")
JOINTLY AND SEVERALLY,  AND  UNCONDITIONALLY  PROMISE TO PAY TO THE ORDER OF THE
FIRST NATIONAL BANK OF BOSTON, a national banking  association  having an office
and  "Notice  Address"  at Bank  of  Boston-Worcester  Tower,  P.O.  Box  15073,
Worcester,  Massachusetts  01615-0073 (together with its successors and assigns,
the "Lender"),  successor-by-merger to WORCESTER COUNTY INSTITUTION FOR SAVINGS,
a Massachusetts savings bank ("WCiS"), the principal sum of TWO HUNDRED THOUSAND
AND 00/100 DOLLARS  ($200,000.00),  with interest on the unpaid balance  thereof
from the date hereof until paid at the rate and in the manner  herein  provided,
in lawful money of the United States of America.

     Amended and Restated Loan Agreement. The Borrower and WCiS are parties to a
certain Amended and Restated Loan and Security Agreement (the "Agreement") dated
as of June 18, 1993,  which Agreement was amended by a certain letter  agreement
dated  August 26, 1993  ("Amendment  No. 1") by and among the Borrower and WCiS,
and further  amended by a certain  Amendment  No. 2 to Amended and Restated Loan
and  Security  Agreement  dated as of July 29, 1994  ("Amendment  No. 2") by and
between the Borrower and the Lender. As of the date hereof, the Borrower and the
Lender have entered into a certain  Amendment No. 3 to Amended and Restated Loan
and Security  Agreement (the Agreement,  as amended by Amendment No 1, Amendment
No. 2 and Amendment No. 3, is hereinafter  referred to as the "Loan Agreement").
Terms  not  otherwise   specifically   defined  in  this  Term  Promissory  Note
(hereinafter referred to as the "Note") shall have the respective meanings given
to them in the Agreement.

     Principal  Advances.  The Lender shall  advance sums  hereunder,  up to the
principal amount hereof,  for a period of six (6) months from the date hereof in
accordance with the provisions of the Loan Agreement (the "Advance Period").






     Interest Rate. During the Advance Period, the unpaid principal of this Note
from time to time  outstanding  shall bear  interest,  computed  on the basis of
actual  number of days  elapsed  over a year  assumed  to have 360  days,  at an
interest rate per annum equal to one and  one-quarter  percent (1.25%) per annum
above the rate of  interest  established  from time to time by the Lender as its
Base Lending Rate (the "Base  Rate"),  such  interest rate to be determined on a
daily basis and adjusted from time to time on the  effective  date of any change
in the Base Rate by the Lender  (the  "Adjusted  Base  Rate").  Thereafter,  the
unpaid principal  amount of this Note from time to time  outstanding  shall bear
interest at the Adjusted  Base Rate unless the  Borrower  shall have elected the
Fixed Rate Option (as hereinafter  defined) by irrevocable  notice to the Lender
received not less than ten (10)  business days prior to the last business day of
the  Advance  Period.  In the absence of such  election,  the  principal  amount
outstanding hereunder shall bear interest at the Adjusted Base Rate.

     "Fixed Rate Option" as used herein  shall mean the  one-time  option of the
Borrower to have  interest  computed  hereunder on the basis of an interest rate
per annum equal to two and one-half  percent  (2.50%) per annum above the "Fixed
Rate" (as  hereinafter  defined) (the "Adjusted  Fixed Rate").  The "Fixed Rate"
shall be the fixed rate of  interest  quoted by the  Lender for the  outstanding
principal balance hereunder for the remainder of the term hereunder.

     Certain Provisions Regarding Interest. To the extent used herein, Base Rate
means the rate of interest per annum announced, from time to time, by the Lender
as its Base Rate.  The Borrower  acknowledges  that the Base Rate is a reference
rate and not  necessarily  the lowest rate  charged by the Lender to  borrowers.
Interest per annum shall be  calculated  for the actual  number of days elapsed,
from time to time, over a year assumed to have 360 days. Therefore,  each dollar
of  principal  outstanding  hereunder  for all or any part of a day shall accrue
interest equal to 1/360th of the annual interest accruing hereunder on each such
dollar.  Interest shall accrue on each day or part thereof that any principal is
outstanding including Sundays,  holidays and all days during which the Lender is
not open for the conduct of business.

     Interest  Increase after Maturity or Acceleration.  Any and all amounts not
paid when due hereunder,  whether after maturity,  by acceleration or otherwise,
shall accrue interest,  payable on demand, at the greater of (i) the annual rate
of eighteen  percent  (18%) or (ii) the annual  rate equal to two  percent  (2%)
above the Base Rate, if permitted by law, calculated as above from the date when
due until so paid.

     Payments.  Commencing  on November  18,  1994,  and on the same day of each
month  thereafter up to and including April 18, 1995,  payments of interest only
shall be made in arrears on the outstanding principal amount of this Note.

     Commencing  on May  18,  1995,  payments  on  this  Note  shall  be made in
fifty-four (54) consecutive monthly installments of principal and interest.  The
first fifty-three (53) such installments shall be equal to  one-fifty-fourth  of
the  principal  amount of this Note which has 



                                      -2-



been advanced, plus accrued and unpaid interest in arrears. The last installment
shall comprise the then unpaid principal  balance of this Note together with all
accrued  and unpaid  interest  and any and all other  fees,  charges,  costs and
expenses due and payable to Lender hereunder.

     Late Charges. If any payment due hereunder is not paid within ten (10) days
of its due date, the Borrower will also pay to Lender, on demand and in addition
to all other amounts payable hereunder,  an amount equal to five percent (5%) of
the amount of such payment.  The assessment or collection of late charges is not
intended  and shall not be  construed  to permit  payment of any amount  payable
hereunder  beyond the  applicable  due date  thereof.  The time period  which is
allowed  before the  assessment of late charges is not intended and shall not be
construed  as a grace or cure period with respect to payment or  performance  of
any obligation hereunder.

     Prepayment.  To the extent that interest accrues  hereunder at the Adjusted
Base Rate,  the Borrower  shall have the right to prepay all or a portion of the
entire  outstanding  principal  balance of this Note without  penalty so long as
such  prepayment  includes  payment of all accrued and unpaid interest and other
accrued  costs and charges of Lender.  If Borrower  shall have elected the Fixed
Rate Option, the Borrower shall have the right to prepay all or a portion of the
entire  outstanding  principal  balance  of this  Note  ("Prepayment")  upon (a)
delivery of sixty (60) days' prior written notice to the Lender,  (b) payment of
all accrued  interest  and other  accrued  charges and costs of Lender,  and (c)
payment of a Prepayment  premium  determined as provided in the next sentence of
this paragraph. Such Prepayment premium shall be in an amount equal to the daily
interest for the remaining term hereunder on the principal  amount so prepaid at
a daily rate equal to one-three hundred sixtieth (1/360th) of the difference (if
positive)  of (i) the  Fixed  Rate  applicable  thereto  minus  (ii) the rate of
interest  obtainable  by  the  Lender  upon  the  purchase  of  debt  securities
customarily issued by the Treasury of the United States of America, in an amount
equal  to  the  principal  amount  so  prepaid,   which  have  a  maturity  date
approximating  the Maturity Date. The Lender's  determination  of such amount of
interest, in the absence of manifest error, shall be conclusive.

     Application of Payments.  Any payments received by the Lender on account of
this Note prior to maturity or other acceleration,  shall be applied:  first, to
any fees,  charges,  costs and  expenses  then owed to the  Lender by  Borrower;
second to accrued and unpaid  interest on the unpaid  balance of principal;  and
third, to the unpaid balance of principal  hereof.  Any payments received by the
Lender on account of this Note after  maturity  or other  acceleration  shall be
applied in such manner as the Lender may determine.

     Note Issued Pursuant to Loan Agreement. This Note is issued pursuant to the
Loan  Agreement,  and the holder  hereof is entitled to the benefits of the Loan
Agreement, and all other agreements, instruments, guarantees and other documents
executed  and  delivered in  connection  therewith  and  herewith  (collectively
referred to herein as the "Financing Instruments").
     


                                      -3-



     Maturity Date. The entire  outstanding  principal  balance hereof  together
with all accrued and unpaid interest  thereon and all fees,  charges,  costs and
expenses due Lender  hereunder shall be due and payable on October 18, 1999 (the
"Maturity Date").

     Security  Provided in Other Writings.  Payment and performance of this Note
may be secured, from time to time, now or hereafter,  as provided in one or more
security agreements,  mortgages,  pledges, assignments or any other instruments,
documents or agreements ("Security"),  whether or not such Security specifically
refers to this Note.  Any and all such Security may provide,  in general  terms,
that such Security secures obligations of the Borrower to the Lender however and
whenever evidenced,  created or arising. Payment and performance of this Note is
hereby secured by such Security without specific reference to this Note, and, in
addition, this Note is secured by any and all Security which specifically refers
to or provides security for this Note.

     Grant of Security  in Accounts  and Other  Property  in  Possession  of the
Lender.  To secure the payment and performance of this Note, the Borrower hereby
grants to the Lender a continuing  security  interest in and to: (a) any and all
deposits and sums at any time  credited by or due from the Lender (or any of its
banking  or  lending  affiliates)  to the  Borrower;  and (b)  any or all  cash,
instruments,  securities and other property of the Borrower,  in the possession,
custody or control  (whether for  safekeeping or otherwise) of, or in transit to
or from,  the  Lender or any such  affiliate,  including  such  property  in the
possession  of any  third  party  acting  on  behalf  of the  Lender or any such
affiliate,  regardless  of the reason for the  receipt,  possession,  custody or
control of such property or any prior release thereof, conditional or otherwise.
Upon  demand,  maturity  or  acceleration  of  the  payment  of  this  Note,  as
applicable,  the  Lender  may,  at any time,  sell or dispose of any or all such
property and apply the proceeds  thereof against the  indebtedness of this Note.
With respect to all such property, the Lender shall have the rights and remedies
of a secured party under the Uniform  Commercial Code and other applicable laws,
the choice and manner of exercise of any right or remedy  being in the  Lender's
sole  discretion.  No such right or remedy shall be  exclusive,  and each may be
exercised  by the  Lender  concurrently  or in any order or  combination  as the
Lender  may  select,  from  time to time.  The  Lender  shall  have the right to
foreclose  the  security  interest  granted  herein  by any  available  judicial
procedure and to sell the same with or without judicial process;  the Lender may
sell or  otherwise  dispose of such  property  or any part  thereof at public or
private sales,  at such price or prices,  and upon such terms,  either for cash,
credit or future delivery,  as the Lender may elect;  and, except as to any part
of such property which is perishable or which  threatens to decline  speedily in
value, or is of the type  customarily  sold on a recognized  market,  the Lender
shall give the Borrower reasonable  notification of such sale or sales, it being
agreed that in all events  written  notice mailed to the Borrower at least seven
(7) days  prior to such sale is  reasonable  notification.  The  Lender may (but
shall  have no  obligation  to) bid for and  become  the  purchaser  of any such
property.

     Setoff.  With respect to any and all  deposits and sums  referred to above,
upon the Maturity Date or  acceleration  of the payment of this Note, the Lender
may, at any time,  apply


                                      -4-



or setoff all or any portion of such  deposits or sums against the  indebtedness
evidenced by this Note, regardless of any other collateral or security available
to the Lender.

     Payment  of  Costs  and  Attorney's  Fees.  The  Borrower  agrees,  and all
co-makers and guarantors  also agree,  jointly and  severally,  to pay all costs
incurred  by  the  Lender,   including  all  attorneys'   reasonable   fees  and
out-of-pocket costs and expenses,  including court costs, in connection with (i)
the  administration  or  implementation of the loan evidenced by this Note, (ii)
the  collection  of the  indebtedness  evidenced  by this  Note,  or  (iii)  the
preservation,  protection,  collection  or  enforcement  of any of the  Lender's
rights  or  remedies  hereunder  or  under  any  other  instrument  securing  or
guaranteeing  this Note,  against the Borrower or any co-maker or guarantor,  or
against any  collateral  securing  this Note or securing  any other  instrument,
document or agreement securing or guaranteeing this Note (whether or not suit is
instituted by or against the Lender).

     Waivers and Consents by Borrower and Others. By making or guaranteeing this
Note or by making any agreement to pay any of the indebtedness evidenced by this
Note, the Borrower, and each co-maker, guarantor, and other person or entity now
or hereafter liable for the payment of any of the indebtedness evidenced by this
Note, respectively,  agrees to waive: presentment for payment;  protest; demand;
notice of protest,  demand,  dishonor and  non-payment  of this Note;  all other
notices;  all other  defenses in the nature  thereof,  including all  suretyship
defenses;  and any and all other  demands or notices  otherwise  required  to be
given in connection  with the delivery,  acceptance,  endorsement,  performance,
default  or  enforcement  of  this  Note,  any and all  borrowings  or  advances
hereunder,  any and all  guarantees  or  undertakings  hereof,  and any security
taken,  granted or released,  from time to time,  in  connection  herewith.  The
Borrower and each such  co-maker,  guarantor  and other person or entity  hereby
consents,  without notice:  (a) to the substitution,  exchange or release,  from
time to time, of any collateral  securing this Note or any part thereof;  (b) to
the acceptance, from time to time, by the Lender of any additional collateral or
security for this Note, or the  acceptance,  from time to time, of other makers,
guarantors or other obligors of this Note, (c) to the modification or amendment,
from time to time, of this Note and any other instrument,  document or agreement
securing  or  guaranteeing  this  Note,  at the  request of any person or entity
liable thereon;  (d) to the granting of any extension of the time for payment of
this  Note or any  other  indulgence  for  the  performance  of the  agreements,
covenants  and  conditions  contained  in this  Note,  or any other  instrument,
document or agreement  securing or guaranteeing this Note, at the request of any
person  or  entity  liable  thereon;  (e)  to  any  and  all  other  extensions,
forbearances  and indulgences  whatsoever  granted by the Lender with respect to
this Note, any other liability of the Borrower,  or any collateral securing this
Note or any other  liability  of the  Borrower  to the  Lender;  and any and all
assignments  or transfers  of this Note and any part or all of the  indebtedness
evidenced  hereby  or  any  security  therefor  or  guarantees  thereof  to  any
successor,  assignee,  participant  or other party.  The happening of any one or
more of the  foregoing  events shall not alter or diminish the  liability of any
person or entity liable on this Note.  The release by the Lender of the Borrower
or any one or more  co-makers or  guarantors  shall not release any other person
obligated on account of this Note, except only for payments actually received by
Lender  free


                                      -5-



and clear of the rights of all other parties.  No person or entity  obligated on
account of this Note may seek  contribution from any other person or entity also
obligated unless and until all liabilities, obligations, and indebtedness to the
Lender of the person from whom  contribution  is sought have been  satisfied  in
full.

     Joint  and  Several   Obligations;   Binding  Effect.  This  Note  and  the
liabilities of the Borrower shall be the joint and several obligation of each of
the undersigned, if more than one, and each guarantor, co-maker, and surety, and
shall  be  binding  upon  each  of them  and  each of  their  respective  heirs,
representatives,  successors and assigns,  and shall inure to the benefit of the
Lender and its successors, indorsees and assigns. Each reference in this Note to
the  Borrower,  any  co-maker  and any  guarantor  refers to each such person or
entity individually and also to all such persons and entities jointly.  The term
"Lender"  shall include the Lender and each other payee hereof,  or any indorsee
of this Note in  possession  hereof,  or the bearer hereof if the Note is at the
time payable to the bearer.

     The  Lender's  Rights  Reserved.  No delay or  omission  on the part of the
Lender in exercising or enforcing any of the Lender's rights, powers, privileges
or remedies or discretions  hereunder or under any instrument or agreement which
is given or may be  given to  secure  or  guaranty  the  indebtedness  evidenced
hereby,  shall  operate  as a waiver  thereof,  or of any  other  right,  power,
privilege  or remedy of such holder on that  occasion or on any other  occasion,
nor shall any delay,  omission  or waiver on any one  occasion be deemed to be a
bar to or waiver of the same or any other right on any future  occasion,  and no
waiver of a default hereunder shall operate as a waiver of any other default nor
as a continuing waiver.

     Default.  The entire unpaid principal  balance of this Note and all accrued
and unpaid  interest  thereon and all other fees,  charges,  costs and  expenses
hereunder shall become immediately due and payable, without demand, prior to the
maturity of this Note,  at the sole option of the Lender,  (exercisable  without
demand,  notice or protest,  which are hereby  waived)  regardless  of any prior
forbearance  or  indulgence  by the Lender,  upon the  occurrence of one or more
Events of Default as that term is defined in the Loan Agreement.

     Commercial Purposes.  The Borrower hereby represents to the Lender that the
proceeds  of this Note shall be used  exclusively  for  business  or  commercial
purposes and not for personal, family or household purposes.

     Payment of Proceeds. The proceeds of any and all loans or advances pursuant
to this Note may be paid to or at the direction of the Borrower.

     Authority to Debit Accounts.  The Borrower hereby  authorizes the Lender to
charge or debit any deposit  account of the  Borrower  with the Lender to effect
any payment due hereunder, all without prior notice.

     Authority to Complete  this Note.  In the event that this Note is delivered
in an incomplete form in any respect, the Borrower and each co-maker,  guarantor
and other person


                                      -6-


or entity liable hereon,  hereby authorizes the Lender,  without further notice,
to complete  any blank spaces and to date the Note,  if undated,  as of the date
funds are first advanced hereunder.

     Currency  and  Payments.  All payments on this Note shall be made in lawful
currency of the United States of America, in each case without deduction, setoff
or  counterclaim.  All  payments  on this  Note  shall  be  made in  immediately
available  funds.  With  respect  to any  payment  on this Note which is made by
check, the Lender may treat such amount as outstanding  pending final collection
thereof,  and interest  hereunder  shall  continue to accrue  pending such final
collection.

     Acknowledgment of Terms and Receipt of a Copy. The Borrower has read all of
the terms and  conditions  of this Note and has  received  an exact copy of this
Note.

     Severability of Provisions.  Any  determination  that any provision of this
Note or any application  thereof is invalid,  illegal,  or  unenforceable in any
respect  in  any  instance   shall  not  affect  the   validity,   legality  and
enforceability  of such  provision  in any  other  instance,  nor the  validity,
legality or enforceability of any other provision hereof.

     Headings. The headings appearing in this Note are used for convenience only
and should not be deemed to affect the interpretation of this Note.

     Sealed Instrument.  This Note shall take effect as a sealed instrument.

     Books and  Records;  Copies as  Evidence.  The  Lender's  books and records
concerning  the  Lender's  loans and  advances to the  Borrower,  the accrual of
interest thereon, and the repayment of such loans, advances and interest,  shall
be prima  facie  evidence  of the  indebtedness  owed under  this  Note.  In any
proceeding with respect to this Note, any photographic,  photostatic,  microfilm
or similar  reproduction  of this Note shall be admissible in evidence as though
it were the  original,  whether or not the original  hereof is in existence  and
whether or not such reproduction was made in the regular course of business.

     Governing Law; Jurisdiction for Proceedings.  This Note is delivered to the
Lender in  Boston,  Massachusetts  and shall be  governed  by and  construed  in
accordance with the laws of the Commonwealth of  Massachusetts  for all purposes
and in all respects.  The Borrower, and each co-maker and guarantor of this Note
submits to the  non-exclusive  jurisdiction of the courts of the Commonwealth of
Massachusetts  for all  purposes  with  respect to this Note and any  collateral
given to secure their  respective  liabilities,  obligations and indebtedness to
the Lender, and their respective relationships with the Lender.

     Legal Limitation on Interest.  Notwithstanding  any other provision of this
Note to the contrary,  in the event that interest  pursuant to the provisions of
this Note is  finally  determined  by a court of  competent  jurisdiction  to be
subject to usury or other similar laws affecting the maximum allowable  interest
chargeable  then,  and  only  then,  and  only  to  the  extent  of  such


                                      -7-



final  determination,  the maximum  amount of interest  payable  under this Note
shall be the maximum  amount of interest  determined by such court to be allowed
by such laws.

     Notices and Notice Addresses. The respective Notice Addresses of the Lender
and the Borrower are those stated at the  beginning of this Note,  together with
the following  additions:  (a) for the Lender,  "Attention:  Commercial  Banking
Department";  and (b) for the  Borrower,  "Attention:  Kevin W.  Quinlan,  Chief
Financial Officer".  To the extent required or voluntarily given, all notices or
demands  hereunder shall be sufficient and shall be deemed to have been given if
made in writing and given in accordance with the provisions for notice contained
in the Loan  Agreement.  Any party may change its Notice  Address  hereunder  by
giving  notice  of such  change  to the  other  party  in  accordance  with  the
provisions of this subsection.



                                      -8-



     IN WITNESS  WHEREOF,  the Borrower has executed this Note, as an instrument
under seal as of the date appearing on the first page of this Note.


                                                        BOSTON BIOMEDICA, INC.


                                                     By:
- ----------------------                                  ------------------------
Witness as to Borrower                                  Kevin W. Quinlan
                                                        Treasurer
                                                        Hereunto duly authorized

                                                     BTRL CONTRACTS AND
                                                     SERVICES, INC.


                                                     By:
                                                        ------------------------
                                                        Kevin W. Quinlan
                                                        Treasurer
                                                        Hereunto duly authorized

                                                     NORTH AMERICAN LABORATORY
                                                     GROUP, INC.


                                                     By:
                                                        ------------------------
                                                        Kevin W. Quinlan
                                                        Treasurer
                                                        Hereunto duly authorized






ATTEST:



- -------------------------------
Clerk of Boston Biomedica, Inc.

ATTEST:




                                      -9-



                                                                 EXHIBIT 10.18.3

                                                                       EXECUTION



                    AMENDED AND RESTATED TERM PROMISSORY NOTE


$849,000.00                                                Boston, Massachusetts
Due:  October 18, 1998                                   Dated: October 11, 1994


     FOR VALUE RECEIVED, the undersigned,  BOSTON BIOMEDICA, INC., ("BBI"), BTRL
CONTRACTS AND SERVICES,  INC. ("BTRL") and NORTH AMERICAN LABORATORY GROUP, INC.
("NALG"), each of which is a Massachusetts  corporation validly created, legally
existing  and  in  good  standing  under  the  laws  of  the   Commonwealth   of
Massachusetts  and each of which has its "Notice  Address"  at 375 West  Street,
West Bridgewater,  Massachusetts  02379 (BBI, BTRL and NALG, together with their
successors and assigns,  are collectively  referred to herein as the "Borrower")
JOINTLY AND SEVERALLY,  AND  UNCONDITIONALLY  PROMISE TO PAY TO THE ORDER OF THE
FIRST NATIONAL BANK OF BOSTON, a national banking  association  having an office
and  "Notice  Address"  at Bank  of  Boston-Worcester  Tower,  P.O.  Box  15073,
Worcester,  Massachusetts  01615-0073 (together with its successors and assigns,
the "Lender"),  successor-by-merger to WORCESTER COUNTY INSTITUTION FOR SAVINGS,
a  Massachusetts  savings bank  ("WCiS"),  the  principal  sum of EIGHT  HUNDRED
FORTY-NINE  THOUSAND  AND 00/100  DOLLARS  ($849,000.00),  with  interest on the
unpaid  balance  thereof  from the date hereof until paid at the rate and in the
manner herein provided, in lawful money of the United States of America.

     Amended and Restated Loan Agreement. The Borrower and WCiS are parties to a
certain Amended and Restated Loan and Security Agreement (the "Agreement") dated
as of June 18, 1993,  which Agreement was amended by a certain letter  agreement
dated  August 26, 1993  ("Amendment  No. 1") by and among the Borrower and WCiS,
and further  amended by a certain  Amendment  No. 2 to Amended and Restated Loan
and  Security  Agreement  dated as of July 29, 1994  ("Amendment  No. 2") by and
between the Borrower and the Lender. As of the date hereof, the Borrower and the
Lender have entered into a certain  Amendment No. 3 to Amended and Restated Loan
and Security  Agreement (the Agreement,  as amended by Amendment No 1, Amendment
No. 2 and Amendment No. 3 is hereinafter  referred to as the "Loan  Agreement").
Terms not  otherwise  specifically  defined in this  Amended and  Restated  Term
Promissory  Note  (hereinafter  referred  to  as  the  "Note")  shall  have  the
respective meanings given to them in the Loan Agreement.

     Interest  Rate.  The  unpaid  principal  of  this  Note  from  time to time
outstanding shall bear interest,  computed on the basis of actual number of days
elapsed  over a year  assumed to have 360 days,  at an  interest  rate per annum
equal to two and one-half  percent  (2.50%) per annum above the "Fixed Rate" (as
hereinafter  defined) (the "Adjusted Fixed Rate"). The 





"Fixed  Rate"  shall be the fixed rate of  interest  quoted by the Lender on the
date hereof for the  outstanding  balance  hereunder for the entire term of this
Note.

     Certain  Provisions  Regarding  Interest.   Interest  per  annum  shall  be
calculated for the actual number of days elapsed, from time to time, over a year
assumed  to have 360  days.  Therefore,  each  dollar of  principal  outstanding
hereunder for all or any part of a day shall accrue interest equal to 1/360th of
the annual  interest  accruing  hereunder  on each such dollar.  Interest  shall
accrue on each day or part thereof that any principal is  outstanding  including
Sundays,  holidays  and all days which the Lender is not open for the conduct of
business.

     Interest  Increase after Maturity or Acceleration.  Any and all amounts not
paid when due hereunder,  whether after maturity,  by acceleration or otherwise,
shall accrue interest,  payable on demand, at the greater of (i) the annual rate
of eighteen  percent  (18%) or (ii) the annual  rate equal to two  percent  (2%)
above the Adjusted Fixed Rate, if permitted by law, calculated as above from the
date when due until so paid.

     Payments.  Commencing  on November  18,  1994,  and on the same day of each
month  thereafter,  payments  on this  Note  shall be made in  forty-eight  (48)
consecutive  monthly   installments  of  principal  plus  interest.   The  first
forty-seven (47) such payments shall each comprise the sum of Seventeen Thousand
Six Hundred Eighty-seven and 50/100 ($17,687.50) Dollars in principal repayment,
plus accrued and unpaid interest in arrears. The last installment shall comprise
the then unpaid  principal  balance of this Note  together  with all accrued and
unpaid interest and any and all other fees, charges,  costs and expenses due and
payable to the Lender hereunder.

     Late Charges. If any payment due hereunder is not paid within ten (10) days
of its due date, the Borrower will also pay to Lender, on demand and in addition
to all other amounts payable hereunder,  an amount equal to five percent (5%) of
the amount of such payment.  The assessment or collection of late charges is not
intended  and shall not be  construed  to permit  payment of any amount  payable
hereunder  beyond the  applicable  due date  thereof.  The time period  which is
allowed  before the  assessment of late charges is not intended and shall not be
construed  as a grace or cure period with respect to payment or  performance  of
any obligation hereunder.

     Prepayment. The Borrower shall have the right to prepay all or a portion of
the entire outstanding  principal balance of this Note  ("Prepayment")  upon (a)
delivery of sixty (60) days' prior written notice to the Lender,  (b) payment of
all accrued  interest  and other  accrued  charges and costs of Lender,  and (c)
payment of a Prepayment  premium  determined as provided in the next sentence of
this paragraph. Such Prepayment premium shall be in an amount equal to the daily
interest for the remaining term hereunder on the principal  amount so prepaid at
a daily rate equal to one-three hundred sixtieth (1/360th) of the difference (if
positive)  of (i) the  Fixed  Rate  applicable  thereto  minus  (ii) the rate of
interest  obtainable  by  the  Lender  upon  the  purchase  of  debt  securities
customarily issued by the Treasury of the United States of America, in an amount
equal  to  the  principal  amount  so  prepaid,   which  have



                                      -2-


a maturity date  approximating the Maturity Date. The Lender's  determination of
such amount of interest, in the absence of manifest error, shall be conclusive.

     Application of Payments.  Any payments received by the Lender on account of
this Note prior to maturity or other acceleration,  shall be applied:  first, to
any fees,  charges,  costs and  expenses  then owed to the  Lender by  Borrower;
second to accrued and unpaid  interest on the unpaid  balance of principal;  and
third, to the unpaid balance of principal  hereof.  Any payments received by the
Lender on account of this Note after  maturity  or other  acceleration  shall be
applied in such manner as the Lender may determine.

     Note Issued Pursuant to Loan Agreement. This Note is issued pursuant to the
Loan  Agreement,  and the holder  hereof is entitled to the benefits of the Loan
Agreement, and all other agreements, instruments, guarantees and other documents
executed  and  delivered in  connection  therewith  and  herewith  (collectively
referred to herein as the "Financing Instruments").

     Maturity Date. The entire  outstanding  principal  balance hereof  together
with all accrued and unpaid interest  thereon and all fees,  charges,  costs and
expenses due Lender  hereunder shall be due and payable on October 18, 1998 (the
"Maturity Date").

     Security  Provided in Other Writings.  Payment and performance of this Note
may be secured, from time to time, now or hereafter,  as provided in one or more
security agreements,  mortgages,  pledges, assignments or any other instruments,
documents or agreements ("Security"),  whether or not such Security specifically
refers to this Note.  Any and all such Security may provide,  in general  terms,
that such Security secures obligations of the Borrower to the Lender however and
whenever evidenced,  created or arising. Payment and performance of this Note is
hereby secured by such Security without specific reference to this Note, and, in
addition, this Note is secured by any and all Security which specifically refers
to or provides security for this Note.

     Grant of Security  in Accounts  and Other  Property  in  Possession  of the
Lender.  To secure the payment and performance of this Note, the Borrower hereby
grants to the Lender a continuing  security  interest in and to: (a) any and all
deposits and sums at any time  credited by or due from the Lender (or any of its
banking  or  lending  affiliates)  to the  Borrower;  and (b)  any or all  cash,
instruments,  securities and other property of the Borrower,  in the possession,
custody or control  (whether for  safekeeping or otherwise) of, or in transit to
or from,  the  Lender or any such  affiliate,  including  such  property  in the
possession  of any  third  party  acting  on  behalf  of the  Lender or any such
affiliate,  regardless  of the reason for the  receipt,  possession,  custody or
control of such property or any prior release thereof, conditional or otherwise.
Upon  demand,  maturity  or  acceleration  of  the  payment  of  this  Note,  as
applicable,  the  Lender  may,  at any time,  sell or dispose of any or all such
property and apply the proceeds  thereof against the  indebtedness of this Note.
With respect to all such property, the Lender shall have the rights and remedies
of a secured party under the Uniform  Commercial Code and other applicable laws,
the choice and manner of exercise of any right


                                      -3-


or remedy being in the Lender's sole  discretion.  No such right or remedy shall
be  exclusive,  and each may be exercised by the Lender  concurrently  or in any
order or  combination  as the Lender may select,  from time to time.  The Lender
shall have the right to foreclose the security  interest  granted  herein by any
available  judicial  procedure  and to sell the same  with or  without  judicial
process;  the Lender may sell or otherwise  dispose of such property or any part
thereof at public or  private  sales,  at such  price or  prices,  and upon such
terms, either for cash, credit or future delivery, as the Lender may elect; and,
except as to any part of such property which is perishable or which threatens to
decline  speedily in value, or is of the type  customarily  sold on a recognized
market, the Lender shall give the Borrower reasonable  notification of such sale
or sales,  it being  agreed  that in all  events  written  notice  mailed to the
Borrower at least seven (7) days prior to such sale is reasonable  notification.
The  Lender  may  (but  shall  have no  obligation  to) bid for and  become  the
purchaser of any such property.

     Setoff.  With respect to any and all  deposits and sums  referred to above,
upon the Maturity Date or  acceleration  of the payment of this Note, the Lender
may, at any time,  apply or setoff all or any  portion of such  deposits or sums
against  the  indebtedness  evidenced  by this  Note,  regardless  of any  other
collateral or security available to the Lender.

     Payment  of  Costs  and  Attorney's  Fees.  The  Borrower  agrees,  and all
co-makers and guarantors  also agree,  jointly and  severally,  to pay all costs
incurred  by  the  Lender,   including  all  attorneys'   reasonable   fees  and
out-of-pocket costs and expenses,  including court costs, in connection with (i)
the  administration  or  implementation of the loan evidenced by this Note, (ii)
the  collection  of the  indebtedness  evidenced  by this  Note,  or  (iii)  the
preservation,  protection,  collection  or  enforcement  of any of the  Lender's
rights  or  remedies  hereunder  or  under  any  other  instrument  securing  or
guaranteeing  this Note,  against the Borrower or any co-maker or guarantor,  or
against any  collateral  securing  this Note or securing  any other  instrument,
document or agreement securing or guaranteeing this Note (whether or not suit is
instituted by or against the Lender).

     Waivers and Consents by Borrower and Others. By making or guaranteeing this
Note or by making any agreement to pay any of the indebtedness evidenced by this
Note, the Borrower, and each co-maker, guarantor, and other person or entity now
or hereafter liable for the payment of any of the indebtedness evidenced by this
Note, respectively,  agrees to waive: presentment for payment;  protest; demand;
notice of protest,  demand,  dishonor and  non-payment  of this Note;  all other
notices;  all other  defenses in the nature  thereof,  including all  suretyship
defenses;  and any and all other  demands or notices  otherwise  required  to be
given in connection  with the delivery,  acceptance,  endorsement,  performance,
default  or  enforcement  of  this  Note,  any and all  borrowings  or  advances
hereunder,  any and all  guarantees  or  undertakings  hereof,  and any security
taken,  granted or released,  from time to time,  in  connection  herewith.  The
Borrower and each such  co-maker,  guarantor  and other person or entity  hereby
consents,  without notice:  (a) to the substitution,  exchange or release,  from
time to time, of any collateral  securing this Note or any part thereof;  (b) to
the acceptance, from time to time, by the Lender of any additional collateral or
security for this Note, or the  acceptance,  from time to time, of other makers,
guarantors or other obligors of 


                                      -4-



this Note, (c) to the modification or amendment, from time to time, of this Note
and any other  instrument,  document or agreement  securing or guaranteeing this
Note, at the request of any person or entity liable thereon; (d) to the granting
of any  extension  of the time for payment of this Note or any other  indulgence
for the  performance of the  agreements,  covenants and conditions  contained in
this  Note,  or  any  other  instrument,   document  or  agreement  securing  or
guaranteeing  this Note, at the request of any person or entity liable  thereon;
(e) to any and all other  extensions,  forbearances  and indulgences  whatsoever
granted by the Lender  with  respect to this Note,  any other  liability  of the
Borrower,  or any  collateral  securing this Note or any other  liability of the
Borrower to the Lender;  and any and all  assignments  or transfers of this Note
and  any  part  or all of the  indebtedness  evidenced  hereby  or any  security
therefor or guarantees thereof to any successor,  assignee, participant or other
party.  The happening of any one or more of the foregoing events shall not alter
or  diminish  the  liability  of any person or entity  liable on this Note.  The
release by the Lender of the Borrower or any one or more co-makers or guarantors
shall not release any other  person  obligated  on account of this Note,  except
only for  payments  actually  received by Lender free and clear of the rights of
all other  parties.  No person or entity  obligated  on account of this Note may
seek  contribution  from any other  person or entity also  obligated  unless and
until all liabilities, obligations, and indebtedness to the Lender of the person
from whom contribution is sought have been satisfied in full.

     Joint  and  Several   Obligations;   Binding  Effect.  This  Note  and  the
liabilities of the Borrower shall be the joint and several obligation of each of
the undersigned, if more than one, and each guarantor, co-maker, and surety, and
shall  be  binding  upon  each  of them  and  each of  their  respective  heirs,
representatives,  successors and assigns,  and shall inure to the benefit of the
Lender and its successors, indorsees and assigns. Each reference in this Note to
the  Borrower,  any  co-maker  and any  guarantor  refers to each such person or
entity individually and also to all such persons and entities jointly.  The term
"Lender"  shall include the Lender and each other payee hereof,  or any indorsee
of this Note in  possession  hereof,  or the bearer hereof if the Note is at the
time payable to the bearer.

     Lender's Rights Reserved. No delay or omission on the part of the Lender in
exercising  or  enforcing  any of the Lender's  rights,  powers,  privileges  or
remedies or discretions  hereunder or under any instrument or agreement which is
given or may be given to secure or guaranty the indebtedness  evidenced  hereby,
shall operate as a waiver thereof,  or of any other right,  power,  privilege or
remedy of such holder on that occasion or on any other  occasion,  nor shall any
delay, omission or waiver on any one occasion be deemed to be a bar to or waiver
of the same or any  other  right on any  future  occasion,  and no  waiver  of a
default  hereunder  shall  operate  as a waiver  of any other  default  nor as a
continuing waiver.

     Default.  The entire unpaid principal  balance of this Note and all accrued
and unpaid  interest  thereon and all other fees,  charges,  costs and  expenses
hereunder shall become immediately due and payable, without demand, prior to the
maturity of this Note,  at the sole option of the Lender,  (exercisable  without
demand,  notice or protest,  which are hereby  



                                      -5-



waived)  regardless of any prior  forbearance or indulgence by the Lender,  upon
the  occurrence  of one or more Events of Default as that term is defined in the
Loan Agreement.

     Commercial Purposes.  The Borrower hereby represents to the Lender that the
proceeds  of this Note shall be used  exclusively  for  business  or  commercial
purposes and not for personal, family or household purposes.

     Payment of Proceeds. The proceeds of any and all loans or advances pursuant
to this Note may be paid to or at the direction of the Borrower.

     Authority to Debit Accounts.  The Borrower hereby  authorizes the Lender to
charge or debit any deposit  account of the  Borrower  with the Lender to effect
any payment due hereunder, all without prior notice.

     Authority to Complete  this Note.  In the event that this Note is delivered
in an incomplete form in any respect, the Borrower and each co-maker,  guarantor
and other person or entity liable hereon, hereby authorizes the Lender,  without
further  notice,  to complete any blank spaces and to date the Note, if undated,
as of the date funds are first advanced hereunder.

     Currency  and  Payments.  All payments on this Note shall be made in lawful
currency of the United States of America, in each case without deduction, setoff
or  counterclaim.  All  payments  on this  Note  shall  be  made in  immediately
available  funds.  With  respect  to any  payment  on this Note which is made by
check, the Lender may treat such amount as outstanding  pending final collection
thereof,  and interest  hereunder  shall  continue to accrue  pending such final
collection.

     Acknowledgment of Terms and Receipt of a Copy. The Borrower has read all of
the terms and  conditions  of this Note and has  received  an exact copy of this
Note.

     Severability of Provisions.  Any  determination  that any provision of this
Note or any application  thereof is invalid,  illegal,  or  unenforceable in any
respect  in  any  instance   shall  not  affect  the   validity,   legality  and
enforceability  of such  provision  in any  other  instance,  nor the  validity,
legality or enforceability of any other provision hereof.

     Headings. The headings appearing in this Note are used for convenience only
and should not be deemed to affect the interpretation of this Note.

     Sealed Instrument.  This Note shall take effect as a sealed instrument.

     Books and  Records;  Copies as  Evidence.  The  Lender's  books and records
concerning  the  Lender's  loans and  advances to the  Borrower,  the accrual of
interest thereon, and the repayment of such loans, advances and interest,  shall
be prima  facie  evidence  of the  indebtedness  owed under  this  Note.  In any
proceeding with respect to this Note, any



                                      -6-



photographic,  photostatic, microfilm or similar reproduction of this Note shall
be  admissible  in evidence as though it were the  original,  whether or not the
original hereof is in existence and whether or not such reproduction was made in
the regular course of business.

     Governing Law; Jurisdiction for Proceedings.  This Note is delivered to the
Lender in  Boston,  Massachusetts  and shall be  governed  by and  construed  in
accordance with the laws of the Commonwealth of  Massachusetts  for all purposes
and in all respects.  The Borrower, and each co-maker and guarantor of this Note
submits to the  non-exclusive  jurisdiction of the courts of the Commonwealth of
Massachusetts  for all  purposes  with  respect to this Note and any  collateral
given to secure their  respective  liabilities,  obligations and indebtedness to
the Lender, and their respective relationships with the Lender.

     Legal Limitation on Interest.  Notwithstanding  any other provision of this
Note to the contrary,  in the event that interest  pursuant to the provisions of
this Note is  finally  determined  by a court of  competent  jurisdiction  to be
subject to usury or other similar laws affecting the maximum allowable  interest
chargeable  then,  and  only  then,  and  only  to  the  extent  of  such  final
determination,  the maximum amount of interest  payable under this Note shall be
the maximum  amount of interest  determined  by such court to be allowed by such
laws.

     Notices and Notice Addresses. The respective Notice Addresses of the Lender
and the Borrower are those stated at the  beginning of this Note,  together with
the following  additions:  (a) for the Lender,  "Attention:  Commercial  Banking
Group"; and (b) for the Borrower,  "Attention: Kevin W. Quinlan, Chief Financial
Officer".  To the extent required or voluntarily  given,  all notices or demands
hereunder  shall be sufficient and shall be deemed to have been given if made in
writing and given in accordance with the provisions for notice  contained in the
Loan  Agreement.  Any party may change its Notice  Address  hereunder  by giving
notice of such change to the other party in  accordance  with the  provisions of
this subsection.

     Continuing Obligation.  This Note amends and restates, in its entirety, (i)
a $400,000  principal  amount Term  Promissory Note from BBI and BTRL dated July
29, 1992; and (ii) a $500,000  principal  amount Term Promissory Note dated June
18, 1993.  Upon the execution and delivery of this Note, this Note shall replace
the  $400,000  Term  Promissory  Note  and the  $500,000  Term  Note  and  shall
immediately  evidence  all  outstanding  indebtedness  under the  $400,000  Term
Promissory Note and the $500,000 Term Note. The Borrower and Lender hereby agree
that  the  indebtedness  embodied  in and  evidenced  by this  Note is the  same
indebtedness  embodied in and evidenced by the $400,000 Term Promissory Note and
the $500,000 Term Promissory Note,  increased as provided herein,  and that such
indebtedness is a continuing  obligation of the Borrower to the Lender,  and has
been and continues to be fully enforceable, absolute and in existence.



                                      -7-



     IN WITNESS  WHEREOF,  the Borrower has executed this Note, as an instrument
under seal as of the date appearing on the first page of this Note.


                                                          BOSTON BIOMEDICA, INC.



                                                  By:
- ----------------------                               ---------------------------
Witness as to Borrower                                 Kevin W. Quinlan
                                                       Treasurer
                                                       Hereunto duly authorized

                                                  BTRL CONTRACTS AND
                                                  SERVICES, INC.


                                                  By:
                                                     ---------------------------
                                                       Kevin W. Quinlan
                                                       Treasurer
                                                       Hereunto duly authorized

                                                  NORTH AMERICAN LABORATORY
                                                  GROUP, INC.


                                                  By:
                                                     ---------------------------
                                                       Kevin W. Quinlan
                                                       Treasurer
                                                       Hereunto duly authorized



ATTEST:



- ---------------------------
Clerk of Boston Biomedica, Inc.



   
                                       -8-

                                                                 EXHIBIT 10.18.4

                                                                       EXECUTION


                              TERM PROMISSORY NOTE

$350,000.00                                                Boston, Massachusetts
Due:  August 2, 2000                                       Dated: August 2, 1995

     FOR VALUE RECEIVED, the undersigned,  BOSTON BIOMEDICA, INC., ("BBI"), BTRL
CONTRACTS  AND  SERVICES,   INC.   ("BTRL")  and  BBI-NORTH   AMERICAN  CLINICAL
LABORATORIES,  INC.,  formerly known as NORTH AMERICAN  LABORATORY GROUP,  INC.,
("NACL"), each of which is a Massachusetts  corporation validly created, legally
existing  and  in  good  standing  under  the  laws  of  the   Commonwealth   of
Massachusetts  and each of which has its "Notice  Address"  at 375 West  Street,
West  Bridgewater,  Massachusetts  02379, with BBI having its principal place of
business at its Notice Address, BTRL having its principal place of business at 3
Taft Court,  Rockville,  Maryland  20850 and NACL having its principal  place of
business at 75 North Mountain Road, New Britain,  Connecticut  06053 (BBI,  BTRL
and NACL, together with their successors and assigns, are collectively  referred
to herein as the "Borrower") JOINTLY AND SEVERALLY,  AND UNCONDITIONALLY PROMISE
TO PAY TO THE ORDER OF THE FIRST  NATIONAL  BANK OF BOSTON,  a national  banking
association  having an office and "Notice  Address" at Bank of  Boston-Worcester
Tower,  P.O. Box 15073, 100 Front Street,  Worcester,  Massachusetts  01608-1438
(together with its successors and assigns, the "Lender"), successor-by-merger to
WORCESTER COUNTY INSTITUTION FOR SAVINGS, a Massachusetts savings bank ("WCiS"),
the principal sum of THREE HUNDRED FIFTY THOUSAND  DOLLARS  ($350,000.00),  with
interest on the unpaid  balance  thereof  from the date hereof until paid at the
rate and in the manner herein provided,  in lawful money of the United States of
America.

     Second Amended and Restated Loan Agreement. The Borrower and the Lender are
parties to a certain  Second  Amended and Restated  Loan and Security  Agreement
(the  "Loan  Agreement")  dated  as of the  date  hereof.  Terms  not  otherwise
specifically  defined in this Term Promissory Note  (hereinafter  referred to as
the  "Note")  shall  have  the  respective  meanings  given  to them in the Loan
Agreement.

     Principal  Advances.  The Lender shall  advance sums  hereunder,  up to the
principal amount hereof,  for a period of six (6) months from the date hereof in
accordance with the provisions of the Loan Agreement (the "Advance Period").

     Interest  Rate.  The  unpaid  principal  of  this  Note  from  time to time
outstanding shall bear interest,  computed on the basis of actual number of days
elapsed  over a year  assumed to have 360 days,  at an  interest  rate per annum
equal to one percent  (1.00%)  per annum above the rate of interest  established
from time to time by the Lender as its Base Lending Rate (the "Base Rate"), such
interest  rate to be  determined on a daily basis and adjusted from time to time
on the effective date of any change in the Base Rate by the Lender.
     





     Certain Provisions Regarding Interest. To the extent used herein, Base Rate
means the rate of interest per annum announced, from time to time, by the Lender
as its Base Rate.  The Borrower  acknowledges  that the Base Rate is a reference
rate and not  necessarily  the lowest rate  charged by the Lender to  borrowers.
Interest per annum shall be  calculated  for the actual  number of days elapsed,
from time to time, over a year assumed to have 360 days. Therefore,  each dollar
of  principal  outstanding  hereunder  for all or any part of a day shall accrue
interest equal to 1/360th of the annual interest accruing hereunder on each such
dollar.  Interest shall accrue on each day or part thereof that any principal is
outstanding including Sundays,  holidays and all days during which the Lender is
not open for the conduct of business.

     Interest  Increase after Maturity or Acceleration.  Any and all amounts not
paid when due hereunder,  whether after maturity,  by acceleration or otherwise,
shall accrue interest,  payable on demand, at the greater of (i) the annual rate
of eighteen  percent  (18%) or (ii) the annual  rate equal to two  percent  (2%)
above the Base Rate, if permitted by law, calculated as above from the date when
due until so paid.

     Payments.  Commencing on August 18, 1995, and on the same day of each month
thereafter  up to and  including  February 18, 1996,  payments of interest  only
shall be made in arrears on the outstanding principal amount of this Note.

     Commencing  on March  18,  1996,  payments  on this  Note  shall be made in
fifty-four (54) consecutive monthly installments of principal and interest.  The
first fifty-three (53) such installments shall be equal to  one-fifty-fourth  of
the  principal  amount of this Note which has been  advanced,  plus  accrued and
unpaid interest in arrears.  The last installment shall comprise the then unpaid
principal balance of this Note together with all accrued and unpaid interest and
any and all other fees,  charges,  costs and  expenses due and payable to Lender
hereunder.

     Late Charges. If any payment due hereunder is not paid within ten (10) days
of its due date, the Borrower will also pay to Lender, on demand and in addition
to all other amounts payable hereunder,  an amount equal to five percent (5%) of
the amount of such payment.  The assessment or collection of late charges is not
intended  and shall not be  construed  to permit  payment of any amount  payable
hereunder  beyond the  applicable  due date  thereof.  The time period  which is
allowed  before the  assessment of late charges is not intended and shall not be
construed  as a grace or cure period with respect to payment or  performance  of
any obligation hereunder.

     Prepayment.  To the extent that interest accrues  hereunder at the Adjusted
Base Rate,  the Borrower  shall have the right to prepay all or a portion of the
entire  outstanding  principal  balance of this Note without  penalty so long as
such  prepayment  includes  payment of all accrued and unpaid interest and other
accrued  costs and charges of Lender.  If Borrower  shall have elected the Fixed
Rate Option, the Borrower shall have the right to prepay all or a portion of the
entire  outstanding  principal  balance  of this  Note 


                                      -2-



("Prepayment") upon (a) delivery of sixty (60) days' prior written notice to the
Lender,  (b) payment of all accrued interest and other accrued charges and costs
of Lender, and (c) payment of a Prepayment premium determined as provided in the
next sentence of this paragraph.  Such Prepayment  premium shall be in an amount
equal to the daily  interest for the remaining  term  hereunder on the principal
amount so prepaid at a daily rate equal to one-three hundred sixtieth  (1/360th)
of the difference (if positive) of (i) the Fixed Rate  applicable  thereto minus
(ii) the rate of interest  obtainable  by the Lender  upon the  purchase of debt
securities  customarily  issued by the Treasury of the United States of America,
in an amount  equal to the  principal  amount so prepaid,  which have a maturity
date approximating the Maturity Date. The Lender's  determination of such amount
of interest, in the absence of manifest error, shall be conclusive.

     Application of Payments.  Any payments received by the Lender on account of
this Note prior to maturity or other acceleration,  shall be applied:  first, to
any fees, charges, costs and expenses then owed to the Lender by the Borrower in
connection  with this Note;  second to accrued and unpaid interest on the unpaid
balance of principal;  and third, to the unpaid balance of principal hereof. Any
payments  received by the Lender on account of this Note after maturity or other
acceleration shall be applied in such manner as the Lender may determine.

     Note Issued Pursuant to Loan Agreement. This Note is issued pursuant to the
Loan  Agreement,  and the holder  hereof is entitled to the benefits of the Loan
Agreement, and all other agreements, instruments, guarantees and other documents
executed  and  delivered in  connection  therewith  and  herewith  (collectively
referred to herein as the "Financing Instruments").

     Maturity Date. The entire  outstanding  principal  balance hereof  together
with all accrued and unpaid interest  thereon and all fees,  charges,  costs and
expenses  due Lender  hereunder  shall be due and payable on August 2, 2000 (the
"Maturity Date").

     Security  Provided in Other Writings.  Payment and performance of this Note
may be secured, from time to time, now or hereafter,  as provided in one or more
security agreements,  mortgages,  pledges, assignments or any other instruments,
documents or agreements ("Security"),  whether or not such Security specifically
refers to this Note.  Any and all such Security may provide,  in general  terms,
that such Security secures obligations of the Borrower to the Lender however and
whenever evidenced,  created or arising. Payment and performance of this Note is
hereby secured by such Security without specific reference to this Note, and, in
addition, this Note is secured by any and all Security which specifically refers
to or provides security for this Note.

     Grant of Security  in Accounts  and Other  Property  in  Possession  of the
Lender.  To secure the payment and performance of this Note, the Borrower hereby
grants to the Lender a continuing  security  interest in and to: (a) any and all
deposits and sums at any time  credited by or due from the Lender (or any of its
banking  or  lending  affiliates)  to the  



                                      -3-



Borrower; and (b) any or all cash, instruments, securities and other property of
the Borrower, in the possession,  custody or control (whether for safekeeping or
otherwise)  of, or in  transit  to or from,  the  Lender or any such  affiliate,
including such property in the possession of any third party acting on behalf of
the Lender or any such  affiliate,  regardless  of the  reason for the  receipt,
possession,  custody or control of such property or any prior  release  thereof,
conditional or otherwise.  Upon demand,  maturity or acceleration of the payment
of this Note, as applicable, the Lender may, at any time, sell or dispose of any
or all such property and apply the proceeds  thereof against the indebtedness of
this Note.  With respect to all such property,  the Lender shall have the rights
and  remedies of a secured  party under the  Uniform  Commercial  Code and other
applicable  laws, the choice and manner of exercise of any right or remedy being
in the Lender's sole discretion. No such right or remedy shall be exclusive, and
each may be exercised by the Lender  concurrently or in any order or combination
as the Lender may select,  from time to time. The Lender shall have the right to
foreclose  the  security  interest  granted  herein  by any  available  judicial
procedure and to sell the same with or without judicial process;  the Lender may
sell or  otherwise  dispose of such  property  or any part  thereof at public or
private sales,  at such price or prices,  and upon such terms,  either for cash,
credit or future delivery,  as the Lender may elect;  and, except as to any part
of such property which is perishable or which  threatens to decline  speedily in
value, or is of the type  customarily  sold on a recognized  market,  the Lender
shall give the Borrower reasonable  notification of such sale or sales, it being
agreed that in all events  written  notice mailed to the Borrower at least seven
(7) days  prior to such sale is  reasonable  notification.  The  Lender may (but
shall  have no  obligation  to) bid for and  become  the  purchaser  of any such
property.

     Setoff.  With respect to any and all  deposits and sums  referred to above,
upon the Maturity Date or  acceleration  of the payment of this Note, the Lender
may, at any time,  apply or setoff all or any  portion of such  deposits or sums
against  the  indebtedness  evidenced  by this  Note,  regardless  of any  other
collateral or security available to the Lender.

     Payment  of  Costs  and  Attorney's  Fees.  The  Borrower  agrees,  and all
co-makers and guarantors  also agree,  jointly and  severally,  to pay all costs
incurred  by  the  Lender,   including  all  attorneys'   reasonable   fees  and
out-of-pocket costs and expenses,  including court costs, in connection with (i)
the  administration  or  implementation of the loan evidenced by this Note, (ii)
the  collection  of the  indebtedness  evidenced  by this  Note,  or  (iii)  the
preservation,  protection,  collection  or  enforcement  of any of the  Lender's
rights  or  remedies  hereunder  or  under  any  other  instrument  securing  or
guaranteeing  this Note,  against the Borrower or any co-maker or guarantor,  or
against any  collateral  securing  this Note or securing  any other  instrument,
document or agreement securing or guaranteeing this Note (whether or not suit is
instituted by or against the Lender).

     Waivers and Consents by Borrower and Others. By making or guaranteeing this
Note or by making any agreement to pay any of the indebtedness evidenced by this
Note, the Borrower, and each co-maker, guarantor, and other person or entity now
or hereafter


                                      -4-


liable  for the  payment  of any of the  indebtedness  evidenced  by this  Note,
respectively,  agrees to waive: presentment for payment; protest; demand; notice
of protest,  demand,  dishonor and  non-payment of this Note; all other notices;
all other defenses in the nature thereof, including all suretyship defenses; and
any and  all  other  demands  or  notices  otherwise  required  to be  given  in
connection with the delivery, acceptance,  endorsement,  performance, default or
enforcement of this Note, any and all borrowings or advances hereunder,  any and
all  guarantees  or  undertakings  hereof,  and any security  taken,  granted or
released,  from time to time, in connection herewith. The Borrower and each such
co-maker,  guarantor and other person or entity hereby consents, without notice:
(a) to the  substitution,  exchange  or  release,  from  time  to  time,  of any
collateral securing this Note or any part thereof;  (b) to the acceptance,  from
time to time,  by the Lender of any  additional  collateral or security for this
Note, or the acceptance, from time to time, of other makers, guarantors or other
obligors of this Note, (c) to the modification or amendment,  from time to time,
of this  Note and any  other  instrument,  document  or  agreement  securing  or
guaranteeing  this Note, at the request of any person or entity liable  thereon;
(d) to the granting of any extension of the time for payment of this Note or any
other indulgence for the performance of the agreements, covenants and conditions
contained in this Note, or any other instrument,  document or agreement securing
or  guaranteeing  this  Note,  at the  request  of any  person or entity  liable
thereon;  (e) to any and all  other  extensions,  forbearances  and  indulgences
whatsoever  granted by the Lender with respect to this Note, any other liability
of the Borrower,  or any collateral securing this Note or any other liability of
the  Borrower to the Lender;  and any and all  assignments  or transfers of this
Note and any part or all of the  indebtedness  evidenced  hereby or any security
therefor or guarantees thereof to any successor,  assignee, participant or other
party.  The happening of any one or more of the foregoing events shall not alter
or  diminish  the  liability  of any person or entity  liable on this Note.  The
release by the Lender of the Borrower or any one or more co-makers or guarantors
shall not release any other  person  obligated  on account of this Note,  except
only for  payments  actually  received by Lender free and clear of the rights of
all other  parties.  No person or entity  obligated  on account of this Note may
seek  contribution  from any other  person or entity also  obligated  unless and
until all liabilities, obligations, and indebtedness to the Lender of the person
from whom contribution is sought have been satisfied in full.

     Joint  and  Several   Obligations;   Binding  Effect.  This  Note  and  the
liabilities of the Borrower shall be the joint and several obligation of each of
the undersigned, if more than one, and each guarantor, co-maker, and surety, and
shall  be  binding  upon  each  of them  and  each of  their  respective  heirs,
representatives,  successors and assigns,  and shall inure to the benefit of the
Lender and its successors, indorsees and assigns. Each reference in this Note to
the  Borrower,  any  co-maker  and any  guarantor  refers to each such person or
entity individually and also to all such persons and entities jointly.  The term
"Lender"  shall include the Lender and each other payee hereof,  or any indorsee
of this Note in  possession  hereof,  or the bearer hereof if the Note is at the
time payable to the bearer.



                                      -5-



     The  Lender's  Rights  Reserved.  No delay or  omission  on the part of the
Lender in exercising or enforcing any of the Lender's rights, powers, privileges
or remedies or discretions  hereunder or under any instrument or agreement which
is given or may be  given to  secure  or  guaranty  the  indebtedness  evidenced
hereby,  shall  operate  as a waiver  thereof,  or of any  other  right,  power,
privilege  or remedy of such holder on that  occasion or on any other  occasion,
nor shall any delay,  omission  or waiver on any one  occasion be deemed to be a
bar to or waiver of the same or any other right on any future  occasion,  and no
waiver of a default hereunder shall operate as a waiver of any other default nor
as a continuing waiver.

     Default.  The entire unpaid principal  balance of this Note and all accrued
and unpaid  interest  thereon and all other fees,  charges,  costs and  expenses
hereunder shall become immediately due and payable, without demand, prior to the
maturity of this Note,  at the sole option of the Lender,  (exercisable  without
demand,  notice or protest,  which are hereby  waived)  regardless  of any prior
forbearance  or  indulgence  by the Lender,  upon the  occurrence of one or more
Events of Default as that term is defined in the Loan Agreement.

     Commercial Purposes.  The Borrower hereby represents to the Lender that the
proceeds  of this Note shall be used  exclusively  for  business  or  commercial
purposes and not for personal, family or household purposes.

     Payment of Proceeds. The proceeds of any and all loans or advances pursuant
to this Note may be paid to or at the direction of the Borrower.

     Authority to Debit Accounts.  The Borrower hereby  authorizes the Lender to
charge or debit any deposit  account of the  Borrower  with the Lender to effect
any payment due hereunder, all without prior notice.

     Authority to Complete  this Note.  In the event that this Note is delivered
in an incomplete form in any respect, the Borrower and each co-maker,  guarantor
and other person or entity liable hereon, hereby authorizes the Lender,  without
further  notice,  to complete any blank spaces and to date the Note, if undated,
as of the date funds are first advanced hereunder.

     Currency  and  Payments.  All payments on this Note shall be made in lawful
currency of the United States of America, in each case without deduction, setoff
or  counterclaim.  All  payments  on this  Note  shall  be  made in  immediately
available  funds.  With  respect  to any  payment  on this Note which is made by
check, the Lender may treat such amount as outstanding  pending final collection
thereof,  and interest  hereunder  shall  continue to accrue  pending such final
collection.

     Acknowledgment of Terms and Receipt of a Copy. The Borrower has read all of
the terms and  conditions  of this Note and has  received  an exact copy of this
Note.


                                      -6-



     Severability of Provisions.  Any  determination  that any provision of this
Note or any application  thereof is invalid,  illegal,  or  unenforceable in any
respect  in  any  instance   shall  not  affect  the   validity,   legality  and
enforceability  of such  provision  in any  other  instance,  nor the  validity,
legality or enforceability of any other provision hereof.

     Headings. The headings appearing in this Note are used for convenience only
and should not be deemed to affect the interpretation of this Note.

     Sealed Instrument.  This Note shall take effect as a sealed instrument.

     Books and  Records;  Copies as  Evidence.  The  Lender's  books and records
concerning  the  Lender's  loans and  advances to the  Borrower,  the accrual of
interest thereon, and the repayment of such loans, advances and interest,  shall
be prima  facie  evidence  of the  indebtedness  owed under  this  Note.  In any
proceeding with respect to this Note, any photographic,  photostatic,  microfilm
or similar  reproduction  of this Note shall be admissible in evidence as though
it were the  original,  whether or not the original  hereof is in existence  and
whether or not such reproduction was made in the regular course of business.

     Governing Law; Jurisdiction for Proceedings.  This Note is delivered to the
Lender in  Boston,  Massachusetts  and shall be  governed  by and  construed  in
accordance with the laws of the Commonwealth of  Massachusetts  for all purposes
and in all respects.  The Borrower, and each co-maker and guarantor of this Note
submits to the  non-exclusive  jurisdiction of the courts of the Commonwealth of
Massachusetts  for all  purposes  with  respect to this Note and any  collateral
given to secure their  respective  liabilities,  obligations and indebtedness to
the Lender, and their respective relationships with the Lender.

     Legal Limitation on Interest.  Notwithstanding  any other provision of this
Note to the contrary,  in the event that interest  pursuant to the provisions of
this Note is  finally  determined  by a court of  competent  jurisdiction  to be
subject to usury or other similar laws affecting the maximum allowable  interest
chargeable  then,  and  only  then,  and  only  to  the  extent  of  such  final
determination,  the maximum amount of interest  payable under this Note shall be
the maximum  amount of interest  determined  by such court to be allowed by such
laws.

     Notices and Notice Addresses. The respective Notice Addresses of the Lender
and the Borrower are those stated at the  beginning of this Note,  together with
the following  additions:  (a) for the Lender,  "Attention:  Commercial  Banking
Department";  and (b) for the  Borrower,  "Attention:  Kevin W.  Quinlan,  Chief
Financial Officer".  To the extent required or voluntarily given, all notices or
demands  hereunder shall be sufficient and shall be deemed to have been given if
made in writing and given in accordance with the provisions for notice contained
in the Loan  Agreement.  Any party may change its Notice  Address  hereunder  by
giving  notice  of such  change  to the  other  party  in  accordance  with  the
provisions of this subsection.



                                      -7-



     IN WITNESS  WHEREOF,  the Borrower has executed this Note, as an instrument
under seal as of the date appearing on the first page of this Note.


                                                    BOSTON BIOMEDICA, INC.



/s/   ?                                             By: /s/ Kevin W. Quinlan
- ----------------------                                 -------------------------
Witness as to Borrower                                  Kevin W. Quinlan
                                                        Treasurer
                                                        Hereunto duly authorized


                                                    BTRL CONTRACTS AND
                                                    SERVICES, INC.


                                                    By: /s/ Kevin W. Quinlan
                                                       -------------------------
                                                        Kevin W. Quinlan
                                                        Treasurer
                                                        Hereunto duly authorized


                                                    BBI - NORTH AMERICAN
                                                    CLINICAL LABORATORIES, INC.


                                                    By: /s/ Kevin W. Quinlan
                                                       -------------------------
                                                        Kevin W. Quinlan
                                                        Treasurer
                                                        Hereunto duly authorized







                                      -8-

                                                                 EXHIBIT 10.18.5

                                                                       EXECUTION

                              TERM PROMISSORY NOTE

$100,000.00                                                Boston, Massachusetts
Due: December 1, 2000                                   Dated: December 29, 1995

         FOR VALUE RECEIVED, the undersigned,  BOSTON BIOMEDICA,  INC., ("BBI"),
BTRL  CONTRACTS AND SERVICES,  INC.  ("BTRL") and  BBI-NORTH  AMERICAN  CLINICAL
LABORATORIES,  INC.  ("NACL"),  each of  which  is a  Massachusetts  corporation
validly  created,  legally  existing and in good standing  under the laws of The
Commonwealth of Massachusetts  and each of which has its "Notice Address" at 375
West  Street,  West  Bridgewater,  Massachusetts  02379,  with  BBI  having  its
principal  place of business at its Notice  Address,  BTRL having its  principal
place of business at 3 Taft Court, Rockville, Maryland 20850 and NACL having its
principal place of business at 75 North Mountain Road, New Britain,  Connecticut
06053 (BBI,  BTRL and NACL,  together  with their  successors  and assigns,  are
collectively  referred to herein as the "Borrower")  JOINTLY AND SEVERALLY,  AND
UNCONDITIONALLY  PROMISE  TO PAY TO THE  ORDER  OF THE  FIRST  NATIONAL  BANK OF
BOSTON, a national banking  association having an office and "Notice Address" at
Bank of  Boston-Worcester  Tower,  P.O. Box 15073, 100 Front Street,  Worcester,
Massachusetts   01608-1438  (together  with  its  successors  and  assigns,  the
"Lender") the principal sum of ONE HUNDRED  THOUSAND  DOLLARS  ($100,000),  with
interest on the unpaid  balance  thereof  from the date hereof until paid at the
rate and in the manner herein provided,  in lawful money of the United States of
America.

         Note Issued Pursuant to Loan Agreement. This Note is issued pursuant to
a certain Second  Amended and Restated Loan and Security  Agreement by and among
the Borrower and the Lender, dated as of August 2, 1995, as amended by a certain
First  Amendment to Second  Amended and Restated Loan and Security  Agreement by
and among the  Borrower and the Lender,  dated as of December  11,  1995,  and a
certain  Second  Amendment  to Second  Amended and  Restated  Loan and  Security
Agreement  by and  among  the  Borrower  and the  Lender,  dated  as of the date
herewith  (as so amended  and as may be further  amended,  restated  or modified
hereafter,  the "Loan  Agreement"),  and the holder  hereof is  entitled  to the
benefits  of  the  Loan  Agreement,  and  all  other  agreements,   instruments,
guarantees and other documents  defined therein as the "Financing  Instruments".
Terms  not  otherwise   specifically   defined  in  this  Term  Promissory  Note
(hereinafter referred to as the "Note") shall have the respective meanings given
to them in the Loan Agreement.

         Interest  Rate.  The  unpaid  principal  of this Note from time to time
outstanding shall bear interest,  computed on the basis of actual number of days
elapsed  over a year assumed to have three  hundred and sixty (360) days,  at an
interest  rate per annum equal to one  percent  (1%) per annum above the rate of
interest  established  from time to time by the Lender as its Base  Lending Rate
(the "Base  Rate"),  such  interest  rate to be  determined on a daily basis and
adjusted from time to time on the effective  date of any change in the Base Rate
by the Lender (the "Adjusted Base Rate");  provided,  however, that the Borrower
may,





at any time,  elect to have interest  computed  hereunder  pursuant to the Fixed
Rate  Option (as  hereinafter  defined) by written  notice to the Lender,  which
notice,  once sent to the Lender,  shall be  irrevocable.  In the absence of the
election of the Fixed Rate Option,  the principal amount  outstanding  hereunder
shall bear interest at the Adjusted Base Rate.

         "Fixed Rate Option" as used herein  shall mean the  one-time  option of
the  Borrower to have  interest  computed  hereunder on the basis of an interest
rate per annum  equal to two and  one-half  percent  (2.50%) per annum above the
"Fixed Rate" (as  hereinafter  defined) (the "Adjusted Fixed Rate") for a period
of three,  four or five years (the "Fixed Rate Period").  The "Fixed Rate" shall
be the fixed rate of interest quoted by the Lender for the outstanding principal
balance  hereunder for the remainder of the term  hereunder.  Upon expiration of
the Fixed Rate Period,  the principal  amount  outstanding  hereunder shall then
immediately  bear interest at the Adjusted Base Rate for the balance at the term
hereof, if any.

         Certain Provisions Regarding Interest.  The Borrower  acknowledges that
the Base Rate is a reference rate and not necessarily the lowest rate charged by
the Lender to borrowers.  Interest per annum shall be calculated  for the actual
number of days elapsed, from time to time, over a year assumed to have 360 days.
Therefore, each dollar of principal outstanding hereunder for all or any part of
a day shall accrue  interest  equal to 1/360th of the annual  interest  accruing
hereunder on each such dollar. Interest shall accrue on each day or part thereof
that any  principal  is  outstanding  including  Sundays,  holidays and all days
during which the Lender is not open for the conduct of business.

         Interest  Increase after Maturity or Acceleration.  Any and all amounts
not paid when due  hereunder,  whether after the Maturity  Date (as  hereinafter
defined),  by  acceleration  or  otherwise,  shall accrue  interest,  payable on
demand,  at the annual rate equal to four  percent (4%) above the Base Rate (the
"Default Rate"), if permitted by law, calculated as above from the date when due
until so paid.

         Payments.  Commencing on January 1st, 1996, and on the same day of each
month thereafter until the Maturity Date, payments on this Note shall be made in
sixty (60) consecutive monthly installments of principal and interest. The first
fifty-nine (59) such installments shall be equal to one-sixtieth (1/60th) of the
principal amount of this Note, plus accrued and unpaid interest in arrears.  The
last installment  shall comprise the then unpaid principal  balance of this Note
together  with all  accrued  and  unpaid  interest  and any and all other  fees,
charges, costs and expenses due and payable to the Lender hereunder.

         Late Charges.  If any payment due hereunder is not paid within ten (10)
days of its due date, the Borrower will also pay to the Lender, on demand and in
addition  to all other  amounts  payable  hereunder,  an  amount  equal to three
percent (3%) of the amount of such payment. The assessment or collection of late
charges is not


                                      -2-


intended  and shall not be  construed  to permit  payment of any amount  payable
hereunder  beyond the  applicable  due date  thereof.  The time period  which is
allowed  before the  assessment of late charges is not intended and shall not be
construed  as a grace or cure period with respect to payment or  performance  of
any obligation hereunder.

         Prepayment.  "Prepayment"  shall mean any  payment  of the  outstanding
principal due hereunder, whether in whole or in part, (a) on any date in advance
of the date scheduled therefor,  or (b) following  acceleration of the loan as a
consequence  of the occurrence of any Event of Default,  as defined  below.  Any
Prepayment  made by the Borrower  (other than a payment of the full  outstanding
principal  balance due under the Note) must be in an amount which is an integral
multiple of $10,000. Prior to the making of any Prepayment,  the Borrower shall:
(a) deliver  five (5) days' prior  written  notice to the Lender  apprising  the
Lender of the making of such Prepayment,  (b) pay all accrued interest and other
accrued  charges and costs of Lender to the date of  prepayment on the principal
amount so prepaid, (c) pay a Prepayment premium equal to one percent (1%) of the
amount prepaid in the event that such Prepayment is from a refinancing,  and (d)
if, at the time of  Prepayment,  the Borrower has elected the Fixed Rate Option,
pay the Fixed Rate  Prepayment  Premium as defined in the next  sentence of this
paragraph.  The "Fixed Rate  Prepayment  Premium" shall be an amount  reasonably
determined  by the  Lender for the loss,  if any,  including  any lost  profits,
resulting from such prepayment. The Borrower shall pay the Prepayment premium or
the Fixed Rate Prepayment Premium, whichever is applicable, upon presentation by
the Lender of a  statement  therefor,  which in either case shall be deemed true
and correct,  absent manifest error. In addition,  in the case of the Fixed Rate
Prepayment Premium,  such statement shall set forth the Lender's  calculation of
the same, which statement and calculation  (including the method of calculation)
shall be deemed true and correct,  absent manifest error. Any amounts prepaid by
the Borrower may not be subsequently re-borrowed from the Lender.

         Application of Payments. Any payments received by the Lender on account
of this Note prior to the Maturity Date or by acceleration  or otherwise,  shall
be applied:  first,  to any fees,  charges,  costs and expenses then owed to the
Lender by the  Borrower  in  connection  with this Note;  second to accrued  and
unpaid  interest on the unpaid  balance of principal;  and third,  to the unpaid
balance of principal  hereof.  Any payments received by the Lender on account of
this Note after the  Maturity  Date or by  acceleration  or  otherwise  shall be
applied in such manner as the Lender may determine.

         Maturity Date. The entire outstanding principal balance hereof together
with all accrued and unpaid interest  thereon and all fees,  charges,  costs and
expenses due the Lender  hereunder  shall be due and payable on December 1, 2000
(the "Maturity Date").

         Security  Provided in Other  Writings.  Payment and performance of this
Note may be secured, from time to time, now or hereafter,  as provided in one or
more  security  agreements,   mortgages,   pledges,  assignments  or  any  other
instruments,  documents or agreements ("Security"), whether or not such Security
specifically  refers to this Note.  Any and all such  Security may  provide,  in
general  terms,  that such Security  secures  obligations of the Borrower to the
Lender  however  and  whenever  evidenced,   created  or  arising.


                                      -3-


Payment and performance of this Note is hereby secured by such Security  without
specific  reference to this Note, and, in addition,  this Note is secured by any
and all  Security  which  specifically  refers to or provides  security for this
Note, or is referenced in the Loan Agreement or otherwise.

         Grant of Security in Accounts and Other  Property in  Possession of the
Lender.  To secure the payment and performance of this Note, the Borrower hereby
grants to the Lender a continuing  security  interest in and to: (a) any and all
deposits and sums at any time  credited by or due from the Lender (or any of its
banking  or  lending  affiliates)  to the  Borrower;  and (b)  any or all  cash,
instruments,  securities and other property of the Borrower,  in the possession,
custody or control  (whether for  safekeeping or otherwise) of, or in transit to
or from,  the  Lender or any such  affiliate,  including  such  property  in the
possession  of any  third  party  acting  on  behalf  of the  Lender or any such
affiliate,  regardless  of the reason for the  receipt,  possession,  custody or
control of such property or any prior release thereof, conditional or otherwise.
Upon  demand,  maturity  or  acceleration  of  the  payment  of  this  Note,  as
applicable,  the  Lender  may,  at any time,  sell or dispose of any or all such
property and apply the proceeds  thereof against the  indebtedness of this Note.
With respect to all such property, the Lender shall have the rights and remedies
of a secured party under the Uniform  Commercial Code and other applicable laws,
the choice and manner of exercise of any right or remedy  being in the  Lender's
sole  discretion.  No such right or remedy shall be  exclusive,  and each may be
exercised  by the  Lender  concurrently  or in any order or  combination  as the
Lender  may  select,  from  time to time.  The  Lender  shall  have the right to
foreclose  the  security  interest  granted  herein  by any  available  judicial
procedure and to sell the same with or without judicial process;  the Lender may
sell or  otherwise  dispose of such  property  or any part  thereof at public or
private sales,  at such price or prices,  and upon such terms,  either for cash,
credit or future delivery,  as the Lender may elect;  and, except as to any part
of such property which is perishable or which  threatens to decline  speedily in
value, or is of the type  customarily  sold on a recognized  market,  the Lender
shall give the Borrower reasonable  notification of such sale or sales, it being
agreed that in all events  written  notice mailed to the Borrower at least seven
(7) days  prior to such sale is  reasonable  notification.  The  Lender may (but
shall  have no  obligation  to) bid for and  become  the  purchaser  of any such
property.

         Setoff.  With  respect to any and all  deposits  and sums  referred  to
above,  upon the Maturity Date or upon acceleration of the payment of this Note,
the Lender may, at any time, apply or setoff all or any portion of such deposits
or sums against the indebtedness evidenced by this Note, regardless of any other
collateral or security available to the Lender.

         Payment of Costs and  Attorney's  Fees.  The Borrower  agrees,  and all
co-makers and guarantors  also agree,  jointly and  severally,  to pay all costs
incurred  by  the  Lender,   including  all  attorneys'   reasonable   fees  and
out-of-pocket costs and expenses,  including court costs, in connection with (i)
the  administration  or  implementation of the loan evidenced by this Note, (ii)
the  collection  of the  indebtedness  evidenced  by this  Note,  or  (iii)  the



                                      -4-


preservation,  protection,  collection  or  enforcement  of any of the  Lender's
rights  or  remedies  hereunder  or  under  any  other  instrument  securing  or
guaranteeing  this Note,  against the Borrower or any co-maker or guarantor,  or
against any  collateral  securing  this Note or securing  any other  instrument,
document or agreement securing or guaranteeing this Note (whether or not suit is
instituted by or against the Lender).

         Waivers and Consents by Borrower and Others.  By making or guaranteeing
this Note or by making any agreement to pay any of the indebtedness evidenced by
this Note,  the  Borrower,  and each  co-maker,  guarantor,  and other person or
entity  now or  hereafter  liable  for the  payment  of any of the  indebtedness
evidenced by this Note, respectively,  agrees to waive: presentment for payment;
protest;  demand;  notice of protest,  demand,  dishonor and non-payment of this
Note; all other notices; all other defenses in the nature thereof, including all
suretyship defenses; and any and all other demands or notices otherwise required
to  be  given  in  connection  with  the  delivery,   acceptance,   endorsement,
performance,  default or  enforcement  of this Note,  any and all  borrowings or
advances  hereunder,  any and all  guarantees or  undertakings  hereof,  and any
security taken, granted or released,  from time to time, in connection herewith.
The Borrower and each such co-maker, guarantor and other person or entity hereby
consents,  without notice:  (a) to the substitution,  exchange or release,  from
time to time, of any collateral  securing this Note or any part thereof;  (b) to
the acceptance, from time to time, by the Lender of any additional collateral or
security for this Note, or the  acceptance,  from time to time, of other makers,
guarantors  or  other   obligors  of  this  Note,   (c)  to  the   modification,
substitution,  extension or  amendment,  from time to time, of this Note and any
other instrument,  document or agreement  securing or guaranteeing this Note, at
the request of any person or entity liable  thereon;  (d) to the granting of any
extension of the time for payment of this Note or any other  indulgence  for the
performance of the agreements,  covenants and conditions contained in this Note,
or any other  instrument,  document or agreement  securing or guaranteeing  this
Note, at the request of any person or entity liable thereon;  (e) to any and all
other extensions,  forbearances and indulgences whatsoever granted by the Lender
with  respect  to  this  Note,  any  other  liability  of the  Borrower,  or any
collateral  securing  this Note or any other  liability  of the  Borrower to the
Lender;  and any and all  assignments  or transfers of this Note and any part or
all of the indebtedness  evidenced hereby or any security therefor or guarantees
thereof to any successor, assignee, participant or other party. The happening of
any one or more  of the  foregoing  events  shall  not  alter  or  diminish  the
liability of any person or entity liable on this Note. The release by the Lender
of the Borrower or any one or more co-makers or guarantors shall not release any
other  person  obligated  on  account  of this Note,  except  only for  payments
actually  received by Lender free and clear of the rights of all other  parties.
No person or entity obligated on account of this Note may seek contribution from
any other  person or entity  also  obligated  unless and until all  liabilities,
obligations, and indebtedness to the Lender of the person from whom contribution
is sought have been satisfied in full.

         Joint  and  Several  Obligations;  Binding  Effect.  This  Note and the
liabilities of the Borrower shall be the joint and several obligation of each of
the undersigned, if more than


                                      -5-



one, and each guarantor, co-maker, and surety, and shall be binding upon each of
them  and  each of  their  respective  heirs,  representatives,  successors  and
assigns,  and shall  inure to the  benefit  of the  Lender  and its  successors,
indorsees and assigns. Each reference in this Note to the Borrower, any co-maker
and any guarantor refers to each such person or entity  individually and also to
all such persons and  entities  jointly.  The term  "Lender"  shall  include the
Lender and each other payee  hereof,  or any indorsee of this Note in possession
hereof, or the bearer hereof if the Note is at the time payable to the bearer.

         The Lender's Rights  Reserved.  No delay or omission on the part of the
Lender in exercising or enforcing any of the Lender's rights, powers, privileges
or remedies or discretions  hereunder or under any instrument or agreement which
is given or may be  given to  secure  or  guaranty  the  indebtedness  evidenced
hereby,  shall  operate  as a waiver  thereof,  or of any  other  right,  power,
privilege  or remedy of such holder on that  occasion or on any other  occasion,
nor shall any delay,  omission  or waiver on any one  occasion be deemed to be a
bar to or waiver of the same or any other right on any future  occasion,  and no
waiver of a default hereunder shall operate as a waiver of any other default nor
as a continuing waiver.

         Default.  The  entire  unpaid  principal  balance  of this Note and all
accrued  and unpaid  interest  thereon and all other  fees,  charges,  costs and
expenses  hereunder shall become  immediately  due and payable,  without demand,
prior  to  the  maturity  of  this  Note,  at the  sole  option  of the  Lender,
(exercisable  without  demand,  notice  or  protest,  which are  hereby  waived)
regardless  of any prior  forbearance  or  indulgence  by the  Lender,  upon the
occurrence  of one or more Events of Default as that term is defined in the Loan
Agreement.

         Commercial Purposes.  The Borrower hereby represents to the Lender that
the proceeds of this Note shall be used  exclusively  for business or commercial
purposes and not for personal, family or household purposes.

         Payment of  Proceeds.  The  proceeds  of any and all loans or  advances
pursuant to this Note may be paid to or at the direction of the Borrower.

         Authority to Debit Accounts.  The Borrower hereby authorizes the Lender
to charge or debit any deposit account of the Borrower with the Lender to effect
any payment due hereunder, all without prior notice.

         Authority  to  Complete  this  Note.  In the  event  that  this Note is
delivered in an incomplete form in any respect,  the Borrower and each co-maker,
guarantor  and other  person or entity  liable  hereon,  hereby  authorizes  the
Lender,  without  further  notice,  to complete any blank spaces and to date the
Note, if undated, as of the date funds are first advanced hereunder.

         

                                      -6-



         Currency  and  Payments.  All  payments  on this Note  shall be made in
lawful currency of the United States of America, in each case without deduction,
setoff or  counterclaim.  All payments on this Note shall be made in immediately
available  funds.  With  respect  to any  payment  on this Note which is made by
check, the Lender may treat such amount as outstanding  pending final collection
thereof,  and interest  hereunder  shall  continue to accrue  pending such final
collection.

         Acknowledgment  of Terms and Receipt of a Copy.  The  Borrower has read
all of the terms and  conditions  of this Note and has received an exact copy of
this Note.

         Severability  of Provisions.  Any  determination  that any provision of
this Note or any application  thereof is invalid,  illegal,  or unenforceable in
any  respect  in any  instance  shall not  affect  the  validity,  legality  and
enforceability  of such  provision  in any  other  instance,  nor the  validity,
legality or enforceability of any other provision hereof.

         Headings.  The headings appearing in this Note are used for convenience
only and should not be deemed to affect the interpretation of this Note.

         Sealed Instrument.  This Note shall take effect as a sealed instrument.

         Books and Records;  Copies as Evidence.  The Lender's books and records
concerning  the  Lender's  loans and  advances to the  Borrower,  the accrual of
interest thereon, and the repayment of such loans, advances and interest,  shall
be prima  facie  evidence  of the  indebtedness  owed under  this  Note.  In any
proceeding with respect to this Note, any photographic,  photostatic,  microfilm
or similar  reproduction  of this Note shall be admissible in evidence as though
it were the  original,  whether or not the original  hereof is in existence  and
whether or not such reproduction was made in the regular course of business.

         Governing Law; Jurisdiction for Proceedings.  This Note is delivered to
the Lender in Boston,  Massachusetts  and shall be governed by and  construed in
accordance with the laws of The Commonwealth of  Massachusetts  for all purposes
and in all respects.  The Borrower, and each co-maker and guarantor of this Note
submits to the  non-exclusive  jurisdiction of the courts of The Commonwealth of
Massachusetts  for all  purposes  with  respect to this Note and any  collateral
given to secure their  respective  liabilities,  obligations and indebtedness to
the Lender, and their respective relationships with the Lender.

         Legal  Limitation on Interest.  Notwithstanding  any other provision of
this Note to the contrary, in the event that interest pursuant to the provisions
of this Note is finally  determined by a court of competent  jurisdiction  to be
subject to usury or other similar laws affecting the maximum allowable  interest
chargeable  then,  and  only  then,  and  only  to  the  extent  of  such  final
determination,  the maximum amount of interest  payable under this Note shall be
the maximum  amount of interest  determined  by such court to be allowed by such
laws.


                                      -7-



         Notices and Notice  Addresses.  The respective  Notice Addresses of the
Lender and the Borrower are those stated at the beginning of this Note, together
with the following additions: (a) for the Lender, "Attention: Commercial Banking
Department";  and (b) for the  Borrower,  "Attention:  Kevin W.  Quinlan,  Chief
Financial Officer".  To the extent required or voluntarily given, all notices or
demands  hereunder shall be sufficient and shall be deemed to have been given if
made in writing and given in accordance with the provisions for notice contained
in the Loan  Agreement.  Any party may change its Notice  Address  hereunder  by
giving  notice  of such  change  to the  other  party  in  accordance  with  the
provisions of this subsection.


         IN  WITNESS  WHEREOF,  the  Borrower  has  executed  this  Note,  as an
instrument under seal as of the date appearing on the first page of this Note.

                                                       BORROWER

                                                 BOSTON BIOMEDICA, INC.



/s/ Kevin W. Quinlan                By: /s/ Richard T. Schumacher
- ----------------------                  ----------------------------------------
Witness as to Borrower                  Richard T. Schumacher
                                        President
                                        Hereunto duly authorized

                                    BTRL CONTRACTS AND SERVICES, INC.



                                    By: /s/ Richard T. Schumacher
                                        ----------------------------------------
                                        Richard T. Schumacher
                                        President
                                        Hereunto duly authorized

                                    BBI - NORTH AMERICAN CLINICAL
                                    LABORATORIES, INC.



                                    By: /s/ Richard T. Schumacher
                                        ----------------------------------------
                                        Richard T. Schumacher
                                        President
                                        Hereunto duly authorized




                                      -8-

                                                                 EXHIBIT 10.18.6

                                                                       EXECUTION

                              TERM PROMISSORY NOTE

$750,000.00                                                Boston, Massachusetts
Due: December 1, 2002                                   Dated: December 11, 1995

         FOR VALUE RECEIVED, the undersigned,  BOSTON BIOMEDICA,  INC., ("BBI"),
BTRL  CONTRACTS AND SERVICES,  INC.  ("BTRL") and  BBI-NORTH  AMERICAN  CLINICAL
LABORATORIES,  INC.  ("NACL"),  each of  which  is a  Massachusetts  corporation
validly  created,  legally  existing and in good standing  under the laws of the
Commonwealth of Massachusetts  and each of which has its "Notice Address" at 375
West  Street,  West  Bridgewater,  Massachusetts  02379,  with  BBI  having  its
principal  place of business at its Notice  Address,  BTRL having its  principal
place of business at 3 Taft Court, Rockville, Maryland 20850 and NACL having its
principal place of business at 75 North Mountain Road, New Britain,  Connecticut
06053 (BBI,  BTRL and NACL,  together  with their  successors  and assigns,  are
collectively  referred to herein as the "Borrower")  JOINTLY AND SEVERALLY,  AND
UNCONDITIONALLY  PROMISE  TO PAY TO THE  ORDER  OF THE  FIRST  NATIONAL  BANK OF
BOSTON, a national banking  association having an office and "Notice Address" at
Bank of  Boston-Worcester  Tower,  P.O. Box 15073, 100 Front Street,  Worcester,
Massachusetts   01608-1438  (together  with  its  successors  and  assigns,  the
"Lender")  the  principal   sum  of  SEVEN   HUNDRED  FIFTY   THOUSAND   DOLLARS
($750,000.00),  with interest on the unpaid balance thereof from the date hereof
until paid at the rate and in the manner herein provided, in lawful money of the
United States of America.

         Note Issued Pursuant to Loan Agreement. This Note is issued pursuant to
a certain Real Estate Loan  Agreement  (the "Loan  Agreement")  by and among the
Borrower  and the Lender,  and the holder  hereof is entitled to the benefits of
the Loan Agreement, and all other agreements,  instruments, guarantees and other
documents  defined  therein as the  "Financing  Documents".  Terms not otherwise
specifically  defined in this Term Promissory Note  (hereinafter  referred to as
the  "Note")  shall  have  the  respective  meanings  given  to them in the Loan
Agreement.

         Interest  Rate.  The  unpaid  principal  of this Note from time to time
outstanding shall bear interest,  computed on the basis of actual number of days
elapsed  over a year assumed to have three  hundred and sixty (360) days,  at an
interest  rate per annum equal to one  percent  (1%) per annum above the rate of
interest  established  from time to time by the Lender as its Base  Lending Rate
(the "Base  Rate"),  such  interest  rate to be  determined on a daily basis and
adjusted from time to time on the effective  date of any change in the Base Rate
by the Lender (the "Adjusted Base Rate");  provided,  however, that the Borrower
may, at any time,  elect to have  interest  computed  hereunder  pursuant to the
Fixed Rate  Option (as  hereinafter  defined)  by written  notice to the Lender,
which notice, once sent to the Lender,  shall be irrevocable.  In the absence of
the  election  of the  Fixed  Rate  Option,  the  principal  amount  outstanding
hereunder shall bear interest at the Adjusted Base Rate.






         "Fixed Rate Option" as used herein  shall mean the  one-time  option of
the  Borrower to have  interest  computed  hereunder on the basis of an interest
rate per annum  equal to two and  one-half  percent  (2.50%) per annum above the
"Fixed Rate" (as  hereinafter  defined) (the "Adjusted Fixed Rate") for a period
of three,  four or five years (the "Fixed Rate Period").  The "Fixed Rate" shall
be the fixed rate of interest quoted by the Lender for the outstanding principal
balance  hereunder for the remainder of the term  hereunder.  Upon expiration of
the Fixed Rate Period,  the principal  amount  outstanding  hereunder shall then
immediately  bear interest at the Adjusted Base Rate for the balance at the term
hereof, if any.

         Certain Provisions Regarding Interest.  The Borrower  acknowledges that
the Base Rate is a reference rate and not necessarily the lowest rate charged by
the Lender to borrowers.  Interest per annum shall be calculated  for the actual
number of days elapsed, from time to time, over a year assumed to have 360 days.
Therefore, each dollar of principal outstanding hereunder for all or any part of
a day shall accrue  interest  equal to 1/360th of the annual  interest  accruing
hereunder on each such dollar. Interest shall accrue on each day or part thereof
that any  principal  is  outstanding  including  Sundays,  holidays and all days
during which the Lender is not open for the conduct of business.

         Interest  Increase after Maturity or Acceleration.  Any and all amounts
not paid when due  hereunder,  whether after the Maturity  Date (as  hereinafter
defined),  by  acceleration  or  otherwise,  shall accrue  interest,  payable on
demand,  at the annual rate equal to four  percent (4%) above the Base Rate (the
"Default Rate"), if permitted by law, calculated as above from the date when due
until so paid.

         Payments.  Commencing on January 1st, 1996, and on the same day of each
month thereafter until the Maturity Date, payments on this Note shall be made in
eighty-four (84) consecutive monthly installments of principal and interest. The
first  eighty-three (83) such installments  shall be equal to  one-eighty-fourth
(1/84th) of the principal  amount of this Note, plus accrued and unpaid interest
in arrears.  The last  installment  shall  comprise  the then  unpaid  principal
balance of this Note together  with all accrued and unpaid  interest and any and
all other  fees,  charges,  costs and  expenses  due and  payable  to the Lender
hereunder.

         Late Charges.  If any payment due hereunder is not paid within ten (10)
days of its due date, the Borrower will also pay to the Lender, on demand and in
addition  to all other  amounts  payable  hereunder,  an  amount  equal to three
percent (3%) of the amount of such payment. The assessment or collection of late
charges is not  intended  and shall not be  construed  to permit  payment of any
amount payable hereunder beyond the applicable due date thereof. The time period
which is allowed before the assessment of late charges is not intended and shall
not be  construed  as a  grace  or  cure  period  with  respect  to  payment  or
performance of any obligation hereunder.



                                      -2-


         Prepayment.  "Prepayment"  shall mean any  payment  of the  outstanding
principal due hereunder, whether in whole or in part, (a) on any date in advance
of the date scheduled therefor,  or (b) following  acceleration of the loan as a
consequence  of the occurrence of any Event of Default,  as defined  below.  Any
Prepayment  made by the Borrower  (other than a payment of the full  outstanding
principal  balance due under the Note) must be in an amount which is an integral
multiple of $10,000. Prior to the making of any Prepayment,  the Borrower shall:
(a) deliver  five (5) days' prior  written  notice to the Lender  apprising  the
Lender of the making of such Prepayment,  (b) pay all accrued interest and other
accrued  charges and costs of Lender to the date of  prepayment on the principal
amount so prepaid, (c) pay a Prepayment premium equal to one percent (1%) of the
amount prepaid in the event that such Prepayment is from a refinancing,  and (d)
if, at the time of  Prepayment,  the Borrower has elected the Fixed Rate Option,
pay the Fixed Rate  Prepayment  Premium as defined in the next  sentence of this
paragraph.  The "Fixed Rate  Prepayment  Premium" shall be an amount  reasonably
determined  by the  Lender for the loss,  if any,  including  any lost  profits,
resulting from such prepayment. The Borrower shall pay the Prepayment premium or
the Fixed Rate Prepayment Premium, whichever is applicable, upon presentation by
the Lender of a  statement  therefor,  which in either case shall be deemed true
and correct,  absent manifest error. In addition,  in the case of the Fixed Rate
Prepayment Premium,  such statement shall set forth the Lender's  calculation of
the same, which statement and calculation  (including the method of calculation)
shall be deemed true and correct,  absent manifest error. Any amounts prepaid by
the Borrower may not be subsequently re-borrowed from the Lender.

         Notwithstanding   the  foregoing,   "Prepayment"   as  defined  in  the
immediately  preceding  paragraph shall not include  repayment of Fifty Thousand
and 00/100 Dollars ($50,000.00) upon the sale of the so-called "Manley Property"
in full compliance with, and as more particularly described in, a certain Letter
Agreement between the Borrower and the Lender of even date and delivery herewith
(the "Letter Agreement").

         Application of Payments. Any payments received by the Lender on account
of this Note prior to the Maturity Date or by acceleration  or otherwise,  shall
be applied:  first,  to any fees,  charges,  costs and expenses then owed to the
Lender by the  Borrower  in  connection  with this Note;  second to accrued  and
unpaid  interest on the unpaid  balance of principal;  and third,  to the unpaid
balance of principal  hereof.  Any payments received by the Lender on account of
this Note after the  Maturity  Date or by  acceleration  or  otherwise  shall be
applied in such manner as the Lender may determine.

         Maturity Date. The entire outstanding principal balance hereof together
with all accrued and unpaid interest  thereon and all fees,  charges,  costs and
expenses due the Lender  hereunder  shall be due and payable on December 1, 2002
(the "Maturity Date").

         Security  Provided in Other  Writings.  Payment and performance of this
Note may be secured, from time to time, now or hereafter,  as provided in one or
more  security  agreements,   mortgages,   pledges,  assignments  or  any  other
instruments,  documents or agreements ("Security"), whether or not such Security
specifically  refers to this Note.  Any


                                      -3-


and all such Security may provide,  in general terms, that such Security secures
obligations  of the  Borrower  to the Lender  however  and  whenever  evidenced,
created or arising.  Payment and  performance  of this Note is hereby secured by
such Security  without specific  reference to this Note, and, in addition,  this
Note is secured by any and all Security which specifically refers to or provides
security for this Note, or is referenced in the Loan Agreement or otherwise.

         Grant of Security in Accounts and Other  Property in  Possession of the
Lender.  To secure the payment and performance of this Note, the Borrower hereby
grants to the Lender a continuing  security  interest in and to: (a) any and all
deposits and sums at any time  credited by or due from the Lender (or any of its
banking  or  lending  affiliates)  to the  Borrower;  and (b)  any or all  cash,
instruments,  securities and other property of the Borrower,  in the possession,
custody or control  (whether for  safekeeping or otherwise) of, or in transit to
or from,  the  Lender or any such  affiliate,  including  such  property  in the
possession  of any  third  party  acting  on  behalf  of the  Lender or any such
affiliate,  regardless  of the reason for the  receipt,  possession,  custody or
control of such property or any prior release thereof, conditional or otherwise.
Upon  demand,  maturity  or  acceleration  of  the  payment  of  this  Note,  as
applicable,  the  Lender  may,  at any time,  sell or dispose of any or all such
property and apply the proceeds  thereof against the  indebtedness of this Note.
With respect to all such property, the Lender shall have the rights and remedies
of a secured party under the Uniform  Commercial Code and other applicable laws,
the choice and manner of exercise of any right or remedy  being in the  Lender's
sole  discretion.  No such right or remedy shall be  exclusive,  and each may be
exercised  by the  Lender  concurrently  or in any order or  combination  as the
Lender  may  select,  from  time to time.  The  Lender  shall  have the right to
foreclose  the  security  interest  granted  herein  by any  available  judicial
procedure and to sell the same with or without judicial process;  the Lender may
sell or  otherwise  dispose of such  property  or any part  thereof at public or
private sales,  at such price or prices,  and upon such terms,  either for cash,
credit or future delivery,  as the Lender may elect;  and, except as to any part
of such property which is perishable or which  threatens to decline  speedily in
value, or is of the type  customarily  sold on a recognized  market,  the Lender
shall give the Borrower reasonable  notification of such sale or sales, it being
agreed that in all events  written  notice mailed to the Borrower at least seven
(7) days  prior to such sale is  reasonable  notification.  The  Lender may (but
shall  have no  obligation  to) bid for and  become  the  purchaser  of any such
property.

         Setoff.  With  respect to any and all  deposits  and sums  referred  to
above,  upon the Maturity Date or upon acceleration of the payment of this Note,
the Lender may, at any time, apply or setoff all or any portion of such deposits
or sums against the indebtedness evidenced by this Note, regardless of any other
collateral or security available to the Lender.

         Payment of Costs and  Attorney's  Fees.  The Borrower  agrees,  and all
co-makers and guarantors  also agree,  jointly and  severally,  to pay all costs
incurred  by  the  Lender,   including  all  attorneys'   reasonable   fees  and
out-of-pocket costs and expenses,  including court


                                      -4-


costs, in connection with (i) the  administration  or implementation of the loan
evidenced by this Note,  (ii) the  collection of the  indebtedness  evidenced by
this Note, or (iii) the preservation,  protection,  collection or enforcement of
any of the Lender's rights or remedies  hereunder or under any other  instrument
securing or  guaranteeing  this Note,  against the  Borrower or any  co-maker or
guarantor,  or against any  collateral  securing this Note or securing any other
instrument, document or agreement securing or guaranteeing this Note (whether or
not suit is instituted by or against the Lender).

         Waivers and Consents by Borrower and Others.  By making or guaranteeing
this Note or by making any agreement to pay any of the indebtedness evidenced by
this Note,  the  Borrower,  and each  co-maker,  guarantor,  and other person or
entity  now or  hereafter  liable  for the  payment  of any of the  indebtedness
evidenced by this Note, respectively,  agrees to waive: presentment for payment;
protest;  demand;  notice of protest,  demand,  dishonor and non-payment of this
Note; all other notices; all other defenses in the nature thereof, including all
suretyship defenses; and any and all other demands or notices otherwise required
to  be  given  in  connection  with  the  delivery,   acceptance,   endorsement,
performance,  default or  enforcement  of this Note,  any and all  borrowings or
advances  hereunder,  any and all  guarantees or  undertakings  hereof,  and any
security taken, granted or released,  from time to time, in connection herewith.
The Borrower and each such co-maker, guarantor and other person or entity hereby
consents,  without notice:  (a) to the substitution,  exchange or release,  from
time to time, of any collateral  securing this Note or any part thereof;  (b) to
the acceptance, from time to time, by the Lender of any additional collateral or
security for this Note, or the  acceptance,  from time to time, of other makers,
guarantors  or  other   obligors  of  this  Note,   (c)  to  the   modification,
substitution,  extension or  amendment,  from time to time, of this Note and any
other instrument,  document or agreement  securing or guaranteeing this Note, at
the request of any person or entity liable  thereon;  (d) to the granting of any
extension of the time for payment of this Note or any other  indulgence  for the
performance of the agreements,  covenants and conditions contained in this Note,
or any other  instrument,  document or agreement  securing or guaranteeing  this
Note, at the request of any person or entity liable thereon;  (e) to any and all
other extensions,  forbearances and indulgences whatsoever granted by the Lender
with  respect  to  this  Note,  any  other  liability  of the  Borrower,  or any
collateral  securing  this Note or any other  liability  of the  Borrower to the
Lender;  and any and all  assignments  or transfers of this Note and any part or
all of the indebtedness  evidenced hereby or any security therefor or guarantees
thereof to any successor, assignee, participant or other party. The happening of
any one or more  of the  foregoing  events  shall  not  alter  or  diminish  the
liability of any person or entity liable on this Note. The release by the Lender
of the Borrower or any one or more co-makers or guarantors shall not release any
other  person  obligated  on  account  of this Note,  except  only for  payments
actually  received by Lender free and clear of the rights of all other  parties.
No person or entity obligated on account of this Note may seek contribution from
any other  person or entity  also  obligated  unless and until all  liabilities,
obligations, and indebtedness to the Lender of the person from whom contribution
is sought have been satisfied in full.



                                      -5-


         Joint  and  Several  Obligations;  Binding  Effect.  This  Note and the
liabilities of the Borrower shall be the joint and several obligation of each of
the undersigned, if more than one, and each guarantor, co-maker, and surety, and
shall  be  binding  upon  each  of them  and  each of  their  respective  heirs,
representatives,  successors and assigns,  and shall inure to the benefit of the
Lender and its successors, indorsees and assigns. Each reference in this Note to
the  Borrower,  any  co-maker  and any  guarantor  refers to each such person or
entity individually and also to all such persons and entities jointly.  The term
"Lender"  shall include the Lender and each other payee hereof,  or any indorsee
of this Note in  possession  hereof,  or the bearer hereof if the Note is at the
time payable to the bearer.

         The Lender's Rights  Reserved.  No delay or omission on the part of the
Lender in exercising or enforcing any of the Lender's rights, powers, privileges
or remedies or discretions  hereunder or under any instrument or agreement which
is given or may be  given to  secure  or  guaranty  the  indebtedness  evidenced
hereby,  shall  operate  as a waiver  thereof,  or of any  other  right,  power,
privilege  or remedy of such holder on that  occasion or on any other  occasion,
nor shall any delay,  omission  or waiver on any one  occasion be deemed to be a
bar to or waiver of the same or any other right on any future  occasion,  and no
waiver of a default hereunder shall operate as a waiver of any other default nor
as a continuing waiver.

         Default.  The  entire  unpaid  principal  balance  of this Note and all
accrued  and unpaid  interest  thereon and all other  fees,  charges,  costs and
expenses  hereunder shall become  immediately  due and payable,  without demand,
prior  to  the  maturity  of  this  Note,  at the  sole  option  of the  Lender,
(exercisable  without  demand,  notice  or  protest,  which are  hereby  waived)
regardless  of any prior  forbearance  or  indulgence  by the  Lender,  upon the
occurrence  of one or more Events of Default as that term is defined in the Loan
Agreement.

         Commercial Purposes.  The Borrower hereby represents to the Lender that
the proceeds of this Note shall be used  exclusively  for business or commercial
purposes and not for personal, family or household purposes.

         Payment of  Proceeds.  The  proceeds  of any and all loans or  advances
pursuant to this Note may be paid to or at the direction of the Borrower.

         Authority to Debit Accounts.  The Borrower hereby authorizes the Lender
to charge or debit any deposit account of the Borrower with the Lender to effect
any payment due hereunder, all without prior notice.

         Authority  to  Complete  this  Note.  In the  event  that  this Note is
delivered in an incomplete form in any respect,  the Borrower and each co-maker,
guarantor  and other  person or entity  liable  hereon,  hereby  authorizes  the
Lender,  without  further  notice,  to complete any blank spaces and to date the
Note, if undated, as of the date funds are first advanced hereunder.


                                      -6-


         Currency  and  Payments.  All  payments  on this Note  shall be made in
lawful currency of the United States of America, in each case without deduction,
setoff or  counterclaim.  All payments on this Note shall be made in immediately
available  funds.  With  respect  to any  payment  on this Note which is made by
check, the Lender may treat such amount as outstanding  pending final collection
thereof,  and interest  hereunder  shall  continue to accrue  pending such final
collection.

         Acknowledgment  of Terms and Receipt of a Copy.  The  Borrower has read
all of the terms and  conditions  of this Note and has received an exact copy of
this Note.

         Severability  of Provisions.  Any  determination  that any provision of
this Note or any application  thereof is invalid,  illegal,  or unenforceable in
any  respect  in any  instance  shall not  affect  the  validity,  legality  and
enforceability  of such  provision  in any  other  instance,  nor the  validity,
legality or enforceability of any other provision hereof.

         Headings.  The headings appearing in this Note are used for convenience
only and should not be deemed to affect the interpretation of this Note.

         Sealed Instrument.  This Note shall take effect as a sealed instrument.

         Books and Records;  Copies as Evidence.  The Lender's books and records
concerning  the  Lender's  loans and  advances to the  Borrower,  the accrual of
interest thereon, and the repayment of such loans, advances and interest,  shall
be prima  facie  evidence  of the  indebtedness  owed under  this  Note.  In any
proceeding with respect to this Note, any photographic,  photostatic,  microfilm
or similar  reproduction  of this Note shall be admissible in evidence as though
it were the  original,  whether or not the original  hereof is in existence  and
whether or not such reproduction was made in the regular course of business.

         Governing Law; Jurisdiction for Proceedings.  This Note is delivered to
the Lender in Boston,  Massachusetts  and shall be governed by and  construed in
accordance with the laws of The Commonwealth of  Massachusetts  for all purposes
and in all respects.  The Borrower, and each co-maker and guarantor of this Note
submits to the  non-exclusive  jurisdiction of the courts of The Commonwealth of
Massachusetts  for all  purposes  with  respect to this Note and any  collateral
given to secure their  respective  liabilities,  obligations and indebtedness to
the Lender, and their respective relationships with the Lender.

         Legal  Limitation on Interest.  Notwithstanding  any other provision of
this Note to the contrary, in the event that interest pursuant to the provisions
of this Note is finally  determined by a court of competent  jurisdiction  to be
subject to usury or other similar laws affecting the maximum allowable  interest
chargeable  then,  and  only  then,  and  only  to  the  extent  of  such  final
determination,  the maximum amount of interest  payable under this Note shall be
the maximum  amount of interest  determined  by such court to be allowed by such
laws.


                                      -7-



         Notices and Notice  Addresses.  The respective  Notice Addresses of the
Lender and the Borrower are those stated at the beginning of this Note, together
with the following additions: (a) for the Lender, "Attention: Commercial Banking
Department";  and (b) for the  Borrower,  "Attention:  Kevin W.  Quinlan,  Chief
Financial Officer".  To the extent required or voluntarily given, all notices or
demands  hereunder shall be sufficient and shall be deemed to have been given if
made in writing and given in accordance with the provisions for notice contained
in the Loan  Agreement.  Any party may change its Notice  Address  hereunder  by
giving  notice  of such  change  to the  other  party  in  accordance  with  the
provisions of this subsection.



                                      -8-


         IN  WITNESS  WHEREOF,  the  Borrower  has  executed  this  Note,  as an
instrument under seal as of the date appearing on the first page of this Note.

                                                 BORROWER

                                                 BOSTON BIOMEDICA, INC.



/s/ Suanne C. St. Charles                      By: /s/ Richard T. Schumacher
- --------------------------                         -----------------------------
Witness as to Borrower                             Richard T. Schumacher
                                                   President
                                                   Hereunto duly authorized

                                               BTRL CONTRACTS AND SERVICES, INC.



                                               By: /s/ Richard T. Schumacher
                                                   -----------------------------
                                                   Richard T. Schumacher
                                                   President
                                                   Hereunto duly authorized

                                               BBI - NORTH AMERICAN CLINICAL 
                                               LABORATORIES, INC.



                                               By: /s/ Richard T. Schumacher
                                                   -----------------------------
                                                   Richard T. Schumacher
                                                   President
                                                   Hereunto duly authorized



                                      -9-

                                                                 EXHIBIT 10.18.7

                              TERM PROMISSORY NOTE

$250,000.00                                                Boston, Massachusetts
Due:  July 31, 2001                                         Dated: July 31, 1996

         FOR VALUE  RECEIVED,  the  undersigned,  (a)  BOSTON  BIOMEDICA,  INC.,
(together  with its  successors  and assigns,  "BBI"),  (b) BTRL  CONTRACTS  AND
SERVICES,  INC.  (together  with its  successors  and  assigns,  "BTRL") and (c)
BBI-NORTH AMERICAN CLINICAL LABORATORIES, INC., formerly known as NORTH AMERICAN
LABORATORY GROUP, INC. (together with its successors and assigns,  "NACL"), each
of which is a Massachusetts corporation validly created, legally existing and in
good standing under the laws of the  Commonwealth of  Massachusetts  and each of
which  has  its  "Notice  Address"  at  375  West  Street,   West   Bridgewater,
Massachusetts  02379,  with BBI having its  principal  place of  business at its
Notice  Address,  BTRL having its  principal  place of business at 3 Taft Court,
Rockville,  Maryland 20850 and NACL having its principal place of business at 75
North  Mountain  Road, New Britain,  Connecticut  06053 (BBI,  BTRL and NACL are
collectively  referred to herein as the "Borrower")  JOINTLY AND SEVERALLY,  AND
UNCONDITIONALLY  PROMISE  TO PAY TO THE  ORDER  OF THE  FIRST  NATIONAL  BANK OF
BOSTON, a national banking  association having an office and "Notice Address" at
Bank of  Boston-Worcester  Tower,  P.O. Box 15073, 100 Front Street,  Worcester,
Massachusetts   01608-1438  (together  with  its  successors  and  assigns,  the
"Lender"),  successor-by-merger  to WORCESTER COUNTY  INSTITUTION FOR SAVINGS, a
Massachusetts  savings bank  ("WCiS"),  the  principal  sum of TWO HUNDRED FIFTY
THOUSAND AND 00/100 DOLLARS  ($250,000.00),  with interest on the unpaid balance
thereof  from the date  hereof  until paid at the rate and in the manner  herein
provided, in lawful money of the United States of America.

         Second Amended and Restated Loan Agreement. The Borrower and the Lender
are  parties  to a  certain  Second  Amended  and  Restated  Loan  and  Security
Agreement,  dated as of August  2,  1995,  as  amended  by (a) a  certain  First
Amendment to Second Amended and Restated Loan and Security  Agreement,  dated as
of December 11, 1995, and (b) a Second  Amendment to Second Amended and Restated
Loan and Security  Agreement,  dated of even date herewith  (said Second Amended
and Restated Loan Agreement,  as so amended,  is hereinafter  referred to as the
"Loan  Agreement").  Terms  not  otherwise  specifically  defined  in this  Term
Promissory  Note  (hereinafter  referred  to  as  the  "Note")  shall  have  the
respective meanings given to them in the Loan Agreement.

         Principal Advances. The Lender shall advance sums hereunder,  up to the
principal amount hereof, for a period of six (6) months from the date hereof, in
accordance with the provisions of the Loan Agreement (the "Advance Period").

         Interest  Rate.  The  unpaid  principal  of this Note from time to time
outstanding shall bear interest,  computed on the basis of actual number of days
elapsed  over a year assumed to have three  hundred and sixty (360) days,  at an
interest  rate per annum equal to one  percent  (1%) per annum above the rate of
interest  established  from time to time by the






Lender as its Base  Lending Rate (the "Base  Rate"),  such  interest  rate to be
determined on a daily basis and adjusted from time to time on the effective date
of any  change  in the Base  Rate by the  Lender  (the  "Adjusted  Base  Rate");
provided,  however,  that the Borrower may, at any time,  elect to have interest
computed hereunder pursuant to the Fixed Rate Option (as hereinafter defined) by
written notice to the Lender,  which notice,  once sent to the Lender,  shall be
irrevocable.  In the  absence  of the  election  of the Fixed Rate  Option,  the
principal amount outstanding  hereunder shall bear interest at the Adjusted Base
Rate.

         "Fixed Rate Option" as used herein  shall mean the  one-time  option of
the  Borrower to have  interest  computed  hereunder on the basis of an interest
rate per annum  equal to two and  one-half  percent  (2.50%) per annum above the
Fixed Rate (as hereinafter  defined) (the "Adjusted Fixed Rate") for a period of
three,  four or five years (the "Fixed Rate Period").  The "Fixed Rate" shall be
the fixed rate of interest  quoted by the Lender for the  outstanding  principal
balance  hereunder for the remainder of the term  hereunder.  Upon expiration of
the Fixed Rate Period,  the principal  amount  outstanding  hereunder shall then
immediately  bear interest at the Adjusted Base Rate for the balance at the term
hereof, if any.

         Certain Provisions Regarding Interest.  To the extent used herein, Base
Rate means the rate of interest per annum  announced,  from time to time, by the
Lender  as its Base  Rate.  The  Borrower  acknowledges  that the Base Rate is a
reference  rate and not  necessarily  the lowest  rate  charged by the Lender to
borrowers.  Interest per annum shall be calculated for the actual number of days
elapsed,  from time to time,  over a year  assumed to have 360 days.  Therefore,
each  dollar of  principal  outstanding  hereunder  for all or any part of a day
shall accrue interest equal to 1/360th of the annual interest accruing hereunder
on each such dollar.  Interest shall accrue on each day or part thereof that any
principal is outstanding  including Sundays,  holidays and all days during which
the Lender is not open for the conduct of business.

         Interest  Increase after Maturity or Acceleration.  Any and all amounts
not paid  when  due  hereunder,  whether  after  maturity,  by  acceleration  or
otherwise,  shall accrue interest,  payable on demand, at the greater of (i) the
annual  rate of  eighteen  percent  (18%) or (ii) the  annual  rate equal to two
percent (2%) above the Base Rate, if permitted by law,  calculated as above from
the date when due until so paid.

         Payments.  Commencing on September 1, 1996, and on the same day of each
month thereafter up to and including February 1, 1997, payments of interest only
shall be made in arrears on the outstanding principal amount of this Note.

         Commencing  on March 1,  1997,  payments  on this Note shall be made in
fifty-four (54) consecutive monthly installments of principal and interest.  The
first fifty-three (53) such installments shall be equal to  one-fifty-fourth  of
the  principal  amount of this Note which has been  advanced,  plus  accrued and
unpaid interest in arrears.  The last installment shall comprise the then unpaid
principal balance of this Note together with all accrued and 


                                      -2-


unpaid interest and any and all other fees, charges,  costs and expenses due and
payable to Lender hereunder.

         Late Charges.  If any payment due hereunder is not paid within ten (10)
days of its due date,  the  Borrower  will also pay to Lender,  on demand and in
addition to all other amounts payable hereunder, an amount equal to five percent
(5%) of the amount of such payment. The assessment or collection of late charges
is not  intended  and shall not be  construed  to permit  payment  of any amount
payable hereunder beyond the applicable due date thereof.  The time period which
is allowed  before the  assessment of late charges is not intended and shall not
be construed as a grace or cure period with respect to payment or performance of
any obligation hereunder.

         Prepayment.  "Prepayment"  shall mean any  payment  of the  outstanding
principal due hereunder, whether in whole or in part, (a) on any date in advance
of the date scheduled therefor,  or (b) following  acceleration of the loan as a
consequence  of the occurrence of any Event of Default,  as defined  below.  Any
Prepayment  made by the Borrower  (other than a payment of the full  outstanding
principal  balance due under the Note) must be in an amount which is an integral
multiple of $10,000. Prior to the making of any Prepayment,  the Borrower shall:
(a) deliver  five (5) days' prior  written  notice to the Lender  apprising  the
Lender of the making of such Prepayment,  (b) pay all accrued interest and other
accrued  charges and costs of Lender to the date of  prepayment on the principal
amount so prepaid, (c) pay a Prepayment premium equal to one percent (1%) of the
amount prepaid in the event that such Prepayment is from a refinancing,  and (d)
if, at the time of  Prepayment,  the Borrower has elected the Fixed Rate Option,
pay the Fixed Rate  Prepayment  Premium as defined in the next  sentence of this
paragraph.  The "Fixed Rate  Prepayment  Premium" shall be an amount  reasonably
determined  by the  Lender for the loss,  if any,  including  any lost  profits,
resulting from such prepayment. The Borrower shall pay the Prepayment premium or
the Fixed Rate Prepayment Premium, whichever is applicable, upon presentation by
the Lender of a  statement  therefor,  which in either case shall be deemed true
and correct,  absent manifest error. In addition,  in the case of the Fixed Rate
Prepayment Premium,  such statement shall set forth the Lender's  calculation of
the same, which statement and calculation  (including the method of calculation)
shall be deemed true and correct,  absent manifest error. Any amounts prepaid by
the Borrower may not be subsequently re-borrowed from the Lender.

         Application of Payments. Any payments received by the Lender on account
of this Note prior to the Maturity Date or by acceleration  or otherwise,  shall
be applied:  first,  to any fees,  charges,  costs and expenses then owed to the
Lender by the  Borrower  in  connection  with this Note;  second to accrued  and
unpaid  interest on the unpaid  balance of principal;  and third,  to the unpaid
balance of principal  hereof.  Any payments received by the Lender on account of
this Note after the  Maturity  Date or by  acceleration  or  otherwise  shall be
applied in such manner as the Lender may determine.


                                      -3-


         Note Issued Pursuant to Loan Agreement. This Note is issued pursuant to
the Loan  Agreement,  and the holder  hereof is entitled to the  benefits of the
Loan  Agreement,  and all other  agreements,  instruments,  guarantees and other
documents   executed  and  delivered  in   connection   therewith  and  herewith
(collectively referred to herein as the "Financing Instruments").

         Maturity Date. The entire outstanding principal balance hereof together
with all accrued and unpaid interest  thereon and all fees,  charges,  costs and
expenses  due Lender  hereunder  shall be due and  payable on July 31, 2001 (the
"Maturity Date").

         Security  Provided in Other  Writings.  Payment and performance of this
Note may be secured, from time to time, now or hereafter,  as provided in one or
more  security  agreements,   mortgages,   pledges,  assignments  or  any  other
instruments,  documents or agreements ("Security"), whether or not such Security
specifically  refers to this Note.  Any and all such  Security may  provide,  in
general  terms,  that such Security  secures  obligations of the Borrower to the
Lender  however  and  whenever  evidenced,   created  or  arising.  Payment  and
performance  of this Note is hereby  secured by such Security  without  specific
reference to this Note,  and, in  addition,  this Note is secured by any and all
Security which specifically refers to or provides security for this Note.

         Grant of Security in Accounts and Other  Property in  Possession of the
Lender.  To secure the payment and performance of this Note, the Borrower hereby
grants to the Lender a continuing  security  interest in and to: (a) any and all
deposits and sums at any time  credited by or due from the Lender (or any of its
banking  or  lending  affiliates)  to the  Borrower;  and (b)  any or all  cash,
instruments,  securities and other property of the Borrower,  in the possession,
custody or control  (whether for  safekeeping or otherwise) of, or in transit to
or from,  the  Lender or any such  affiliate,  including  such  property  in the
possession  of any  third  party  acting  on  behalf  of the  Lender or any such
affiliate,  regardless  of the reason for the  receipt,  possession,  custody or
control of such property or any prior release thereof, conditional or otherwise.
Upon  demand,  maturity  or  acceleration  of  the  payment  of  this  Note,  as
applicable,  the  Lender  may,  at any time,  sell or dispose of any or all such
property and apply the proceeds  thereof against the  indebtedness of this Note.
With respect to all such property, the Lender shall have the rights and remedies
of a secured party under the Uniform  Commercial Code and other applicable laws,
the choice and manner of exercise of any right or remedy  being in the  Lender's
sole  discretion.  No such right or remedy shall be  exclusive,  and each may be
exercised  by the  Lender  concurrently  or in any order or  combination  as the
Lender  may  select,  from  time to time.  The  Lender  shall  have the right to
foreclose  the  security  interest  granted  herein  by any  available  judicial
procedure and to sell the same with or without judicial process;  the Lender may
sell or  otherwise  dispose of such  property  or any part  thereof at public or
private sales,  at such price or prices,  and upon such terms,  either for cash,
credit or future delivery,  as the Lender may elect;  and, except as to any part
of such property which is perishable or which  threatens to decline  speedily in
value, or is of the type  customarily  sold on a recognized  market,  the Lender
shall give the Borrower reasonable  notification of such


                                      -4-


sale or sales,  it being agreed that in all events  written notice mailed to the
Borrower at least seven (7) days prior to such sale is reasonable  notification.
The  Lender  may  (but  shall  have no  obligation  to) bid for and  become  the
purchaser of any such property.

         Setoff.  With  respect to any and all  deposits  and sums  referred  to
above,  upon the Maturity Date or  acceleration of the payment of this Note, the
Lender may, at any time,  apply or setoff all or any portion of such deposits or
sums against the  indebtedness  evidenced by this Note,  regardless of any other
collateral or security available to the Lender.

         Payment of Costs and  Attorney's  Fees.  The Borrower  agrees,  and all
co-makers and guarantors  also agree,  jointly and  severally,  to pay all costs
incurred  by  the  Lender,   including  all  attorneys'   reasonable   fees  and
out-of-pocket costs and expenses,  including court costs, in connection with (i)
the  administration  or  implementation of the loan evidenced by this Note, (ii)
the  collection  of the  indebtedness  evidenced  by this  Note,  or  (iii)  the
preservation,  protection,  collection  or  enforcement  of any of the  Lender's
rights  or  remedies  hereunder  or  under  any  other  instrument  securing  or
guaranteeing  this Note,  against the Borrower or any co-maker or guarantor,  or
against any  collateral  securing  this Note or securing  any other  instrument,
document or agreement securing or guaranteeing this Note (whether or not suit is
instituted by or against the Lender).

         Waivers and Consents by Borrower and Others.  By making or guaranteeing
this Note or by making any agreement to pay any of the indebtedness evidenced by
this Note,  the  Borrower,  and each  co-maker,  guarantor,  and other person or
entity  now or  hereafter  liable  for the  payment  of any of the  indebtedness
evidenced by this Note, respectively,  agrees to waive: presentment for payment;
protest;  demand;  notice of protest,  demand,  dishonor and non-payment of this
Note; all other notices; all other defenses in the nature thereof, including all
suretyship defenses; and any and all other demands or notices otherwise required
to  be  given  in  connection  with  the  delivery,   acceptance,   endorsement,
performance,  default or  enforcement  of this Note,  any and all  borrowings or
advances  hereunder,  any and all  guarantees or  undertakings  hereof,  and any
security taken, granted or released,  from time to time, in connection herewith.
The Borrower and each such co-maker, guarantor and other person or entity hereby
consents,  without notice:  (a) to the substitution,  exchange or release,  from
time to time, of any collateral  securing this Note or any part thereof;  (b) to
the acceptance, from time to time, by the Lender of any additional collateral or
security for this Note, or the  acceptance,  from time to time, of other makers,
guarantors or other obligors of this Note, (c) to the modification or amendment,
from time to time, of this Note and any other instrument,  document or agreement
securing  or  guaranteeing  this  Note,  at the  request of any person or entity
liable thereon;  (d) to the granting of any extension of the time for payment of
this  Note or any  other  indulgence  for  the  performance  of the  agreements,
covenants  and  conditions  contained  in this  Note,  or any other  instrument,
document or agreement  securing or guaranteeing this Note, at the request of any
person  or  entity  liable  thereon;  (e)  to  any  and  all  other  extensions,
forbearances  and indulgences  whatsoever  granted by the Lender with respect to
this Note,


                                      -5-



any other liability of the Borrower, or any collateral securing this Note or any
other  liability of the Borrower to the Lender;  and any and all  assignments or
transfers of this Note and any part or all of the indebtedness  evidenced hereby
or any  security  therefor or  guarantees  thereof to any  successor,  assignee,
participant  or other party.  The  happening of any one or more of the foregoing
events shall not alter or diminish the  liability of any person or entity liable
on this  Note.  The  release by the  Lender of the  Borrower  or any one or more
co-makers or guarantors  shall not release any other person obligated on account
of this Note,  except  only for  payments  actually  received by Lender free and
clear of the  rights of all other  parties.  No  person or entity  obligated  on
account of this Note may seek  contribution from any other person or entity also
obligated unless and until all liabilities, obligations, and indebtedness to the
Lender of the person from whom  contribution  is sought have been  satisfied  in
full.

         Joint  and  Several  Obligations;  Binding  Effect.  This  Note and the
liabilities of the Borrower shall be the joint and several obligation of each of
the undersigned, if more than one, and each guarantor, co-maker, and surety, and
shall  be  binding  upon  each  of them  and  each of  their  respective  heirs,
representatives,  successors and assigns,  and shall inure to the benefit of the
Lender and its successors, indorsees and assigns. Each reference in this Note to
the  Borrower,  any  co-maker  and any  guarantor  refers to each such person or
entity individually and also to all such persons and entities jointly.  The term
"Lender"  shall include the Lender and each other payee hereof,  or any indorsee
of this Note in  possession  hereof,  or the bearer hereof if the Note is at the
time payable to the bearer.

         The Lender's Rights  Reserved.  No delay or omission on the part of the
Lender in exercising or enforcing any of the Lender's rights, powers, privileges
or remedies or discretions  hereunder or under any instrument or agreement which
is given or may be  given to  secure  or  guaranty  the  indebtedness  evidenced
hereby,  shall  operate  as a waiver  thereof,  or of any  other  right,  power,
privilege  or remedy of such holder on that  occasion or on any other  occasion,
nor shall any delay,  omission  or waiver on any one  occasion be deemed to be a
bar to or waiver of the same or any other right on any future  occasion,  and no
waiver of a default hereunder shall operate as a waiver of any other default nor
as a continuing waiver.

         Default.  The  entire  unpaid  principal  balance  of this Note and all
accrued  and unpaid  interest  thereon and all other  fees,  charges,  costs and
expenses  hereunder shall become  immediately  due and payable,  without demand,
prior  to  the  maturity  of  this  Note,  at the  sole  option  of the  Lender,
(exercisable  without  demand,  notice  or  protest,  which are  hereby  waived)
regardless  of any prior  forbearance  or  indulgence  by the  Lender,  upon the
occurrence  of one or more Events of Default as that term is defined in the Loan
Agreement.

         Commercial Purposes.  The Borrower hereby represents to the Lender that
the proceeds of this Note shall be used  exclusively  for business or commercial
purposes and not for personal, family or household purposes.


         
                                      -6-



         Payment of  Proceeds.  The  proceeds  of any and all loans or  advances
pursuant to this Note may be paid to or at the direction of the Borrower.

         Authority to Debit Accounts.  The Borrower hereby authorizes the Lender
to charge or debit any deposit account of the Borrower with the Lender to effect
any payment due hereunder, all without prior notice.

         Authority  to  Complete  this  Note.  In the  event  that  this Note is
delivered in an incomplete form in any respect,  the Borrower and each co-maker,
guarantor  and other  person or entity  liable  hereon,  hereby  authorizes  the
Lender,  without  further  notice,  to complete any blank spaces and to date the
Note, if undated, as of the date funds are first advanced hereunder.

         Currency  and  Payments.  All  payments  on this Note  shall be made in
lawful currency of the United States of America, in each case without deduction,
setoff or  counterclaim.  All payments on this Note shall be made in immediately
available  funds.  With  respect  to any  payment  on this Note which is made by
check, the Lender may treat such amount as outstanding  pending final collection
thereof,  and interest  hereunder  shall  continue to accrue  pending such final
collection.

         Acknowledgment  of Terms and Receipt of a Copy.  The  Borrower has read
all of the terms and  conditions  of this Note and has received an exact copy of
this Note.

         Severability  of Provisions.  Any  determination  that any provision of
this Note or any application  thereof is invalid,  illegal,  or unenforceable in
any  respect  in any  instance  shall not  affect  the  validity,  legality  and
enforceability  of such  provision  in any  other  instance,  nor the  validity,
legality or enforceability of any other provision hereof.

         Headings.  The headings appearing in this Note are used for convenience
only and should not be deemed to affect the interpretation of this Note.

         Sealed Instrument.  This Note shall take effect as a sealed instrument.

         Books and Records;  Copies as Evidence.  The Lender's books and records
concerning  the  Lender's  loans and  advances to the  Borrower,  the accrual of
interest thereon, and the repayment of such loans, advances and interest,  shall
be prima  facie  evidence  of the  indebtedness  owed under  this  Note.  In any
proceeding with respect to this Note, any photographic,  photostatic,  microfilm
or similar  reproduction  of this Note shall be admissible in evidence as though
it were the  original,  whether or not the original  hereof is in existence  and
whether or not such reproduction was made in the regular course of business.

         Governing Law; Jurisdiction for Proceedings.  This Note is delivered to
the Lender in Boston,  Massachusetts  and shall be governed by and  construed in
accordance with the


                                      -7-


laws of the Commonwealth of Massachusetts  for all purposes and in all respects.
The  Borrower,  and each  co-maker  and  guarantor  of this Note  submits to the
non-exclusive  jurisdiction of the courts of the  Commonwealth of  Massachusetts
for all purposes  with respect to this Note and any  collateral  given to secure
their respective  liabilities,  obligations and indebtedness to the Lender,  and
their respective relationships with the Lender.

         Legal  Limitation on Interest.  Notwithstanding  any other provision of
this Note to the contrary, in the event that interest pursuant to the provisions
of this Note is finally  determined by a court of competent  jurisdiction  to be
subject to usury or other similar laws affecting the maximum allowable  interest
chargeable  then,  and  only  then,  and  only  to  the  extent  of  such  final
determination,  the maximum amount of interest  payable under this Note shall be
the maximum  amount of interest  determined  by such court to be allowed by such
laws.

         Notices and Notice  Addresses.  The respective  Notice Addresses of the
Lender and the Borrower are those stated at the beginning of this Note, together
with the following additions: (a) for the Lender, "Attention: Commercial Banking
Department";  and (b) for the  Borrower,  "Attention:  Kevin W.  Quinlan,  Chief
Financial Officer".  To the extent required or voluntarily given, all notices or
demands  hereunder shall be sufficient and shall be deemed to have been given if
made in writing and given in accordance with the provisions for notice contained
in the Loan  Agreement.  Any party may change its Notice  Address  hereunder  by
giving  notice  of such  change  to the  other  party  in  accordance  with  the
provisions of this subsection.


            [THE REMAINDER OF THIS PAGE IS LEFT INTENTIONALLY BLANK]



                                      -8-


         IN  WITNESS  WHEREOF,  the  Borrower  has  executed  this  Note,  as an
instrument under seal as of the date appearing on the first page of this Note.


                                                 BOSTON BIOMEDICA, INC.



/s/ Lori Rosenberg                               By: /s/ Kevin W. Quinlan
- ------------------------                             ---------------------------
Witness as to Borrower                               Kevin W. Quinlan
                                                     Treasurer
                                                     Hereunto duly authorized


                                                 BTRL CONTRACTS AND
                                                 SERVICES, INC.


                                                 By: /s/ Kevin W. Quinlan
                                                     ---------------------------
                                                     Kevin W. Quinlan
                                                     Treasurer
                                                     Hereunto duly authorized


                                                 BBI - NORTH AMERICAN
                                                 CLINICAL LABORATORIES, INC.


                                                 By: /s/ Kevin W. Quinlan
                                                     ---------------------------
                                                     Kevin W. Quinlan
                                                     Treasurer
                                                     Hereunto duly authorized





                                      -9-

                                                                   EXHIBIT 10.20

================================================================================



                                 PREFERRED STOCK



                               PURCHASE AGREEMENT





                                 1150 SHARES OF
                               PREFERRED STOCK OF
                                  BIOSEQ, INC.






                          Dated: as of October 7, 1996



================================================================================







                       PREFERRED STOCK PURCHASE AGREEMENT
                       ----------------------------------

                                TABLE OF CONTENTS
                                -----------------

<TABLE>
<CAPTION>
PARTIES

RECITALS

<S>                                                                                                                <C>
ARTICLE 1. PURCHASE AND SALE OF SECURITIES.........................................................................  1
   1.1 Authorization:  Filing of Amended and Restated Articles of Organization.....................................  1
   1.2 Purchase and Sale of Securities.............................................................................  2
   1.3 Closing.....................................................................................................  2


ARTICLE 2. REPRESENTATIONS AND WARRANTIES OF THE COMPANY...........................................................  2
   2.1. Organization and Qualification.............................................................................  2
   2.2. Subsidiaries...............................................................................................  3
   2.3 Capitalization..............................................................................................  3
   2.4 Authorization of Transaction................................................................................  3
   2.5 Approvals; Compliance With Laws.............................................................................  3
   2.6 Financial Statements........................................................................................  4
   2.7 Title to Properties.........................................................................................  4
   2.8 Payment of Taxes............................................................................................  4
   2.9 Absence of Undisclosed Liabilities..........................................................................  4
   2.10 Absence of Certain Changes.................................................................................  5
   2.11 Contracts and Commitments..................................................................................  6
   2.12 Intellectual Property......................................................................................  6
   2.13 Compliance with Other Instruments..........................................................................  6
   2.14 Litigation.................................................................................................  7
   2.15 Permits and Licenses; Compliance with Law..................................................................  7
   2.16 Offerees; Sales of Securities..............................................................................  7
   2.17 Brokerage..................................................................................................  7
   2.18 Investment Materials.......................................................................................  7
   2.19 Disclosure.................................................................................................  8
   2.20 Certain Transactions.......................................................................................  8
   2.21 Corporate Documents; Minute Books..........................................................................  8
   2.22 Employee Benefit Plans.....................................................................................  8
   2.23 Environmental and Safety Laws..............................................................................  8
   2.24 Insurance..................................................................................................  8
   2.25 Labor Agreements and Actions...............................................................................  9
   2.26 Registration Rights........................................................................................  9


ARTICLE 3. REPRESENTATIONS AND WARRANTIES OF INVESTOR..............................................................  9
   3.1 Investment Intent...........................................................................................  9
   3.2 Authorization...............................................................................................  9
   3.3 Restricted Securities.......................................................................................  9
   3.4 Brokerage...................................................................................................  9
   3.5 Due Organization............................................................................................ 10
   3.6. No Conflict................................................................................................ 10



                                      -i-



  CONDITIONS OF INVESTOR'S AND COMPANY'S OBLIGATION................................................................ 10
   4.1 Representations and Warranties.............................................................................. 10
   4.2 Performance; No Breach...................................................................................... 10
   4.3 Consents and Waivers........................................................................................ 10
   4.4 Corporate Proceedings....................................................................................... 10
   4.5 Other Agreements............................................................................................ 11
   4.6 Charter..................................................................................................... 11
   4.7 Legal Action................................................................................................ 11
   4.8 No Material Adverse Change.................................................................................. 11
   4.8. Officer's Certificate...................................................................................... 11
   4.9 Compliance Certificate...................................................................................... 11
   4.10 Opinion of Counsel for Company............................................................................. 12
   4.11 Representations and Warranties............................................................................. 12
   4.12 Performance; No Breach..................................................................................... 12
   4.13 Consents and Waivers....................................................................................... 12
   4.14 Corporate Proceedings...................................................................................... 12
   4.15 Legal Action............................................................................................... 12
   4.16 Compliance Certificate..................................................................................... 13
 

ARTICLE 5. COVENANTS OF THE COMPANY................................................................................ 13
   5.1 Corporate Existence......................................................................................... 13
   5.2 Furnishing of Financial Statements and Information.......................................................... 13
   5.3 Inspection.................................................................................................. 14
   5.4 Meetings of Board of Directors.............................................................................. 14
   5.5 Transactions with Affiliates................................................................................ 14
   5.6 Use of Proceeds............................................................................................. 14
   5.7 Employee Nondisclosure and Inventions Agreement............................................................. 15
   5.8 Changes in Outstanding Securities........................................................................... 15
   5.9 Most Favored Nation Status.................................................................................. 15
   5.10 Offerees; Sales of Securities.............................................................................. 15
 

ARTICLE 6. REGISTRATION RIGHTS..................................................................................... 15
   6.1 Three Required Registrations................................................................................ 15
   6.2 Piggyback Registration Rights............................................................................... 16
   6.3 Registration Procedures..................................................................................... 17
   6.4 Expenses.................................................................................................... 19
   6.5 Indemnification............................................................................................. 19
   6.6 Exclusive Obligation to Register............................................................................ 21


ARTICLE 7.   PARTICIPATION IN FUTURE OFFERINGS..................................................................... 21
   7.1 Participation in Future Offerings........................................................................... 21
   7.2  Notice..................................................................................................... 21
   7.3 Acceptance.................................................................................................. 22
   7.4 Percentage Interest......................................................................................... 22
   7.5 No Accumulation............................................................................................. 22
   7.6 Termination of Rights....................................................................................... 22


ARTICLE 8.  RESERVED............................................................................................... 22


ARTICLE 9. DEFINITIONS............................................................................................. 22



                                      -ii-



ARTICLE 10. MISCELLANEOUS.......................................................................................... 24
   10.1 Termination................................................................................................ 24
   10.2 Survival of Representations and Covenants.................................................................. 24
   10.3 Breach..................................................................................................... 24
   10.4 Notices.................................................................................................... 24
   10.5 Costs and Expenses......................................................................................... 25
   10.6 Confidentiality............................................................................................ 25
   10.7 Assignment; Rights of Successors and Assigns............................................................... 25
   10.8 Research and Development Services.......................................................................... 26
   10.9 Entire Agreement........................................................................................... 26
   10.10 Amendments and Waivers.................................................................................... 26
   10.11 Governing Law; Severability............................................................................... 26
   10.12 Counterparts.............................................................................................. 27
   10.13 Effect of Table of Contents and Headings.................................................................. 27

SIGNATURES

LIST OF SCHEDULES AND EXHIBITS

Schedule A  -        Description of Milestones
Schedule B  -        Disclosure Schedule
Exhibit A   -        Amended and Restated Articles of Organization
Exhibit B   -        Financial Statements
Exhibit C   -        License Agreement between
                     BioSeq, Inc. and BioMolecular Assays, Inc.
Exhibit D   -        Warrant Agreement
Exhibit E   -        Stockholders' Agreement
Exhibit F   -        License Agreement between BioSeq, Inc. and the Investor
Exhibit G   -        Legal Opinion of Company Counsel
Exhibit H   -        Employee Nondisclosure and Inventions Agreement

</TABLE>



                                     -iii-






                       PREFERRED STOCK PURCHASE AGREEMENT
                       ----------------------------------


        PURCHASE  AGREEMENT  entered into as of the 7th day of October,  1996 by
and between BioSeq, Inc. a Massachusetts corporation with its principal place of
business  at 25 Olympia  Avenue,  Unit #F,  Woburn,  MA 01801  (the  "Company"),
BioMolecular Assays, Inc., a Massachusetts corporation and principal stockholder
of the Company (the "Stockholder") and Boston Biomedica, Inc. (the "Investor").

                              W I T N E S S E T H:
                              --------------------

        WHEREAS,  the  Company  and  the  Stockholder  is  desirous  of  raising
additional capital for the Company,  and the Investor is interested in investing
in the Company;

        WHEREAS,  in order to induce the Investor to invest in the Company,  the
Stockholder  has agreed to become a party to this  Agreement with respect to the
representations and warranties contained in Article 2 hereof;

        WHEREAS,  the Company  desires to grant to the Investor and the Investor
desires to acquire from the Company an exclusive,  worldwide  license to use the
Company's Pressure Cycling Reactor Technology; and

        WHEREAS, the Company and the Investor desire to establish a research and
development  arrangement  under which the  Investor  will  perform  research and
development  services  for the Company  with  respect to certain  aspects of the
Pressure Cycling Reactor Technology;

        NOW,  THEREFORE,  in  consideration of the mutual  agreements  contained
herein, the parties hereto agree as follows:

ARTICLE 1.        PURCHASE AND SALE OF SECURITIES

1.1 Authorization:  Filing of Amended and Restated Articles of Organization. The
Company  has  authorized  the  issuance  and  sale  pursuant  to the  terms  and
conditions  hereof of up to 300  shares of its  Series A  Convertible  Preferred
Stock,  par  value  $.01 per  share,  550  shares  of its  Series B  Convertible
Preferred  Stock,  par value  $.01 per  share,  and 300  shares of its  Series C
Convertible  Preferred  Stock,  par value  $.01 per share,  having  the  rights,
restrictions, privileges and preferences as set forth in the form of the Amended
and Restated  Articles of Organization of the Company (the "Charter"),  attached
hereto as Exhibit A. Such shares of Series A Convertible Preferred Stock, Series
B  Convertible  Preferred  Stock and Series C  Convertible  Preferred  Stock are
sometimes  hereinafter  referred to  collectively  as the  "Shares." The Company
shall adopt and file the Charter with the Secretary of State of the Commonwealth
of Massachusetts on or before the first Closing (as defined below).

1.2 Purchase and Sale of Securities. Subject to the terms and conditions of this
Agreement and in reliance upon the representations and warranties of the Company
and the Stockholder






contained  herein,  the Investor  agrees to purchase  from the Company,  and the
Company  agrees  to sell to the  Investor,  on each date set  forth  below,  the
specified number of Shares at the price per share indicated:

            (i) 300 Shares of Series A Convertible Preferred Stock on October 4,
1996, at a per share price of seven  hundred  ($700.00)  dollars,  for aggregate
consideration of two hundred ten thousand ($210,000) dollars;

            (ii)  subject  to the  closing  of  the  Investor's  initial  public
offering,  550 Shares of Series B Convertible  Preferred  Stock on or before the
tenth business day following such closing,  at a per share price of nine hundred
fifty ($950.00) dollars, for aggregate  consideration of five hundred twenty two
thousand five hundred  ($522,500.00)  dollars,  provided,  however,  that if the
Investor's  public  offering is not closed by  December  31,  1996,  neither the
Company nor the Investor shall have any obligation under this subparagraph;

            (iii)  300  Shares  of Series C  Convertible  Preferred  Stock on or
before  July 31,  1997,  at a per  share  price  of two  thousand  five  hundred
($2,500.00) dollars, for aggregate consideration of seven hundred fifty thousand
($750,000.00)  dollars,   provided  that  the  Company  attains  the  milestones
described on Schedule A attached hereto;  provided,  however,  in the event that
the Company does not attain such milestones by July 31, 1997, the Investor shall
nevertheless have the right, exercisable in its sole discretion, to purchase the
remaining  300 Shares  until  December  31,  1997 at the price set forth in this
subparagraph  (iii),  and further provided that the Investor's right to purchase
the Shares  referenced in this subsection (iii) shall be applicable only if, and
after,  the Investor has made the full  investment  required by subsection  (ii)
above in accordance with its terms.

1.3 Closing.  The first Closing and each Closing  thereafter of the purchase and
sale of the Shares of Common Stock contemplated by this Agreement  (hereinafter,
each a  "Closing")  shall take place at the offices of Brown,  Rudnick,  Freed &
Gesmer at One Financial Center, Boston,  Massachusetts on October 7, 1996, or at
such other time,  date and place as shall be mutually agreed by the Investor and
the  Company.  At each  Closing,  the  Company  shall  deliver  to the  Investor
certificates  for the number of Shares  subscribed  for  against  payment of the
purchase price therefor.

ARTICLE 2.        REPRESENTATIONS AND WARRANTIES OF THE COMPANY

The Company and Stockholder hereby represent and warrant to the Investor that:

2.1.  Organization  and  Qualification.   The  Company  is  a  corporation  duly
organized,  validly  existing  and  in  good  standing  under  the  laws  of the
jurisdiction  of its  incorporation  and has all  required  corporate  power and
authority to own its property,  to carry on its business as presently  conducted
and to carry out the transactions contemplated hereby. The copies of the Charter
and By-Laws of the  Company,  as amended to date,  which have been  furnished to
counsel for the Investor by the Company,  are correct and complete.  The Company
is qualified to do business as a foreign  corporation and is in good standing in
each jurisdiction where the failure to be so



                                       2


qualified or to be in good standing could have a material  adverse effect on the
Company, its business or prospects.

2.2.  Subsidiaries.  The Company has no investments in any other  corporation or
business organization.

2.3  Capitalization.  Immediately  prior to the first  Closing,  the  authorized
capital stock of the Company  consists of 25,000 shares of Common Stock, .01 par
value,  and 15,000  shares of  Preferred  Stock,  of which 300 shares  have been
designated Series A Convertible Preferred Stock, 550 shares have been designated
Series B Convertible  Preferred Stock and 300 shares have been designated Series
C Convertible Preferred Stock. Immediately prior to the Closing date, there were
issued and  outstanding  4,712 shares of Common Stock and no shares of Preferred
Stock.   All  such  issued  and  outstanding   shares  are  validly  issued  and
outstanding,  fully paid and  non-assessable.  Except as disclosed on Schedule B
hereto, there are no outstanding  warrants,  options or other rights to purchase
or acquire,  or  preemptive  rights with respect to the issuance or sale of, the
Company's  Common  Stock.  There are no  securities  of the Company  directly or
indirectly  convertible  into or exchangeable for shares of capital stock of the
Company,  and there are no restrictions on the transfer of the Company's  Common
Stock, except as disclosed in Schedule B hereto.

2.4  Authorization  of Transaction.  The execution,  delivery and performance of
this  Agreement  have been duly  authorized by all necessary  corporate or other
action of the Company and it is the valid and binding obligation of the Company,
enforceable in accordance with its terms, subject to laws of general application
relating  to  bankruptcy,  insolvency  and the  relief of  debtors  and  general
principles  of equity.  The  issuance  of the  Shares and the Common  Stock upon
conversion of the Shares pursuant to the terms of this Agreement and the Charter
shall be, at the first  Closing,  duly and  validly  authorized,  and no further
approval or authority of the  shareholders or the directors of the Company or of
any governmental  authority or agency will be required for the issuance and sale
of the Shares and the underlying Common Stock as contemplated by this Agreement.
The  Shares  when  issued  and sold to the  Investor  in  compliance  with  this
Agreement,  and the  shares of Common  Stock  issuable  upon  conversion  of the
Shares,  when issued in accordance  with the provisions of the Charter,  will be
duly and validly issued, fully paid and non-assessable. The rights, preferences,
privileges and restrictions of the Series A Convertible  Preferred Stock, Series
B Convertible  Preferred  Stock and Series C Convertible  Preferred Stock are as
set forth in the Charter attached hereto as Exhibit A.

2.5  Approvals;  Compliance  With Laws.  The Company is not in  violation of its
Charter  or  by-laws  as  of  the  date  hereof.  The  execution,  delivery  and
performance of this Agreement and the  transactions  contemplated  hereby (i) do
not require any approval or consent of, or filing with, any governmental  agency
or  authority in the United  States of America or  otherwise  which has not been
obtained and which is not in full force and effect as of the date  hereof,  (ii)
will not conflict  with or  constitute  a breach or violation of the  respective
Charters or by-laws of the Company,  and (iii) will not result in a violation of
or any law or regulation to which they are subject.



                                       3



2.6  Financial  Statements.  Attached  hereto  as  Exhibit  B are the  following
consolidated  financial statements of the Company and unconsolidated  statements
of such companies,  audited or unaudited as indicated,  all of which  statements
are  complete  and correct  and fairly  present  the  financial  position of the
Company on the dates of such  statements and the results of their  operations on
the applicable  basis for the periods  covered thereby and have been prepared in
accordance with generally accepted accounting  principles  consistently  applied
throughout  the  periods  involved  and prior  periods  (except  that  footnotes
required in accordance with generally accepted  accounting  principles which are
not material to the financial statements have not been included):

           Balance Sheet dated September 30, 1996 (unaudited)
           Income  Statement for the Twelve Month Period ended December 31, 1995
           (unaudited)   Income  Statement  for  the  Nine  Month  Period  ended
           September 30, 1996 (unaudited)

           The balance  sheet  included  in the above  financial  statements  is
sometimes referred to hereinafter as the "Base Balance Sheet."

2.7 Title to Properties. The Company has good and marketable title to all of its
properties  and  assets,   free  and  clear  of  all  liens,   restrictions   or
encumbrances.  All machinery and equipment  included in such properties which is
necessary to the business of the Company is in good  condition  and repair,  and
all  leases of real or  personal  property  to which the  Company is a party are
fully effective and afford the Company  peaceful and  undisturbed  possession of
the subject matter of the lease.  The Company is not in violation of any zoning,
building, safety or environmental ordinance,  regulation or requirement or other
law or regulation applicable to the operation of owned or leased properties, and
has not received any notice of violation with which it has not complied.

2.8 Payment of Taxes. The Company has filed all federal, state and local income,
excise or franchise tax returns,  real estate and personal property tax returns,
sales and use tax returns  and other tax returns  required to be filed by it and
has paid all taxes  owing by it  except  taxes  which  have not yet  accrued  or
otherwise become due for which adequate provision has been made in the pertinent
financial  statements referred to in Section 2.6 above. The provisions for taxes
reflected in the above-mentioned  financial statements are adequate to cover any
and all tax  liabilities  of the Company in respect of its business,  properties
and operations  during the periods covered by said financial  statements and all
prior  periods.  Neither  the  Internal  Revenue  Service  nor any other  taxing
authority is now asserting or, to the knowledge of the Company,  threatening  to
assert  against the  Company any  deficiency  or claim for  additional  taxes or
interest thereon or penalties in connection therewith.

2.9 Absence of Undisclosed  Liabilities.  The Company does not have any material
accrued or contingent liability arising out of any transaction or state of facts
existing  prior to the date  hereof  other  than (i) as  reflected  or  reserved
against in the Base Balance  Sheet or (ii)  liabilities  arising in the ordinary
course of its business since the date of the Base Balance Sheet.



                                       4


2.10 Absence of Certain Changes. Except as disclosed on Schedule B hereto, since
the date of the Base Balance Sheet, there has not been:

           (a)  any  change  in the  financial  condition,  properties,  assets,
liabilities,  business or operations of the Company which change by itself or in
conjunction with all other such changes,  whether or not arising in the ordinary
course of business,  has had or will have a material adverse effect with respect
to the Company;

           (b) any contingent  liability incurred by the Company as guarantor or
otherwise with respect to the obligations of others;

           (c) any mortgage, encumbrance or lien placed on any of the properties
of the Company  which  remains in existence on the date hereof or at the time of
any Closing;

           (d) any  obligation  or liability  incurred by the Company other than
obligations and liabilities incurred in the ordinary course of business;

           (e) any  purchase,  sale or other  disposition,  or any  agreement or
other  arrangement for the purchase,  sale or other  disposition,  of any of the
properties  or  assets  of the  Company  other  than in the  ordinary  course of
business;

           (f) any  damage,  destruction  or loss,  whether  or not  covered  by
insurance, materially and adversely affecting the properties, assets or business
of the Company on a consolidated basis;

           (g) any declaration,  setting aside or payment of any dividend on, or
the making of any other  distribution  in respect of, the  capital  stock of the
Company, or any direct or indirect redemption,  purchase or other acquisition by
the Company of its own capital stock;

           (h) any labor  dispute or claim of unfair labor  practices  involving
the Company;  any change in the compensation payable or to become payable by the
Company to any of their  officers,  employees  or agents other than normal merit
increases in  accordance  with their usual  practices,  or any bonus  payment or
arrangement made to or with any of such officers, employees or agents;

           (i) any change with respect to the  management,  supervisory or other
key personnel of the Company;

           (j) any payment or discharge  of a material  lien or liability of the
Company  which  was not  shown on the Base  Balance  Sheet  or  incurred  in the
ordinary course of business thereafter; or

           (k) any obligation or liability incurred by the Company to any of its
officers, directors or shareholders or any loans or advances made by the Company
to any of its officers, directors or shareholders except normal compensation and
expense allowances payable to officers.



                                       5



2.11 Contracts and  Commitments.  Except as set forth on Schedule B, neither the
Company nor any Subsidiary is subject to any contract,  obligation or commitment
which is material or which involves a potential  commitment in excess of $10,000
or any employment  contract,  stock redemption or purchase agreement,  financing
agreement,  license, lease, franchise,  pension,  profit-sharing,  retirement or
stock option  plan.  Copies of each  agreement or document  listed in Schedule B
have been  delivered  to counsel for the  Investor.  Neither the Company nor any
Subsidiary is in default under any contract,  obligation or commitment.  Neither
the  Company  nor any  Subsidiary  is a party  to or bound  by any  contract  or
arrangement which has had or will have a material adverse effect on its business
or prospects.  Neither the Company nor any Subsidiary  has a material  liability
for renegotiation of government contracts or subcontracts.

2.12 Intellectual  Property. Set forth on Schedule B is a true and complete list
of all patents,  patent applications,  trademarks,  service marks, trademark and
service mark applications,  trade names, and copyrights  presently owned or held
by the Company or the  Stockholder,  and any material license or right to any of
the  foregoing.  To the best of the  Company's  knowledge,  the Company  owns or
possesses  or can  obtain by  payment of  royalties  which  will not  materially
adversely  affect the  business of the Company all of the  patents,  trademarks,
service marks, trade names,  copyrights,  proprietary rights,  trade secrets, or
rights or licenses to the foregoing,  reasonably necessary to the conduct of its
business as presently conducted or proposed to be conducted.  To the best of the
Company's  knowledge,  the  Company's  business,  as  presently  conducted or as
proposed to be conducted, does not and will not cause the Company to infringe or
violate any of the patents, trademarks,  service marks, trade names, copyrights,
licenses,  trade secrets or other proprietary rights of any other person. To the
best of the  Company's  knowledge,  the Company  has the right to use,  free and
clear of claims  or rights of  others,  all trade  secrets,  customer  lists and
manufacturing  processes required for or incident to their products, and none of
them is using  any  confidential  information  or trade  secrets  of any  former
employer of any of their past or present employees.

2.13  Compliance  with Other  Instruments.  The Company is not in default in the
performance of any material obligation,  agreement or condition contained in any
bond or debenture or any other evidence of indebtedness or any indenture or loan
agreement of the Company which default  affords to any person the  unconditional
right to accelerate any material indebtedness or terminate any material right or
agreement of the Company.  Neither the execution and delivery of this Agreement,
nor the fulfillment of the terms herein set forth,  nor the  consummation of the
transactions  contemplated hereby, will (i) conflict with or constitute a breach
of, default under or violation of any agreement,  indenture,  mortgage,  deed of
trust or other material  instrument or undertaking by which the Company is bound
or to  which  it or any of its  properties  are  subject,  or (ii)  result  in a
violation of any court decree  binding upon the Company,  or (iii) result in the
creation or  imposition of any material  lien,  charge or  encumbrance  upon any
property or assets of the Company.

2.14  Litigation.  Except  for  matters  described  in  Schedule  B, there is no
litigation  pending  or, to the  knowledge  of the  Company or the  Stockholder,
threatened against the Company, and there are no outstanding court orders, court
decrees,  or court  stipulations  to which the Company is a party which question
this Agreement or affect the transactions  contemplated hereby, or which



                                       6


will  or  could  result  in any  materially  adverse  change  in  the  business,
properties,  operations,  prospects,  assets or in the  condition,  financial or
otherwise,  of Company.  Neither the Company nor the  Stockholder  has reason to
believe that any such action,  suit,  proceeding or investigation may be brought
against the Company.

2.15 Permits and Licenses;  Compliance with Law. The Company has all franchises,
permits,  licenses and other rights and privileges necessary to permit it to own
its  properties  and to conduct  its  present  business.  The  Company is not in
violation of any law, regulation, authorization or order of any public authority
relevant to the  ownership of its  properties  or the carrying on of its present
business.

2.16 Offerees;  Sales of Securities.  Except as disclosed on Schedule B, neither
the Company  nor anyone  acting on its behalf has within the past six (6) months
offered the Common Stock or any similar  security of the Company for sale to, or
solicited any offers to buy the same from, any person or organization other than
the Investor.  Except as disclosed on Schedule B, neither the Company nor anyone
acting on its behalf has in the past sold,  offered for sale or solicited offers
to buy any of said securities so as to bring the offer,  issuance or sale of the
Shares, as contemplated by this Agreement, within the provisions of Section 5 of
the Act.  The Company has  complied  with all  applicable  state  "blue-sky"  or
securities  laws in connection  with the issuance and sale of the Shares and its
Common Stock and other securities.

2.17 Brokerage. Except as disclosed on Schedule B, there are no valid claims for
brokerage commissions,  finder's fees or similar compensation in connection with
the  transactions  contemplated  by this Agreement  based on any  arrangement or
agreement made by or on behalf of the Company and the Company will indemnify and
hold the Investor harmless against any liability or expense to it arising out of
such a claim.

2.18 Investment  Materials.  The written  materials  prepared by the Company and
furnished to the Investor prior to the date hereof describe all material aspects
of the business of the Company,  contains no untrue or misleading statement of a
material  fact or any  omission to state a fact  material to the business of the
Company or necessary to make the statements  contained  therein not  misleading.
The factual information  contained therein is correct, the assumptions,  if any,
are reasonable,  and the projections,  if any, are, to the best knowledge of the
Company and the Stockholder reasonably attainable within the periods indicated.

2.19  Disclosure.   Neither  this  Agreement,   nor  any  financial   statement,
certificate,  list, exhibit, letter or other written statement pertaining to the
Company or the  Stockholder,  made or  delivered to the Investor by the Company,
the Stockholder or any of their respective  agents,  when taken as a whole along
with such  other  information  as  provided  to  Investor,  contains  any untrue
statement of a material  fact or omits to state any material  fact  necessary in
order to make the  statements  contained  therein not misleading in light of the
circumstances under which they were made.

2.20  Certain  Transactions.  Except as  disclosed  on  Schedule  B, except with
respect to reimbursable  business expenses and compensation payable for services
rendered,  the Company is not indebted,  directly or  indirectly,  to any of its
employees,  officers, directors or stockholders or


                                       7



to  their  spouses  or  children,  in any  amount  whatsoever;  and none of said
employees,  officers,  directors  or,  to the best of the  Company's  knowledge,
stockholders,  or any member of their  immediate  families,  are indebted to the
Company  or have  any  direct  or  indirect  ownership  interest  in any firm or
corporation with which the Company is affiliated or with which the Company has a
business relationship.  No such employee,  officer, director or stockholder,  or
any member of their immediate families,  is, directly or indirectly,  interested
in any  material  contract  with the  Company.  The Company is not  guarantor or
indemnitor of any indebtedness of any other person, firm or corporation.

2.21  Corporate  Documents;  Minute Books.  Except for  amendments  necessary to
satisfy  representations and warranties or conditions contained herein (the form
of which  amendments has been approved by the Investor),  the Charter and Bylaws
of the Company are in the form  previously  provided to counsel to the Investor.
The minute books of the Company  previously  provided to counsel to the Investor
contain a complete summary of all meetings of directors and  stockholders  since
the time of incorporation of the Company.

2.22 Employee  Benefit  Plans.  The Company does not have any "employee  benefit
plan" as defined in the Employee  Retirement  Income  Security  Act of 1974,  as
amended.

2.23 Environmental and Safety Laws. To the best of its knowledge, the Company is
not in violation of any applicable  statute,  law, or regulation relating to the
environment or occupational health and safety, and to the best of its knowledge,
no  material  expenditures  are or will be  required in order to comply with any
such existing statute, law, or regulation.

2.24 Insurance. Except as disclosed in Schedule B, the Company has in full force
and effect fire and casualty insurance  policies,  with extended  coverage,  and
insurance  against other hazards,  risks and liabilities to persons and property
to the extent and in the manner  customary for  companies in similar  businesses
similarly situated.

2.25 Labor Agreements and Actions.  The Company is not aware that any officer or
key employee or consultant  intends to terminate his or her employment  with the
Company,  nor does  the  Company  have a  present  intention  to  terminate  the
employment of any of the  foregoing.  Subject to general  principles  related to
wrongful  termination of employees,  the employment of each officer and employee
of the Company is terminable at the will of the Company.

2.26 Registration Rights.  Other than as granted by this Agreement,  the Company
has not granted or agreed to grant any  registration  rights with respect to the
Company's capital stock,  including piggyback registration rights, to any person
or entity.

ARTICLE 3.        REPRESENTATIONS AND WARRANTIES OF INVESTOR

Investor hereby represents and warrants to the Company that:

3.1  Investment  Intent.  The Investor is purchasing or acquiring the Shares for
its, own account for  investment  and not with a present view to, or for sale in
connection with, any



                                       8


distribution  thereof in violation of the Act. The Investor  hereby  consents to
the  imposition  of a legend  substantially  similar  to the  following  on each
certificate for Shares (and shares issued upon conversion of the Shares) and the
Investor agrees to abide by the restrictions contained therein:

            "The shares represented by this certificate have not been registered
            under the  Securities  Act of 1933, as amended (the "Act"),  and may
            not  be  sold,  transferred  or  assigned  unless  such  shares  are
            registered  under the Act or such sale,  transfer or  assignment  is
            exempt from the registration requirements of the Act."

3.2  Authorization.  The Investor has the power and authority to enter into this
Agreement and to perform all of its obligations hereunder.

3.3 Restricted  Securities.  The Investor  understands  that the Shares have not
been  registered  under  the Act by  reason  of a  specific  exemption  from the
registration  provisions of the Act which depends upon, among other things,  the
bona fide  nature of  Investor's  investment  intent as  expressed  herein.  The
Investor acknowledges that the Shares, when received,  must be held indefinitely
unless they are subsequently  registered under the Act or an exemption from such
registration  is available.  The Investor has been advised of or is aware of the
provisions of Rule 144  promulgated  under the Act,  which rule permits  limited
resale  of  securities   purchased  in  a  private   placement  subject  to  the
satisfaction of certain conditions contained therein.

3.4  Brokerage.  There are no valid claims for brokerage  commissions,  finder's
fees or similar compensation in connection with the transactions contemplated by
this Agreement  based upon any  arrangement or agreement made by or on behalf of
the Investor and the Investor  agrees to indemnify and hold harmless the Company
against any liability or expense to it arising out of such a claim to the extent
that such claim arises out of actions or alleged actions of the Investor.

3.5 Due  Organization.  The Investor is a corporation  duly  organized,  validly
existing  and in  good  standing  under  the  laws  of the  jurisdiction  of its
incorporation  and has all  required  corporate  power and  authority to own its
property,  to carry on its business as presently  conducted and to carry out the
transactions contemplated hereby.

3.6. No Conflict. The execution,  delivery and performance of this Agreement and
the consummation of the transactions  contemplated hereby will not conflict with
or constitute a breach or violation of the Amended and Restated  Certificate  of
Incorporation or By-Laws of the Investor.

ARTICLE 4.        CONDITIONS OF INVESTOR'S AND COMPANY'S OBLIGATION

Conditions of Investor's Obligations.

In  addition to the  conditions  set forth in Article 1 of this  Agreement,  the
obligation of the Investor to purchase and pay for the Shares  subscribed for by
the Investor at each Closing shall be subject to the satisfaction of each of the
following conditions:



                                       9


4.1  Representations  and Warranties.  The representations and warranties of the
Company and the Stockholder  contained  herein or in the exhibits annexed hereto
or  otherwise  made in  writing  by or on their  behalf in  connection  with the
transactions  contemplated  hereby  shall be true and  correct  as of the  first
Closing with the same effect as though made on and as of that date.

4.2 Performance;  No Breach.  The Company shall have performed and complied with
all of the  agreements  and  conditions  contained  herein  and  required  to be
performed or complied  with by the Company at or prior to each Closing and shall
not be in breach of any provision of this Agreement.

4.3 Consents and Waivers. All necessary consents, waivers, approvals, amendments
and other action on the part of any person  necessary  to have been  obtained or
effected in order to carry out the  transactions  contemplated by this Agreement
shall have been duly  obtained or effected and shall be in full force and effect
and adequate.

4.4 Corporate  Proceedings.  All corporate and other  proceedings to be taken in
connection with the transactions  contemplated hereby and all documents incident
thereto  shall be  satisfactory  in  substance  and form to the Investor and its
counsel,  and the  Investor  and its counsel  shall have  received  all original
copies or certified or other copies of documents  which they may have reasonably
requested.

4.5  Other  Agreements.  The  Company  shall  have  entered  into (i) a  License
Agreement with BioMolecular  Assays,  Inc. in the form of Exhibit C hereto;  and
(ii) a Warrant Agreement with the Investor, in the form of Exhibit D hereto. The
Company,  the  stockholders  of the Company and the Investor  shall have entered
into a  Stockholders'  Agreement  in the form of Exhibit E hereto.  The  Company
shall  grant a license  to the  Investor  to use its  Pressure  Cycling  Reactor
Technology in the form of Exhibit F hereto.

4.6 Charter.  The Charter,  in a form  satisfactory to the Investor,  shall have
been filed with the Secretary of State for the Commonwealth of Massachusetts.

4.7         Legal Action.

            (a) There shall not have been  instituted or threatened any material
legal  proceeding  seeking to  prohibit  the  consummation  of the  transactions
contemplated by this Agreement,  or to obtain damages from Investor with respect
thereto.

            (b) None of the parties  hereto  shall be  prohibited  by any order,
writ,  injunction or decree of any governmental  body of competent  jurisdiction
from  consummating  the  transactions  contemplated  by this  Agreement,  and no
material action or proceeding shall then be pending which questions the validity
of this Agreement,  any of the  transactions  contemplated  hereby or any action
which  has  been  taken  by any of the  parties  in  connection  herewith  or in
connection with any of the transactions contemplated hereby.



                                       10


4.8 No Material  Adverse Change.  As of each Closing pursuant to Section 1.2(ii)
and  1.2(iii),  the Investor  shall have  received a  Certificate  signed by the
President  and  Treasurer  of the  Company  certifying  which,  if  any,  of the
representations  and  warranties  contained  in  Article  2 hereof  have  become
inaccurate, and there shall have been no material adverse change with respect to
the business, condition (financial or otherwise) or prospects of the Company.

4.9.  Officer's  Certificate.  The Company shall have  delivered a  Certificate,
executed by the Clerk of the Company,  dated the first Closing Date,  certifying
the Board of Director's and stockholders'  resolutions approving this Agreement,
as well as all of the Agreements referred to in Section 4.5 hereof, the issuance
of the Shares, and certifying the Charter and Bylaws of the Company.

4.10  Compliance  Certificate.  The  Investor  shall have  received at the first
Closing a  certificate  signed by the  President  and  Treasurer  of the Company
certifying that the conditions specified in Sections 1, and 4.1 through 4.7 have
been fulfilled.  At any successive  Closing,  the Investor shall have received a
Certificate signed by the President and Treasurer of the Company certifying that
the conditions specified in Sections 1 and 4.2 through 4.7 have been fulfilled.

4.11  Opinion of Counsel for  Company.  The Investor  shall have  received  from
Warner & Stackpole,  LLP, counsel for the Company, a favorable opinion,  in form
and  substance  satisfactory  to the  Investor  and its  counsel,  as to matters
covered in Exhibit G hereto.

Conditions of Company's Obligations.

In  addition to the  conditions  set forth in Article 1 of this  Agreement,  the
obligation of the Company to issue the Shares  subscribed for by the Investor at
each  Closing  shall be subject  to the  satisfaction  of each of the  following
conditions:

4.12  Representations and Warranties.  The representations and warranties of the
Investor contained herein or in the exhibits annexed hereto or otherwise made in
writing by or on its behalf in  connection  with the  transactions  contemplated
hereby  shall be true and  correct as of each  Closing  with the same  effect as
though made on and as of that date.

4.13 Performance; No Breach. The Investor shall have performed and complied with
all of the  agreements  and  conditions  contained  herein  and  required  to be
performed or complied with by it at or prior to each Closing and shall not be in
breach of any provision of this Agreement.

4.14  Consents  and  Waivers.  All  necessary  consents,   waivers,   approvals,
amendments  and other action on the part of the Investor  necessary to have been
obtained or effected in order to carry out the transactions contemplated by this
Agreement  shall have been duly  obtained or effected and shall be in full force
and effect and adequate.

4.15 Corporate  Proceedings.  All corporate and other proceedings to be taken in
connection with the transactions  contemplated hereby and all documents incident
thereto  shall be  satisfactory  in  substance  and form to the  Company and its
counsel, and the Company and its



                                       11


counsel shall have received all original  copies or certified or other copies of
documents which they may have reasonably requested.

4.16        Legal Action.

            (a) There shall not have been  instituted or threatened any material
legal  proceeding  seeking to  prohibit  the  consummation  of the  transactions
contemplated  by this  Agreement,  or to obtain  damages  from the Company  with
respect thereto.

            (b) None of the parties  hereto  shall be  prohibited  by any order,
writ,  injunction or decree of any governmental  body of competent  jurisdiction
from  consummating  the  transactions  contemplated  by this  Agreement,  and no
material action or proceeding shall then be pending which questions the validity
of this Agreement,  any of the  transactions  contemplated  hereby or any action
which  has  been  taken  by any of the  parties  in  connection  herewith  or in
connection with any of the transactions contemplated hereby.

4.17 Compliance  Certificate.  The Company shall have received at each Closing a
certificate  signed by the President  and  Treasurer of the Investor  certifying
that the  conditions  specified  in Sections 1, and 4.12  through 4.16 have been
fulfilled.

ARTICLE 5.        COVENANTS OF THE COMPANY

The Company agrees that,  until the  consummation of a Qualified Public Offering
or, as to the  Investor,  until such earlier time as the Investor owns less than
twenty-five   (25%)   percent  of  the  Series  A  Preferred   (computed  on  an
as-if-converted  basis and  including  the shares of Common Stock into which the
Series A Preferred may have been converted):

5.1 Corporate  Existence.  The Company will maintain and cause any Subsidiary to
maintain its corporate existence in good standing and comply with all applicable
laws and  regulations  of the United States or of any state or states thereof or
of any political subdivision thereof and of any governmental authority.

5.2 Furnishing of Financial Statements and Information. The Company will deliver
to the Investor:

            (a) within five days of their availability,  but in any event within
45 days after the close of each calendar quarter, consolidated balance sheets of
the Company and any  Subsidiaries  as of the end of each such quarter,  together
with the related  statements of consolidated  operations,  retained earnings and
changes in financial  position for each such quarter,  all in reasonable  detail
and  certified  by an  authorized  accounting  officer  of the  Company  and the
President of the Company, subject to year-end adjustments;

            (b) within five days of their availability,  but in any event within
90 days after the end of each fiscal year, a  consolidated  balance sheet of the
Company and any Subsidiaries,  as of the end of such fiscal year,  together with
the related statements of consolidated operations,



                                       12


retained  earnings  and changes in  financial  position  for such  fiscal  year,
prepared in accordance with generally  accepted  accounting  principles,  all in
reasonable  detail  and  duly  certified  by  independent   public   accountants
acceptable to the Investor,  which  accountants  shall have given the Company an
opinion, unqualified as to the scope of the audit due to any restrictions placed
upon the auditors by the Company, regarding such statements;

            (c) within  thirty (30) days prior to the  beginning  of each fiscal
year, an annual budget for such year detailing relevant  financial  information,
including projected income and expense, borrowings,  capital expenditures,  cash
flow,  sources  and uses of funds and  working  capital,  with a  comparison  of
budgeted amounts to actual amounts for the preceding year.

            (d) with reasonable promptness, such other financial data related to
the  business,   affairs  and  financial   condition  of  the  Company  and  any
Subsidiaries  as is  available  to the  Company  and as from  time  to time  the
Investor may reasonably request;

(e) contemporaneously with the filing or mailing thereof, copies of all material
filed with the  Securities  and  Exchange  Commission  or made  available to any
stockholders of the Company; and

            (f) within 15 days after the Company learns of the  commencement  of
any  material  suit,  legal or  equitable,  or of any  material  administrative,
arbitration or other proceeding against the Company,  any of its Subsidiaries or
their respective businesses, assets or properties,  written notice of the nature
and extent of such suit or proceeding.

5.3 Inspection.  The Company will permit an agent  designated by the Investor to
visit and inspect at the Investor's expense any of the properties of the Company
or any  Subsidiaries,  including  their books and records (and to make  extracts
therefrom),  and to discuss  their  affairs,  finances,  and accounts with their
officers,  all to such  reasonable  extent  and at  such  reasonable  times  and
intervals as the Investor may reasonably request. If the Company determines that
such  inspection  might  result  in the  disclosure  of trade  secrets  or other
confidential  information,   the  Company  may  require  such  persons  to  sign
nondisclosure agreements with respect thereto.

5.4  Meetings of Board of  Directors.  The Company  shall cause  meetings of the
Board of Directors to be called not less often than once each calendar  quarter,
shall  give  notice  of each  such  meeting  to the  Investor,  shall  permit  a
representative of the Investor to attend such meeting as a guest of the Board of
Directors  (if a designee  of the  Investor is not then a member of the Board of
Directors),  and shall  provide  copies of minutes of all  actions  taken by the
Board of Directors, whether at meetings or by written consent, to the Investor.

5.5 Transactions with Affiliates. Except for transactions approved by a majority
of  disinterested  directors,  neither the  Company nor any of its  Subsidiaries
shall enter into any transaction with any director, officer, employee, or holder
of more than five (5%) percent of the outstanding shares of any class of capital
stock of the  Company  or any of its  Subsidiaries,  family  member  of any such
person,  or any  corporation,  partnership,  trust, or other entity in which any
such  person,  or family  member of any such  person,  is a  director,  officer,
trustee,  partner,  or



                                       13


holder of more than five (5%) percent of the outstanding  stock thereof,  except
for  transactions  on customary  terms and  conditions  related to such person's
employment,  and except that the Company may maintain  its current  relationship
with BioMolecular Assays in substantially the same form as currently exists.

5.6 Use of Proceeds.  The Company  shall use the  proceeds  from the sale of the
Shares (i) to fund  pre-operational  start-up  expenses,  (ii) to fund operating
losses prior to  profitable  operations,  (iii) for the  acquisition  of capital
equipment and other capital items and (iv) to pay the expenses of this offering;
provided that  notwithstanding  the foregoing,  33% of the proceeds of the first
investment  pursuant to Section  1.2(i)  hereof,  and 67% of the proceeds of the
second and third  investments  pursuant to Sections 1.2(ii) and 1.2(iii) hereof,
shall be used to fund research and development efforts aimed at demonstration of
the technical  feasibility  of, and  commercial  development  for, the Company's
pressure cycling reactor technology.

5.7 Employee  Nondisclosure and Inventions Agreement.  The Company shall use its
best efforts and shall cause any of its  Subsidiaries  to use their best efforts
to enter  into an  Employee  Nondisclosure  and  Inventions  Agreement  with all
current and future  officers,  key employees,  and other employees who will have
access to confidential information about the Company or any of its Subsidiaries.
Such Employee  Nondisclosure  and Inventions  Agreement  shall be in the form of
Exhibit H hereto.

5.8 Changes in  Outstanding  Securities.  The Company  shall not take any action
with  respect to its  outstanding  equity  securities  which will  result in the
Investor  holding  equity  securities  of the Company  equal to or greater  than
twenty (20%) percent of the outstanding equity securities of the Company.

5.9 Most Favored  Nation Status.  During the five (5) year period  commencing on
the date of the Closing of the Investor's purchase of Shares pursuant to Section
1.2(ii) hereof,  the Company will not grant to any persons or entities acquiring
shares or rights to acquire  capital stock of the Company in  connection  with a
capital-raising  transaction  (an  "Investor  Group"),  rights  with  respect to
matters which also  constitute the subject  matter of this Agreement  (including
the  Stockholder  Agreement,  the  Warrant and the terms and  conditions  of the
Series  Preferred but  specifically  excluding the subject matter of the License
Agreement)  that are more  favorable  than the rights  granted  to the  Investor
hereunder or thereunder,  without granting to the Investor substantially similar
rights; provided, however, that the foregoing covenant shall not apply to rights
granted by the Company to the  members of any  Investor  Group which  invests in
such  transaction  an amount  equal to at least  five (5) times the  amount  the
Investor  has then  invested in the  Company  hereunder  (including  any amounts
invested  pursuant to that certain Warrant Agreement between the Company and the
Investor of even date).  The foregoing  provision  shall also be inapplicable to
the price term of any  securities  (excluding  antidilutiono  provisions) of the
Company to be purchased by any Investor Group.

5.10 Offerees; Sales of Securities. Neither the Company nor anyone acting on its
behalf  shall  offer  for sale or  solicit  offers  to buy any of the  Company's
securities so as to bring such offer,  issuance or sale within the provisions of
Section  5 of the  Act.  The  Company  will  comply



                                       14


with all applicable  state  "blue-sky" or securities laws in connection with the
issuance and sale of its securities in the future.

ARTICLE 6.        REGISTRATION RIGHTS

6.1         Three Required Registrations.

            (a) From and after the  earliest to occur of (i) five (5) years from
the date  hereof and (ii) six months  after the  closing of the  initial  public
offering of the Company, if on any three occasions the Investor shall notify the
Company  in writing  that it intends to offer or cause to be offered  for public
sale all or any portion of the Registrable Securities,  under such circumstances
as, in the opinion of Investor's  counsel,  would require  registration  thereof
under the Act,  then the Company will prepare and file with the  Commission  and
use its best efforts to cause to become effective a Registration Statement under
the Act  relating to such  Registrable  Securities  as may be  requested  by the
Investor.

            (b) In the event that the Investor  determines for any reason not to
proceed with a registration at any time before a Registration Statement has been
declared  effective  by the  Commission,  and such  Registration  Statement,  if
theretofore  filed  with  the  Commission,  is  withdrawn  with  respect  to the
Registrable  Securities covered thereby, and the Investor agrees to bear its own
expenses  incurred in connection  therewith and to reimburse the Company for the
out-of-pocket  expenses  incurred by it attributable to the registration of such
Registrable Securities,  then the Investor shall not be deemed to have exercised
one of its three required registration rights pursuant to this Section.

            (c) Without the written consent of the Investor, neither the Company
nor any holder of  securities  of the  Company may  include  securities  in such
registration if, in the good faith judgment of the managing  underwriter of such
public  offering,  the inclusion of such  securities  would  interfere  with the
successful  marketing  of  the  Registrable  Securities  or  would  require  the
exclusion  of  any  portion  of  the  Registrable   Securities  proposed  to  be
registered.

6.2         Piggyback Registration Rights.

            (a) If at any time the Company  shall  determine  to register any of
its  securities  under  the Act and in  connection  therewith  the  Company  may
lawfully register any of the Registrable  Securities,  the Company will promptly
give  written  notice  thereof  to the  Investor.  Upon the  written  request of
Investor given within 30 days after receipt of any such notice from the Company,
the  Company  will,  except  as  herein  provided,  cause  all such  Registrable
Securities  which the Investor has  requested to be registered to be included in
such Registration  Statement,  all to the extent requisite to permit the sale or
other  disposition of the Registrable  Securities.  Nothing herein shall prevent
the Company from at any time abandoning or delaying any registration.

            (b) If any  registration  pursuant  to this  Section  6.2  shall  be
underwritten  in whole or in part, the Company may require that the  Registrable
Securities  requested for inclusion  pursuant



                                       15


to this  Section  6.2 be  included  in the  underwriting  on the same  terms and
conditions as the securities  otherwise being sold through the underwriters.  In
the event that the Registrable  Securities  requested for inclusion  pursuant to
this Section 6.2 would constitute more than 25% of the total number of shares to
be included in a proposed underwritten public offering, and if in the good faith
judgment of the managing  underwriter  of such public  offering the inclusion of
all  of  the  Registrable   Securities  originally  covered  by  a  request  for
registration  would  reduce the number of shares to be offered by the Company or
interfere  with the  successful  marketing of the shares of stock offered by the
Company,  then the number of Registrable  Securities otherwise to be included in
the  underwritten  public  offering  may be reduced pro rata among the  Investor
requesting such registration and any other selling security holder (based on the
number of Registrable  Securities for which registration is requested  expressed
as a  percentage  of the total number of shares  being  registered  on behalf of
selling  security holders  (including the Investor));  provided,  however,  that
after any such required  reduction the Registrable  Securities to be included in
such offering shall  constitute at least 25% of the total number of shares to be
included in such offering.

6.3  Registration  Procedures.  If and  whenever  the Company is required by the
provisions  of Sections  6.1 or 6.2 to effect the  registration  of  Registrable
Securities under the Act, the Company will:

            (a) prepare and file with the  Commission a  Registration  Statement
with  respect  to such  securities,  and use its  best  efforts  to  cause  such
Registration  Statement to become and remain effective for such period as may be
reasonably necessary to effect the sale of such securities;

            (b) prepare and file with the  Commission  such  amendments  to such
Registration  Statement and supplements to the prospectus  contained  therein as
may be necessary to keep such Registration  Statement  effective for such period
as  may  be  reasonably  necessary  to  effect  the  sale  of  such  Registrable
Securities;

            (c)  furnish  to  the  Investor  and  to  the  underwriters  of  the
securities being registered such reasonable number of copies of the Registration
Statement,  preliminary prospectus, final prospectus and such other documents as
such  underwriters  may  reasonably  request in order to  facilitate  the public
offering of such securities;

            (d) use its best  efforts  to  register  or qualify  the  securities
covered by such  Registration  Statement under the state  securities or blue sky
laws of such  jurisdictions  as Investor may  reasonably  request within 20 days
following the original filing of such  Registration  Statement,  except that the
Company  shall not for any purpose be  required to execute a general  consent to
service of process or to qualify to do business as a foreign  corporation in any
jurisdiction wherein it is not so qualified;

            (e) notify the  Investor,  promptly  after it shall  receive  notice
thereof, of the time when such Registration  Statement has become effective or a
supplement to any prospectus  forming a part of such registration  statement has
been filed;




                                       16



(f) notify the  Investor  promptly  of any  request  by the  Commission  for the
amending or  supplementing of such  Registration  Statement or prospectus or for
additional information;

            (g) prepare and file with the Commission,  promptly upon the request
of the Investor, any amendments or supplements to such Registration Statement or
prospectus  which,  in the opinion of counsel for the Investor (and concurred in
by  counsel  for the  Company),  is  required  under  the Act or the  rules  and
regulations  thereunder in connection  with the  distribution of the Registrable
Securities by the Investor;

            (h) prepare  and  promptly  file with the  Commission  and  promptly
notify  the  Investor  of the filing of such  amendment  or  supplement  to such
Registration  Statement  or  prospectus  as  may be  necessary  to  correct  any
statements  or  omissions  if, at the time when a  prospectus  relating  to such
securities  is  required  to be  delivered  under the Act,  any event shall have
occurred as the result of which any such  prospectus or any other  prospectus as
then in effect would  include an untrue  statement of a material fact or omit to
state any material fact necessary to make the statements  therein,  in the light
of the circumstances in which they were made, not misleading;

            (i) advise the Investor,  promptly  after it shall receive notice or
obtain  knowledge  thereof,  of the issuance of any stop order by the Commission
suspending the effectiveness of such Registration Statement or the initiation or
threatening of any proceeding for that purpose and promptly use its best efforts
to prevent the  issuance of any stop order or to obtain its  withdrawal  if such
stop order should be issued;

            (j) not  file  any  amendment  or  supplement  to such  Registration
Statement or prospectus to which the Investor shall have reasonably  objected on
the grounds that such  amendment or  supplement  does not comply in all material
respects  with  the  requirements  of  the  Act  or the  rules  and  regulations
thereunder,  after  having  been  furnished  with a copy  thereof  at least five
business days prior to the filing thereof,  unless in the opinion of counsel for
the Company the filing of such  amendment or supplement is reasonably  necessary
to protect the Company  from any  liabilities  under any  applicable  federal or
state law and such filing will not violate applicable law; and

            (k) at the request of the Investor, furnish on the effective date of
the Registration  Statement and, if such  registration  includes an underwritten
public offering, at the closing provided for in the underwriting agreement:  (i)
an opinion,  dated each such date, of the counsel  representing  the Company for
the purposes of such registration, addressed to the underwriters, if any, and to
the Investor,  covering such matters as such  underwriters  and the Investor may
reasonably  request, in which opinion such counsel shall state (without limiting
the generality of the  foregoing)  that such  Registration  Statement has become
effective under the Act and that (a) to the best of such counsel's  knowledge no
stop  order  suspending  the  effectiveness  thereof  has  been  issued  and  no
proceedings for that purpose have been instituted or are pending or contemplated
under the Act,  (b) the  Registration  Statement,  related  prospectus  and each
amendment  or  supplement  thereto  appear  on  their  face to be  appropriately
responsive  to  the  requirements  of the  Act  and  the  applicable  rules  and
regulations  of  the  Commission  thereunder



                                       17


applicable to the form of the Registration  Statement  (except that such counsel
need express no opinion as to financial  statements  contained therein),  (c) to
the best of the  knowledge  of such  counsel  after  investigation,  neither the
Registration Statement,  the prospectus nor any amendment nor supplement thereto
contains any untrue  statement  of a material  fact or omits to state a material
fact required to be stated therein or necessary to make the  statements  therein
not misleading,  (d) the description in the Registration Statement or prospectus
or any amendment or supplement thereto of all legal and governmental proceedings
and all contracts and other legal documents or instruments  filed as exhibits to
the  Registration  Statement  are  accurate and fairly  present the  information
required  to be  shown,  and (e) such  counsel  does  not  know of any  legal or
governmental proceedings, pending or threatened, required to be described in the
Registration  Statement or prospectus  or any  amendment or  supplement  thereto
which are not  described  as  required,  nor of any  contracts  or  documents or
instruments  of the  character  required  to be  described  in the  Registration
Statement or  prospectus  or amendment or  supplement  thereto or to be filed as
exhibits to the  Registration  Statement,  which are not  described and filed as
required; and (ii) a letter dated each such date, from the independent certified
public accountants of the Company, addressed to the underwriters, if any, and to
the Investor,  covering such matters as such  underwriters  and the Investor may
reasonably  request,  in which  letter such  accountants  shall  state  (without
limiting the generality of the foregoing)  that they are  independent  certified
public accountants within the meaning of the Act and that in the opinion of such
accountants  the financial  statements  and other  financial data of the Company
included in the  Registration  Statement or the  prospectus  or any amendment or
supplement   thereto  comply  in  all  material  respects  with  the  applicable
accounting requirements of the Act.

6.4         Expenses.

            (a) With respect to each  inclusion of  Registrable  Securities in a
Registration  Statement  pursuant to Section 6.1 or 6.2 hereof,  all fees, costs
and  expenses  of and  incidental  to such  registration,  inclusion  and public
offering (as specified in paragraph (b) below) in connection  therewith shall be
borne by the Company;  provided,  however,  that the Investor shall bear its pro
rata share of the underwriting discount and commissions and transfer taxes.

            (b) The fees,  costs and expenses of registration to be borne by the
Company as provided in paragraph (a) above shall  include,  without  limitation,
all  registration,   filing  and  NASD  fees,   printing   expenses,   fees  and
disbursements of counsel and accountants for the Company, fees and disbursements
of counsel  for the  underwriter  or  underwriters  of such  securities  (if the
Company  and/or  selling  security  holders  are  required to bear such fees and
disbursements), all legal fees and disbursements and other expenses of complying
with  state  securities  or blue sky  laws of any  jurisdictions  in  which  the
securities to be offered are to be registered or qualified, and the premiums and
other costs of  policies  of  insurance  against  liability  arising out of such
public offering;  the fees and  disbursements of any counsel and accountants for
the Investor shall be borne by the Investor.

6.5         Indemnification.



                                       18


            (a) The Company will  indemnify  and hold  harmless the Investor and
any  underwriter  (as defined in the Act) for the Investor  and each person,  if
any, who controls  the  Investor or such  underwriter  within the meaning of the
Act, from and against, and will reimburse the Investor and each such underwriter
and  controlling  person with respect to, any and all loss,  damage,  liability,
cost and expense to which the Investor or any such  underwriter  or  controlling
person may become  subject under the Act or  otherwise,  insofar as such losses,
damages,  liabilities,  costs or expenses are caused by any untrue  statement or
alleged  untrue  statement of any material fact  contained in such  Registration
Statement,  any  prospectus  contained  therein or any  amendment 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,  in light of the circumstances in which they were made,
not misleading;  provided,  however,  that the Company will not be liable in any
such case to the extent that any such loss, damage,  liability,  cost or expense
arises out of or is based upon an untrue  statement or alleged untrue  statement
or omission or alleged omission so made in conformity with information furnished
by the  Investor,  such  underwriter  or  such  controlling  person  in  writing
specifically for use in the preparation thereof.

            (b) The Investor will  indemnify and hold harmless the Company,  any
underwriter and any controlling  person of the Company or such  underwriter from
and against,  and will reimburse the Company,  underwriter or controlling person
with respect to, any and all loss, damage,  liability,  cost or expense to which
the  Company,  any  underwriter  or any  controlling  person  thereof may become
subject  under  the  Act  or  otherwise,   insofar  as  such  losses,   damages,
liabilities,  costs or  expenses  are  caused by any  untrue or  alleged  untrue
statement of any material fact  contained in such  Registration  Statement,  any
prospectus  contained therein or any amendment or supplement  thereto,  or arise
out of or are based upon the omission or the alleged omission to state therein a
material fact required to be stated  therein or necessary to make the statements
therein,  in light of the circumstances in which they were made, not misleading,
in each case to the extent,  but only to the extent,  that such untrue statement
or alleged  untrue  statement  or  omission or alleged  omission  was so made in
reliance upon and in strict conformity with written information furnished by the
Investor specifically for use in the preparation thereof.

            (c) Promptly after receipt by an  indemnified  party pursuant to the
provisions  of  paragraph  (a) or (b)  of  this  Section  6.5 of  notice  of the
commencement  of any  action  involving  the  subject  matter  of the  foregoing
indemnity  provisions,  such indemnified party will, if a claim thereof is to be
made against the indemnifying  party pursuant to the provisions of paragraph (a)
or (b), promptly notify the indemnifying party of the commencement  thereof; but
the  omission to so notify the  indemnifying  party will not relieve it from any
liability which it may have to any  indemnified  party otherwise than hereunder.
In case such action is brought against any indemnified party and it notifies the
indemnifying  party of the commencement  thereof,  the indemnifying  party shall
have the right to participate  in, and, to the extent that it may wish,  jointly
with any other  indemnifying  party  similarly  notified,  to assume the defense
thereof, with counsel satisfactory to such indemnified party; provided, however,
that if the defendants in any action include both the indemnified  party and the
indemnifying  party and the indemnified  party shall have  reasonably  concluded
that  there  may be legal  defenses  available  to it and/or  other  indemnified
parties  which  are  different  from or  additional  to those  available  to the
indemnifying



                                       19


party, or if there is a conflict of interest which would prevent counsel for the
indemnifying party from also representing the indemnified party, the indemnified
party or parties shall have the right to select separate  counsel to participate
in the  defense of such action on behalf of such  indemnified  party or parties.
After  notice  from  the  indemnifying  party  to the  indemnified  party of its
election so to assume the defense of any action, the indemnifying party will not
be liable to such indemnified party pursuant to the provisions of paragraphs (a)
or (b)  hereof  for any legal or other  expense  subsequently  incurred  by such
indemnified  party in connection  with the defense thereof other than reasonable
costs of  investigation,  unless (i) the  indemnified  party shall have employed
counsel in  accordance  with the  proviso of the  preceding  sentence,  (ii) the
indemnifying  party  shall  not  have  employed  counsel   satisfactory  to  the
indemnified  party to represent the  indemnified  party within a reasonable time
after the notice of the  commencement of the action,  or (iii) the  indemnifying
party has authorized the employment of counsel for the indemnified  party at the
expense of the indemnifying party.

6.6 Exclusive  Obligation to Register.  Except as provided in this Article,  the
Company will have no  obligation  to the Investor to register  under the Act any
Registrable Securities received by any such Investor pursuant to this Agreement.

ARTICLE 7.   PARTICIPATION IN FUTURE OFFERINGS

7.1  Participation  in Future  Offerings.  In order to afford the  Investor  the
opportunity to maintain its percentage ownership interest in the Company, except
for securities  offered by the Company in a public  offering which is registered
under  Section 5 of the Act,  the Company  agrees to offer to the  Investor  pro
rata,  according to its percentage ownership interest in the Company (calculated
in accordance  with Section 7.4 hereof),  the  opportunity to acquire any Common
Stock or other Voting Stock or securities  that bear rights to acquire,  convert
into or be  redeemed or  exchanged  for shares of Common  Stock or other  Voting
Stock (including without limitation any rights, options, warrants or convertible
debt or equity  instruments that provide any right to subscribe for, purchase or
otherwise acquire shares of Common Stock or other Voting Stock) (any such shares
being herein  referred to as "New  Shares")  which may be offered by the Company
during the period commencing after the first Closing hereunder and ending on the
effective  date  of  the  Company's   initial  public  offering  pursuant  to  a
Registration  Statement  under the Act. For  purposes of this Section 7.1,  "New
Shares" does not include (i) the shares of Common Stock issuable upon conversion
of the  Preferred  Stock  purchased  hereunder  or upon  exercise of the Warrant
issued to the Investor of even date; (ii)  securities  issued as a result of any
stock split, stock dividend or reclassification  of Common Stock,  distributable
on a pro rata basis to all holders of Common Stock;  (iii) securities  issued to
any officer,  director or employee of or consultant to the Company pursuant to a
stock option plan, employee stock purchase plan,  restricted stock plan or other
employee  stock plan or agreement  approved by the Board of  Directors;  or (iv)
securities  issued in connection with any merger or consolidation or acquisition
approved by the Board of Directors  and by the Investor in  accordance  with the
Company's Charter.

7.2 Notice.  The Company  shall  deliver  written  notice to the Investor of the
terms and  conditions of each offering,  borrowing or other similar  transaction
pursuant to which the



                                       20


Company  intends to issue New Shares.  Such  notice  shall be  delivered  to the
Investor  not later than  thirty (30) days prior to the date upon which any such
transaction is scheduled to be  consummated.  By such notice,  the Company shall
offer to sell to the Investor the  applicable  amount of  securities  calculated
pursuant to Section 7.4.

7.3  Acceptance.  The  Investor may accept any such offer in whole or in part by
delivering to the Company a written agreement to make such purchase, executed by
that  Investor,  specifying  the amount of the securities to be purchased by the
Investor, not later than ten (10) business days following the date of receipt by
the  Company.  The terms and  conditions,  price,  timing of  closing  and other
provisions of such  agreement by the Investor shall be not less favorable to the
Company than those of the other  agreement to purchase  such New Shares,  except
that the  Investor  need not pay any  non-cash  consideration  paid by the other
purchasers in the offering.

7.4 Percentage Interest.  The amount of New Shares to be offered to the Investor
for purchase  pursuant to this Article shall,  with respect to each  transaction
subject  hereto,  be calculated by multiplying  (a) the aggregate  number of New
Shares to be offered,  times (b) the percentage ownership of Common Stock of the
Company  held by the  Investor at the time the New Shares are offered  (assuming
conversion  of all  Preferred  Stock of the Company  into  Common  Stock and the
exercise of all then outstanding  options,  warrants and other rights to acquire
Common Stock).

7.5 No Accumulation. Each transaction or proposed issuance under this Article is
a separate  transaction.  The failure of the Investor to exercise in whole or in
part any prior offer shall not  increase  its rights with  respect to the future
transaction  subject  hereto and the rights of the  Investor  under this Article
with  respect to any  transaction  are  reduced pro rata to the extent that such
Investor  acquires  securities of the Company by participating  directly in such
transaction.

7.6  Termination of Rights.  The rights provided to the Investor in this Article
shall  terminate  at such  time  as the  Common  Stock  of the  Company  becomes
registered under Section 12(g) of the Exchange Act.

ARTICLE 8.  RESERVED

ARTICLE 9.  DEFINITIONS

For purposes of this  Agreement  the  following  terms shall have the  indicated
respective meanings:

            "Act" means the Securities  Act of 1933, as amended,  or any similar
Federal  statute,  and the rules and regulations of the Commission  issued under
that Act, as they each may, from time to time, be in effect.



                                       21


            "Base Balance Sheet" means the most recent balance sheet included in
the financial statements listed in Section 2.6.

            "Charter"  means the  Certificate  of  Incorporation  or  equivalent
document as amended and restated from time to time.

            "Closing" shall have the meaning provided in Section 1.3.

            "Commission"  means the Securities and Exchange  Commission,  or any
other Federal agency at the time administering the securities laws of the United
States.

            "Common  Stock"  shall  include  any class of  capital  stock of the
Company,  now  or  hereafter  authorized,   the  right  of  which  to  share  in
distributions either of earnings or assets of the Company is without limit as to
any  amount  or  percentage,  and  common  stock or other  securities  issued in
substitution or exchange for the presently authorized Common Stock in connection
with a reorganization, reclassification, merger or sale of assets.

            "Exchange  Act"  means  the  Securities  Exchange  Act of  1934,  as
amended,  or any similar Federal  statute,  and the rules and regulations of the
Commission  issued  under the Act,  as they each may,  from time to time,  be in
effect.

            "Preferred  Stock" shall include any class of Preferred Stock of the
Company,  now or hereafter  authorized,  and Preferred Stock or other securities
issued in substitution or exchange for the presently  authorized Preferred Stock
in connection with a reorganization, reclassification, merger or sale of assets.

            "Qualified  Public  Offering" means a firm  commitment  underwritten
public  offering  of  shares  of  Common  Stock of the  Company  pursuant  to an
effective  registration  statement  in which (i) the net proceeds to the Company
from such  offering  are at least  $10  million  and (ii) the price  paid by the
public for such shares is at least $1,300 per share  (appropriately  adjusted to
reflect subdivisions and combinations of the Common Stock of the Company).

            "Registrable  Securities"  means the Shares of Common Stock issuable
to the  Investor  upon  conversion  of the  shares  of  Preferred  Stock  issued
hereunder;  and any  other  shares of  capital  stock of the  Company  issued in
respect   of  the   Shares   (because   of  stock   splits,   stock   dividends,
reclassifications,   recapitalizations,   mergers,  consolidations,  or  similar
events),  New Shares  received  through the Investor's  exercise of its right to
purchase  additional  capital stock under Article 7 hereof or additional  shares
received  pursuant  to Section 8.1 hereof;  provided,  however,  that any shares
previously  sold by the Investor to the public  pursuant to a registered  public
offering or Rule 144 under the Act shall cease to be Registrable Securities.

            "Registration  Statement" means a registration statement (other than
a  registration  statement on Form S-8 solely with  respect to employee  benefit
plans or any  successor  form or forms used for the  purpose  specified  by such
form)  filed by the  Company  with  the  Commission  under  the Act for a public
offering and sale of securities of the Company.



                                       22


"Shares"  means the 1150 shares of Preferred  Stock of the Company  which may be
purchased pursuant to this Agreement.

            "Subsidiary" means any corporation,  association,  trust or business
entity of which the Company shall at any time own,  directly or  indirectly,  at
least a  majority  of the  capital  stock or  other  interest  entitled  to vote
generally.

            "Voting Stock" means any class of equity  security  entitled to vote
generally in the election of directors of the Company.

ARTICLE 10.       MISCELLANEOUS

10.1        Termination.

            (a)  At any  time  prior  to  the  Closing,  this  Agreement  may be
terminated  (i) by mutual  consent of the parties,  (ii) by either side if there
has been a material misrepresentation,  breach of warranty or breach of covenant
by the other side in its  representations,  warranties  and  covenants set forth
herein,  (iii) by the  Investor if the  conditions  stated in Article 4 have not
been satisfied at or prior to the Closing.

            (b) If  this  Agreement  shall  be  terminated  in  accordance  with
paragraph (a), all obligations of the parties  hereunder shall terminate without
liability of any party to the others  except as provided in Section 10.5. In the
event that this Agreement is so  terminated,  each party will return all papers,
documents,  financial  statements  and  other  data  furnished  to it by or with
respect to each other party to such other party  (including  any copies  thereof
made by the first party).

10.2 Survival of Representations and Covenants. All representations, warranties,
covenants,  agreements and obligations made herein or in any schedule,  exhibit,
notice,  certificate  or other  document  executed  in  connection  herewith  or
delivered by any party to another party incident  hereto shall be deemed to have
been  relied upon by the other party  hereto and  survive the  execution  and/or
delivery thereof, and all statements  contained in any such schedules,  exhibit,
notice,  certificate or other document  delivered by the Company hereunder or in
connection herewith shall be deemed to constitute representations and warranties
made by the Company herein.

10.3  Breach.  In the event that there shall be a breach of any  representation,
warranty,  covenant,  agreement or obligation of the Company or the  Stockholder
after the Closing, which breach shall remain uncured for a period of thirty (30)
days after  notice of such breach is given by the Investor to the Company or the
Stockholder, the Company shall immediately redeem the Shares at a price equal to
the original purchase price therefore.

10.4  Notices.  Any  notice  or other  communication  in  connection  with  this
Agreement  shall be deemed to be  delivered  if in writing  (or in the form of a
telegram)  addressed as provided



                                       23


below and if either (a) actually  delivered at said address,  or (b) in the case
of a letter,  three  business  days shall have elapsed after the same shall have
been  deposited in the United States mails,  postage  prepaid and  registered or
certified:

            If to the Company or the Stockholder, to:

            BioSeq, Inc.
            25 Olympia Avenue, Unit F
            Woburn, Massachusetts  01801
            Attention:  President

            with a copy to:

            Kenneth S. Boger, Esquire
            Warner & Stackpole, LLP
            75 State Street
            Boston, Massachusetts  02109

            If to the Investor, to:

            Boston Biomedica, Inc.
            375 West Street
            West Bridgewater, Massachusetts  02379
            Attention:  Richard T. Schumacher, President

            with a copy to:

            Steven R. London, Esquire
            Brown, Rudnick, Freed & Gesmer
            One Financial Center
            Boston, Massachusetts  02111

and in any case at such other address as the addressee  shall have  specified by
written  notice.  All  periods  of  notice  shall be  measured  from the date of
delivery thereof.

10.5  Costs and  Expenses.  Each of the  parties  shall bear their own costs and
expenses in  connection  with the  purchase  of the Shares and the  negotiation,
execution,  performance  and  enforcement of this Agreement and any  amendments,
waivers or consents with respect thereto.

10.6  Confidentiality.  The Investor shall keep confidential and not disclose or
divulge  any  confidential,  proprietary  or secret  information  which they may
obtain from the Company in connection with the transactions contemplated herein,
or pursuant to inspection rights granted hereunder unless such information is or
hereafter becomes public information.




                                       24


10.7  Assignment;  Rights of Successors  and Assigns.  This  Agreement  shall be
assignable by the Investor to its  affiliates and any successor of the Investor.
All representations, warranties, covenants, agreements and obligations hereunder
made by or on behalf of the parties hereto shall be binding upon and shall inure
to the benefit of the respective  successors and assigns of the parties  hereto,
whether so expressed or not.

10.8 Research and Development Services.  The Investor shall perform research and
development  services for the Company related to the Company's  Pressure Cycling
Reactor  Technology  in areas to be agreed upon by the Investor and the Company.
The cost for such research and  development  services shall be $125 per hour for
senior  staff(officers and department directors and managers),  $75 per hour for
middle-management  support staff (supervisors and medical technicians),  and $50
per hour for all other  personnel.  Subject  to the  closing  of the  Investor's
second  investment  pursuant to Section 1.2(ii) of this Agreement,  in the event
that the  Company  requests  of the  Investor  less than  $100,000  of  research
services  (based on the above  rates),  the Company shall  nevertheless  pay the
Investor  a minimum  of  $100,000  for any  research  and  development  services
performed by the Investor between the date of the Investor's investment pursuant
to Section 1.2(ii) hereof and September 30, 1997.  Subject to the closing of the
Investor's third investment  pursuant to Section 1.2(iii) of this Agreement,  in
the event that the  Company  requests  of the  Investor  less than  $150,000  of
research services (based on the above rates), the Company shall nevertheless pay
the  Investor  a minimum of  $150,000  for  research  and  development  services
performed by the Investor  after the date of such third closing  until  December
31,  1998.  The  scope and  nature  of each  research  and  development  project
performed by the Investor for the Company shall be jointly  designed,  developed
and agreed upon by the Investor and the Company.

10.9 Entire  Agreement.  This  Agreement  (including  all  exhibits or schedules
appended to this Agreement and all documents  delivered  pursuant to or referred
to in this Agreement,  all of which are hereby incorporated herein by reference)
constitutes  the  entire  agreement  between  the  parties,  and  all  promises,
representations, understandings, warranties and agreements with reference to the
subject matter hereof and  inducements  to the making of this  Agreement  relied
upon by any  party  hereto,  have  been  expressed  herein  or in the  documents
incorporated herein by reference.

10.10  Amendments and Waivers.  Changes in or additions to this Agreement may be
made or compliance with any term,  covenant,  agreement,  condition or provision
set forth herein or therein may be omitted or waived  (either  generally or in a
particular  instance and either  retroactively or  prospectively),  upon written
consent of the Company and the  Investor;  provided  however,  that no waiver or
consent on any one  instance  shall be deemed to be or be construed as a further
or  continuing  waiver of any such term or  condition  unless  it  expressly  so
provides.

10.11 Governing Law; Severability This Agreement shall be deemed a contract made
under the laws of the  Commonwealth  of  Massachusetts  and,  together  with the
rights and  obligations of the parties  hereunder,  shall be construed under and
governed by the laws of such Commonwealth. The invalidity or unenforceability of
any provision of this Agreement shall not affect the validity or  enforceability
of any other provision hereof.



                                       25


10.12  Counterparts.  This  Agreement may be executed in multiple  counterparts,
each of which  shall be  deemed  in  original  but all of which  together  shall
constitute one and the same instrument.

10.13 Effect of Table of Contents and Headings. Any table of contents,  title of
an article or section  heading herein  contained is for convenience or reference
only and shall not affect the meaning of  construction  of any of the provisions
hereof.

            IN WITNESS  WHEREOF,  this  Agreement  has been executed as a sealed
instrument  by the  parties  hereto  or their  duly  authorized  representatives
effective as of the date first above written.

                            [SIGNATURE PAGE FOLLOWS]



                                       26


Corporate Seal                             BioSeq, Inc.


ATTEST:                                    By: ____________________________
                                               James A. Laugharn, President
- -----------------------------
Clerk


Corporate Seal                             BioMolecular Assays, Inc. (only with
                                           respect to Article 2 hereof)
ATTEST:

                                           By: _______________________________
Clerk                                          James A. Laugharn, President



Corporate Seal                             INVESTOR:

ATTEST:                                    Boston Biomedica, Inc.


______________________________             By: ________________________________
Clerk                                          Richard T. Schumacher, President




                                       27


                         LIST OF SCHEDULES AND EXHIBITS



Schedule A - Description of Milestones

Schedule B - Disclosure Schedule

Exhibit A - Amended and Restated Articles of Organization

Exhibit B - Financial Statements

Exhibit C - License Agreement between BioSeq, Inc. and BioMolecular Assays, Inc.

Exhibit D - Warrant Agreement

Exhibit E - Stockholders' Agreement

Exhibit F - License Agreement between BioSeq, Inc. and the Investor

Exhibit G - Legal Opinion of Company Counsel

Exhibit H - Employee Nondisclosure and Developments Agreement


                                       28


                                   SCHEDULE A
                                       TO
                       PREFERRED STOCK PURCHASE AGREEMENT
                              DATED OCTOBER 7, 1996

                            Description of Milestones
                            -------------------------

1.       Conclusive  demonstration  of  the  ability  to  achieve  and  maintain
         enzymatic synchrony.

2.       Conclusive  demonstration  of the  ability  to  control  the  extent of
         digestions  in order to allow  the  routine  generation  of  groups  of
         deletions of variable or constant length.

3.       Conclusive demonstration of the ability to immobilize the DNA substrate
         at  the  5"  end,  under  pressure,  and  using  available  solid-phase
         technologies.






                                       29




                                   SCHEDULE B
                                       to
                   Preferred Stock Purchase Agreement between
                     BioSeq, Inc. and Boston Biomedica, Inc.
                                 October 7, 1996


         The  following  references  are to sections of the  Purchase  Agreement
between BioSeq, Inc. and Boston Biomedica, Inc. dated 4 October, 1996.

SECTION 2.3, CAPITALIZATION

         The following options to purchase shares of Common Stock of the Company
are currently outstanding:

Name of Option Holder                    Option to Purchase (Number of Shares)
- ---------------------                    -------------------------------------
Donald R. Johnson, Ph.D.                 10 shares of Common Stock
Henry Paulus, Ph.D.                      7.5 shares of Common Stock
Carson H. Powers                         10 shares of Common Stock
Irwin Gruverman                          50 shares of Common Stock (agreement)
BioMolecular Assays, Inc.                217 shares of Common Stock (convertible
                                             loan arrangement)

         The Company has  reserved  1,086 shares of its Common  Stock,  $.01 par
value,  for issuance  pursuant to the exercise of options that may be granted to
employees of the Company pursuant to plans or agreements  approved by a majority
of the Board of Directors.

SECTION 2.10, ABSENCE OF CERTAIN CHANGES

         The Company  entered into a Stock Purchase  Agreement  dated August 21,
1996 between the Company and G&G Diagnostics  Limited Partnership II, a Delaware
limited partnership,  pursuant to which G&G purchased 100 shares of Common Stock
of the Company for an aggregate purchase price $50,000.

SECTION 2.11, CONTRACTS AND COMMITMENTS

         The Company has entered into the following contracts and commitments:

1.       Letter  Agreement dated September 14, 1995 granting options to purchase
         up to 7.5 shares of Common Stock of the Company to Henry Paulus, Ph.D.

2.       Letter  Agreement dated September 24, 1995 granting options to purchase
         up to 10 shares of Common Stock of the Company to Carson H. Powers.




                                       30




3.       Letter  Agreement dated October 2, 1995 granting options to purchase up
         to 10 shares of Common Stock of the Company to Donald R. Johnson, Ph.D.

4.       Letter  Agreement  dated  August 20,  1996 from Irwin  Gruverman,  P.E.
         regarding  his  consulting  services in  consideration  of 50 shares of
         Common Stock of the Company.

5.       Stock Purchase  Agreement dated August 21, 1996 between the Company and
         G&G Diagnostics Limited Partnership II, a Delaware limited partnership,
         pursuant  to which G&G  purchased  100  shares  of common  stock of the
         Company for an aggregate purchase price of $50,000.

6.       Agreement between BioMolecular Assays, Inc. and the Company dated as of
         September, 1996 regarding provision of services.

SECTION 2.12, INTELLECTUAL PROPERTY

1.       Technology  Transfer and Patent  Assignment  Agreement dated as of even
         date  herewith  between  BioMolecular  Assays,  Inc.  and the  Company,
         pursuant  to which  BioMolecular  Assays,  Inc.  has  assigned  certain
         technology   rights,   trademark   rights  and  the  following   patent
         applications to the Company on the terms set forth therein:

         a.            type              US application
                       title             "Controlling Enzymatic Activity"
                       date              March 7, 1995

         b.            type              US CIP application
                       title             "Controlling Enzymatic Activity"
                       date              June 7, 1995

         c.            type              PCT and US CIP application
                       title             "Pressure Cycling Reactor"
                       date              March 7, 1996

         d.            type              US application
                       title             "Pressure Controlled Binding
                                          Application"
                       date              July 3, 1996

         e.            type              US application
                       title             "Pressure Controlled Separation and
                                          Purification Process"
                       date              scheduled to file by September 1996

2.       Application of BioMolecular  Assays, Inc. for Service Mark Registration
         Based on  Intent  to Use for the mark  "BIOSEQ"  dated  May 3,  1996 in
         international  class  42  for  Research,   Development  and  Consulting
         Services in the field of  Pharmaceuticals,  Diagnostics  and  Molecular
         Biology, which BMA has agreed to assign to BioSeq as referenced in item
         1. above.




                                       31


SECTION 2.16, OFFEREES; SALES OF SECURITIES

         Within the past six months the Company issued shares of Common Stock to
the following shareholders:

          NAME OF HOLDER                                    NUMBER OF SHARES OF
          --------------                                    -------------------
                                                               COMMON STOCK
                                                               ------------

BioMolecular Assays, Inc.                                         1,196
Dreier, Gustav H.                                                   205
G&G Diagnostics Limited Partnership II                              100
Green, David J.                                                     285
Laugharn, Jr., James A.                                             333
Litt, Gerald                                                        100
Powers, Carson II.                                                  100
Rudd, Edwin A.                                                      146
Smith, James H.                                                      25
TOTAL                                                             2,490

SECTION 2.20, CERTAIN TRANSACTIONS

         BioMolecular Assays, Inc. and the Company have an agreement pursuant to
which  Bimolecular  Assays,  Inc. provides services to the Company pursuant to a
payment schedule as set forth therein.

         $32,500 of  convertible  debt was issued in March 1996 to  BioMolecular
Assays, Inc. which is convertible into 217 shares of common stock of the Company
at BioMolecular Assays' option.

SECTION 2.24, INSURANCE

         The Company  plans to carry  general  liability  insurance  and special
equipment insurance but does not have such insurance policies in place as of the
date hereof.



                                       32

                                                                   EXHIBIT 10.21

NEITHER THIS WARRANT NOR THE SHARES OF STOCK ISSUABLE UPON EXERCISE  HEREOF HAVE
BEEN  REGISTERED  UNDER  THE  SECURITIES  ACT OF  1933,  AS  AMENDED,  OR  STATE
SECURITIES LAWS. NO SALE,  TRANSFER OR OTHER DISPOSITION OF THIS WARRANT OR SAID
SHARES MAY BE EFFECTED WITHOUT AN EXEMPTION FROM REGISTRATION UNDER SAID ACT AND
APPLICABLE STATE SECURITIES LAWS.


Warrant No. 1               STOCK PURCHASE WARRANT            No. of Shares 1150


                  To Subscribe for and Purchase Common Stock of
                                  BIOSEQ, INC.


         THIS CERTIFIES  THAT, for value  received,  Boston  Biomedica,  Inc. or
registered assigns, is entitled to subscribe for and purchase from BioSeq, Inc.,
a corporation  incorporated under the laws of Massachusetts  (hereinafter called
the "Company"), up to 1150 fully paid and non-assessable shares of the Company's
Common Stock,  no par value per share (the "Common  Stock"),  during each period
set forth below, the specified number of shares of Common Stock at the price per
share  indicated,  subject,  however,  to the  provisions and upon the terms and
conditions  hereinafter set forth. This Warrant is being issued pursuant to that
certain  Preferred  Stock  Purchase  Agreement  between  the  Company and Boston
Biomedica,  Inc. ("Boston Biomedica") dated as of October 7, 1996 (the "Purchase
Agreement").

         (i) 300 Shares,  during the five-year  period  commencing on October 7,
1996,  at a per share price of seven  hundred  seventy  ($770.00)  dollars,  for
aggregate consideration of two hundred thirty-one thousand ($231,000) dollars;

         (ii) 550 Shares,  during the five-year period commencing on the closing
of Boston  Biomedica's  investment in the Company pursuant to Section 1.2(ii) of
the  Purchase  Agreement,  at a per  share  price  of  one  thousand  forty-five
($1,045.00)  dollars,  for aggregate  consideration of five hundred seventy-four
thousand seven hundred fifty ($574,750.00) dollars;

         (iii) 300 Shares, during the five year-period commencing on the closing
of Boston  Biomedica's  investment in the Company pursuant to Section 1.2(iii)of
the Purchase Agreement, at a per share price of two thousand seven hundred fifty
($2,750.00)  dollars,  for aggregate  consideration of eight hundred twenty-five
thousand ($825,000.00) dollars.

1. Exercise of Warrant.  The rights represented by this Warrant may be exercised
by the holder hereof, in whole or in part (but not as to a fractional share), by
the surrender of this Warrant  (properly  endorsed if required) at the office of
any duly  appointed  transfer agent for the Common Stock or at the office of the
Company at 25 Olympia  Avenue,  Unit F, Woburn,  Massachusetts  01801,  and upon
payment  to the  Company,  or for  the  account  of the  Company,  by






cash or by certified check or bank draft, of the Warrant Purchase Price for such
shares.  The Company agrees that the shares so purchased  shall be and be deemed
to be issued to the holder  hereof as the record  owner of such shares as of the
close of business on the date on which this Warrant shall have been  surrendered
and payment made for such shares as  aforesaid.  Certificates  for the shares so
purchased shall be delivered to the holder hereof within a reasonable  time, not
exceeding 10 days, after the rights  represented by this Warrant shall have been
so exercised,  and, unless this Warrant has expired, a new Warrant  representing
the number of shares,  if any, with respect to which this Warrant shall not then
have been exercised  shall also be issued to the holder hereof within such time.
The purchase  rights  represented  hereby shall not be exercisable to the extent
that the exercise thereof would cause Boston Biomedica's  percentage interest in
the equity of the Company to equal or exceed twenty (20%) percent.

2. Shares to be Issued;  Reservation of Shares. The Company covenants and agrees
that all shares which may be issued upon the exercise of the rights  represented
by this Warrant will,  upon  issuance,  be validly  authorized,  duly issued and
outstanding,  fully paid and non-assessable,  and free from all taxes, liens and
charges with respect to the issue  thereof.  The Company  further  covenants and
warrants that it will from time to time take all action  required to assure that
the par  value per share of the  Common  Stock is at all times  equal to or less
than the effective  Warrant  Purchase Price.  The Company further  covenants and
agrees  that,  during the period  within  which the rights  represented  by this
Warrant may be exercised, the Company will at times have authorized and reserved
a sufficient number of shares of its Common Stock to provide for the exercise of
the rights  represented  by this  Warrant and will at its expense  expeditiously
upon each such  reservation  of shares procure the listing  thereof  (subject to
issuance or notice of  issuance)  on all stock  exchanges,  if any, on which the
Common Stock may then be listed.

3. Adjustment of Warrant  Purchase Price.  The Warrant  Purchase Price in effect
from time to time shall be subject to adjustment as follows:

         (a) Adjustment of Warrant Purchase Price Upon Issuance of Common Stock.
Except as provided in subparagraph  (b), if and whenever the Company shall issue
or sell or is, in accordance with subparagraphs (a)(1) through (a)(6), deemed to
have  issued or sold any shares of Common  Stock for a  consideration  per share
less than the Warrant Purchase Price in effect  immediately prior to the time of
such issuance or sale,  then,  forthwith upon such issuance or sale, the Warrant
Purchase  Price shall be reduced to an amount equal to the quotient  obtained by
dividing:

                  (i) an amount equal to the sum of

(x) the number of shares of all Common Stock outstanding or deemed in accordance
with  subparagraphs  (a)(1) through  (a)(6) hereof to be issued and  outstanding
immediately  prior to such  issuance  or sale (with  each share of Common  Stock
issuable  hereunder being deemed for such purpose to be issued and  outstanding)
multiplied by the Warrant Purchase Price in effect immediately prior to the time
of such issuance or sale, plus

(y) the  aggregate  consideration  received by the Company for such  issuance or
sale,



                                      -2-



by

                  (ii) the total number of shares of Common Stock outstanding or
deemed in  accordance  with  subparagraphs  (a)(1)  through  (a)(6) hereof to be
issued and outstanding  immediately after such issuance or sale (with each share
of Common Stock  issuable  hereunder  being deemed for such purpose to be issued
and outstanding).

                  For  purposes  of  this   subparagraph   (a),  the   following
subparagraphs (a)(1) to (a)(6) shall also be applicable:

                           (a)(1) Issuance of Rights or Options.  In case at any
time the Company shall in any manner grant (whether directly or by assumption in
a merger or  otherwise)  any  warrants or other  rights to  subscribe  for or to
purchase,  or any  options for the  purchase  of,  Common  Stock or any stock or
security  convertible  into or  exchangeable  for Common  Stock (such  warrants,
rights or options being called  "Options" and such  convertible or  exchangeable
stock or securities being called "Convertible  Securities")  whether or not such
Options or the right to convert or exchange any such Convertible  Securities are
immediately  exercisable,  and the price per  share  for which  Common  Stock is
issuable upon the exercise of such Options or upon the conversion or exchange of
such  Convertible  Securities  (determined by dividing (i) the total amount,  if
any,  received or receivable by the Company as consideration for the granting of
such Options,  plus the minimum  aggregate  amount of  additional  consideration
payable to the Company upon the exercise of all such Options,  plus, in the case
of such Options which relate to Convertible  Securities,  the minimum  aggregate
amount of additional consideration, if any, payable upon the issuance or sale of
such Convertible Securities and upon the conversion or exchange thereof, by (ii)
the total maximum number of shares of Common Stock issuable upon the exercise of
such  Options  or upon  the  conversion  or  exchange  of all  such  Convertible
Securities  issuable upon the exercise of such  Options)  shall be less than the
Warrant Purchase Price in effect  immediately  prior to the time of the granting
of such Options,  then the shares of Common Stock  issuable upon the exercise of
such  Options or upon  conversion  or  exchange of such  Convertible  Securities
issuable  upon the exercise of such Options  shall be deemed to have been issued
for such  price  per share as of the date of  granting  of such  Options  or the
issuance of such  Convertible  Securities and  thereafter  shall be deemed to be
outstanding.  Except as otherwise provided in subparagraph (a)(3), no adjustment
of the Warrant  Purchase  Price  shall be made upon the actual  issuance of such
Common Stock or of such Convertible  Securities upon exercise of such Options or
upon the actual  issuance of such Common  Stock upon  conversion  or exchange of
such Convertible Securities.

                           (a)(2)  Issuance of Convertible  Securities.  In case
the Company  shall in any manner issue  (whether  directly or by assumption in a
merger or  otherwise)  or sell any  Convertible  Securities,  whether or not the
rights to exchange or convert any such  Convertible  Securities are  immediately
exercisable,  and the price per share for which  Common  Stock is issuable  upon
such  conversion  or  exchange  (determined  by  dividing  (i) the total  amount
received or receivable by the Company as consideration  for the issuance or sale
of such Convertible Securities,  plus the minimum aggregate amount of additional
consideration,  if any,  payable to the



                                      -3-


Company  upon the  conversion  or exchange  thereof,  by (ii) the total  maximum
number of shares of Common Stock issuable upon the conversion or exchange of all
such  Convertible  Securities)  shall be less than the Warrant Purchase Price in
effect  immediately  prior to the time of such issuance or sale, then the shares
of Common  Stock  issuable  upon  conversion  or  exchange  of such  Convertible
Securities  shall be deemed to have been  issued  for such price per share as of
the date of the issuance or sale of such  Convertible  Securities and thereafter
shall be deemed to be outstanding.  Except as otherwise provided in subparagraph
(a)(3),  no further  adjustment of the Warrant Purchase Price shall be made upon
the actual  issuance of such Common  Stock upon  conversion  or exchange of such
Convertible  Securities.  If any  such  issuance  or sale  of  such  Convertible
Securities is made upon exercise of any options to purchase any such Convertible
Securities for which  adjustments of the Warrant Purchase Price have been or are
to be made  pursuant to other  provisions of this  subparagraph  (a), no further
adjustment  of the  Warrant  Purchase  Price  shall  be made by  reason  of such
issuance or sale.

                           (a)(3)  Change in Option  Price or  Conversion  Rate.
Upon the happening of any of the following events, namely, if the purchase price
provided for in any Option  referred to in subparagraph  (a)(1),  the additional
consideration,   if  any,  payable  upon  the  conversion  or  exchange  of  any
Convertible Securities referred to in subparagraph (a)(1) or (a)(2), or the rate
at which Convertible Securities referred to in subparagraph (a)(1) or (a)(2) are
convertible  into or  exchangeable  for Common  Stock  shall  change at any time
(including,  but not  limited  to,  changes  under or by  reason  of  provisions
designed to protect against  dilution),  the Warrant Purchase Price in effect at
the time of such event shall  forthwith be  readjusted  to the Warrant  Purchase
Price  which  would  have  been in  effect  at such  time  had such  Options  or
Convertible  Securities  still  outstanding  provided for such changed  purchase
price,  additional  consideration or conversion rate, as the case may be, at the
time  initially  granted,  issued  or  sold,  but  only if as a  result  of such
adjustment  the  Warrant  Purchase  Price  then in effect  hereunder  is thereby
reduced;  and on the  expiration  of any such  Options  without  exercise of any
thereof  or the  termination  of any such  right to  convert  or  exchange  such
Convertible  Securities  without  conversion  or  exchange of any  thereof,  the
Warrant  Purchase Price then in effect hereunder shall forthwith be increased to
the Warrant  Purchase  Price which would have been in effect at the time of such
expiration or termination had such Option or Convertible  Securities  never been
issued.

                           (a)(4) Consideration for Stock. In case any shares of
Common  Stock,  Options or  Convertible  Securities  shall be issued or sold for
cash,  the  consideration  received  therefor  shall be deemed to be the  amount
received by the Company therefor,  without  deduction  therefrom of any expenses
incurred or any  underwriting  commissions or concessions paid or allowed by the
Company in connection therewith.  In case any shares of Common Stock, Options or
Convertible  Securities  shall be issued or sold for a consideration  other than
cash,  the amount of the  consideration  other than cash received by the Company
shall be deemed to be the fair value of such consideration as determined in good
faith by the Board of Directors of the Company,  without deduction  therefrom of
any expenses  incurred or any  underwriting  commissions or concessions  paid or
allowed by the Company in  connection  therewith.  In case any Options  shall be
issued in  connection  with the  issuance  and sale of other  securities  of the
Company,  together  comprising  one  integral  transaction  in which no specific
consideration is allocated to such Options by the parties thereto,  such Options
shall be deemed to have been



                                      -4-


issued  for such  consideration  as  determined  in good  faith by the  Board of
Directors of the Company.

                           (a)(5)  Record Date. In case the Company shall take a
record of the holders of its Common Stock for the purpose of entitling  them (a)
to receive a dividend or other distribution  payable in Common Stock, Options or
Convertible Securities or (b) to subscribe for or purchase Common Stock, Options
or Convertible Securities,  then such record date shall be deemed to be the date
of the issuance or sale of the shares of Common Stock deemed to have been issued
or sold upon the  declaration  of such  dividend  or the  making  of such  other
distribution  or the  date of the  granting  of such  right of  subscription  or
purchase, as the case may be.

                           (a)(6) Treasury Shares. The disposition of any shares
owned  or held by or for the  account  of the  Company  shall be  considered  an
issuance or sale of Common Stock for the purposes of this subparagraph (a).

         (b) Certain Issuances of Common Stock Excepted.  Anything herein to the
contrary  notwithstanding,  the  Company  shall  not be  required  to  make  any
adjustment of the Warrant Purchase Price upon issuance of

                  (i)      Common Stock upon the exercise of this Warrant;

                  (ii) options to purchase  Common Stock of the Company  granted
to  employees  of the  Company,  and shares  issued upon the  exercise  thereof,
pursuant  to  plans  or  agreements  approved  by a  majority  of the  Board  of
Directors;  provided that this subparagraph (b)(ii) shall not apply to the grant
of any options if, upon such grant,  the shares  issuable upon exercise of those
options,  when added to the shares  issuable upon  exercise of then  outstanding
options falling within this  subparagraph  (b)(ii) and shares  previously issued
upon exercise of any such options (all such shares being hereinafter referred to
as the "Option Shares") shall exceed 15% of the total number of shares of Common
Stock  then   outstanding   (including  as  outstanding  for  purposes  of  this
calculation  (i) all shares of Common Stock into which this Warrant or any other
then outstanding convertible securities of the Company may be converted and (ii)
all of the Option Shares.

         (c)  Subdivision or  Combination  of Common Stock.  In case the Company
shall at any time  subdivide (by any stock split,  stock  dividend or otherwise)
its  outstanding  shares of Common  Stock into a greater  number of shares,  the
Warrant Purchase Price in effect  immediately prior to such subdivision shall be
proportionately  reduced,  and,  conversely,  in case the outstanding  shares of
Common  Stock shall be  combined  into a smaller  number of shares,  the Warrant
Purchase  Price  in  effect  immediately  prior  to such  combination  shall  be
proportionately increased.

         (d) Reorganization or Reclassification.  If any capital  reorganization
or  reclassification  of the capital  stock of the Company  shall be effected in
such a way that  holders of Common  Stock shall be  entitled  to receive  stock,
securities or assets with respect to or in



                                      -5-


exchange  for Common  Stock,  then,  as a condition  of such  reorganization  or
reclassification,  lawful and  adequate  provisions  shall be made  whereby  the
holder of this Warrant shall thereupon have the right to receive, upon the basis
and upon the terms and conditions  specified herein and in lieu of the shares of
Common  Stock  immediately  theretofore  receivable  upon the  exercise  of this
Warrant, such shares of stock,  securities or assets as may be issued or payable
with respect to or in exchange for a number of outstanding shares of such Common
Stock equal to the number of shares of such Common  Stock  receivable  upon such
exercise had such reorganization or reclassification not taken place, and in any
such case  appropriate  provision  shall be made with  respect to the rights and
interests  of such  holder  to the end that  the  provisions  hereof  (including
without  limitation  provisions for  adjustments of the Warrant  Purchase Price)
shall  thereafter be applicable,  as nearly as may be, in relation to any shares
of stock,  securities or assets thereafter deliverable upon the exercise of such
rights.

         (e)  Notice  of  Adjustment.  In case  any  adjustment  of the  Warrant
Purchase  Price is required  hereunder,  the Company  shall give written  notice
thereof,  by first  class  mail,  postage  prepaid  or by  telex  or  facsimile,
addressed  to the holder of this  Warrant at the address of such holder as shown
on the books of the Company, which notice shall state the Warrant Purchase Price
resulting  from  such  adjustment,   setting  forth  in  reasonable  detail  the
calculation upon which such adjustment is based.

         (f)      Other Notices.  In case at any time:

                  (1) the Company  shall  declare any  dividend  upon its Common
Stock payable in cash or stock or make any other  distribution to the holders of
its Common Stock;

                  (2) the Company shall offer for  subscription  pro rata to the
holders  of its Common  Stock any  additional  shares of stock of any class,  or
other rights;

                  (3)   there   shall   be   any   capital   reorganization   or
reclassification  of the capital  stock of the Company,  or a  consolidation  or
merger of the Company with or into,  or a sale of all or  substantially  all its
assets to, another entity or entities; or

                  (4) there shall be a  voluntary  or  involuntary  dissolution,
liquidation or winding up of the Company;

         then,  in any one or more of said  cases,  the Company  shall give,  by
first class mail,  postage prepaid,  or by telex or facsimile,  addressed to the
holder of this  Warrant at the  address of such  holder as shown on the books of
the Company, (i) at least 10 days' prior written notice of the date on which the
books of the Company  shall close or a record shall be taken for such  dividend,
distribution or subscription rights or for determining rights to vote in respect
of any  such  reorganization,  reclassification,  consolidation,  merger,  sale,
dissolution,  liquidation  or  winding  up and  (ii)  in the  case  of any  such
reorganization,  reclassification,  consolidation,  merger,  sale,  dissolution,
liquidation  or winding up, at least 20 days' prior  written  notice of the date
when the same shall take place.  Such notice in  accordance  with the  foregoing
clause shall also specify (a) in the case of any such dividend,  distribution or
subscription  rights,  the date on



                                      -6-


which the holders of Common Stock shall be entitled  thereto and (b) the date on
which the holders of Common  Stock shall be  entitled to exchange  their  Common
Stock for securities or other property deliverable upon any such reorganization,
reclassification,  consolidation,  merger,  sale,  dissolution,  liquidation  or
winding up, as the case may be.

                  (g)  Stock  to be  Reserved.  The  Company  will at all  times
reserve and keep  available out of its authorized  Common Stock,  solely for the
purpose of issuance upon the exercise of this Warrant as herein  provided,  such
number of shares of Common Stock as shall then be issuable  upon the exercise of
this Warrant.  The Company covenants that all shares of Common Stock which shall
be so issued shall be duly and validly  issued and fully paid and  nonassessable
and free from all taxes, liens and charges with respect to the issuance thereof,
and,  without  limiting the generality of the foregoing,  the Company  covenants
that it will  from  time to time take all such  action  as may be  requisite  to
ensure that the par value per share of the Common Stock is at all times equal to
or less than the Warrant  Purchase Price in effect at the time. The Company will
take all such  action  as may be  necessary  to ensure  that all such  shares of
Common  Stock  may be so  issued  without  violation  of any  applicable  law or
regulation, or of any requirement of any national securities exchange upon which
the Common Stock may be listed or any national securities  association which may
provide quotations of the sale prices of the Common Stock.


4. Common Stock.  As used herein the term "Common  Stock" shall mean and include
the Company's  Common Stock  authorized on the date of the original issue of the
Warrants  and shall also  include any capital  stock of any class of the Company
thereafter authorized which shall not be limited to a fixed sum or percentage in
respect of the rights of the holders  thereof to participate in dividends and in
the  distribution  of assets  upon the  voluntary  or  involuntary  liquidation,
dissolution or winding up of the Company;  provided that the shares which may be
purchased  pursuant to this  Warrant  shall  include only shares of the class of
Common Stock,  no par value  referred to at the beginning of this  agreement and
designated  in the Company's  original  issue of Warrants or, in the case of any
reorganization, reclassification, consolidation, merger or sale of assets of the
character  referred to in  subparagraph  3(d) hereof,  the stock,  securities or
assets provided for in such subparagraph.

5. Transfer.  Subject to the  provisions of the Agreement,  this Warrant and all
rights hereunder are transferable,  in whole or in part, at the offices referred
to in  paragraph 1 hereof by the holder  hereof in person or by duly  authorized
attorney,  upon  surrender of this  Warrant  properly  endorsed.  Each taker and
holder of this Warrant,  by taking or holding the same, consents and agrees that
this Warrant,  when endorsed in blank,  shall be deemed negotiable and that when
this Warrant is so endorsed, the holder hereof may be treated by the Company and
all other persons dealing with this Warrant as the absolute owner hereof for any
purposes and as the person  entitled to exercise the rights  represented by this
Warrant or to the transfer hereof on the books of the Company, any notice to the
contrary notwithstanding; but until each transfer on such books, the Company may
treat the registered holder hereof as the owner hereof for all purposes.



                                      -7-



6.  Exchange.  This Warrant is  exchangeable,  upon its surrender at the offices
referred to in paragraph 1, for new Warrants of like tenor  representing  in the
aggregate the right to subscribe for and purchase the number of shares which may
be  subscribed  for  and  purchased  hereunder,  each of such  new  Warrants  to
represent the right to subscribe for and purchase such number of shares as shall
be designated by the holder hereof at the time of such  surrender.  Upon receipt
of evidence  satisfactory  to the  Company of the loss,  theft,  destruction  or
mutilation  of  this  Warrant  and,  in the  case of any  such  loss,  theft  or
destruction,  upon delivery of a bond of indemnity  satisfactory to the Company,
or, in the case of any such  mutilation,  upon surrender or cancellation of this
Warrant,  the  Company  will  issue to the holder  hereof a new  warrant of like
tenor,  in lieu of this  Warrant,  representing  the right to subscribe  for and
purchase  the  number  of  shares  which  may be  subscribed  for and  purchased
hereunder.

7. Registration Rights. The definition of "Registrable  Securities" contained in
the  Purchase  Agreement  shall  include  the  shares of  Common  Stock or other
securities  issued  hereunder  and such shares shall have the same  registration
rights  as are  accorded  to  the  Registrable  Securities  under  the  Purchase
Agreement.

8.  Governing  Law.  This Warrant  shall be construed and enforced in accordance
with the laws of the Commonwealth of Massachusetts.

         IN WITNESS WHEREOF,  BioSeq,  Inc. has caused this Warrant to be signed
by its duly authorized officers under its corporate seal, and this Warrant to be
dated.

                                  BioSeq, Inc.


                                  By: /s/ James Laugharn
                                    --------------------------------------------
                                      James Laugharn, Jr., President



Attest:

/s/ Justine Laugharn
- ---------------------------
[Clerk]




                                      -8-


                                    EXHIBIT A


                               NOTICE OF EXERCISE


         To:      BioSeq, Inc.

         1. The undersigned  hereby elects to purchase  _______ shares of Common
Stock of BioSeq, Inc. pursuant to the terms of the attached Warrant, and tenders
herewith payment of the purchase price of such shares in full.

         2. Please issue a certificate or certificates  representing said shares
in the name of the  undersigned  or in such other name or names as are specified
below.

            Number of Shares                  ______________________


         3. In the event of partial  exercise,  please  re-issue an  appropriate
Warrant exercisable into the remaining shares.


                                      _____________________________________
                                     (Name)


                                      _____________________________________
                                     (Address)


                                      _____________________________________
                                     (Signature)


                                      _____________________________________
                                     (Date)


                                      -9-


                                                                   EXHIBIT 10.22
                             STOCKHOLDERS' AGREEMENT

         STOCKHOLDERS'  AGREEMENT,  made as of October 7, 1996 (the "Agreement")
by and among Bioseq,  Inc., a Massachusetts  corporation with a principal office
at 25 Olympia Avenue, Unit F, Woburn,  Massachusetts 01801 (the "Company"),  all
of the shareholders of the Company identified on Exhibit A hereto (the "Existing
Stockholders"),  Boston  Biomedica,  Inc., a  Massachusetts  corporation  with a
principal office at 375 West Street, West Bridgewater,  Massachusetts 02379 (the
"Preferred  Holder") and those additional  holders of Preferred Stock and Common
Stock of the  Company  (the  "Additional  Holders")  who may be added as parties
hereto from time to time in  accordance  with the terms of this  Agreement.  The
Existing  Stockholders,  the  Preferred  Holder and the  Additional  Holders are
hereinafter collectively referred to as "Holders."

         WHEREAS,  as of the date hereof the  Preferred  Holder has purchased an
aggregate of 300 shares of Series A Convertible  Preferred Stock, $.01 par value
per share of the Company (the "Series A Preferred"),  which is convertible  into
common  stock,  $.01 par value  per share of the  Company  ("Common  Stock")  in
accordance  with the  terms  of the  Company's  Articles  of  Organization  (the
"Charter"),  pursuant to the terms of a Preferred  Stock  Purchase  Agreement of
even date herewith (the "Purchase Agreement"); and

         WHEREAS,  the  Preferred  Holder  is  obligated  and has an  option  to
purchase  additional  shares of the  Series A  Preferred,  Series B  Convertible
Preferred  Stock,  $.01 par  value  per  share of the  Company  (the  "Series  B
Preferred") and Series C Convertible  Preferred Stock,  $.01 par value per share
of the Company (the "Series C Preferred," together, the Series A Preferred,  the
Series B  Preferred  and the Series C  Preferred  are  referred to herein as the
"Preferred Stock") pursuant to the terms of the Purchase Agreement and a certain
Warrant Agreement referenced therein; and

         WHEREAS,  the purchase and sale of the Preferred Stock as aforesaid has
been  undertaken  by the  Company  and the  Preferred  Holder in reliance on the
agreements of the parties hereto as hereinafter set forth; and

         WHEREAS,  the Company and the Holders wish to confirm their  agreements
by entering into this Stockholders' Agreement, and each considers the provisions
contained  herein  to be in  his,  her  or its  best  interest  and in the  best
interests of the Company;

         NOW,  THEREFORE,  In  consideration of the foregoing and the agreements
set forth below, the parties hereto agree as follows:

         SECTION 1. BOARD OF DIRECTORS.

         In all  elections  of  Directors of the Company held during the term of
this  Agreement  (whether  at a  meeting  or by  written  consent  in  lieu of a
meeting),  each of the Holders  unconditionally agrees to vote all shares of the
Company's Common Stock,  Preferred Stock and any other equity  securities of the
Company or  securities  of the  Company  having  equity  features,




now  owned or  hereafter  acquired  or  controlled  by the  Holder,  whether  by
purchase,  conversion  of other  securities,  exercise  of rights,  warrants  or
options, stock dividends or otherwise (collectively, the "Stock"), and otherwise
to use his or its respective  best efforts to cause and maintain the election to
the Board of Directors of one nominee designated by the Preferred Holder.

         The  obligation  of the  Holders  to vote  their  stock in favor of the
designee  of the  Preferred  Holder  shall  terminate  at  such  time as (a) the
Preferred  Holder owns less than 25% of the Preferred  Stock  (calculated  on an
as-if-converted  basis,  and including any shares of Common Stock into which the
Preferred  Stock  may have  been  converted)  issued  to it under  the  Purchase
Agreement,  or (b) the Preferred Holder does not purchase the shares of Series B
Preferred  referenced  in Section 1.2 (ii) of the Stock  Purchase  Agreement  in
accordance with the terms thereof.

         SECTION 2. RIGHT OF FIRST REFUSAL ON DISPOSITIONS BY HOLDERS.

         (a) No Holder  shall  sell,  assign or  otherwise  transfer or agree to
sell,  assign or  otherwise  transfer  any shares of Stock held or  beneficially
owned by such Holder to any third party (the "Proposed Transferee") other than a
Permitted  Transferee as defined below,  unless in each such case the Holder (an
"Offering  Holder")  shall have first offered to sell those shares (the "Offered
Shares"), in accordance with this Section 2, to all other Holders (collectively,
the "Offeree  Holders"),  on terms and  conditions,  including  price,  not less
favorable  to the  Offeree  Holders  than  those on which  the  Offering  Holder
proposes  to sell such  Offered  Shares to the  Proposed  Transferee.  Any sale,
assignment or other transfer  contrary to the provisions of this Agreement shall
be void, and shall not be recorded on the Company's stock transfer  records.  In
the event of any attempt to make such a transfer,  the Company shall continue to
treat  the  purported  transferor  as the  owner of the  Stock  purported  to be
transferred for all purposes, including without limitation,  voting and dividend
rights.

         (b) The  Offering  Holder  shall give  notice to the Company and to the
Offeree  Holders in  writing  of the  Offering  Holder's  intention  to sell the
Offered  Shares (the  "Notification"),  specifying the number of shares of Stock
proposed to be transferred and the price and terms of the proposed transfer (the
"Terms"),  and offering to sell the Offered Shares to the Offeree Holders on the
Terms specified.

         (c) Each Offeree  Holder shall have the absolute  right (subject to the
last  sentence of this  subsection  (c)),  by delivery of written  notice to the
Company,  the  Offering  Holder and each other  Offeree  Holder (as  hereinafter
provided)  to purchase  that  number of Offered  Shares as shall be equal to the
number of Offered Shares multiplied by a fraction,  the numerator of which shall
be the number of shares of Common  Stock  (including  on an  as-if-converted  or
as-if-exercised  basis any securities of the Company which are convertible  into
or  exercisable  for Common  Stock of the  Company)  then owned by such  Offeree
Holder and the  denominator of which shall be the aggregate  number of shares of
Common Stock  outstanding  (including as outstanding  any shares of Common Stock
issuable  upon  conversion  or exercise  of any  outstanding  securities  of the
Company).  The amount of Offered  Shares that each Offeree Holder is entitled to
purchase  under  this  Section  2(c)  shall  be  referred  to as its  "Pro  Rata
Fraction." Notwithstanding the foregoing,

                                       2


no Offeree  Holder  shall have the right to purchase  any of the Offered  Shares
unless all of the Offered Shares are subscribed for by the Offeree Holders under
this Section 2.

         (d) The Offeree  Holders  shall have a right to  oversubscription  such
that if any Offeree Holder declines to purchase its Pro Rata Fraction, the other
Offeree Holders shall, among them, have the right to purchase the balance of the
Offered Shares not so purchased. Such right of oversubscription may be exercised
by an Offeree  Holder by  accepting  the offer of the Offered  Shares as to more
than its Pro Rata  Fraction.  If, as a result  thereof,  such  oversubscriptions
exceed  the  total  number  of  Offered  Shares  available  in  respect  of such
oversubscription privilege, the oversubscribing Offeree Holders shall be reduced
with respect to their  oversubscriptions  on a pro rata basis in accordance with
their  respective  Pro Rata  Fractions  or as they  may  otherwise  agree  among
themselves.

         (e) The notice to be provided by an Offeree  Holder under  Section 2(c)
hereof shall state the number of Offered  Shares the Offeree  Holder  desires to
purchase.  The notice  shall be  delivered  in person or mailed to the  Offering
Holder, the Company, and each other Offeree Holder within 10 days of the date of
the  Notification.  Such  notice  shall,  when  taken  in  conjunction  with the
Notification,  be deemed to constitute a valid,  legally binding and enforceable
agreement  for the sale and  purchase  of such  Offered  Shares  (subject to the
aforesaid  limitations as to an Offeree Holder's right to purchase more than its
Pro Rata Fraction and to the condition  that all of the Offered  Shares be fully
subscribed for by the Offeree  Holders).  Sales of the Offered Shares to be sold
to purchasing  Offeree  Holders  pursuant to this Section 2 shall be made at the
offices of the Company on the 45th day  following  the date of the  Notification
(or if such 45th day is not a business day, then on the next succeeding business
day).  Such sales shall be effected by the  Offering  Holder's  delivery to each
purchasing  Offeree  Holder of a  certificate  or  certificates  evidencing  the
Offered  Shares to be  purchased  by it,  duly  endorsed  for  transfer  to such
purchasing  Offeree  Holder,  against  payment  to the  Offering  Holder  of the
purchase price therefor by such purchasing Offeree Holder.

         (f) If the Offeree  Holders do not  subscribe  to  purchase  all of the
Offered  Shares,  the  Offering  Holder shall not be required to sell any of the
Offered Shares to the Offeree Holders hereunder;  and in such event all (but not
less than all) of the Offered  Shares may be sold by the Offering  Holder to the
Proposed  Transferee at any time within 90 days after the date the  Notification
was made,  subject to the provisions of Section 2 and Section 3 hereof. Any such
sale shall be to the  Proposed  Transferee,  at not less than the price and upon
other  terms  and  conditions,  if  any,  not  more  favorable  to the  Proposed
Transferee than the Terms specified in the  Notification.  If the Offered Shares
are not sold  within  the 90 day  period,  they  shall  again be  subject to the
requirements  of a prior  offer  pursuant  to this  Section  2.  Subject  to the
provisions  of Section 3 hereof,  if Offered  Shares are sold  pursuant  to this
Section 2 to any  purchaser  who is not a party to this  Agreement,  the Offered
Shares so sold shall be subject to the  restrictions  imposed by this  Section 2
with respect to any subsequent sales.

         (g) Notwithstanding any other provisions of this Section 2, each Holder
shall be entitled to transfer, without compliance with this Section 2, shares of
Stock held by it:


                                       3


                  (i) to the trustees of a trust revocable by such Holder alone,
the  beneficiaries  of  which  consist  solely  of the  Holder  and  transferees
enumerated in subsection (iv) below;

                  (ii) in the  case of a  Holder  who is an  individual,  to his
guardian or conservator;

                  (iii) in the case of a deceased  Holder,  to his  executors or
administrators or to trustees under his will;

                  (iv) in the  case of a  Holder  who is an  individual,  or his
guardian,  conservator or trustee under an inter vivos trust,  or his executors,
administrators or trustees under his will, to the Holder's spouse, to any of his
children or their issue (or to custodians  for the benefit of minor  children or
issue) or to the Holder's parents or siblings;

                  (v) to its partners or other equity owners or to a liquidating
trust or similar entity  established for the purpose of holding its assets prior
to distribution to its partners or other equity owners;

                  (vi) to any  entity  which is  controlled  by or under  common
control with such Holder; or

                  (vii) in the case of any Holder who is or becomes an  employee
of the Company,  to the Company in accordance  with written  agreements  entered
into in  connection  with the original  issuance of Stock to such Holder (or the
grant of a right to acquire  such  Stock)  giving  the  Company a right of first
refusal or a right to repurchase such Stock;

Each such transferee is referred to herein as a "Permitted Transferee." All such
Permitted  Transferees  (other than the Company  pursuant to clause (vii) above)
shall remain  subject to the terms of this  Agreement  and shall be deemed to be
"Holders" for purposes hereof.

         SECTION 3.  RIGHT TO PARTICIPATE IN SALES.

         Upon  compliance by an Offering  Holder with the  provisions of Section
2(a) through 2(c) hereby and prior to any  transfer  under  Section 2(e) hereof,
the  Offering  Holder  shall  provide  each  Offeree  with  written  notice (the
"Transfer Notice") of, and the opportunity to participate in, such transfer upon
the same terms as set forth in the original Notification under Section 2(b). Any
Offeree which elects to  participate  in such transfer shall notify the Offering
Holder  not later  than  fifteen  days after  receipt  of the  Transfer  Notice,
specifying the number of shares of Stock which such Offeree desires to transfer.
The Offering  Holder will not  transfer any shares of Stock  pursuant to Section
2(e)  in such  transaction  unless  the  transferee  thereof  at the  same  time
purchases  from each Offeree Holder who elects to participate in the transfer as
aforesaid  at least the lesser of (a) the number of shares of Stock set forth in
such Offeree Holder's notice to the Offering Holder or (b) that number of shares
computed  by  multiplying  the  total  number  of  shares  of Stock to which the
proposed transfer relates by a fraction, the numerator of which is the aggregate
number of shares of Stock owned by such Offeree  Holder and the  denominator  of
which is the aggregate  number of shares of Stock  outstanding.  Notwithstanding
the foregoing,  at





all times during the term of this  agreement  Boston  Biomedica,  Inc.  shall be
permitted,  should it elect to do so in accordance with the notice provisions of
this  Section 3, to sell a number of shares of stock  pursuant to this Section 3
which is not less than the largest  number of shares being sold pursuant  hereto
by any of BioMolecular  Assays,  Inc., James A. Laugharn and David J. Green, and
the number of shares  being sold by all such  parties  shall be reduced on a pro
rata basis to accommodate the foregoing entitlement.

         SECTION 4.  MISCELLANEOUS.

         Section 4.1. Specific  Performance;  Other Rights.  The Company and the
Holders  recognize  that the  rights of the  parties  under this  Agreement  are
unique, and accordingly the Holders shall, in addition to such other remedies as
may be available  to any of them at law or in equity,  have the right to enforce
their rights hereunder by actions for injunctive relief and specific performance
to  the  extent  permitted  by  law.  Without  limiting  the  generality  of the
foregoing,  if any  transfer of shares of Stock of a Holder is made or attempted
to be made in  contravention  of the  provisions  of this  Agreement,  the other
Holders  shall have the right to enforce  their rights  hereunder by actions for
injunctive  relief and  specific  performance  to the extent  permitted  by law.
Except as provided  herein,  this  Agreement is not intended to limit or abridge
any rights of the parties which may exist apart from this Agreement.

         Section 4.2. Stock Legend. Each certificate for shares of Stock subject
to this Agreement shall have endorsed, stamped or written thereon a legend which
shall read substantially as follows:

         "THE SECURITIES  REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN
TRANSFER RESTRICTIONS AND OTHER PROVISIONS OF A CERTAIN STOCKHOLDERS'  AGREEMENT
DATED AS OF OCTOBER 7, 1996 (COPIES OF WHICH ARE AVAILABLE AT THE OFFICES OF THE
COMPANY FOR EXAMINATION)."

         Section  4.3.  Termination.  This  Agreement  shall  terminate  on  the
earliest  to occur of (a) the  closing of the sale of shares of Common  Stock of
the Company in a Qualified Public Offering, as defined in the Purchase Agreement
(and shall not apply to any Stock being sold as part of such  offering)  and (b)
such time as none of the Preferred Stock is outstanding.

         Section  4.4.  Notices,  Etc.  All  notices  and  other  communications
hereunder  shall be in  writing  and shall be deemed  to have  been  given  when
delivered or sent by  overnight  courier or mailed by  certified  mail,  postage
prepaid,  addressed (a) if to the Company, to the Chief Executive Officer at the
address first set forth above,  with a copy to Warner & Stackpole  LLP, 75 State
Street, Boston,  Massachusetts 02109, Attn: Kenneth S. Boger, Esquire; (b) if to
any Holder, to the address set below its name on Exhibit A hereto; and (c) if to
any other  person who  becomes  subject to the terms of this  Agreement,  to his
address  as the  same may  appear  in the  records  of the  Company,  and to the
Company.  Each of the  parties  may change  his,  her or its  notice  address as
referenced above by notice to each of the other parties delivered as aforesaid.


                                       5


         Section  4.5.  Entire  Agreement.  The parties  hereto  agree that this
Agreement  constitutes the entire agreement  between the parties with respect to
the subject matter hereof and supersedes all prior agreements and understandings
between them as to such subject matter.

         Section 4.6. Waivers and Further Agreements. Any waiver of any terms or
conditions of this  Agreement  shall not be effective  unless given in a writing
signed by the party against whom such waiver is sought to be enforced, nor shall
it operate as a waiver of any other  breach of such terms or  conditions  or any
other term or condition,  nor shall any failure to enforce any provision  hereof
operate as a waiver of such provision or of any other provision  hereof. No such
waiver, unless it by its own terms explicitly provides to the contrary, shall be
construed to effect a continuing  waiver of the provision  being waived,  and no
such waiver in any instance  shall  constitute a waiver in any other instance or
for any other  purpose or impair the right of the party against whom such waiver
is claimed in all other  instances  or for all other  purposes  to require  full
compliance with such provision.

         Section 4.7. Further  Assurances.  Each of the parties hereto agrees to
execute all such further  instruments and documents and to take all such further
action as the other  party may  reasonably  require in order to  effectuate  the
terms and purposes of this Agreement.

         Section 4.8.  Amendments.  This Agreement may not be amended, nor shall
any  waiver be  effected  except by an  instrument  in writing  executed  by the
holders of a majority  of the Stock,  which vote shall  include the holders of a
majority of the  Preferred  Stock (on an  as-if-converted  basis,  and including
shares of Common Stock into which any Preferred  Stock may have been  converted)
then owned or controlled by a Holder hereunder.

         Section 4.9.  Successors and Assigns.  This Agreement  shall be binding
upon and shall inure to the benefit of the parties  hereto and their  respective
heirs, executors, legal representatives, successors and permitted assigns.

         Section 4.10. Severability. If any provision of this Agreement shall be
held or deemed to be invalid,  inoperative  or  unenforceable  as applied to any
particular case in any jurisdiction or jurisdictions, or in all jurisdictions or
in all cases,  because of the conflict of any provision with any constitution or
statute  or rule of public  policy or for any other  reason,  such  circumstance
shall not have the effect of rendering  the provision or provisions in question,
invalid,  inoperative or unenforceable in any other jurisdiction or in any other
case or circumstance  or of rendering any other  provision or provisions  herein
contained  invalid,  inoperative or  unenforceable to the extent that such other
provisions  are not  themselves  actually  in conflict  with such  constitution,
statute or rule of public  policy,  but this  Agreement  shall be  reformed  and
construed in any such  jurisdiction  or case as if such invalid,  inoperative or
unenforceable  provision had never been  contained  herein,  and such  provision
shall be reformed so that it would be valid,  operative and  enforceable  to the
maximum extent permitted in such jurisdiction or in such case.

         Section 4.11.  Counterparts.  This  Agreement may be executed in two or
more counterparts,  each of which shall be deemed an original,  but all of which
together  shall  constitute 


                                       6

one and the same  instrument,  and in pleading or proving any  provision of this
Agreement,  it  shall  not be  necessary  to  produce  more  than  one  of  such
counterparts.

         Section  4.12.  Additional  Parties.  The Company may issue  additional
shares of Preferred  Stock to persons or entities not initially  parties to this
Agreement (the  Additional  Holders) under the terms of the Purchase  Agreement.
Each Additional  Holder shall execute a counterpart of this Agreement,  and upon
such  execution  this  agreement,  including  Exhibit  A hereto  which  shall be
modified  accordingly and distributed to each Holder hereunder,  shall be deemed
to have been  amended to add such  additional  Holder as a party hereto with all
rights and obligations of the other Holders hereunder.

         Section  4.13.  Section  Headings.   The  headings  contained  in  this
Agreement  are for  reference  purposes only and shall not in any way affect the
meaning or interpretation of this Agreement.

         Section 4.14.  Governing Law. This  Agreement  shall be governed by and
construed  in  accordance  with  the  internal  laws  of  the   Commonwealth  of
Massachusetts.





                      THIS SPACE LEFT INTENTIONALLY BLANK.




                                       7






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

THE COMPANY:                             BIOSEQ, INC.


                                         By:  /s/ J. Laugharn
                                           -------------------------------------
                                             Name:   James Laugharn
                                             Title:  President and CEO

THE PREFERRED HOLDER:                    BOSTON BIOMEDICA, INC.


                                         By:  /s/ Richard T. Schumacher
                                           -------------------------------------
                                             Name:   Richard T. Schumacher
                                             Title:  President and CEO

THE EXISTING HOLDERS:                   BIOMOLECULAR ASSAYS, INC.


                                         By:  /s/ J. Laugharn
                                           -------------------------------------
                                             Name:  James Laugharn
                                             Title: President and CEO


                                        /s/ David J. Green
                                        ----------------------------------------
                                        David J. Green

                                        /s/ James A. Laugharn, Jr.
                                        ----------------------------------------
                                        James A. Laugharn, Jr.

                                        ________________________________________
                                        Edwin A. Rudd

                                        ________________________________________
                                        Gustav H. Dreier

                                        ________________________________________
                                        James H. Smith

                                        ________________________________________
                                        Carson H. Powers

                                        ________________________________________
                                        Gerald J. Litt

                                        ________________________________________
                                        G&G Diagnostics Limited Partnership II








                                                                       EXHIBIT A
<TABLE>
<CAPTION>

                                                                          Number and Type of Shares
                                                                          -------------------------
Names & Addresses                                          Common Stock         Series A Preferred         Other
- -----------------                                          ------------         ------------------         -----

<S>                                                       <C>                   <C>                         <C>
THE EXISTING STOCKHOLDERS:
     BioMolecular Assays, Inc.
     25 Olympia Avenue, Unit F
     Woburn, MA  01801

     David J. Green
     51 Amberwood Drive
     Winchester, MA  01890

     James A. Laugharn, Jr.
     6 Chesterford Road
     Winchester, MA  01890

     Edwin A. Rudd
     52 Brookdale Road
     Salem, NH  03079

     Gustav H. Dreier
     189 Moxley Street
     Jefferson, NY  12093


     James H. Smith
     138 Chace Hill Road
     Sterling, MA  01545

     G&G Diagnostics Limited Partnership II                      100
     30 Ossipee Road
     Newton, MA  02164

     Carson H. Powers
     P.O. Box 77
     Georgetown, CT  06829

     Gerald J. Litt
     16 Cove Island Road
     Centerville, MA  02632

</TABLE>

                                                                   EXHIBIT 10.23
                                LICENSE AGREEMENT

         THIS  AGREEMENT  is made and entered  into as of October 7, 1996 by and
between  BioMolecular  Assays,  Inc. ("BMA"),  a Massachusetts  corporation with
principal offices at 25 Olympia Avenue, Woburn,  Massachusetts 01801-6307 (as to
certain  provisions  hereof)  and  BioSeq,  Inc.  ("BioSeq"),   a  Massachusetts
corporation  with  principal  offices at 25  Olympia  Avenue,  Unit #F,  Woburn,
Massachusetts 01801-6307; and Boston Biomedica, Inc. a Massachusetts corporation
with principal offices at 375 West Street, West Bridgewater, Massachusetts 02379
("BBI").

         WHEREAS,  BMA is the owner of all right,  title and  interest in and to
the BMA Patents (as defined below) and the Technology (as defined below) related
thereto;

         WHEREAS, BioSeq has obtained from BMA an exclusive, worldwide right and
license under the BMA Patents and the  Technology,  in accordance with the terms
of a certain License Agreement dated October 7, 1996 (the "BMA License");

         WHEREAS,  pursuant to the BMA License  BioSeq has developed a prototype
instrument  (the  "Instrument")  to be used  for  nucleic  acid  (DNA  and  RNA)
sequencing and analysis (the "Field");

         WHEREAS, BBI wishes to obtain an exclusive, worldwide right and license
as  provided  herein,  under  the BMA  Patents  and  Technology,  to  operate  a
fee-for-service laboratory using the Instrument and associated "pressure cycling
reactor"  technology within the Field; and BioSeq is willing to grant BBI such a
license in accordance  with the terms of this  Agreement,  and BMA is willing to
join in and confirm the validity of such license;

         NOW THEREFORE,  in  consideration  of the premises and mutual covenants
herein  contained  and other good and  valuable  consideration,  the receipt and
sufficiency  of which  are  hereby  acknowledge,  the  parties  hereto  agree as
follows:

1. Definitions.

        1.1.  "Affiliate"  shall mean,  at any time,  any person or legal entity
              then directly or indirectly  controlled  by,  controlling or under
              common  control  with the party with respect to which this term is
              associated.


        1.2.  "BMA  Patents"  shall mean those  patents and patent  applications
              identified  on  schedule  1.2 hereto,  and any and all  divisions,
              continuations,  continuations-in-part,  extensions, substitutions,
              reissues,  re-examinations  or  additions  of or  to  any  of  the
              foregoing,  and any patents  which issue from any of the foregoing
              applications,  and  any  foreign  counterparts  of  the  foregoing
              currently  or in the future  filed or issued and not  specifically
              listed



              on Schedule 1.2 hereto, and any other patents, patent applications
              and the like of BMA that are  necessary  or  appropriate  to make,
              use, sell, offer for sale or otherwise practice the Technology.


        1.3.  "Field"  shall  mean  nucleic  acid (DNA and RNA)  sequencing  and
              analysis.


        1.4.  "Instrument"  means a device using the BMA Patents and  Technology
              to perform nucleic acid (DNA and RNA) sequencing and analysis.


        1.5.  "Net  Revenues"  shall mean the amounts  billed or invoiced (or if
              not invoiced or billed,  the amounts received) by BBI for Services
              within the Field using the BMA Patents or Technology, less (a) the
              amounts of actual trade and cash  discounts and rebates given with
              respect to services that were not already  credited at the time of
              invoice,  (b) actual credited  allowances on account of refunds or
              price  adjustments  with respect to Services that were not already
              credited at the time of invoice,  (c) sales taxes,  excise  taxes,
              import/export duties and rebates (including rebates to third party
              payers)  actually  paid with  respect to  Services,  and (d) other
              reasonable   and  customary   allowances   actually   credited  to
              customers,  provided  that if BBI provides any such Service to any
              party  other  than to an  independent  third  party in a bona fide
              arm's length  transaction,  Net  Revenues  shall be based upon the
              resale  to  an   independent   third  party  in  an  arm's  length
              transaction  by the entity to which such  Service  was sold by BBI
              or, if there is no such resale,  Net Revenues  shall be calculated
              as above on the fair market price in the relevant  country of sale
              or transfer.  If a transaction  involves  goods or services  other
              than  Services,  then Net Revenues shall be the product of (a) the
              overall amount charged by BBI with respect to the  transaction and
              (b) a fraction  which shall  reflect the fair market  value of the
              Services as a component of the transaction relative to the overall
              amount charged by BBI with respect to the transaction.


        1.6.  "Services"  shall  mean  providing   laboratory   services  as  an
              independent  reference laboratory to third persons,  using the BMA
              Patents and Technology within the Field.  "Services" shall include
              all work in connection with preparation of samples for analysis by
              an Instrument,  and analysis of the  information and data produced
              as a result of the  analysis  by an  Instrument.  An  "independent
              reference laboratory" is a commercial laboratory unaffiliated, and
              dealing  on  an  arms-length  basis,  with  its  customers,  which
              provides high volume  testing of samples  received from  customers
              and which reports on results of that testing.


                                       2


        1.7.  "Technology" shall mean all know-how,  proprietary  information or
              special  knowledge of BMA and BioSeq  related to  Instruments  and
              Services and involving nucleic acid sequencing and analysis, as it
              may be modified or improved during the term hereof.


        1.8.  "Valid Claim" shall mean a claim of an issued an unexpired  patent
              within the BMA Patents which would be infringed by the  provisions
              of  Services  and which shall not have been  withdrawn,  canceled,
              disclaimed or held invalid by a court of competent jurisdiction in
              an unappealed or unappealable decision.


2. License and Rights

        2.1.  License.  BMA and BioSeq  each (as its rights may  appear)  hereby
              grants to BBI an exclusive,  worldwide right and license under the
              BMA  Patents  and  the  Technology   (the  "License)  to  use  the
              Instrument,  BMA Patents  and  Technology  to provide  Services to
              third parties worldwide. BBI shall have no right to sublicense any
              of the  foregoing  rights.  The  foregoing  license  shall  become
              effective  upon the  earlier of (a)  payment in full by BBI of the
              amount referenced in Section 1.2(iii) of a certain Preferred Stock
              Purchase  Agreement  between  the  parties of even  date,  and (b)
              December 31, 1997.


        2.2.  Equipment.   BioSeq  shall   furnish  one  or  (at  BioSeq's  sole
              discretion)  more  Instruments  to BBI,  at no  cost to BBI,  at a
              mutually   agreeable  site  for  the  purpose  of   pre-commercial
              evaluation  and  testing of the  Instrument  and its  performance.
              During  the period in which the  License  remains  exclusive  (and
              otherwise subject to the provisions of Section 8.2 below),  BioSeq
              will  supply   Instruments   and  associated   equipment  in  such
              quantities  as may be requested by BBI to support its provision of
              Services,  upon such  reasonable and customary  terms of supply as
              may be agreed between the parties and at a price equal to BioSeq's
              fully-allocated  cost of production of the items  supplied.  After
              the License becomes non-exclusive, BioSeq will supply equipment to
              BBI upon  such  reasonable  and  customary  terms as may be agreed
              between the parties  and at prices no less  favorable  to BBI than
              those at which  BioSeq  regularly  sells such  equipment  to other
              commercial,  non-governmental Instrument purchasers.  BioSeq shall
              notify BBI of any  improvements  it makes to the  Instruments  and
              offer BBI the  opportunity  to have its  Instruments  upgraded  or
              replaced to include these improvements at BBI's expense.


        2.3.  Supplies.During the period in which the License remains exclusive,
              BBI shall have the right to purchase reagents and related supplies
              from BioSeq,


                                       3


              as reasonably  required to run the  laboratory and meet the demand
              for  Services,  at a  price  equal  to  BioSeq's  cost  plus  35%.
              Thereafter BBI may continue to purchase such reagents and supplies
              at  prices no less  favorable  to BBI than  those at which  BioSeq
              regularly  sells such  reagents or  supplies to other  commercial,
              non-governmental Instrument purchasers.


        2.4   Improvements.   BBI  shall  keep  BioSeq  fully   advised  of  any
              improvements  by BBI or its  Affiliates  during  the  term of this
              Agreement  relating to the Technology,  whether  patentable or not
              ("BBI Improvements"). At the request of BioSeq, BBI shall grant to
              BioSeq  a  non-exclusive  royalty-free  license  to any  such  BBI
              Improvements, with a right to sublicense.


3. Payments

        3.1.  Royalty.  During the term of the License BBI shall pay to BioSeq a
              royalty,  at the rate stated below, on BBI's Net Revenues  derived
              from  Services.  If Services are performed in whole or in part in,
              and are requested by a client or customer whose principal place of
              business is located in, any country or countries in which there is
              no Valid Claim under a BMA Patent, then the royalty rate otherwise
              applicable to Net Revenues from those Services shall be reduced by
              fifty  percent  (50%) with respect to Services  provided more than
              three years from the first  commercial sale of Services  hereunder
              by  BBI.  Subject  to any  reduction  pursuant  to  the  foregoing
              sentence, for so long as the License is exclusive (see Section 8.2
              below) the  royalty  rate shall be 5% of Net  Revenues  during the
              three  year  period  commencing  at the  earlier  of (a) the first
              commercial sale of Services by BBI, or (b) the end of the one year
              period  following  commencement  of the  License  term,  and shall
              increase  to 8% during the next two years and to 10%  during  each
              year thereafter; provided that if the License becomes nonexclusive
              the royalty  for all Net  Revenues  relating to Services  provided
              after  that date  shall be reduced to zero and BBI shall be deemed
              to hold a fully paid  license  hereunder  from that date  forward.
              Royalties  shall be payable  thirty days following the last day of
              March,  June,  September  and  December of each  calendar  year on
              account of Net Revenues during the quarter ended on such last day.


        3.2.  Reports.  BBI  shall  provide a  royalty  report to BioSeq  within
              thirty days after the end of each quarterly  period  referenced in
              that  last  sentence  of  Section  3.1  hereof,  covering  all Net
              Revenues and  royalties  earned during that period and showing all
              other facts  necessary  to the  calculation  of amounts  due.  All
              royalty  payments shall also be  accompanied by a royalty  report.
              All payments to BioSeq shall be in United States dollars.  Royalty
              payments  based on Net  Revenues in  currencies  other than United
              States  dollars  shall  be  converted  to  United  States 


                                       4


              dollars  according  to the average  official  rate of exchange for
              that currency as published in The Wall Street Journal on the first
              and  last  days of the  calendar  quarter  in which  that  royalty
              accrued  (or,  if not  published  on that day,  the first and last
              publication days for The Wall Street Journal during that quarter).


        3.3.  Books and Records and Audit. BBI shall maintain full, complete and
              accurate books and records covering all  transactions  relating to
              this  Agreement,   including   information   necessary  to  permit
              calculation  and  verification  of amounts  due under  Section 3.1
              hereof.  BioSeq  shall  at any  time  within  one (1)  year of any
              payment  be  entitled  to  audit  the  books  and  records  of BBI
              pertaining  to its  payment  obligations  hereunder,  for the sole
              purpose of confirming the accuracy of the amounts stated to be due
              on the  royalty  reports  submitted  to BioSeq  under  Section 3.1
              hereof.  Any such audit shall be performed  during normal business
              hours  at  BioSeq's  expense  by  a  firm  of  independent  public
              accountants  acceptable  to both BBI and BioSeq.  The  independent
              agent shall  report  only such  information  as would  properly be
              included in such a report.  If such audit reveals an  underpayment
              of five  percent  (5%) or greater of the amount  that  should have
              been paid to BioSeq  for the period  audited,  then BBI shall bear
              the expense of the audit.  In the event of any  underpayment,  BBI
              shall  promptly  remit to BioSeq all amounts due, with interest on
              late  payments  payable at the rate of ten percent  (10%) per year
              compounded annually.


        4.    Patents.  BioSeq shall keep BBI fully informed of all developments
              in regard to the preparation, filing, prosecuting, and maintenance
              of the BMA Patents and shall, to the extent  practicable,  provide
              BBI, for comment, with pre-filing copies of any materials relating
              to BMA  Patents  filed with any patent  office  worldwide.  BioSeq
              shall  reimburse BMA for its reasonable  external  (out-of-pocket)
              costs  arising  out of  actions  occurring  after the date of this
              Agreement in connection with the preparation,  filing, prosecution
              and maintenance of BMA Patents.

5. Representations and Warranties of BMA and BioSeq.

        5.1.  Representations and Warranties of BMA. BMA represents and warrants
              that it is the owner of the entire  right,  title and  interest to
              the BMA Patents,  and that BioSeq is its exclusive licensee of the
              BMA  Patents  and  Technology  for  all  markets,   products,  and
              applications.


        5.2.  Representations  and Warranties of BioSeq.  BioSeq  represents and
              warrants  that it has the right and  authority  to enter into this
              Agreement  and to grant the License  granted  hereunder,  and that
              this  Agreement  and the


                                       5


              License do not and will not  conflict  with the terms of any other
              agreement to which BioSeq is a party or by which it is bound.


        5.3.  Disclaimers.  Except  as  otherwise  expressly  set  forth in this
              Agreement,   BMA  and  BioSeq  and  their   directors,   officers,
              employees,  and  agents  make no  representations  and  extend  no
              warranties of any kind, either express or implied.


6. Representations, Warranties and Acknowledges of BBI.

        6.1.  Representations  and Warranties.  BBI represents and warrants that
              it has the right and  authority to enter into this  Agreement  and
              that this  Agreement  and the  exercise  of the License do not and
              will not conflict  with the terms of any agreement to which BBI is
              a party or by which it is bound.


        6.2.  Disclaimers.  Except  as  otherwise  expressly  set  forth in this
              Agreement, BBI, its directors, officers, employees and agents make
              no  representations  and extend no warranties of any kind,  either
              express or implied.


7. Indemnification

        7.1   Indemnification by BMA. BMA shall indemnify,  defend and hold BBI,
              its directors,  officers, employees and affiliates,  harmless from
              and against all claims,  proceedings,  demands and  liabilities of
              any kind  whatsoever  (including  reasonable  attorneys'  fees and
              costs  and  other  expenses  of  litigation)  resulting  from  the
              material breach of BMA of any of its  representations,  warranties
              or covenants contained in this Agreement.

        7.2   Indemnification by BioSeq. BioSeq shall indemnify, defend and hold
              BBI, its directors,  officers, employees and affiliates,  harmless
              from and against all claims, proceedings,  demands and liabilities
              of any kind whatsoever  (including  reasonable attorneys' fees and
              costs  and  other  expenses  of  litigation)  resulting  from  the
              material   breach  by  BioSeq  of  any  of  its   representations,
              warranties,   acknowledgments  or  covenants   contained  in  this
              Agreement.


        7.3.  Indemnification  by BBI.  BBI  shall  indemnify,  defend  and hold
              BioSeq, its directors, officers, employees and affiliates harmless
              from and against all claims, proceedings,  demands and liabilities
              of any kind whatsoever  (including  reasonable attorneys' fees and
              costs  and  other  expenses  of  litigation)  resulting  from  the
              material breach by BBI of any of its

                                       6


              representations,    warranties,   acknowledgments   or   covenants
              contained in this Agreement.


       7.4  Infringement.

                           (a) Third Party Infringement. Each party shall notify
                  the other promptly of any possible infringements, unauthorized
                  possession,  knowledge  or use of  the  intellectual  property
                  embodied  in any of the BMA  Patents  by others of which  such
                  party  becomes  aware,  and shall  promptly  furnish the other
                  party with full  details of such  infringements,  unauthorized
                  possession,  knowledge  or use.  BioSeq  shall  have the first
                  right,  but not the obligation,  at its expense,  to bring any
                  action  on  account  of any such  infringements,  unauthorized
                  possessions,  knowledge or use, and BBI shall  cooperate  with
                  BioSeq, as BioSeq may reasonably  request,  in connection with
                  any such action.  If,  within sixty (60) days after receipt by
                  BioSeq of a written request from BBI that it bring such action
                  BioSeq  does  not do so,  BBI  shall  have the  right,  at its
                  expense  and in its own  name or in the  name  of  BioSeq,  if
                  required  by law,  to do so on its own behalf and on behalf of
                  BioSeq,  and  BioSeq  shall  cooperate  with  BBI,  as BBI may
                  reasonably  request,  in connection with such action.  No such
                  legal  action may be settled by one party  without the other's
                  prior written consent, which consent shall not be unreasonably
                  withheld.  Damages  recovered  in any such  actions  which are
                  determined to relate to lost sales by BBI, after reimbursement
                  to each party of its  expenses in  prosecuting  such  actions,
                  shall be treated as proceeds  of Net  Revenues  hereunder  and
                  paid to each party accordingly.

                           (b) Third Party Actions. To BioSeq's  knowledge,  the
                  exercise of the rights  granted  herein will not result in the
                  infringement of valid patents of third parties.  Nevertheless,
                  each  party  will  promptly  notify the other in the event any
                  relevant third party patents come to its notice. Neither party
                  gives any warranty  regarding the  infringement of third party
                  rights by practice of the license granted hereunder, and gives
                  no indemnity against costs, damages,  expenses or other losses
                  arising out of proceedings  brought against the other party or
                  any other person by any third party. In the event either party
                  is sued for  infringement  of any rights of any third party in
                  the  exercise of its rights  hereunder,  the other party shall
                  extend to it, at no charge,  good faith assistance and support
                  in defending such action,  and may  participate in the conduct
                  of the  suit  at its own  expense,  but,  shall  be  under  no
                  obligation in respect thereof.

8. Term and Termination.

        8.1.  Term. The term of this Agreement shall extend until the last Valid
              Claim to expire  under the BMA  Patents,  except  as  provided  in
              Section 8.2 below.


                                       7



        8.2   License  Term.  The term of the  License  set  forth in  Section 2
              above, as  distinguished  from the term of this  Agreement,  shall
              commence upon the earlier of (a) BBI's payment pursuant to Section
              1.2(iii) of the Preferred  Stock  Purchase  Agreement  between the
              parties  of even  date,  and (b)  December  31,  1997,  and  shall
              continue on an exclusive basis until the first  commercial sale of
              an Instrument  by BioSeq to a third party  pursuant to a bona fide
              intention   of  BioSeq  to  conduct  a  business   involving   the
              manufacture,  sale and  servicing of  Instruments  in the ordinary
              course of a business,  upon which  occurrence  the  License  shall
              become  non-exclusive  and, upon full payment of any royalties due
              in respect of sales of Services prior to that date, fully paid and
              royalty free.


        8.3.  Termination by BioSeq.  In additional to all other remedies BioSeq
              may have,  BioSeq may  terminate  this  Agreement  and the License
              granted in this  Agreement  in the event that BBI  defaults on any
              payment  to BioSeq and such  default  continues  unremedied  for a
              period of thirty (30) days after BBI  receives  written  notice of
              default from BioSeq;  or BBI fails to perform any of its materials
              obligations, warranties, duties or responsibilities hereunder, and
              such failure continues unremedied for a period of thirty (30) days
              after written notice thereof to BBI by BioSeq.


        8.4.  Termination by BBI. If the claims under the BMA Patents covering a
              Service  are  determined  to be  invalid or  unenforceable  in the
              United  States by any court or tribunal of competent  jurisdiction
              (including a determination in the U.S. Patent and Trademark Office
              that  it not  subject  to  appeal  within  that  Office),  and the
              determination  becomes final in that it is not further  reviewable
              through exhaustion of all permissible application for rehearing or
              review,  or through the  expiration of the time permitted for such
              applications,  BBI may terminate  this Agreement at will and shall
              have no  further  royalty  obligation.  In  addition  to all other
              remedies BBI may have,  BBI may terminate  this  Agreement and the
              License granted in this Agreement tin the event that BMA or BioSeq
              fails to perform  any of its  materials  obligations,  warranties,
              duties or responsibilities  hereunder,  and such failure continues
              unremedied  for a period of thirty (3) days after  written  notice
              thereof by BBI.


        8.5.  BMA  Confirmation  and  Extension.  BMA has joined in the grant of
              License rights to BBI under Section 2 above.  Accordingly,  in the
              event the BMA License  terminates at a time this License Agreement
              is in effect,  such  termination  shall not affect the validity or
              efficacy  of  BBI's  rights  to the  BMA  Patents,  Technology  or
              Instruments, or other rights and privileges granted BBI hereunder;
              and in such event,  if so requested by BBI, BMA shall enter into a
              separate and direct license agreement  extending  directly to


                                       8

              BBI,  without any  involvement  of BioSeq,  all rights,  licenses,
              benefits and privileges granted to BBI hereunder.


9. Miscellaneous

        9.1.  Governing Law; Jurisdiction.  This Agreement shall be governed and
              construed in accordance with the internal laws of the Commonwealth
              of  Massachusetts.  The parties hereto agree to submit to personal
              jurisdiction in the  Commonwealth of  Massachusetts  and to accept
              and agree to venue in that State.


        9.2.  Waiver.  No provision  of the  Agreement  may be waived  except in
              writing  by both  parties  hereto.  No  failure or delay by either
              party hereto in exercising any right or remedy  hereunder or under
              applicable law will operate as a waiver thereof,  or a waiver of a
              particular  right  or  waiver  of  any  right  or  remedy  on  any
              subsequent occasion.


        9.3.  Severability.  It is the  intention  of the parties to comply with
              all  applicable  laws domestic or foreign in  connection  with the
              performance  of their  respective  obligations  hereunder.  In the
              event that any provision of this  Agreement,  or any party hereof,
              is found invalid or unenforceable, the remainder of this Agreement
              will be binding on the parties hereto, and will be construed as if
              the invalid or  unenforceable  provision  or part thereof had been
              deleted,  and the Agreement shall be deemed modified to the extent
              necessary to render the surviving  provisions  enforceable  to the
              fullest extent permitted by law.


        9.4.  Assignment.  BioSeq and BBI may each, without the prior consent of
              the  other,  assign  this  Agreement  to any of  their  respective
              Affiliates and, with the prior written consent of the other, which
              shall not be  unreasonably  withheld,  to any entity  which  shall
              assume all of the assigning  party's  obligations  hereunder.  Any
              purported  assignment is violation of the preceding sentence shall
              be void. The identity of a prospective assignee as an organization
              or  entity  involved  in the  Field  shall  not be a  basis  for a
              reasonable   objection  to  any  assignment   otherwise  permitted
              hereunder.  Any permitted assignee shall assume all obligations of
              its assignor  under this  Agreement.  No assignment  shall relieve
              either party of responsibility  for the performance of any accrued
              obligation which such party than has hereunder.


                                       9


        9.5.  Counterparts.  This Agreement may be executed in duplicate both of
              which  shall be deemed to be  originals,  and both of which  shall
              constitute one and the same Agreement.


        9.6.  Notice. All communications between the parties with respect to any
              of the  provisions of this Agreement will be sent to the addresses
              set out below,  or to other  addresses  as notified by the parties
              for  the  purpose  of  this  clause,  by  prepaid,  registered  or
              certified  air mail which  shall be deemed  received  by the other
              party on the seventh business day following  deposit in the mails,
              or by cable, telex,  facsimile  transmission,  or other electronic
              means of  communication  (which  shall  be  deemed  received  when
              transmitted),  with  confirmation  by letter given by the close of
              business on the next following business day:

         if to BMA, at

                  BioMolecular Assays, Inc.
                  25 Olympia Avenue, Unit #F
                  Woburn, Massachusetts  01801-63070
                  Attention: David J. Green, Chairman

         if to BioSeq, at

                  BioSeq, Inc.
                  25 Olympia Avenue, Unit #F
                  Woburn, Massachusetts  01801-63070
                  Attention: James A. Laugharn, Jr.
                  President and Chief Executive Officer

         with a copy to:

                  Warner & Stackpole LLP
                  75 State Street
                  Boston, Massachusetts  02109
                  Attention: Kenneth S. Boger, Esquire

         if to BBI, at

                  Boston Biomedica, Inc.
                  375 West Street
                  West Bridgewater, Massachusetts  02379
                  Attention: Richard T. Schumacher
                  President and Chief Executive Officer


                                       10


         with a copy to:

                  Brown, Rudnick, Freed & Gesmer, P.C.
                  One Financial Center
                  Boston, Massachusetts  02111
                  Attention: Howard G. Zaharoff, Esquire


        9.7.  Authority.  The  undersigned  represent  that  they are each  duly
              authorized to sign this  Agreement on behalf of the party for whom
              they purport to act.  Each party  represents  that no provision of
              this Agreement will violate the provisions of any other  agreement
              that such  party may have with any other  person or legal  entity.
              Each party has relied on that representation in entering into this
              Agreement


        9.8.  Entire Agreement. This Agreement, including the Schedules appended
              hereto,  contains the entire understanding of the parties relating
              to the matters referred to herein,  and supersedes and mergers all
              prior proposals,  understanding and all other agreements, oral and
              written,  between  the  parties  relating  to the  subject of this
              Agreement

        9.9.  Binding on Successors.  The license granted  hereunder shall inure
              to the  benefit  of and be  binding  upon  BMA,  BioSeq  and  BBI,
              respectively, and their respective successors and assigns.






                             SIGNATURE PAGE FOLLOWS


                                       11


         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed by their duly authorized  representatives  as of the day and year first
above written.


                                     BIOSEQ, INC.


                                     By:  /s/ J. Laugharn
                                        ------------------------------
                                             
                                     Title:  President & CEO
                                           ---------------------------

                                     BOSTON BIOMEDICA, INC.


                                     By:  /s/ Richard T. Schumacher
                                        ------------------------------
                                              Richard T. Schumacher

                                     Title:      President & CEO
                                           ---------------------------
                                                President and CEO


As to its specific obligations hereunder only:

BIOMOLECULAR ASSAYS, INC.


By:  /s/ J. Laugharn
   ----------------------

Title:  President & CEO
      -------------------






                                       12







                                  Schedule 1.2
                              To License Agreement
                     BioSeq, Inc. to Boston Biomedica, Inc.

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

                      BMA Patents and Pending Applications


1.       type     US application
         title    "Controlling Enzymatic Activity"
         date     March 7, 1995

2.       type     US CIP application
         title    "Controlling Enzymatic Activity"
         date     June 7, 1995

3.       type     PCT and US CIP application
         title    "Pressure Cycling Reactor"
         date     March 7, 1996

4.       type     US application
         title    "Pressure Controlled Separation and Purification Process"
         date     scheduled to file by September 1996


                                                                 EXHIBIT 11 

                    BOSTON BIOMEDICA, INC. AND SUBSIDIARIES
              STATEMENT RE COMPUTATION OF PER SHARE EARNINGS 

<TABLE>
<CAPTION>
                                                YEAR ENDED DECEMBER 31,        SIX MONTHS ENDED JUNE 30, 
                                                -----------------------        ------------------------- 
                                             1993        1994        1995         1995          1996 
                                             ----        ----        ----         ----          ---- 
<S>                                        <C>         <C>         <C>          <C>           <C>
WEIGHTED AVERAGE SHARES OUTSTANDING: 
Average common stock outstanding           2,402,534   2,551,946   2,569,641    2,562,399     2,625,241 
Net effect of dilutive common stock 
  equivalents -- based on treasury stock 
  method using average market price           --          --         548,542       --           623,044 
Issuance of "cheap stock"                     35,191      35,191      33,297       35,191         4,358 
                                              ------      ------      ------       ------        ------ 
Weighted average common and common 
  equivalent shares outstanding            2,437,725   2,587,137   3,151,477    2,597,590     3,252,643 
                                           =========   =========   =========    =========     ========= 
ADJUSTED NET INCOME: 
Income before extraordinary item              92,586      96,528     102,990      (36,156)       82,869 
Extraordinary item -- gain on elimination 
  of debt, net of income taxes                49,736      --          --           --            -- 
                                              ------      ------     -------       ------        ------
Net income                                   142,322      96,528     102,990      (36,156)       82,869 
Add: net reduction of interest on debt, less 
  40% taxes based on adjusted treasury stock 
  method                                          --      --          27,258       --            20,894 
                                             -------      ------     -------      -------       -------
Adjusted net income for earnings per share 
  calculation                                142,322      96,528     130,248      (36,156)      103,763 
                                             =======      ======     =======      =======       ======= 
Income (loss) per share                         0.06        0.04        0.04        (0.01)        0.03 
                                                ====        ====        ====        =====         ==== 

                                             1993        1994        1995         1995          1996 
                                             ----        ----        ----         ----          ---- 

SUPPLEMENTARY EARNINGS PER SHARE DATA: (1)

Weighted average common and common 
  equivalent shares outstanding                                    3,151,477                  3,252,643 

Additional shares to retire debt                                     448,530                    448,530
                                                                   ---------                  ---------
Pro forma shares outstanding                                       3,600,007                  3,701,173
                                                                   =========                  =========
Adjusted net income for earnings per share 
  calculation                                                        130,248                    103,763

Add: interest expense, net of tax benefit                            201,539                    101,081
                                                                   ---------                  ---------
Pro forma adjusted net income for
  earnings per share calculation                                     331,787                    204,844
                                                                   =========                  ========= 
Pro forma income per share                                              0.09                       0.06
                                                                        ====                       ==== 

(1) The pro forma income per share assumes the Offering issues only shares sufficient to retire all outstanding
    debt as of January 1, 1995, thereby causing interest expense to be added back to net income, net of tax benefits
    using a 40% combined federal and state tax rate.
</TABLE>


                                                                    EXHIBIT 23.2

                    CONSENT OF INDEPENDENT ACCOUNTANTS


    We consent to the  inclusion  in this  Amendment  No. 1 to the  Registration
Statement on Form S-1 (File No.  333-10759) of our reports dated March 12, 1996,
except as to the  information  in the first  paragraph of Note 11, for which the
date is  September  10,  1996 on our  audits  of the  financial  statements  and
financial statement schedule of Boston Biomedica, Inc. and Subsidiaries. We also
consent to the references to our firm under the captions "Selected  Consolidated
Financial Data" and "Experts."


                                            COOPERS & LYBRAND L.L.P.


Boston, Massachusetts
October 8, 1996


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