EPITOPE INC/OR/
8-K, 2000-05-10
IN VITRO & IN VIVO DIAGNOSTIC SUBSTANCES
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                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

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

                                    FORM 8-K

                                 CURRENT REPORT

                       Pursuant to Section 13 or 15(d) of
                       the Securities Exchange Act of 1934

                Date of Report (Date of earliest event reported):

                                   May 6, 2000

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


                                  EPITOPE, INC.
             (Exact name of Registrant as specified in its charter)

<TABLE>
<S>                                       <C>                          <C>
            OREGON                          1-10492                        93-0779127
 (State or other jurisdiction             (Commission                    (IRS Employer
     of incorporation)                      File No.)                  Identification No.)
</TABLE>

                             8505 SW Creekside Place
               Beaverton, Oregon                        97008-7108
               (Address of principal executive offices) (Zip code)

                                 (503) 641-6115
              (Registrant's telephone number, including area code)


<PAGE>


Item 5.        Other Events.

On May 8, 2000, Epitope, Inc. announced that the company had signed a definitive
merger  agreement  dated as of May 6,  2000,  with  STC  Technologies,  Inc.,  a
privately-held company based in Bethlehem,  Pennsylvania. The agreement has been
approved by the board of  directors of each  company,  and is subject to typical
terms and conditions,  including a vote of Epitope and STC shareholders expected
to take place in August 2000.

STC develops,  manufactures and markets proprietary in vitro diagnostic products
and  medical  devices for use in clinical  laboratories,  physician  offices and
workplace  testing.  STC is the  leading  supplier  of oral fluid  assays to the
insurance risk assessment testing market and also manufactures and markets other
substance-abuse testing products.

Under the terms of the agreement,  STC shareholders  will receive Epitope common
stock in the  merger.  The total  number of Epitope  shares to be issued will be
based on the average closing price of Epitope common stock over a 20 trading-day
period prior to the completion of the merger. It is estimated that Epitope would
issue a total of 20 million  shares to holders  of STC shares and  options,  and
that Epitope shareholders would own, on a fully diluted basis,  approximately 50
percent  of the  shares  of the  combined  company  at the  time the  merger  is
effected.

The actual  number of shares to be issued in the merger  will be  determined  as
follows:  (i) 25 million shares if the average Epitope stock price is between $6
and $8 per share,  (ii) Epitope stock worth $200 million if the average  Epitope
stock  price is  between $8 and $10 per  share,  (iii) 20 million  shares if the
average  Epitope stock price is between $10 and $13 per share,  and (iv) Epitope
stock  worth $260  million if the average  Epitope  stock price is above $13 per
share.

On a proforma  basis,  the new  company  will have close to $20 million in cash,
trailing  12-month  revenues of $26.3 million,  a gross margin of 65%, and a net
loss of $4.1 million.  Combining operations is expected to result in at least $2
million in savings due to cost  synergies  from the  consolidation  of duplicate
overhead  and  consolidation  of certain  manufacturing  operations.  For the 12
months ended March 31, 2000, STC  Technologies  posted revenues of $14.8 million
and a net loss of $1.0 million.

The  merger  will be tax  free to the  shareholders  of  both  companies  and is
expected to be accounted for as a pooling of interests.

Holders of  approximately  52 percent of the  outstanding  STC shares have given
irrevocable proxies to vote in favor of the merger.

This  report  contains  forward-looking  statements.  Actual  results  could  be
significantly  different.  Factors  that  could  affect  results  include  those
relating  to  the  proposed  merger,   including  failure  to  achieve  expected
synergies,  failure to obtain required regulatory or shareholder  approval,  and
unexpected  liabilities resulting from the two companies' operations prior to or
after the merger occurs. Other factors that could affect results include loss of
key personnel; failure to comply with regulations of the FDA or other regulatory
agencies;  obstacles to international  marketing of


<PAGE>

products;  loss or impairment of sources of capital;  ability to develop product
distribution channels; ability to develop new products; development of competing
products;  market  acceptance  of oral fluid  testing  products;  and changes in
international,  federal or state laws or regulations.  Although  forward-looking
statements help to provide complete information about future prospects,  readers
should keep in mind that forward-looking  statements are much less reliable than
historical  information.  Readers are cautioned  not to place undue  reliance on
forward-looking  statements,  and are  encouraged  to  review  the risk  factors
discussed  in  Epitope's  Annual  Report on Form 10-K for the fiscal  year ended
September 30, 1999.

ADDITIONAL INFORMATION AND WHERE TO FIND IT:

Epitope  plans to file a  Registration  Statement on SEC Form S-4 in  connection
with the merger  and to mail a Proxy  Statement/Prospectus  to  Epitope  and STC
shareholders  containing  information  about the merger.  Investors and security
holders   are  urged  to  read  the   Registration   Statement   and  the  Proxy
Statement/Prospectus   carefully  when  they  are  available.  The  Registration
Statement and the Proxy  Statement/Prospectus will contain important information
about  Epitope,  STC,  the merger and related  matters.  Investors  and security
holders  will be able to obtain free copies of these  documents  through the web
site   maintained   by  the  U.S.   Securities   and  Exchange   Commission   at
http//www.sec.gov.

Epitope files annual,  quarterly and special reports, proxy statements and other
information with the Securities and Exchange  Commission.  You may read and copy
any reports, statements and other information filed by Epitope at the SEC public
reference  rooms  at 450  Fifth  St.,  N.W.,  Washington,  D.C.  20549 or at the
Commission's  other public reference rooms in New York and Chicago.  Please call
the  Commission at  800/SEC-0330  for further  information  on public  reference
rooms. Copies of Epitope's filings with the Commission also are available to the
public from commercial  document-retrieval services and may be obtained for free
at the web site maintained by the Commission at http//www.sec.gov, or by writing
Epitope at: Epitope  Investor  Relations,  8505 SW Creekside  Place,  Beaverton,
Oregon 97008.

Epitope, its directors, executive officers and certain members of management and
employees may be soliciting  proxies from Epitope  shareholders  in favor of the
approval of the merger  agreement.  A description  of any  interests,  direct or
indirect,  that  Epitope's  directors and executive  officers have in the merger
will be included in the Proxy Statement/Prospectus.

Item 7. Financial Statements, Pro Forma Financial Information and Exhibits.

               (a)    Not applicable.

               (b)    Not applicable.

               (c)    Exhibits.

The  exhibits  filed  herewith  are listed in the exhibit  index  following  the
signature page of this report.



<PAGE>


                                   SIGNATURES

Pursuant  to the  requirements  of the  Securities  Exchange  Act of  1934,  the
Registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned hereunto duly authorized.

                                            EPITOPE, INC.


Dated:  May 9, 2000                         By: /s/ Charles E. Bergeron
                                            Charles E. Bergeron
                                            Chief Financial Officer


<PAGE>


                                  EXHIBIT INDEX

2       Agreement  and Plan of Merger dated as of May 6, 2000,  by and among the
        registrant, STC Technologies, Inc., and Edward Merger Subsidiary, Inc.

99      Press release dated May 8, 2000










                          AGREEMENT AND PLAN OF MERGER

                                   DATED AS OF

                                   MAY 6, 2000

                                      AMONG

                                  EPITOPE, INC.

                         EDWARD MERGER SUBSIDIARY, INC.

                                       AND

                             STC TECHNOLOGIES, INC.



<PAGE>

                                Table of Contents

<TABLE>
                                                                                          Page

<S>                                                                                         <C>
ARTICLE I  DEFINITIONS.......................................................................2

ARTICLE II  THE MERGERS......................................................................2
Section 2.1.  STC MERGER.....................................................................2
Section 2.2.  EPITOPE MERGER.................................................................7
Section 2.3.  Exchange of Certificates......................................................10
Section 2.4.  Affiliates....................................................................12

ARTICLE III  REPRESENTATIONS AND WARRANTIES OF EPITOPE......................................12
Section 3.1.  Corporate Existence and Power.................................................12
Section 3.2.  Corporate Authorization.......................................................13
Section 3.3.  Governmental Authorization....................................................13
Section 3.4.  Non-Contravention.............................................................13
Section 3.5.  Capitalization................................................................14
Section 3.6.  Subsidiaries..................................................................14
Section 3.7.  Epitope SEC Documents.........................................................15
Section 3.8.  Financial Statements; No Material Undisclosed ..................................
                  Liabilities...............................................................15
Section 3.9.  Information to be Supplied....................................................16
Section 3.10.  Absence of Certain Changes...................................................16
Section 3.11.  Litigation...................................................................17
Section 3.12.  Taxes........................................................................17
Section 3.13.  Employee Benefits............................................................18
Section 3.14.  Compliance with Laws; Licenses, Permits and
                         Registrations......................................................19
Section 3.15.  Title to Properties..........................................................20
Section 3.16.  Intellectual Property........................................................20
Section 3.17.  Environmental Matters........................................................21
Section 3.18.  Finders' Fees; Opinions of Financial Advisor.................................22
Section 3.19.  Required Vote; Board Approval................................................22
Section 3.20.  State Takeover Statutes......................................................23
Section 3.21.  Pooling Matters; Tax Treatment...............................................23
Section 3.22.  Certain Agreements...........................................................23
Section 3.23.  Epitope Rights Agreement.....................................................24
Section 3.24.  Employment Agreements........................................................24
Section 3.25.  Transactions With Directors, Officers
                  AND AFFILIATES............................................................24
Section 3.26.  Material Contracts...........................................................24
Section 3.27.  Certain Business Practices...................................................25
Section 3.28.  Insurance....................................................................26
Section 3.29.  Product Information..........................................................26
Section 3.30.  Product Liability Claims.....................................................27

ARTICLE IV  REPRESENTATIONS AND WARRANTIES OF STC...........................................27
Section 4.1.  Corporate Existence and Power.................................................27
Section 4.2.  Corporate Authorization.......................................................28
Section 4.3.  Governmental Authorization....................................................28
Section 4.4.  Non-Contravention.............................................................28
Section 4.5.  Capitalization................................................................29
Section 4.6.  Subsidiaries..................................................................29
Section 4.7.  Financial Statements; No Material Undisclosed
                  Liabilities...............................................................29
Section 4.8.  Information to be Supplied....................................................30
Section 4.9.  Absence of Certain Changes....................................................30
Section 4.10.  Litigation...................................................................31
Section 4.11.  Taxes........................................................................31
Section 4.12.  Employee Benefits............................................................32
Section 4.13.  Compliance with Laws; Licenses, Permits and
                   Registrations............................................................33
Section 4.14.  Title to Properties..........................................................33
Section 4.15.  Intellectual Property........................................................34
Section 4.16.  Environmental Matters........................................................35
Section 4.17.  Finders' Fees; Opinions of Financial Advisor.................................36
Section 4.18.  Required Vote and Waiver; Board Approval.....................................36
Section 4.19.  State Takeover Statutes......................................................36
Section 4.20.  Pooling Matters; Tax Treatment...............................................37
Section 4.21.  Certain Agreements...........................................................37
Section 4.22.  Employment Agreements........................................................37
Section 4.23.  Transactions With Directors, Officers and
                    Affiliates..............................................................37
Section 4.24.  Material Contracts...........................................................38
Section 4.25.  Certain Business Practices...................................................39
Section 4.26.  Insurance....................................................................39
Section 4.27.  Product Information..........................................................39
Section 4.28.  Product Liability Claims.....................................................40

ARTICLE V  REPRESENTATIONS AND WARRANTIES OF MERGER SUB.....................................40
Section 5.1.  Organization..................................................................40
Section 5.2.  Corporate Authorization.......................................................41
Section 5.3.  Non-Contravention.............................................................41
Section 5.4.  No Business Activities........................................................41
Section 5.5.  Taxes.........................................................................41

ARTICLE VI  COVENANTS OF EPITOPE............................................................41
Section 6.1.  Epitope Interim Operations....................................................41
Section 6.2.  Acquisition Proposals; Board Recommendation...................................44

ARTICLE VII  COVENANTS OF STC...............................................................46
Section 7.1.  STC Interim Operations........................................................46
Section 7.2.  Acquisition Proposals; Board Recommendation...................................48

ARTICLE VIII  COVENANTS OF STC AND EPITOPE..................................................49
Section 8.1.  Reasonable Best Efforts.......................................................49
Section 8.2.  Certain Filings; Cooperation in Receipt of Consents;
                  Listing...................................................................49
Section 8.3.  Headquarters..................................................................51
Section 8.4.  Public Announcements..........................................................51
Section 8.5.  Access to Information; Notification of Certain
                  Matters...................................................................51
Section 8.6.  Further Assurances............................................................52
Section 8.7.  Tax and Accounting Treatment..................................................52
Section 8.8.  Affiliates....................................................................53
Section 8.9.  Confidentiality...............................................................53
Section 8.10.  Benefit Matters..............................................................55
Section 8.11.  Antitrust Matters............................................................55
Section 8.12.  Exemption From Liability Under Section 16(b).................................56
Section 8.13.  Indemnification and Insurance................................................57

ARTICLE IX  CONDITIONS TO THE MERGER........................................................58
Section 9.1.  Conditions to the Obligations of Each Party...................................58
Section 9.2.  Conditions to the Obligations of Epitope and
                     Merger Sub.............................................................59
Section 9.3.  Conditions to the Obligations of STC..........................................60

ARTICLE X  TERMINATION......................................................................61
Section 10.1.  Termination..................................................................61
Section 10.2.  Effect of Termination........................................................63
Section 10.3.  Fees and Expenses............................................................64

ARTICLE XI  MISCELLANEOUS...................................................................64
Section 11.1.  Notices......................................................................64
Section 11.2.  Survival of Representations, Warranties and
                   Covenants After the Effective Time.......................................65
Section 11.3.  Amendments; No Waivers.......................................................66
Section 11.4.  Assignment...................................................................66
Section 11.5.  Governing Law................................................................66
Section 11.6.  Counterparts; Effectiveness..................................................66
Section 11.7.  No Third Party Beneficiaries.................................................66
Section 11.8.  Interpretation...............................................................66
Section 11.9.  Enforcement..................................................................67
Section 11.10.  Entire Agreement............................................................67
Section 11.11.  Severability................................................................67
</TABLE>

<PAGE>

APPENDICES

Appendix I -   Definitions


EXHIBITS

Exhibit A -    Epitope Stockholders Agreement
Exhibit B -    STC Stockholders Agreement
Exhibit C -    Certificate of Merger for STC Merger
Exhibit D -    Articles of Merger for Epitope Merger
Exhibit E -    Certificate of Merger for Epitope Merger
Exhibit F -    Certificate of Incorporation of Merger Sub
Exhibit G -    Bylaws of Merger Sub
Exhibit H -    Principal Officers of Surviving Corporation
Exhibit I -    Epitope Representation Letter
Exhibit J -    STC Representation Letter
Exhibit K -    Form of STC Affiliate Agreement
Exhibit L -    Form of Epitope Affiliate Agreement
Exhibit M -    Indemnification Agreements
Exhibit N -    List of Employees
Exhibit O -    Merger Sub Representation Letter

<PAGE>

                          AGREEMENT AND PLAN OF MERGER

        AGREEMENT AND PLAN OF MERGER, dated as of May 6, 2000 (the "Agreement"),
by and among Epitope,  Inc., an Oregon  corporation  ("Epitope"),  Edward Merger
Subsidiary,  Inc.,  a Delaware  corporation  and a  wholly-owned  subsidiary  of
Epitope  ("Merger  Sub") and SdTC  Technologies,  Inc.,  a Delaware  corporation
("STC").

                                    RECITALS:

        WHEREAS,  the Boards of  Directors  of Epitope and STC deem it advisable
and in the best interests of each  corporation  and its respective  stockholders
that  Epitope  and STC  engage  in a  business  combination  as peer  firms in a
combination  of equals in order to  advance  the  long-term  strategic  business
interests of Epitope and STC;

        WHEREAS,  the  combination  of Epitope  and STC shall be effected by the
terms of this Agreement through the mergers as outlined below;

        WHEREAS,  the respective  Boards of Directors of STC and Merger Sub have
each (i)  determined  that the merger of STC with and into  Merger Sub (the "STC
Merger") is fair to, and in the best  interests of, their  respective  companies
and  stockholders,  (ii) have  approved and declared  the  advisability  of this
Agreement and (ii) have approved the STC Merger,  and (iii) have recommended the
approval  and  adoption  of  this  Agreement  by  their   respective   company's
stockholders;

        WHEREAS,  the  respective  Boards of Directors of Epitope and Merger Sub
have each (i)  determined  that the merger of Epitope  with and into  Merger Sub
(the  "Epitope  Merger";  the Epitope  Merger and the STC Merger are referred to
collectively  as the  "Mergers") is fair to, and in the best interests of, their
respective  companies  and  stockholders,  (ii) have  approved  and declared the
advisability  of  this  Agreement  and  the  Epitope  Merger,   and  (iii)  have
recommended  the  approval and  adoption of this  Agreement by their  respective
company's stockholders;

        WHEREAS,  for Federal  income tax purposes,  it is intended that each of
the  Mergers  shall  qualify as a  reorganization  within the meaning of Section
368(a)  of  the   Internal   Revenue   Code  of  1986,   as   amended   (a  "368
Reorganization"), and the regulations promulgated thereunder;

        WHEREAS,  for  accounting  purposes,  it is  intended  that  each of the
Mergers  shall be  accounted  for as a pooling of  interests  transaction  under
United States generally accepted  accounting  principles applied on a consistent
basis ("GAAP"); and

        WHEREAS,   simultaneously  with  the  execution  and  delivery  of  this
Agreement:  (i) STC  has  entered  into  an  agreement  (the  "STC  Stockholders
Agreement") with certain  stockholders of Epitope pursuant to which such Epitope
stockholders  have  agreed to vote the shares of Epitope  Common  Stock owned by
them in favor of the Epitope Merger under certain circumstances, which agreement
is  accompanied  by  irrevocable  proxies  to vote  such  shares  in  accordance
therewith;  and  (ii)  Epitope  has  entered  into an  agreement  (the  "Epitope
Stockholders Agreement" and, together with the STC Stockholders  Agreement,  the
"Stockholders  Agreements," in the respective forms attached as Exhibits A and B
hereto) with certain stockholders of STC pursuant to which such STC stockholders
have agreed to vote the shares of STC Common Stock owned


<PAGE>

by them in favor of the STC Merger under certain circumstances,  which agreement
is  accompanied  by  irrevocable  proxies  to vote  such  shares  in  accordance
therewith.

        NOW, THEREFORE, in consideration of the premises, which are incorporated
into  and  made  part  of this  Agreement,  and of the  mutual  representations,
warranties,  covenants, agreements and conditions set forth herein and for other
good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereby agree as follows:

                                    ARTICLE I

                                   DEFINITIONS

        For  purposes  of this  Agreement,  the  capitalized  terms used in this
Agreement shall have the meanings  specified or referred to in Appendix I hereto
which is incorporated herein by reference.

                                   ARTICLE II

                                   THE MERGERS

        SECTION 2.1. STC Merger.

             (a) The STC Merger. Upon the terms and subject to the conditions of
        this Agreement and in accordance with the Delaware  General  Corporation
        Law of the State of Delaware (the "Delaware  Law"), at the STC Effective
        Time (as defined  below),  STC shall be merged with and into Merger Sub.
        As a result of the STC Merger, the separate  corporate  existence of STC
        shall cease and Merger Sub shall  continue as the surviving  corporation
        of the STC Merger (the "Surviving Corporation").

             (b) STC Effective Time. As soon as practicable after the Closing of
        the STC  Merger,  the  Certificate  of Merger for the STC  Merger  ("STC
        Certificate of Merger"),  in  substantially  the form attached hereto as
        Exhibit  C,  prepared  and  executed  in  accordance  with the  relevant
        provisions  of the Delaware  Law,  shall be filed with the  Secretary of
        State of  Delaware.  The parties  hereto  agree to take all such further
        actions  as may be  required  by law to make the Merger  effective.  The
        Merger  shall  become  effective  in  accordance  with the terms of this
        Agreement,   the  STC  Certificate  of  Merger  at  the  time  and  date
        contemplated therein (such time and date being referred to herein as the
        "STC Effective Time").

             (c) The  Closing.  The  Closing  of the  Mergers  and  transactions
        contemplated  by this  Agreement will take place at 11:00 a.m. on a date
        mutually agreed upon by the parties hereto, which shall be no later than
        the third Business Day following the date on which all of the conditions
        to the  obligations  of the parties  hereunder set forth in Article VIII
        hereof have been  satisfied or waived.  The place of Closing shall be at
        such place as may be mutually agreed upon by the parties hereto.

             (d) Effects of the STC Merger. At and after the STC Effective Time,
        the STC Merger  will have the  effects  set forth in the  Delaware  Law.
        Without limiting the

                                      -2-
<PAGE>

        generality of the foregoing,  and subject thereto, at the Effective Time
        all the property,  rights,  privileges,  powers and franchises of Merger
        Sub and STC shall be vested in the Surviving Corporation, and all debts,
        liabilities  and  duties of Merger  Sub and STC shall  become the debts,
        liabilities and duties of the Surviving  Corporation.  In addition,  the
        STC Merger shall have the following effects:

                 (i) Articles of Incorporation. The Certificate of Incorporation
             of Merger Sub as in effect as of the date  hereof  shall be amended
             to change the name of Merger Sub to OraSure Technologies, Inc., but
             otherwise shall read as set forth in Exhibit F and such Certificate
             of  Incorporation,  as so  amended,  shall  be the  Certificate  of
             Incorporation of the Surviving Corporation (as set forth in Exhibit
             F  hereto)  and  the  Certificate  of  Incorporation  shall  be the
             Certificate of Incorporation of the Surviving Corporation.

                 (ii)  Bylaws.  The  Bylaws of Merger Sub as in effect as of the
             date hereof  shall be amended to reflect the change of Merger Sub's
             name to OraSure Technologies, Inc., but otherwise shall read as set
             forth in Exhibit G and shall,  as so amended,  be the Bylaws of the
             Surviving Corporation.

                 (iii) Board of Directors.  At the STC Effective Time, the Board
             of Directors of the  Surviving  Corporation  shall consist of seven
             (7) persons. Of the seven persons initially elected to the Board of
             Directors  of  the  Surviving  Corporation,  three  (3)  (the  "STC
             Designees") shall be persons named by the Board of Directors of STC
             and three (3) (the "Epitope  Designees")  shall be persons named by
             the Board of  Directors  of  Epitope  and one (1) shall be a person
             mutually  acceptable  to both the  Boards of  Directors  of STC and
             Epitope. The Board of Directors of the Surviving  Corporation shall
             be divided into three classes,  with the initial terms of office of
             the first,  second and third classes expiring at the first,  second
             and third  annual  meetings of the  stockholders  of the  Surviving
             Corporation,   respectively.  One  STC  Designee  and  one  Epitope
             Designee shall be placed in each class of the Board of Directors of
             the Surviving Corporation. If, prior to the STC Effective Time, (i)
             any of the  individuals  named  by STC or  Epitope  to serve on the
             Board of Directors of the Surviving  Corporation  following the STC
             Effective Time resigns,  retires or otherwise  ceases to serve as a
             director  of STC or  Epitope,  as the  case  may be,  or  otherwise
             becomes unable or unwilling to serve as a director of the Surviving
             Corporation,  or (ii) STC or Epitope shall  determine to replace an
             individual  named by such party to serve on the Board of  Directors
             of the  Surviving  Corporation,  the  party  that  designated  such
             individual  may name a  replacement  to  become a  director  of the
             Surviving Corporation. The persons named as members of the Board of
             Directors  of the  Surviving  Corporation  pursuant to this Section
             2.1.(d)(iii) shall be named in the Joint Proxy Statement/Prospectus
             and the Registration  Statement,  subject to receipt of the consent
             of such individuals to be so named.

                 (iv)  Management.  The  principal  officers  of  the  Surviving
             Corporation  at the Effective Time shall be as listed on Exhibit H.
             All other management

                                       -3-
<PAGE>

             positions of the Surviving  Corporation shall be determined jointly
             by  the  Surviving  Corporation's  President  and  Chief  Executive
             Officer.

             (e) Effect on Capital Stock.  At the STC Effective  Time, by virtue
        of the STC Merger  and  without  any  action on the part of the  parties
        hereto or their respective stockholders:

                 (i)  STC  Common   Stock.   Each  share  of  STC  Common  Stock
             outstanding immediately prior to the STC Effective Time (except for
             shares of STC Common  Stock  held by persons  who object to the STC
             Merger  and  comply  with  all   provisions  of  the  Delaware  Law
             concerning the right of such holders to dissent from the STC Merger
             and demand  appraisal for their shares) shall be converted into and
             become shares of Surviving  Corporation Common Stock at an exchange
             ratio (the "Exchange  Ratio")  determined as follows (together with
             any cash in lieu of  fractional  shares  of  Surviving  Corporation
             Common Stock to be paid pursuant to Section 2.1(e)(iv) (the "Merger
             Consideration")  which fraction of a share shall be rounded to four
             decimal places):

                     (A) If the  Average  Epitope  Stock  Price is greater  than
                 $13.00,  the  Exchange  Ratio shall be the  quotient of (i) the
                 quotient of (x) $260 million divided by (y) the Average Epitope
                 Stock Price, divided by (ii) the sum of the number of shares of
                 STC  Common  Stock  outstanding  immediately  prior  to the STC
                 Effective  Time and the  number of shares of STC  Common  Stock
                 underlying STC Common Stock Equivalents; or

                     (B) If the Average  Epitope Stock Price is equal to or less
                 than  $13.00,  but equal to or more than  $10.00,  the Exchange
                 Ratio shall be the quotient of 20 million shares divided by the
                 sum of the  number of shares of STC  Common  Stock  outstanding
                 immediately  prior to the STC Effective  Time and the number of
                 shares  of  STC  Common  Stock   underlying  STC  Common  Stock
                 Equivalents; or

                     (C) If the Average Epitope Stock Price is less than $10.00,
                 the Exchange Ratio shall be the quotient of (i) the quotient of
                 (x) $200  million  divided  by (y) the  Average  Epitope  Stock
                 Price,  divided  by (ii) the sum of the number of shares of STC
                 Common Stock outstanding immediately prior to the STC Effective
                 Time and the  number of shares of STC Common  Stock  underlying
                 STC Common Stock  Equivalents;  provided  however,  that in the
                 event the quotient in clause (i) of this subsection (C) exceeds
                 25  million  shares,  such  quotient  shall be  deemed to be 25
                 million shares for the purposes of completing  the  calculation
                 set forth in this subsection (C), and; provided  further,  that
                 in the event that the Average  Epitope Stock Price is less than
                 $6.00,  STC  shall  have the  termination  rights  provided  in
                 Section 10.1(h).

                 (ii) STC Stock  held by Merger  Sub and STC.  Each share of STC
             Common Stock or STC Preferred  Stock held by STC as treasury  stock
             or owned

                                      -4-
<PAGE>

             by Merger Sub immediately  prior to the STC Effective Time shall be
             cancelled without payment of any  consideration  therefor and shall
             cease to exist.

                 (iii)  Merger Sub Common  Stock.  Each share of common stock of
             Merger Sub outstanding and each share held in treasury  immediately
             prior to the STC Effective  Time shall be converted into and become
             one share of Surviving Corporation Common Stock.

                 (iv)  Fractional  Shares.  No fraction of a share of  Surviving
             Corporation  Common  Stock shall be issued in  connection  with the
             conversion   of  STC  Common  Stock  in  the  STC  Merger  and  the
             distribution  of  Surviving  Corporation  Common  Stock in  respect
             thereof,  but in lieu of such  fraction,  the Exchange  Agent shall
             make a cash payment (without interest and subject to the payment of
             any applicable withholding Taxes) equal to the same fraction of the
             market value of a full share of Surviving Corporation Common Stock,
             computed on the basis of the mean of the high and low sales  prices
             of Surviving  Corporation Common Stock as reported on NASDAQ on the
             first  full  day on which  Surviving  Corporation  Common  Stock is
             traded on the Nasdaq Stock Market after the STC Effective Time.

             (f) Stock Options and Other Stock Compensation.

                 (i) On or prior to the STC  Effective  Time,  STC will take all
             action necessary such that each stock option or other stock related
             right  or  other  form  of  stock  related  incentive  or  deferred
             compensation  that was granted  pursuant to the STC Employee  Plans
             (as defined in Section 4.12(a)) prior to the STC Effective Time and
             which remains  outstanding  immediately  prior to the STC Effective
             Time shall cease to represent a right with respect to shares of STC
             Common Stock and shall be  converted,  at the STC  Effective  Time,
             into a right,  on the same terms and conditions as were  applicable
             under such stock option or other stock  related right or other form
             of stock related incentive or deferred compensation,  as applicable
             (but taking into  account any changes  thereto  (except  that there
             shall be no acceleration in the vesting or  exercisability  of such
             option,   right  or  incentive   compensation  by  reason  of  this
             Agreement,  the STC Merger, the Epitope Merger or the other matters
             contemplated by this  Agreement),  provided for in the STC Employee
             Plans or in the terms of such right by reason of this  Agreement or
             the transactions  contemplated hereby), with respect to that number
             of shares of  Surviving  Corporation  Common  Stock  determined  by
             multiplying  the  number of shares of STC Common  Stock  subject to
             such stock  option or other  stock  related  right or other form of
             stock related incentive or deferred compensation, as applicable, by
             the Exchange  Ratio,  rounded,  if necessary,  to the nearest whole
             share of Surviving  Corporation  Common Stock, at (in the case of a
             stock  option  or  stock  appreciation  right)  a price  per  share
             (rounded  to the  nearest  one-hundredth  of a cent)  equal  to the
             per-share  exercise  price  specified in such stock option or stock
             appreciation  right, as applicable,  divided by the Exchange Ratio;
             provided,  however,  that in the case of any stock  option to which
             Section  421 of the Code  applies  by reason  of its  qualification
             under  Section  422 of the Code,  the

                                      -5-
<PAGE>

             option price,  the number of shares  subject to such option and the
             terms and conditions of exercise of such option shall be determined
             in a manner  consistent with the  requirements of Section 424(a) of
             the Code.

                 (ii) As soon as practicable  after the STC Effective  Time, the
             Surviving Corporation shall deliver to the holders of stock options
             or other  stock  related  rights  or other  forms of stock  related
             incentive  or deferred  compensation  appropriate  notices  setting
             forth such  holders'  rights  pursuant  to the STC  Employee  Plans
             (except  that  there  shall be no  acceleration  in the  vesting or
             exercisability of such option,  right or incentive  compensation by
             reason of this Agreement, the STC Merger, the Epitope Merger or the
             other matters  contemplated  by this  Agreement) and the agreements
             evidencing  the grants of such stock options or other stock related
             rights  or other  forms  of stock  related  incentive  or  deferred
             compensation  shall  continue  in  effect  on the  same  terms  and
             conditions  (subject to the  adjustments  required by this  Section
             2.1(f)(ii)  after  giving  effect to the STC Merger and the Epitope
             Merger and the terms of the STC Employee  Plans  (except that there
             shall be no acceleration in the vesting or  exercisability  of such
             option,   right  or  incentive   compensation  by  reason  of  this
             Agreement,  the STC Merger, the Epitope Merger or the other matters
             contemplated by this  Agreement)).  To the extent permitted by law,
             the  Surviving  Corporation  shall comply with the terms of the STC
             Employee  Plans  and  shall  take  such  reasonable  steps  as  are
             necessary  or required by, and subject to the  provisions  of, such
             STC Employee  Plans,  to have the stock options which  qualified as
             incentive  stock options  prior to the  Effective  Time continue to
             qualify as incentive  stock  options of the  Surviving  Corporation
             after the Effective Time.

                 (iii) The Surviving Corporation shall take all corporate action
             necessary to reserve for issuance a sufficient  number of shares of
             Surviving  Corporation  Common Stock for delivery  upon exercise of
             stock options or other stock related rights or other forms of stock
             related incentive or deferred  compensation in accordance with this
             Section  2.1(f).   Promptly  after  the  STC  Effective  Time,  the
             Surviving  Corporation shall file a registration  statement on Form
             S-3 or Form  S-8,  as the  case may be (or any  successor  or other
             appropriate  forms),  with  respect  to  the  shares  of  Surviving
             Corporation  Common  Stock  subject to such stock  options or other
             stock related  rights or other forms of stock related  incentive or
             deferred  compensation,   and  shall  use  commercially  reasonable
             efforts  to  maintain  the   effectiveness  of  such   registration
             statement  or  registration  statements  (and  maintain the current
             status of the prospectus or prospectuses  contained therein) for so
             long as such stock options or other stock  related  rights or other
             forms of stock related  incentive or deferred  compensation  remain
             outstanding.  With respect to those  individuals  who subsequent to
             the Mergers  will be subject to the  reporting  requirements  under
             Section 16(a) of the Exchange Act, where applicable,  the Surviving
             Corporation  shall  administer  the STC Employee  Plans in a manner
             consistent with the exemptions  provided by Rule 16b-3  promulgated
             under the Exchange Act.

                                      -6-
<PAGE>

             (g) Certain Adjustments. If, between the date of this Agreement and
        the Effective  Time, the  outstanding STC Common Stock or Epitope Common
        Stock  shall  have been  changed  into a  different  number of shares or
        different  class by  reason of any  reclassification,  recapitalization,
        stock split, reverse stock split,  combination or exchange of shares, or
        a stock dividend or dividend  payable in any other  securities  shall be
        declared  with a record date within such  period,  or any similar  event
        shall have  occurred,  the  Exchange  Ratio shall each be  appropriately
        adjusted to provide to the holders of STC Common Stock the same economic
        effect as contemplated by this Agreement prior to such event.

             (h) Appraisal Rights. Notwithstanding Section 2.1(e), shares of STC
        Common Stock outstanding immediately prior to the STC Effective Time and
        held by a holder who has not voted in favor of the Mergers or  consented
        thereto in writing and who has demanded appraisal for such shares of STC
        Common Stock,  as the case may be, in  accordance  with the Delaware Law
        shall not be converted into the shares of Surviving  Corporation  Common
        Stock  unless such holder  fails to perfect or  withdraws  or  otherwise
        loses  his right to  appraisal.  If after  the STC  Effective  Time such
        holder fails to perfect or  withdraws  or loses his right to  appraisal,
        such  shares of STC  Common  Stock  shall be treated as if they had been
        converted  as of the STC  Effective  Time into the  shares of  Surviving
        Corporation  Common Stock in accordance with Section  2.1(e).  STC shall
        give the Surviving  Corporation prompt notice of any demands received by
        STC for  appraisal  of shares of STC  Common  Stock,  and the  Surviving
        Corporation  shall have the right to participate in all negotiations and
        proceedings with respect to such demands. STC shall not, except with the
        prior  written  consent of the Surviving  Corporation,  make any payment
        with respect to, or settle or offer to settle, any such demands.

        SECTION 2.2. Epitope Merger.

             (a)  The  Epitope  Merger.  Upon  the  terms  and  subject  to  the
        conditions  of  this  Agreement  and in  accordance  with  the  Business
        Corporation  Act of the  State of Oregon  (the  "Oregon  Law"),  and the
        Delaware General Corporation Law of the State of Delaware (the "Delaware
        Law"), at the Epitope Effective Time (as defined below),  which shall be
        immediately  following the STC Effective  Time,  Epitope shall be merged
        with and into  Merger  Sub.  As a result  of the  Merger,  the  separate
        corporate existence of Epitope shall cease and Merger Sub shall continue
        as the  surviving  corporation  of the Epitope  Merger  (the  "Surviving
        Corporation").

             (b)  Epitope  Effective  Time.  As soon as  practicable  after  the
        Closing of the Mergers, the Articles of Merger for the Epitope Merger in
        substantially  the form  attached  hereto as  Exhibit  D,  prepared  and
        executed in accordance  with the relevant  provisions of the Oregon Law,
        shall  be  filed  with  the  Secretary  of  State  of  Oregon,  and  the
        Certificate of Merger for the Epitope Merger,  in substantially the form
        attached  hereto as Exhibit E, prepared and executed in accordance  with
        the relevant  provisions  of the Delaware  Law,  shall be filed with the
        Secretary  of State of  Delaware.  The parties  hereto agree to take all
        such  further  actions  as may be  required  by law to make the  Epitope
        Merger   effective.   The  Epitope  Merger  shall  become  effective  in
        accordance with the terms of this Agreement,  the Articles of Merger and
        the  Certificate  of  Merger at the time and date

                                      -7-
<PAGE>

        contemplated therein (such time and date being referred to herein as the
        Epitope Effective Time or "Effective Time").

             (c)  Effects  of the  Epitope  Merger.  At and  after  the  Epitope
        Effective  Time,  the Epitope  Merger will have the effects set forth in
        the Delaware Law and the Oregon Law.  Without limiting the generality of
        the foregoing,  and subject thereto,  at the Epitope  Effective Time all
        the property, rights,  privileges,  powers and franchises of Epitope and
        Merger Sub shall be vested in the Surviving Corporation,  and all debts,
        liabilities and duties of Epitope and Merger Sub shall become the debts,
        liabilities and duties of the Surviving  Corporation.  In addition,  the
        Epitope Merger shall have the following effects:

                 (i)   Certificate   of   Incorporation.   The   Certificate  of
             Incorporation  of Merger  Sub as in  effect  as of the date  hereof
             shall be  amended  to  change  the name of  Merger  Sub to  OraSure
             Technologies,  Inc.,  but  otherwise  shall  read as set  forth  in
             Exhibit F and such  Certificate  of  Incorporation,  as so amended,
             shall  be  the  Certificate  of   Incorporation  of  the  Surviving
             Corporation.

                 (ii)  Bylaws.  The  Bylaws of Merger Sub as in effect as of the
             date hereof  shall be amended to reflect the change of Merger Sub's
             name to OraSure Technologies, Inc., but otherwise shall read as set
             forth in Exhibit G and shall,  as so amended,  be the Bylaws of the
             Surviving Corporation.

                 (iii) Board of Directors.  At the Effective  Time, the Board of
             Directors of the Surviving  Corporation  shall consist of the seven
             (7) persons and be divided  into the classes  specified  in Section
             2.1(d)(iii).

                 (iv)  Management.  The  principal  officers  of  the  Surviving
             Corporation  at the Effective Time shall be as listed on Exhibit H.
             All other management  positions of the Surviving  Corporation shall
             be determined jointly by the Surviving  Corporation's President and
             Chief Executive Officer.

             (d) Effect on Capital  Stock.  At the Epitope  Effective  Time,  by
        virtue of the  Epitope  Merger and without any action on the part of the
        parties hereto or their respective stockholders:

                 (i) Epitope  Common Stock.  Each share of Epitope  Common Stock
             outstanding  immediately  prior to the Epitope Effective Time shall
             be  converted  into and  become one share  (the  "Epitope  Exchange
             Ratio") of Surviving  Corporation Common Stock (the "Epitope Merger
             Consideration").

                 (ii) Epitope  Stock held by Epitope and Merger Sub.  Each share
             of Epitope  Common Stock held by Epitope as treasury stock or owned
             by Merger Sub immediately prior to the Epitope Effective Time shall
             be  cancelled  without  payment of any  consideration  therefor and
             shall cease to exist.

                 (iii)  Merger Sub Common  Stock.  Each share of Common Stock of
             Merger Sub outstanding and each share held in treasury  immediately
             prior to the

                                      -8-
<PAGE>

             Epitope Effective Time shall be converted into and become one share
             of Surviving Corporation Common Stock.

             (e) Stock Options and Other Stock Compensation.

                 (i) On or prior to the Epitope  Effective  Time,  Epitope  will
             take all  action  necessary  such that each  stock  option or other
             stock  related  right or other form of stock  related  incentive or
             deferred  compensation  that was  granted  pursuant  to the Epitope
             Employee Plans (as defined in Section 4.12(a)) prior to the Epitope
             Effective Time and which remains  outstanding  immediately prior to
             the Epitope  Effective  Time shall cease to  represent a right with
             respect to shares of Epitope  Common Stock and shall be  converted,
             at the Epitope  Effective Time, into a right, on the same terms and
             conditions  as were  applicable  under such  stock  option or other
             stock  related  right or other form of stock  related  incentive or
             deferred  compensation,  as applicable (but taking into account any
             changes  thereto,  provided for in the Epitope Employee Plans or in
             the  terms  of  such  right  by  reason  of this  Agreement  or the
             transactions  contemplated  hereby), with respect to that number of
             shares  of  Surviving   Corporation   Common  Stock  determined  by
             multiplying the number of shares of Epitope Common Stock subject to
             such stock  option or other  stock  related  right or other form of
             stock related incentive or deferred compensation, as applicable, by
             the  Epitope  Exchange  Ratio,  at a price per  share  equal to the
             per-share  exercise  price  specified in such stock option or stock
             appreciation right, as applicable.

                 (ii) As soon as practicable  after the Epitope  Effective Time,
             the  Surviving  Corporation  shall  deliver to the holders of stock
             options  or other  stock  related  rights  or other  forms of stock
             related  incentive  or deferred  compensation  appropriate  notices
             setting forth such holders' rights pursuant to the Epitope Employee
             Plans  and the  agreements  evidencing  the  grants  of such  stock
             options  or other  stock  related  rights  or other  forms of stock
             related incentive or deferred compensation shall continue in effect
             on the same terms and conditions (after giving effect to the Merger
             and  the  terms  of the  Epitope  Employee  Plans.  To  the  extent
             permitted by law, the Surviving  Corporation  shall comply with the
             terms of the Epitope  Employee Plans and shall take such reasonable
             steps  as  are  necessary  or  required  by,  and  subject  to  the
             provisions  of,  such  Epitope  Employee  Plans,  to have the stock
             options  which  qualified as incentive  stock  options prior to the
             Effective  Time  continue to qualify as incentive  stock options of
             the Surviving Corporation after the Effective Time.

                 (iii) The Surviving Corporation shall take all corporate action
             necessary to reserve for issuance a sufficient  number of shares of
             Surviving  Corporation  Common Stock for delivery  upon exercise of
             stock options or other stock related rights or other forms of stock
             related incentive or deferred  compensation in accordance with this
             Section 2.2(d)(ii).  Promptly after the Epitope Effective Time, the
             Surviving  Corporation shall file a registration  statement on Form
             S-3 or Form  S-8,  as the  case may be (or any  successor  or other
             appropriate  forms),  with  respect  to  the  shares  of  Surviving
             Corporation  Common  Stock  subject to such

                                      -9-
<PAGE>

             stock options or other stock related rights or other forms of stock
             related   incentive  or  deferred   compensation,   and  shall  use
             commercially  reasonable  efforts to maintain the  effectiveness of
             such  registration   statement  or  registration   statements  (and
             maintain  the  current  status of the  prospectus  or  prospectuses
             contained therein) for so long as such stock options or other stock
             related  rights  or  other  forms  of stock  related  incentive  or
             deferred  compensation  remain  outstanding.  With respect to those
             individuals  who  subsequent  to the Merger  will be subject to the
             reporting  requirements  under  Section  16(a) of the Exchange Act,
             where  applicable,  the Surviving  Corporation shall administer the
             Epitope  Employee Plans in a manner  consistent with the exemptions
             provided by Rule 16b-3 promulgated under the Exchange Act.

                 (f) Certain Adjustments. If, between the date of this Agreement
             and the Epitope  Effective  Time, the  outstanding  common stock of
             Merger Sub or Epitope  Common  Stock shall have been changed into a
             different  number  of shares  or  different  class by reason of any
             reclassification,  recapitalization,  stock  split,  reverse  stock
             split,  combination  or exchange of shares,  or a stock dividend or
             dividend  payable in any other  securities shall be declared with a
             record  date within such  period,  or any similar  event shall have
             occurred,   the  Epitope  Exchange  Ratio  shall  be  appropriately
             adjusted  to  provide to the  holders of STC Common  Stock the same
             economic  effect as  contemplated  by this Agreement  prior to such
             event.

        SECTION 2.3. Exchange of Certificates.

             (a) Prior to the  Effective  Time,  Epitope and STC shall cause the
        Surviving Corporation,  and the Surviving Corporation agrees, to appoint
        the Exchange Agent to act as the exchange  agent in connection  with the
        Mergers. Except as otherwise provided in this Article II, from and after
        the Effective Time, each holder of a certificate that immediately  prior
        to the STC Effective Time or Epitope Effective Time, as the case may be,
        represented  outstanding  shares of STC Common  Stock or Epitope  Common
        Stock (collectively, the "Certificates") shall be entitled to receive in
        exchange  therefor,  upon  surrender  thereof to the Exchange  Agent,  a
        certificate or certificates  representing  the number of whole shares of
        Surviving  Corporation Common Stock into which such holder's shares were
        converted in the STC Merger or Epitope Merger, as the case may be. Prior
        to the Effective  Time,  the Surviving  Corporation  will deliver to the
        Exchange  Agent,  in trust for the  benefit of the holders of STC Common
        Stock and Epitope Common Stock, (i) certificates  representing shares of
        Surviving Corporation Common Stock (such shares of Surviving Corporation
        Common Stock together with any dividends or  distributions  with respect
        thereto,  being hereinafter referred to as the "Exchange Fund") and (ii)
        cash in an amount  sufficient  for payment in lieu of fractional  shares
        necessary  to make the  exchanges  contemplated  by this Article II on a
        timely basis.

             (b) Promptly  after the Effective  Time,  the Exchange  Agent shall
        mail to each record holder of STC Common Stock and Epitope  Common Stock
        as of the Effective  Time, a letter of transmittal  (which shall specify
        that  delivery  shall  be  effected,  and  risk of  loss  and  title  to
        Certificates  shall pass, only upon proper delivery of the  Certificates
        to the  Exchange  Agent)  and  instructions  for  use in  effecting  the
        surrender  of  Certificates  in

                                      -10-
<PAGE>

        exchange for certificates  representing shares of Surviving  Corporation
        Common Stock.  Upon  surrender to the Exchange  Agent of a  Certificate,
        together with such letter of transmittal  duly  executed,  and any other
        required documents,  the holder of such Certificate shall be entitled to
        receive  in  exchange  therefor,  certificates  representing  shares  of
        Surviving  Corporation Common Stock as set forth in this Article II, and
        such Certificate shall forthwith be canceled. No holder of a Certificate
        or  Certificates  shall be  entitled  to receive  any  dividend or other
        distribution from the Surviving  Corporation until the surrender of such
        holder's  Certificate  for a certificate  or  certificates  representing
        shares of Surviving Corporation Common Stock. Upon such surrender, there
        shall  be paid to the  holder  the  amount  of any  dividends  or  other
        distributions  (without interest) that theretofore  became payable,  but
        that were not paid by  reason  of the  foregoing,  with  respect  to the
        number of whole shares of Surviving Corporation Common Stock represented
        by the  certificates  issued  upon  surrender,  which  amount  shall  be
        delivered to the Exchange Agent by the Surviving  Corporation  from time
        to time as such  dividends  or  other  distributions  are  declared.  If
        delivery of certificates  representing  shares of Surviving  Corporation
        Common  Stock is to be made to a person  other  than the person in whose
        name the Certificate surrendered is registered or if any certificate for
        shares of Surviving  Corporation  Common Stock as the case may be, is to
        be issued in a name other than that in which the Certificate surrendered
        therefor  is  registered,  it shall be a condition  of such  delivery or
        issuance that the Certificate so surrendered  shall be properly endorsed
        or otherwise in proper form for transfer and that the person  requesting
        such delivery or issuance shall pay any transfer or other Taxes required
        by  reason of such  delivery  or  issuance  to a person  other  than the
        registered  holder of the  Certificate  surrendered  or establish to the
        satisfaction of the Surviving Corporation that such Tax has been paid or
        is not applicable.  Until  surrendered in accordance with the provisions
        of this Section 2.4, each  Certificate  shall represent for all purposes
        only the right to receive shares of Surviving  Corporation  Common Stock
        (and, in the case of Certificates  theretofore  representing  STC Common
        Stock, cash in lieu of fractional shares) as provided in this Article II
        without any interest thereon.

             (c) After the  Effective  Time,  there shall be no transfers on the
        stock transfer  books of the Surviving  Corporation of the shares of STC
        Common Stock or Epitope Common Stock that were outstanding  prior to the
        Effective Time. If, after the Effective Time, Certificates are presented
        to the Surviving  Corporation  for transfer,  they shall be canceled and
        exchanged for shares of Surviving  Corporation  Common Stock as provided
        in this Article II, in accordance  with the procedures set forth in this
        Section 2.3.

             (d) Any  portion  of the  Exchange  Fund  and  any  cash in lieu of
        fractional shares of Surviving  Corporation  Common Stock made available
        to  the  Exchange  Agent  which  remains  undistributed  to  the  former
        stockholders  of STC for one year after the STC Effective  Time shall be
        delivered  to  the   Surviving   Corporation,   upon  demand,   and  any
        stockholders of STC who have not theretofore  complied with this Article
        II shall  thereafter look only to the Surviving  Corporation for payment
        of their claim for Surviving  Corporation Common Stock, any cash in lieu
        of  fractional  shares of  Surviving  Corporation  Common  Stock and any
        dividends or distributions with respect to Surviving  Corporation Common
        Stock.  Any portion of the Exchange Fund which remains  undistributed to
        the  former  stockholders  of  Epitope  for one year  after the  Epitope

                                      -11-
<PAGE>

        Effective  Time shall be delivered to the  Surviving  Corporation,  upon
        demand,  and any  stockholders  of  Epitope  who  have  not  theretofore
        complied  with  this  Article  II  shall  thereafter  look  only  to the
        Surviving   Corporation   for  payment  of  their  claim  for  Surviving
        Corporation  Common  Stock,  and any  dividends  or  distributions  with
        respect to Surviving Corporation Common Stock.

             (e) None of STC,  Epitope,  or the Surviving  Corporation  shall be
        liable to any  holder of shares of STC Common  Stock or  Epitope  Common
        Stock,   as  the  case  may  be,  for  such  shares  (or   dividends  or
        distributions with respect thereto) or cash in lieu of fractional shares
        of Surviving  Corporation  Common Stock  delivered to a public  official
        pursuant to any applicable  abandoned property,  escheat or similar law.
        Any amounts remaining  unclaimed by holders of any such shares two years
        after the Effective Time (or such earlier date immediately prior to such
        time as such amounts would  otherwise  escheat to or become  property of
        any  Governmental  Entity) shall, to the extent  permitted by applicable
        law, become the property of the Surviving  Corporation free and clear of
        any claims or interest of any such holders or their successors,  assigns
        or personal representatives previously entitled thereto.

        SECTION  2.4.  Affiliates.  Notwithstanding  anything  to  the  contrary
herein,  to the  fullest  extent  permitted  by law  and  pooling  of  interests
accounting   treatment,   no  certificates   representing  shares  of  Surviving
Corporation  Common  Stock or cash  shall be  delivered  to a Person  who may be
deemed an  "affiliate"  of STC or Epitope in accordance  with Section 8.8 hereof
for  purposes  of Rule 145  under  the  Securities  Act  and,  for  purposes  of
qualifying  the  Merger for  pooling of  interests  accounting  treatment  under
Opinion  16  of  the  Accounting  Principles  Board  and  applicable  rules  and
regulations  of the SEC,  until such  Person has  executed  and  delivered a STC
Affiliate  Agreement  (as  defined  in Section  8.8(a)) or an Epitope  Affiliate
Agreement  (as  defined  in Section  8.8(b)),  as the case may be,  pursuant  to
Section 8.8.

                                  ARTICLE III

                    REPRESENTATIONS AND WARRANTIES OF EPITOPE

        Except as disclosed in (i) the Epitope Disclosure  Schedule delivered to
STC  separately  prior to, or  contemporaneously  with,  the date  hereof  (each
section  or  subsection  of  which   qualifies  the   correspondingly   numbered
representation,  warranty or covenant to the extent  specified  therein) or (ii)
the  Epitope  SEC  Documents  filed  on or prior  to the  date  hereof,  Epitope
represents and warrants to STC that:

        SECTION 3.1.  Corporate  Existence  and Power.  Epitope is a corporation
duly  incorporated,  validly existing and in good standing under the laws of the
State of Oregon,  and has all corporate powers required to carry on its business
as now  conducted.  Epitope  is  duly  qualified  to do  business  as a  foreign
corporation and is in good standing in each jurisdiction  where the character of
the property  owned or leased by it or the nature of its  activities  makes such
qualification   necessary,   except  where  the  failure  to  be  so  qualified,
individually  or in the  aggregate,  would not be  reasonably  likely to have an
Epitope  Material  Adverse Effect.  Epitope has heretofore made available to STC
true and complete copies of Epitope's  articles of  incorporation  and bylaws as
currently in effect.

                                      -12-
<PAGE>

        SECTION  3.2.  Corporate  Authorization.  The  execution,  delivery  and
performance by Epitope of this Agreement and the  consummation by Epitope of the
transactions  contemplated  hereby are within  Epitope's  corporate  powers and,
except for the Epitope Stockholder Approval (as defined herein),  have been duly
authorized  by all necessary  corporate  action.  Assuming  that this  Agreement
constitutes the valid and binding obligation of STC, this Agreement  constitutes
a valid and binding  agreement of Epitope,  enforceable  in accordance  with its
terms, except as such  enforceability may be limited by bankruptcy,  insolvency,
reorganization,  moratorium  and  similar  laws,  now or  hereafter  in  effect,
relating to or affecting creditors' rights and remedies generally and to general
principles of equity (regardless of whether such enforceability is considered in
a proceeding in equity or at law).

        SECTION 3.3.  Governmental  Authorization.  The execution,  delivery and
performance by Epitope of this Agreement and the  consummation by Epitope of the
transactions  contemplated  hereby  require  no action by or in  respect  of, or
filing with, any  Governmental  Entity other than (a) the filing of (i) Articles
of Merger in accordance  with the Oregon Law,  (ii) a  Certificate  of Merger in
accordance  with the Delaware  Law,  and (iii)  appropriate  documents  with the
relevant  authorities of other states or  jurisdictions  in which Epitope or any
Epitope  Subsidiary  is  qualified  to do  business;  (b)  compliance  with  any
applicable  requirements of the Hart-Scott-Rodino  Antitrust Improvements Act of
1976 (the "HSR  Act") by  stockholders  of STC who will  acquire  the  Surviving
Corporation  Common  Stock with a value in excess of $15  million as a result of
the  Mergers and who do not have an  exemption  from the HSR Act  therefor;  (c)
compliance  with  any  applicable  requirements  of the  Securities  Act and the
Exchange Act; (d) such as may be required under any applicable  state securities
or blue sky laws;  and (e) such  other  consents,  approvals,  actions,  orders,
authorizations, registrations, declarations and filings that, if not obtained or
made, would not,  individually or in the aggregate,  (x) be reasonably likely to
have an Epitope  Material  Adverse Effect or (assuming for this purpose that the
Effective Time had occurred) a Surviving Corporation Material Adverse Effect, or
(y)  prevent or  materially  impair the  ability  of Epitope to  consummate  the
transactions contemplated by this Agreement.

        SECTION 3.4. Non-Contravention.  The execution, delivery and performance
by Epitope of this Agreement and the consummation by Epitope of the transactions
contemplated  hereby  do not  and  will  not (a)  contravene  or  conflict  with
Epitope's articles of incorporation or bylaws, (b) assuming  compliance with the
matters referred to in Section 3.3,  contravene or conflict with or constitute a
violation of any provision of any law, regulation,  judgment,  injunction, order
or decree binding upon or applicable to Epitope or any Epitope  Subsidiary,  (c)
constitute a default under or give rise to a right of termination,  cancellation
or acceleration of any right or obligation of Epitope or any Epitope  Subsidiary
or to a loss of any benefit or status to which Epitope or any Epitope Subsidiary
is entitled under any provision of any agreement,  contract or other  instrument
binding upon Epitope or any Epitope Subsidiary or any license, franchise, permit
or other similar authorization held by Epitope or any Epitope Subsidiary, or (d)
result in the creation or  imposition of any Lien on any asset of Epitope or any
Epitope Subsidiary other than, in the case of each of (b), (c) and (d), any such
items that would not,  individually or in the aggregate (x) be reasonably likely
to have an Epitope Material  Adverse Effect or (y) prevent or materially  impair
the  ability of Epitope to  consummate  the  transactions  contemplated  by this
Agreement.

                                      -13-
<PAGE>

        SECTION 3.5. Capitalization.

        (a) The  authorized  capital  stock of Epitope  consists  of  30,000,000
shares of Epitope Common Stock,  and 1,000,000 shares of preferred stock, no par
value  per  share,  of  Epitope  ("Epitope  Preferred  Stock").  At the close of
business on April 30, 2000, (i)  16,393,495  shares of Epitope Common Stock were
issued and  outstanding,  (ii)  stock  options  ("Epitope  Stock  Options")  and
warrants  ("Epitope  Warrants") to purchase an aggregate of 4,136,571  shares of
Epitope Common Stock were issued and  outstanding (of which options and warrants
to  purchase an  aggregate  of  3,012,999  shares of Epitope  Common  Stock were
exercisable), (iii) no shares of Epitope Common Stock were held in its treasury,
(iii) no shares of Epitope Preferred Stock were issued and outstanding, and (iv)
no shares of Epitope  Series A Preferred  Stock were  reserved for issuance upon
exercise of the Epitope Stock Purchase Rights. All outstanding shares of capital
stock of Epitope have been duly authorized and validly issued and are fully paid
and nonassessable.

        (b) As of the date hereof,  except (i) as set forth in this Section 3.5,
and (ii) for changes since  September 30, 1999,  resulting  from the exercise of
stock options or warrants outstanding on such date, there are no outstanding (x)
shares of capital stock or other voting securities of Epitope, (y) securities of
Epitope  convertible  into or exchangeable for shares of capital stock or voting
securities  of Epitope,  or (z) options or other rights to acquire from Epitope,
and no obligation of Epitope to issue, any capital stock,  voting  securities or
securities  convertible  into  or  exchangeable  for  capital  stock  or  voting
securities  of Epitope (the items in clauses (x), (y) and (z) being  referred to
collectively as the "Epitope Securities").  There are no outstanding obligations
of Epitope or any Epitope Subsidiary to repurchase,  redeem or otherwise acquire
any Epitope  Securities.  There are no  outstanding  contractual  obligations of
Epitope  to  provide  funds to, or make any  investment  (in the form of a loan,
capital   contribution  or  otherwise)  in,  any  other  Person.  There  are  no
stockholder  agreements,  voting trusts or other agreements or understandings to
which  Epitope is a party,  or of which  Epitope is aware,  relating  to voting,
registration  or  disposition  of any  shares of  capital  stock of  Epitope  or
granting to any person or group of persons the right to elect,  or to  designate
or nominate for election, a director to the board of directors of Epitope.

SECTION 3.6.   Subsidiaries.

        (a)  Each  Significant  Subsidiary  of  Epitope  is a  corporation  duly
incorporated  or an entity duly organized,  and is validly  existing and in good
standing under the laws of its  jurisdiction of  incorporation  or organization,
has  all  powers  and   authority  and  all  material   governmental   licenses,
authorizations,  consents and approvals required to carry on its business as now
conducted  and is duly  qualified  to do business as a foreign  entity and is in
good standing in each jurisdiction  where the character of the property owned or
leased by it or the nature of its activities makes such qualification necessary,
in each case with such exceptions as,  individually  or in the aggregate,  would
not be reasonably likely to have, an Epitope Material Adverse Effect.

                                      -14-
<PAGE>

        (b)  All of the  outstanding  shares  of  capital  stock  of,  or  other
ownership  interest in, each Epitope  Subsidiary  has been validly issued and is
fully paid and nonassessable.  All of the outstanding capital stock of, or other
ownership  interest in, each of Epitope's  Subsidiaries,  is owned,  directly or
indirectly,  by  Epitope,  is owned  free and  clear of any Lien and free of any
other limitation or restriction  (including any limitation or restriction on the
right  to  vote,  sell or  otherwise  dispose  of such  capital  stock  or other
ownership  interests) with such exceptions as, individually or in the aggregate,
would not be reasonably  likely to have,  an Epitope  Material  Adverse  Effect.
There  are no  outstanding  (i)  securities  of  Epitope  or any of the  Epitope
Subsidiaries  convertible  into or  exchangeable  or  exercisable  for shares of
capital stock or other voting  securities  or ownership  interests in any of the
Epitope  Subsidiaries,  (ii)  options,  warrants or other rights to acquire from
Epitope or any of the Epitope  Subsidiaries,  and no other obligation of Epitope
or  any of  the  Epitope  Subsidiaries  to  issue,  any  capital  stock,  voting
securities or other ownership  interests in, or any securities  convertible into
or  exchangeable  or  exercisable  for any capital stock,  voting  securities or
ownership interests in, any of the Epitope  Subsidiaries or (iii) obligations of
Epitope or any of the Epitope  Subsidiaries  to repurchase,  redeem or otherwise
acquire any  outstanding  securities of any of the Epitope  Subsidiaries  or any
capital  stock  of,  or  other  ownership  interests  in,  any  of  the  Epitope
Subsidiaries.

        SECTION 3.7. Epitope SEC Documents.

             (a) Epitope has made  available  to STC the Epitope SEC  Documents.
        Epitope has filed all  reports,  filings,  registration  statements  and
        other documents  required to be filed by it with the SEC since September
        30, 1997. No Epitope  Subsidiary  is required to file any form,  report,
        registration statement or prospectus or other document with the SEC.

             (b) As of its filing date, each Epitope SEC Document complied as to
        form in all material  respects with the applicable  requirements  of the
        Securities Act and/or the Exchange Act, as the case may be.

             (c) No Epitope SEC  Document  filed  pursuant to the  Exchange  Act
        contained,  as of its filing  date,  any untrue  statement of a material
        fact or omitted to state any  material  fact  necessary in order to make
        the statements  made therein,  in the light of the  circumstances  under
        which they were  made,  not  misleading.  No Epitope  SEC  Document,  as
        amended or supplemented, if applicable, filed pursuant to the Securities
        Act  contained,  as of  the  date  such  document  or  amendment  became
        effective,  any untrue  statement of a material fact or omitted to state
        any material fact required to be stated therein or necessary to make the
        statements therein not misleading.

        SECTION 3.8. Financial Statements; No Material Undisclosed Liabilities.

             (a) The audited  consolidated  financial  statements  and unaudited
        consolidated  interim  financial  statements of Epitope  included in the
        Epitope  10-K  and the  Epitope  10-Q  fairly  present  in all  material
        respects, in conformity with GAAP consistently applied (except as may be
        indicated in the notes thereto and except that  financial

                                      -15-
<PAGE>

        statements on Form 10-Q do not contain all GAAP notes to such  financial
        statements),  the  consolidated  financial  position  of Epitope and its
        consolidated Subsidiaries as of the dates thereof and their consolidated
        results  of   operations,   consolidated   cash  flows  and  changes  in
        stockholders'  equity  for the  periods  then ended  (subject  to normal
        year-end  adjustments  in the case of any  unaudited  interim  financial
        statements).

             (b) There are no liabilities  of Epitope or any Epitope  Subsidiary
        of  any  kind  whatsoever,   whether  accrued,   contingent,   absolute,
        determined,  determinable or otherwise,  in each case, that are required
        by GAAP to be set  forth on a  consolidated  balance  sheet of  Epitope,
        other than:

                 (i) liabilities or obligations disclosed or provided for in the
             Epitope Balance Sheet or disclosed in the notes thereto;

                 (ii)  liabilities  or  obligations   under  this  Agreement  or
             incurred in connection with the transactions  contemplated  hereby;
             and

                 (iii) other  liabilities or obligations that individually or in
             the  aggregate,  would not be reasonably  likely to have an Epitope
             Material Adverse Effect.

             (c)  Epitope and the Epitope  Subsidiaries  keep proper  accounting
        records in which all material assets and  liabilities,  and all material
        transactions,  of Epitope and the Epitope  Subsidiaries  are recorded in
        conformity  with GAAP. No part of Epitope's or any Epitope  Subsidiary's
        accounting system or records, or access thereto, is under the control of
        a Person who is not an employee of Epitope or such Subsidiary.

        SECTION 3.9. Information to be Supplied.

             (a)  The  information  to be  supplied  by  Epitope  expressly  for
        inclusion   or   incorporation   by   reference   in  the  Joint   Proxy
        Statement/Prospectus will (i) in the case of the Registration Statement,
        at the time it becomes effective,  not contain any untrue statement of a
        material  fact or omit to state any material  fact required to be stated
        therein  or  necessary  in  order  to make the  statements  therein  not
        misleading  and (ii) in the case of the  remainder  of the  Joint  Proxy
        Statement/Prospectus,  at the time of the  mailing  thereof,  and at the
        time of the Special  Meetings,  not contain  any untrue  statement  of a
        material  fact or omit to state any material  fact required to be stated
        therein or necessary in order to make the statements  therein,  in light
        of the  circumstances  under which they are made,  not  misleading.  The
        Joint  Proxy   Statement/Prospectus   will  comply   (with   respect  to
        information  relating to Epitope)  as to form in all  material  respects
        with the provisions of the Securities Act and the Exchange Act.

             (b) Notwithstanding the foregoing,  Epitope makes no representation
        or warranty  with  respect to any  statements  made or  incorporated  by
        reference in the Joint Proxy  Statement/Prospectus  based on information
        supplied by STC.

        SECTION  3.10.  Absence of Certain  Changes.  Since  September 30, 1999,
except as otherwise  expressly  contemplated by this Agreement,  Epitope and the
Epitope  Subsidiaries  have  conducted  their  business in the  ordinary  course
consistent with past practice and there has not

                                      -16-
<PAGE>

been (a) any damage,  destruction or other casualty loss (whether or not covered
by  insurance)  affecting  the  business  or assets of  Epitope  or any  Epitope
Subsidiary  that,  individually  or in  the  aggregate,  has  had  or  would  be
reasonably  likely to have an Epitope Material  Adverse Effect,  (b) any action,
event,  occurrence,  development  or  state  of  circumstances  or  facts  that,
individually or in the aggregate,  has had or would be reasonably likely to have
an  Epitope  Material  Adverse  Effect  or (c)  any  incurrence,  assumption  or
guarantee by Epitope of any material  indebtedness for borrowed money other than
in the  ordinary  course  and in  amounts  and on  terms  consistent  with  past
practices.

        SECTION  3.11.  Litigation.  Section  3.11  of  the  Epitope  Disclosure
Schedule  contains a list and description of each action,  suit,  investigation,
arbitration  or  proceeding  pending  against,  or to the  Knowledge  of Epitope
threatened against, Epitope or any Epitope Subsidiary or any of their respective
assets or properties before any arbitrator or Governmental  Entity. None of such
actions, suits, investigations,  arbitrations or proceedings, individually or in
the aggregate,  would be reasonably  likely to have, an Epitope Material Adverse
Effect.  There are no outstanding  judgments,  decrees,  injunctions,  awards or
orders against Epitope that would be reasonably likely to have,  individually or
in the aggregate, an Epitope Material Adverse Effect.

        SECTION 3.12. Taxes.

             (a) All Tax returns,  statements,  reports and forms (collectively,
        the "Epitope  Returns")  required to be filed with any taxing  authority
        by, or with respect to, Epitope and the Epitope  Subsidiaries  have been
        filed in substantial compliance with all applicable laws.

             (b) Epitope and the Epitope Subsidiaries have timely paid all Taxes
        shown as due and payable on the Epitope Returns that have been so filed,
        and all other Taxes not subject to reporting obligations, and, as of the
        time of  filing,  the  Epitope  Returns  correctly  reflected  the facts
        regarding the income, business, assets,  operations,  activities and the
        status of Epitope  and the Epitope  Subsidiaries  (other than Taxes that
        are being  contested in good faith and for which  adequate  reserves are
        reflected on the Epitope Balance Sheet).

             (c) Epitope and the Epitope  Subsidiaries  have made  provision for
        all Taxes  payable  by them for  which no  Epitope  Return  has yet been
        filed.

             (d) The  charges,  accruals  and reserves for Taxes with respect to
        Epitope and the Epitope  Subsidiaries  reflected on the Epitope  Balance
        Sheet are  adequate  under  GAAP to cover the Tax  liabilities  accruing
        through the date thereof.

             (e)  There is no  action,  suit,  proceeding,  audit  or claim  now
        proposed  or pending  against  or with  respect to Epitope or any of the
        Epitope  Subsidiaries  in respect  of any Tax that  would be  reasonably
        likely to have an Epitope Material Adverse Effect.

             (f) Neither Epitope nor any of the Epitope  Subsidiaries has been a
        member of an affiliated,  consolidated,  combined or unitary group other
        than one of which Epitope was the common parent.

                                      -17-
<PAGE>

             (g) Neither Epitope nor any of the Epitope  Subsidiaries  holds any
        asset subject to a consent under Section 341(f) of the Code.

             (h) The  representations  and  warranties  contained in the Epitope
        Representation  Letter,  attached  hereto  as  Exhibit  I,  are true and
        correct.

        SECTION 3.13. Employee Benefits.

             (a) Section 3.13(a) of the Epitope  Disclosure  Schedule contains a
        correct and complete list  identifying each material  "employee  benefit
        plan",  as defined in Section  3(3) of the  Employee  Retirement  Income
        Security Act of 1974 ("ERISA"),  each  employment,  severance or similar
        contract, plan, arrangement or policy and each other plan or arrangement
        (written or oral) providing for compensation,  bonuses,  profit-sharing,
        stock option or other stock  related  rights or other forms of incentive
        or  deferred   compensation,   vacation  benefits,   insurance  coverage
        (including any self-insured  arrangements),  health or medical benefits,
        disability benefits,  workers' compensation,  supplemental  unemployment
        benefits,  severance benefits and post-employment or retirement benefits
        (including  compensation,  pension,  health,  medical or life  insurance
        benefits) that is maintained,  administered or contributed to by Epitope
        or any ERISA  Affiliate  (as  defined  below) of Epitope  and covers any
        employee or former employee of Epitope or any Epitope Subsidiary. Copies
        of such plans (and, if  applicable,  related trust  agreements)  and all
        amendments  thereto  and  written   interpretations  thereof  have  been
        furnished,  or will be made available upon request, to STC together with
        the most recent  annual  report  (Form 5500  including,  if  applicable,
        Schedule B thereto) and summary plan description  prepared in connection
        with any such plan.  Such plans are referred to  collectively  herein as
        the "Epitope Employee Plans".  For purposes of this Section 3.13, "ERISA
        Affiliate"  of any Person means any other Person  which,  together  with
        such Person,  would be treated as a single employer under Section 414 of
        the Code.

             (b) No Epitope Employee Plan is now or at any time has been subject
        to Part 3,  Subtitle  B of Title I or ERISA or Title IV of ERISA.  At no
        time has Epitope or any of its ERISA Affiliates  contributed to, or been
        required  to  contribute  to,  any  "multiemployer  plan," as defined in
        Section 3(37) or ERISA (a "Multiemployer Plan"), and neither Epitope nor
        any of its  ERISA  Affiliates  has,  or  ever  has  had,  any  liability
        (contingent  or  otherwise)   relating  to  the  withdrawal  or  partial
        withdrawal  from a multiemployer  Plan. To the Knowledge of Epitope,  no
        condition  exists and no event has  occurred  that  would be  reasonably
        likely to constitute  grounds for  termination  of any Epitope  Employee
        Plan that is a Retirement Plan. To the Knowledge of Epitope, nothing has
        been done or  omitted  to be done and no  transaction  or holding of any
        asset under or in connection with any Epitope Employee Plan has occurred
        that will make  Epitope or any  Epitope  Subsidiary,  or any  officer or
        director of Epitope or any Epitope Subsidiary,  subject to any liability
        under Title I of ERISA or liable for any tax pursuant to Section 4975 of
        the Code (assuming the taxable period of any such transaction expired as
        of the date hereof) that would be  reasonably  likely to have an Epitope
        Material Adverse Effect.

             (c) Each  Epitope  Employee  Plan that is intended to be  qualified
        under  Section  401(a) of the Code now meets,  and at all time since its
        inception have met, the

                                      -18-
<PAGE>

        requirements  for such  qualification,  and each  trust  forming  a part
        thereof is now, and at all times since its  inception  has been,  exempt
        from tax  pursuant  to  Section  501(a) of the Code.  Each such plan has
        received a determination letter from the Internal Revenue Service to the
        effect that such plan is qualified  and its related trust is exempt from
        federal income taxes. Epitope has furnished, or will make available upon
        request,  to STC  copies of the most  recent  Internal  Revenue  Service
        determination  letters with respect to each such Epitope  Employee Plan.
        Each Epitope  Employee  Plan has been  maintained  and  administered  in
        substantial  compliance with its terms (except that in any case in which
        any  Epitope  Employee  Plan is  currently  required  to  comply  with a
        provision of ERISA or of the Code, but is not yet required to be amended
        to  reflect  such   provision,   such  plan  has  been   maintained  and
        administered in accordance with the provision) and with the requirements
        prescribed  by any and all  statutes,  orders,  rules  and  regulations,
        including but not limited to ERISA and the Code, which are applicable to
        such Epitope  Employee Plan. All material  reports,  returns and similar
        documents  with respect to each  Epitope  Employee  Plan  required to be
        filed with any government  agency or distributed to any Epitope Employee
        Plan participant have been duly timely filed and distributed.

             (d) There is no contract, agreement, plan or arrangement that, as a
        result of the Mergers, would be reasonably likely to obligate Epitope to
        make any payment of any amount that would not be deductible  pursuant to
        the terms of Section 162(m) or Section 280G of the Code.

             (e) Except as disclosed in writing to STC prior to the date hereof,
        there has been no amendment to, written  interpretation  or announcement
        (whether   or  not   written)   relating   to,  or  change  in  employee
        participation  or coverage under,  any Epitope  Employee Plan that would
        increase  materially  the expense of maintaining  such Epitope  Employee
        Plan above the level of the expense  incurred in respect thereof for the
        fiscal year ended September 30, 1999.

             (f) No Epitope  Employee Plan promises or provides  post-retirement
        medical,  life  insurance or other  benefits due now or in the future to
        current, former or retired employees of Epitope or any Subsidiary.

        SECTION 3.14. Compliance with Laws; Licenses, Permits and Registrations.

             (a) Neither Epitope nor any Epitope  Subsidiary is in violation of,
        or has  violated,  any  applicable  provisions  of any  laws,  statutes,
        ordinances,  regulations,  judgments,  injunctions,  orders  or  consent
        decrees,  except for any such  violations  that,  individually or in the
        aggregate,  would not be reasonably  likely to have an Epitope  Material
        Adverse Effect.

             (b) Each of Epitope and the Epitope  Subsidiaries  has all permits,
        licenses, approvals,  authorizations of and registrations with and under
        all federal,  state,  local and foreign laws, and from all  Governmental
        Entities  required by Epitope and the Epitope  Subsidiaries  to carry on
        their  respective  businesses as currently  conducted,  except where the
        failure to have any such permits, licenses, approvals, authorizations or
        registrations,

                                      -19-
<PAGE>

        individually or in the aggregate, would not be reasonably likely to have
        an Epitope Material Adverse Effect.

        SECTION 3.15. Title to Properties.

             (a) Epitope and each Epitope  Subsidiary  have good and  marketable
        title to, or valid  leasehold  interests  in, all their  properties  and
        assets except for such as are no longer used or useful in the conduct of
        their  businesses or as have been disposed of in the ordinary  course of
        business  and  except  for  defects  in  title,  easements,  restrictive
        covenants and similar Liens,  encumbrances  or  impediments  that do not
        materially interfere with the ability of Epitope and its Subsidiaries to
        use their respective assets and conduct their  businesses,  as currently
        used or conducted. All such assets and properties, other than assets and
        properties  in which  Epitope or any Epitope  Subsidiary  has  leasehold
        interests,  are free and clear of all Liens,  except for Liens that,  in
        the aggregate, do not and will not materially interfere with the ability
        of Epitope and the Epitope  Subsidiaries to use their respective  assets
        and conduct their businesses, as currently conducted.

             (b)  Epitope and each  Epitope  Subsidiary  (i) are in  substantial
        compliance  with the terms of all  leases to which  they are a party and
        under which they are in occupancy, and all such leases are in full force
        and effect and (ii) enjoy peaceful and undisturbed  possession under all
        such leases.

        SECTION 3.16. Intellectual Property.

             (a)  Epitope  and  the  Epitope  Subsidiaries  own or  have a valid
        license  to  use  (i)  all  fictional  business  names,  trading  names,
        registered and unregistered trademarks,  service marks, domain names and
        applications   (collectively,   "Marks");   (ii)  all  patents,   patent
        applications,  and  inventions  and  discoveries  that may be patentable
        (collectively,  "Patents"); (iii) all copyrights in both published works
        and unpublished works (collectively,  "Copyrights");  (iv) all rights in
        mask works (collectively, "Rights in Mask Works"); and (v) all know-how,
        trade secrets, and confidential  information,  (such as, customer lists,
        software,  technical information,  data, process technology,  and plans)
        (collectively,  "Trade Secrets"); necessary to (x) carry on the business
        of Epitope as currently  conducted or as proposed to be conducted by the
        Surviving Corporation,  to (y) make, have made, use, distribute and sell
        all products  currently sold by Epitope and all products in development,
        including  all  products  proposed  to be sold  under the  "OraSure"  or
        "OraQuick" trade names.

             (b)  There are no  outstanding  and,  to  Epitope's  Knowledge,  no
        Threatened  disputes or  disagreements  with respect to any agreement to
        which Epitope or an Epitope  subsidiary  is a party,  relating to any of
        Epitope's  Marks,  Patents,  Copyrights,  Rights in Mask Works, or Trade
        Secrets (collectively, "Epitope Intellectual Property").

             (c) Epitope is the owner of all right,  title,  and interest in and
        to the  Epitope  Intellectual  Property,  free and  clear of all  liens,
        security interests, charges,  encumbrances,  equities, and other adverse
        claims.

                                      -20-
<PAGE>

             (d) All former and  current  employees  of  Epitope  have  executed
        written  contracts with Epitope that assign to Epitope all rights to any
        inventions,  improvements,  discoveries,  or information relating to the
        business of Epitope. To Epitope's knowledge,  no employee of Epitope has
        entered into any contract that  restricts or limits in any way the scope
        or type of work in which the  employee  may be engaged or  requires  the
        employee to transfer,  assign,  or disclose  information  concerning his
        work to anyone other than Epitope.

             (e) All of the Patents are  currently in compliance in all material
        respects with formal legal  requirements  (including  payment of filing,
        examination,  and  maintenance  fees and proofs of working or use),  are
        valid and  enforceable,  and are not subject to any maintenance  fees or
        taxes or actions that have not been paid when due.

             (f) Epitope uses  reasonable  procedures  to keep its Trade Secrets
        confidential.  Epitope's  Trade Secrets have been  disclosed  only under
        written agreements that require the recipient to hold such Trade Secrets
        confidential.

             (g) No  Patent  has been or is now  involved  in any  interference,
        reissue,   reexamination,   or  opposition   proceeding.   To  Epitope's
        Knowledge,   there  is  no  potentially  interfering  patent  or  patent
        application of any third party.

             (h) No Patent is  infringed  or, to Epitope's  Knowledge,  has been
        challenged or threatened in any way. To Epitope's Knowledge, none of the
        products  manufactured  and sold or proposed to be sold, nor any process
        or know-how  used,  by Epitope  infringes  or is alleged to infringe any
        Patent or other proprietary right of any other Person.

             (i)  Epitope  is not  required  to make any  payments  to any third
        parties in connection with its use of Epitope Intellectual Property.

             (j) All products  made,  used,  or sold under the Patents have been
        marked with the proper patent notice.

        SECTION 3.17. Environmental Matters.

             (a) To the Knowledge of Epitope, there has not been, as of the date
        hereof, any (i) "release" (as defined in 42 U.S.C.ss.9601(22)) or threat
        of  a  "release"  of  any  "hazardous  substances"  (as  defined  in  42
        U.S.C.ss.9601(14))  or oil or other  petroleum  related  products  on or
        about any of the real property  owned,  operated or leased by Epitope or
        any Epitope  Subsidiary  ("Epitope Real  Property"),  or (ii) release or
        presence of any  pollutant,  contaminant  or condition  giving rise to a
        cause of action under federal, state or local statutory or common law on
        or about any of the Epitope Real  Property  other than such as would not
        reasonably be expected to have an Epitope Material Adverse Effect.

             (b) Neither  Epitope nor any Epitope  Subsidiary  has any contract,
        agreement or otherwise  arranged for disposal or treatment,  or arranged
        with a transporter for transport for disposal or treatment, of hazardous
        substances at any "facility" (as defined in 42 U.S.C.  ss.9601(9)) owned
        or operated by another Person.

                                      -21-
<PAGE>

             (c) Neither  Epitope nor any Epitope  Subsidiary  has  accepted any
        hazardous  substances for transport to disposal or treatment  facilities
        or sites selected by Epitope or any Epitope Subsidiary.

             (d) To the Knowledge of Epitope,  the Epitope Real Property and the
        use thereof is in material  compliance  with,  and each Epitope and each
        Epitope Subsidiary is in compliance with, all applicable laws, statutes,
        ordinances, rules and regulations of any Governmental Entity relating to
        environmental  protection,   underground  storage  tanks,  toxic  waste,
        hazardous  waste,  oil  or  hazardous  substance  handling,   treatment,
        storage, disposal or transportation,  or arranging therefor,  respecting
        any  products or materials  previously  or now located on, or in transit
        from  the  Epitope  Real  Property,  including  without  limitation  the
        Resource Conservation and Recovery Act, the Comprehensive  Environmental
        Response,  Compensation and Liability Act, and the Superfund  Amendments
        and Reauthorization Act of 1986.

             (e) The past disposal  practices  relating to hazardous  substances
        and hazardous  wastes of Epitope and each Epitope  Subsidiary (and their
        respective  predecessors,  if any) have been  accomplished in accordance
        with all applicable laws, statutes, rules, regulations and ordinances.

             (f) Neither  Epitope nor any Epitope  Subsidiary  has been notified
        of, nor, to the Knowledge of Epitope or any Epitope Subsidiary is there,
        any  basis  for  any  potential  liability  of  Epitope  or any  Epitope
        Subsidiary  with  respect to the cleanup of any waste  disposal  site or
        facility.  Neither  Epitope nor any Epitope  Subsidiary has received any
        notification to the effect that any site at which Epitope or any Epitope
        Subsidiary  has disposed of hazardous  substances  or oil has been or is
        under investigation by any Governmental Entity.

             (g) Neither  Epitope nor any Epitope  Subsidiary  has  received any
        notification  of  releases  or  hazardous  substances  or oil  from  any
        Governmental Entity.

        SECTION 3.18. Finders' Fees; Opinions of Financial Advisor.

             (a) Except for Deutsche Bank  Securities  Inc.  (also  operating as
        Deutsche Banc Alex.Brown), there is no investment banker, broker, finder
        or other intermediary that has been retained by, or is authorized to act
        on behalf of, Epitope or any Epitope Subsidiary who might be entitled to
        any  fee  or  commission   from  STC  or  any  of  its  Affiliates  upon
        consummation of the transactions contemplated by this Agreement.

             (b) The Board of  Directors  of Epitope has received the opinion of
        Deutsche Bank Securities  Inc.,  dated as of the date of this Agreement,
        to the effect that, as of such date, the Exchange Ratio is fair,  from a
        financial point of view, to Epitope.

        SECTION 3.19. Required Vote; Board Approval.

             (a) The only votes of the holders of any class or series of capital
        stock  of  Epitope  required  by law,  rule,  regulation  or rule of the
        National  Association of Securities  Dealers,  Inc. to approve and adopt
        this Agreement and/or any of the other transactions

                                      -22-
<PAGE>

        contemplated hereby,  including the Mergers, are the affirmative vote of
        the holders of more than fifty percent of all votes  entitled to be cast
        on the STC Merger  and the  Epitope  Merger  (the  "Epitope  Stockholder
        Approval").

             (b) Epitope's Board of Directors has unanimously (i) determined and
        declared that this Agreement and the transactions  contemplated  hereby,
        including the Merger, are advisable and in the best interests of Epitope
        and its  stockholders,  (ii)  approved and adopted this  Agreement,  the
        Merger and the other transactions contemplated hereby and (iii) resolved
        to  recommend to such  stockholders  that they vote in favor of adopting
        and approving  this  Agreement  and the Mergers in  accordance  with the
        terms hereof,  subject to the Board's  fiduciary duties under applicable
        law, at a special  meeting of the  stockholders of Epitope duly held for
        such purpose (the "Epitope Stockholders Meeting").

        SECTION 3.20. State Takeover Statutes.

             (a)  Epitope  has taken all  actions  required to be taken by it in
        order to exempt this Agreement and the transactions  contemplated hereby
        from the provisions of Sections 60.801 through 60.845 of the Oregon Law,
        and  accordingly,  such  Sections  do not apply to the Mergers or any of
        such  transactions.  No other  "control  share  acquisition,"  "business
        combination,"  "fair price" or other  anti-takeover  laws or regulations
        enacted  under state or federal laws in the United  States apply to this
        Agreement or any of the transactions contemplated hereby.

        SECTION 3.21. Pooling Matters; Tax Treatment.

             (a) Epitope  intends  that the Mergers be  accounted  for under the
        "pooling of interests"  method under the  requirements of Opinion No. 16
        (Business  Combinations)  of  the  Accounting  Principles  Board  of the
        American  Institute  of  Certified  Public  Accountants,  the  Financial
        Accounting  Standards  Board,  and the rules and regulations of the SEC.
        Epitope  will  request  a letter  addressed  to it from  PriceWaterhouse
        Coopers LLP,  dated as of the Closing Date, and (if and when obtained) a
        copy of it will be  delivered  to STC.  Such  letter  (which may contain
        customary    qualifications    and   assumptions)   shall   state   that
        PriceWaterhouse   Coopers  LLP  concurs  with   Epitope's   management's
        conclusion  that no conditions  exist that would  preclude the Surviving
        Corporation from accounting for the Mergers as a "pooling of interests,"
        as described in the first sentence of this Section 3.21(a).

             (b) Neither  Epitope nor any of its  Affiliates has taken or agreed
        to  take,  or  will  take,  any  action  or is  aware  of  any  fact  or
        circumstance  that would  prevent or impede the Mergers from  qualifying
        (i) for  "pooling of  interests"  accounting  treatment  as described in
        Section 3.21(a) above or (ii) as a 368 Reorganization or that would make
        untrue any  representation or warranty  contained in the  Representation
        Letter attached as Exhibit I.

        SECTION  3.22.  Certain  Agreements.   None  of  Epitope,   any  Epitope
Subsidiary or any of their respective Affiliates (i) are parties to or otherwise
bound by any  agreement  or  arrangement

                                      -23-
<PAGE>

that  limits  or  otherwise  restricts  Epitope,  any  Epitope  Subsidiary,  the
Surviving  Corporation or any of their  respective  Affiliates  from engaging or
competing  in any line of business or in any  locations,  and (ii) except in the
ordinary course of business,  have amended,  modified or terminated any material
contract,  agreement  or  arrangement  of Epitope or any Epitope  Subsidiary  or
otherwise waived,  released or assigned any material rights,  claims or benefits
of Epitope or any Epitope Subsidiary thereunder.

        SECTION 3.23.  Epitope Rights  Agreement.  Merger Sub will, prior to the
Effective  Time,  take or cause to be taken all  action so that each  issued and
outstanding  share of STC Common  Stock  (other than shares to be  cancelled  in
accordance  with  Section  2.1(e)(iii)),  upon  conversion  of such  shares into
Surviving  Corporation Common Stock in accordance with Section 2.1(e)(i),  shall
have associated rights to purchase the appropriate number of shares of Surviving
Corporation  Series  A  Preferred  Stock  pursuant  to  the  Merger  Sub  Rights
Agreement.  Epitope has amended the Epitope Rights  Agreement in accordance with
its terms to render it  inapplicable  to the  transactions  contemplated by this
Agreement so that the entering into of this  Agreement and the  consummation  of
the  transactions  contemplated  hereby do not and will  enable or  require  the
Rights granted thereunder (the "Epitope Stock Purchase Rights") to be exercised,
distributed or triggered.  Epitope has delivered to STC a true and complete copy
of the Epitope  Rights  Agreement,  as amended,  in effect as of the date of the
execution of this Agreement.

        SECTION 3.24. Employment Agreements. There exists (i) no union, guild or
collective  bargaining agreement to which Epitope or any Epitope Subsidiary is a
party, (ii) no employment,  consulting or severance agreement between Epitope or
any Subsidiary of Epitope and any Person (except for consulting  agreements that
individually,  and in the aggregate,  are not material to Epitope), and (iii) no
employment,   consulting,   severance  or  indemnification  agreement  or  other
agreement  or plan to which  Epitope or any Epitope  Subsidiary  is a party that
would be altered or result in any bonus,  golden  parachute,  severance or other
payment or obligation to any Person,  or result in any  acceleration of the time
of payment or in the  provision or vesting of any  benefits,  as a result of the
execution or  performance of this Agreement or as a result of the Mergers or the
other transactions contemplated hereby.

        SECTION 3.25.  Transactions  With  Directors,  Officers and  Affiliates.
Except  for any of the  following  matters  which  would not be  required  to be
disclosed  pursuant  to  Item  402 or Item  404 of  Regulation  S-K of the  U.S.
Securities and Exchange Commission (the "Commission"), since September 30, 1999,
there have been no transactions  between Epitope or any of its  Subsidiaries and
any director,  officer,  employee,  stockholder  or  "Affiliate"  (as identified
pursuant  to  Section  8.8  hereof)  of  Epitope  or any  of  its  Subsidiaries,
including,  without  limitation,  loans,  guarantees  or  pledges  to, by or for
Epitope  or any of  Epitope's  Subsidiaries  from,  to,  by or for  any of  such
Persons.  Since September 30, 1999, none of the officers or directors of Epitope
or any of its  Subsidiaries,  and no spouse or relative of any of such  Persons,
has been a director  or officer of, or has had any  material  direct or indirect
interest in, any Person  which during such period has been a supplier,  customer
or sales agent of Epitope or any of its  Subsidiaries  or has  competed  with or
been  engaged in any  business of the kind being  conducted by Epitope or any of
its Subsidiaries.

        SECTION 3.26.  Material  Contracts.  Schedule  3.26  delivered to STC by
Epitope prior to the execution of this  Agreement  lists all material  contracts
and  agreements  to  which,  as of the

                                      -24-
<PAGE>

date hereof, Epitope or any Epitope Subsidiary is a party or by which Epitope or
any Epitope Subsidiary is bound or under which Epitope or any Epitope Subsidiary
has or may acquire any rights,  which were not filed prior to the date hereof as
exhibits  to  Epitope  Commission  Filings,  which  involve  or  relate  to  (i)
obligations  of Epitope or any Epitope  Subsidiary  for borrowed  money or other
indebtedness where the amount of such obligations exceeds $250,000 individually,
(ii) the lease by Epitope or any  Epitope  Subsidiary,  as lessee or lessor,  of
real  property for rent of more than  $250,000 per annum,  (iii) the purchase or
sale of goods  (other than raw material to be purchased by Epitope on terms that
are  customary and  consistent  with the past practice of Epitope and in amounts
and at prices  substantially  consistent  with past  practices  of  Epitope)  or
services  with an aggregate  minimum  purchase  price of more than  $250,000 per
annum, (iv) rights to manufacture  and/or distribute any product which accounted
for  more  than  $250,000  of the  consolidated  revenues  of  Epitope  and  its
Subsidiaries  during the fiscal  year ended  September  30,  1999 or under which
Epitope or any  Epitope  Subsidiary  received  or paid  license or other fees in
excess of  $250,000  during  any  year,  (v) the  purchase  or sale of assets or
properties  not in the ordinary  course of business  having a purchase  price in
excess of $250,000,  (vi) the right  (whether or not currently  exercisable)  to
use,  license  (including  any  "in-license"  or  "outlicense"),  sublicense  or
otherwise exploit any intellectual  property right or other proprietary asset of
Epitope  or of any of  Subsidiary  of Epitope or any other  Person  which,  when
considered  together with all such other rights,  is material to Epitope;  (vii)
any material  collaboration or joint venture or similar arrangement;  (viii) the
restriction  on the right or ability of Epitope or any Subsidiary of Epitope (A)
to compete with any other  Person,  (B) to acquire any product or other asset or
any services from any other Person, (C) to solicit, hire or retain any Person as
an employee, consultant or independent contractor, (D) to develop, sell, supply,
distribute,  offer,  support or service any product or any  technology  or other
asset to or for any other Person,  (E) to perform services for any other Person,
or (F) to transact  business or deal in any other manner with any other  Person;
(ix) any currency hedging; or (x) individual capital expenditures or commitments
in excess of $250,000.  All such  contracts and  agreements are duly and validly
executed  by  Epitope  or such  Epitope  Subsidiary,  and are in full  force and
effect. Neither Epitope nor any of its Subsidiaries has violated or breached, or
committed any default under, any contract or agreement, and, to the knowledge of
Epitope,  no other  Person has violated or  breached,  or committed  any default
under, any contract or agreement,  which violation,  breach or default (alone or
in combination with other  violations,  breaches or defaults under such contract
or agreement or under other  contracts or agreements)  has had or may reasonably
be expected to have an Epitope  Material  Adverse Effect.  No event has occurred
which,  after notice or the passage of time or both,  would constitute a default
by Epitope or any  Subsidiary of Epitope under any contract or agreement or give
any Person the right to (A) declare a default or exercise  any remedy  under any
contract or agreement, (B) receive or require a rebate,  chargeback,  penalty or
change in delivery schedule under any contract or agreement,  (C) accelerate the
maturity or performance of any contract or agreement,  or (D) cancel,  terminate
or modify any contract or agreement, in each case which, together with all other
events  of the  types  referred  to in  clauses  (A),  (B),  (C) and (D) of this
sentence  has had or may  reasonably  be  expected  to have an Epitope  Material
Adverse  Effect.  All such  contracts and agreements  will  continue,  after the
Effective Time, to be binding in all material  respects in accordance with their
respective terms until their respective expiration dates.

        SECTION 3.27. Certain Business  Practices.  Neither Epitope,  nor to the
Knowledge of Epitope any director,  officer,  agent or employee of Epitope,  has
(i) used any funds for unlawful

                                      -25-
<PAGE>

contributions,  gifts,  entertainment  or other  unlawful  expenses  relating to
political  activity,  (ii) made any  unlawful  payment to  foreign  or  domestic
government officials or employees or to foreign or domestic political parties or
campaigns or violated  any  provision of the Foreign  Corrupt  Practices  Act of
1977, as amended, or (iii) made any other unlawful payment.

        SECTION 3.28. Insurance.  Epitope has made available to STC a summary of
all material  insurance  policies and all material self  insurance  programs and
arrangements relating to the business,  assets and operations of Epitope and its
Subsidiaries. Each of such insurance policies is in full force and effect. Since
September 30, 1999, neither Epitope nor any of its Subsidiaries has received any
notice or other communication  regarding any actual or possible (i) cancellation
or invalidation of any material  insurance policy,  (ii) refusal of any coverage
or rejection of any material claim under any insurance policy, or (iii) material
adjustment  in the amount of the premiums  payable with respect to any insurance
policy. There is no pending workers'  compensation or other claim under or based
upon any  insurance  policy of  Epitope  or any of its  Subsidiaries  other than
claims incurred in the ordinary course of business.

        SECTION 3.29. Product Information.

             (a) Non- Exempt Products. The products of Epitope listed on Section
        3.29(a) of the Disclosure Schedule (the "Epitope  Non-Exempt  Products")
        are subject to the premarket approval requirements of the Medical Device
        Amendments  to  the  Federal  Food,   Drug  and  Cosmetic  Act  and  all
        premarketing approval letters received from Food and Drug Administration
        (the  "FDA")  are  identified  on  Section  3.29(a)  of  the  Disclosure
        Schedule.

                 (i) All Epitope  Non-Exempt  Products and all  modifications or
             changes to any Non-Exempt Product are in compliance in all material
             respects with the premarketing and postmarking  regulatory controls
             of the Medical  Device  Amendments  to the Federal  Food,  Drug and
             Cosmetic Act.

                 (ii)   All   pre-market   notification   submissions   and  any
             supplementary  materials  submitted  therewith  are accurate in all
             material  respects and each of the Epitope  Non-Exempt  Products is
             suitable for its intended use.

                 (iii)  During the  five-year  period  prior to the date hereof,
             there  have been no adverse  actions  taken by the FDA or any other
             Governmental   Entity  involving   Non-Exempt  Products  including,
             without limitation any recalls of any Epitope  Non-Exempt  Product.
             For  Epitope  Non-Exempt  Products,   Epitope  maintains  a  system
             designed  to keep  records  of  complaints.  There  are no  current
             recalls or, to Epitope's or Epitope  Knowledge,  threatened recalls
             of any Epitope Non-Exempt Product.

                 (iv) All Epitope  Non-Exempt  Products are  manufactured in all
             material  respects  in  accordance  with  the  good   manufacturing
             practices  regulations of the Federal Food,  Drug and Cosmetic Act.
             All  contract  manufacturers  and contract  sterilizers  have been,
             during the five-year  period prior to the date hereof,  and are now
             registered with the Food and Drug Administration and all facilities
             used in

                                      -26-
<PAGE>

             the manufacture and  sterilization of Epitope  Non-Exempt  Products
             have been,  during the  five-year  period prior to the date hereof,
             and  are  now in  compliance  in all  material  respects  with  the
             applicable regulations of the Food and Drug Administration.

                 (v) No  Epitope  Non-Exempt  Products  have  been,  during  the
             five-year period prior to the date hereof, or are now misbranded.

                 (vi) During the five-year period prior to the date hereof,  for
             all Epitope  Non-Exempt  Products,  Epitope has either submitted to
             the  Food  and  Drug   Administration   all   written   information
             disseminated on new uses in a supplemental application or submitted
             an application  for an exemption from  submission of a supplemental
             application.

             (b) Neither Epitope nor any Epitope Subsidiary has any Knowledge of
        any current  investigations by any Governmental or Regulatory including,
        without limitation,  the Food and Drug Administration  regarding Epitope
        or any products of Epitope or any Epitope Subsidiary.

        SECTION 3.30.  Product  Liability  Claims.  During the three-year period
preceding the date hereof,  neither Epitope nor any Epitope  Subsidiary has ever
been notified of or received a claim, informally or in a legal action filed with
a court,  arbitrator,  mediator or with any other  adjudicatory body or incurred
any  uninsured or insured  liability,  in the form of a judgment,  settlement or
other payment or required  activity or  inactivity,  for or based upon breach of
product  warranty (other than warranty service and repair claims in the ordinary
course of business not material in amount of significance),  strict liability in
tort,  negligent  design or  manufacture  of  product,  negligent  provision  of
instructions, warnings or services, fraudulent representations,  deceptive trade
practices or any other  allegation  of liability,  concerning a personal  injury
(whether  physical or  emotional  distress)  or  resulting  in product  recalls,
arising from the materials, design, testing,  manufacture,  packaging,  labeling
(including  instructions  for use) or sale of its products or from the provision
of services (hereafter collectively referred to as "Product Liability").  To the
knowledge  of  Epitope,  no basis  for any  claim  based  upon  alleged  Product
Liability exists which would have an Epitope Material Adverse Effect.

                                   ARTICLE IV

                      REPRESENTATIONS AND WARRANTIES OF STC

        Except as disclosed in the STC Disclosure  Schedule delivered to Epitope
separately prior to, or contemporaneously with, the date hereof (each section or
subsection  of which  qualifies  the  correspondingly  numbered  representation,
warranty  or covenant  to the extent  specified  therein),  STC  represents  and
warrants to Epitope that:

        SECTION 4.1.  Corporate  Existence and Power.  STC is a corporation duly
incorporated,  validly existing and in good standing under the laws of the State
of Delaware,  and has all corporate  powers required to carry on its business as
now conducted. STC is duly qualified to do business as a foreign corporation and
is in good  standing in each  jurisdiction  where the  character

                                      -27-
<PAGE>

of the property owned or leased by it or the nature of its activities makes such
qualification   necessary,   except  where  the  failure  to  be  so  qualified,
individually or in the aggregate,  would not be reasonably  likely to have a STC
Material  Adverse Effect.  STC has heretofore made available to Epitope true and
complete copies of STC's certificate of incorporation and bylaws as currently in
effect.

        SECTION  4.2.  Corporate  Authorization.  The  execution,  delivery  and
performance  by  STC  of  this  Agreement  and  the  consummation  by STC of the
transactions  contemplated  hereby are within STC's corporate powers and, except
for the STC Stockholder Approval (as defined herein),  have been duly authorized
by all necessary corporate action.  Assuming that this Agreement constitutes the
valid and binding obligation of Epitope,  this Agreement constitutes a valid and
binding  agreement of STC,  enforceable in accordance with its terms,  except as
such  enforceability may be limited by bankruptcy,  insolvency,  reorganization,
moratorium  and  similar  laws,  now or  hereafter  in  effect,  relating  to or
affecting  creditors' rights and remedies generally and to general principles of
equity (regardless of whether such  enforceability is considered in a proceeding
in equity or at law).

        SECTION 4.3.  Governmental  Authorization.  The execution,  delivery and
performance  by  STC  of  this  Agreement  and  the  consummation  by STC of the
transactions  contemplated  hereby  require  no action by or in  respect  of, or
filing  with,  any  Governmental  Entity  other  than (a) the  filing of (i) the
Articles of Merger in accordance  with the Oregon Law, (ii) the  Certificate  of
Merger in accordance with the Delaware Law, and (iii) appropriate documents with
the relevant  authorities of other states or  jurisdictions  in which STC or any
STC Subsidiary is qualified to do business;  (b) compliance  with any applicable
requirements  of the  HSR  Act by  stockholders  of STC  who  will  acquire  the
Surviving  Corporation  Common  Stock with a value in excess of $15 million as a
result  of the  Mergers  and  who do not  have  an  exemption  from  the HSR Act
therefor; (c) compliance with any applicable  requirements of the Securities Act
and the Exchange  Act; (d) such as may be required  under any  applicable  state
securities or blue sky laws; and (e) such other  consents,  approvals,  actions,
orders,  authorizations,  registrations,  declarations  and filings that, if not
obtained or made, would not, individually or in the aggregate, (x) be reasonably
likely to have a STC Material  Adverse Effect or (assuming for this purpose that
the  Effective  Time had  occurred) a  Surviving  Corporation  Material  Adverse
Effect, or (y) prevent or materially impair the ability of STC to consummate the
transactions contemplated by this Agreement.

        SECTION 4.4. Non-Contravention.  The execution, delivery and performance
by STC  of  this  Agreement  and  the  consummation  by STC of the  transactions
contemplated  hereby do not and will not (a)  contravene  or conflict with STC's
certificate of incorporation or bylaws, (b) assuming compliance with the matters
referred  to in  Section  4.3,  contravene  or  conflict  with or  constitute  a
violation of any provision of any law, regulation,  judgment,  injunction, order
or decree  binding upon or applicable to STC, (c)  constitute a default under or
give rise to a right of  termination,  cancellation or acceleration of any right
or obligation of STC or any STC Subsidiary or to a loss of any benefit or status
to which STC is entitled under any provision of any agreement, contract or other
instrument  binding upon STC or any STC  Subsidiary  or any license,  franchise,
permit or other similar authorization held by STC, or (d) result in the creation
or imposition of any Lien on any asset of STC other than, in the case of each of
(b),  (c) and  (d),  any such  items  that  would  not,  individually  or in the
aggregate (x) be reasonably  likely to have a STC

                                      -28-
<PAGE>

Material  Adverse Effect or (y) prevent or materially  impair the ability of STC
to consummate the transactions contemplated by this Agreement.

        SECTION 4.5. Capitalization.

             (a) The  authorized  capital  stock of STC  consists  of  6,000,000
        shares of STC Common Stock and 2,000,000  shares of STC Preferred Stock.
        At the close of business  on May 5, 2000,  (i)  2,388,798  shares of STC
        Common Stock were issued and outstanding, (ii) stock options ("STC Stock
        Options")  and  warrants  ("STC  Warrants")  to purchase an aggregate of
        187,477 shares of STC Common Stock were issued and outstanding (of which
        options and warrants to purchase an  aggregate  of 60,060  shares of STC
        Common Stock were exercisable), (iii) 783,548 shares of STC Common Stock
        were held in its treasury,  (iv) 1,080,061 shares of STC Preferred Stock
        were  issued and  outstanding,  and (v) stock  options  and  warrants to
        purchase an aggregate of 0 shares of STC Preferred Stock were issued and
        outstanding (of which options and warrants to purchase an aggregate of 0
        shares of STC Preferred Stock were exercisable).  All outstanding shares
        of capital stock of STC have been duly authorized and validly issued and
        are fully paid and nonassessable.

             (b) As of the date hereof,  except (i) as set forth in this Section
        4.5, (ii) and (ii) for changes since  December 31, 1999,  resulting from
        the exercise of stock  options  outstanding  on such date,  there are no
        outstanding  (x) shares of capital  stock or other voting  securities of
        STC, (y) securities of STC convertible  into or exchangeable  for shares
        of capital  stock or voting  securities  of STC, or (z) options or other
        rights to  acquire  from STC,  and no  obligation  of STC to issue,  any
        capital  stock,  voting  securities  or securities  convertible  into or
        exchangeable for capital stock or voting securities of STC (the items in
        clauses  (x),  (y) and (z) being  referred to  collectively  as the "STC
        Securities").  There are no  outstanding  obligations  of STC or any STC
        Subsidiary  to   repurchase,   redeem  or  otherwise   acquire  any  STC
        Securities.  There are no outstanding  contractual obligations of STC to
        provide funds to, or make any investment (in the form of a loan, capital
        contribution   or  otherwise)  in,  any  other  Person.   There  are  no
        stockholder   agreements,   voting   trusts  or  other   agreements   or
        understandings  to which  STC is a  party,  or of  which  STC is  aware,
        relating to voting, registration or disposition of any shares of capital
        stock of STC or  granting to any person or group of persons the right to
        elect, or to designate or nominate for election, a director to the board
        of directors of STC.

        SECTION 4.6.  Subsidiaries.  STC does not have any subsidiaries and does
not own or control, directly or indirectly,  any stock or equity interest in any
corporation or other Person.

        SECTION 4.7. Financial Statements; No Material Undisclosed Liabilities.

             (a) The audited  consolidated  balance sheets of STC as of December
        31, 1997, 1998 and 1999, together with the related audited statements of
        operations,  stockholders'  equity and cash  flows for the fiscal  years
        then ended and the notes thereto and the unaudited  balance sheet of STC
        as of February 29, 2000, together with the related unaudited  statements
        of operations,  stockholders'  equity and cash flows for the period

                                      -29-
<PAGE>

        then  ended  (the "STC  Financial  Statements")  fairly  present  in all
        material respects,  in conformity with GAAP consistently applied (except
        as may be indicated in the notes  thereto and except that the  unaudited
        interim  financial  statements  do not  contain  all GAAP  notes to such
        financial  statements),  the  financial  position of STC as of the dates
        thereof  and  its  results  of  operations,   stockholders'  equity  and
        consolidated  cash flows for the periods  then ended  (subject to normal
        year-end  adjustments  in the case of any  unaudited  interim  financial
        statements).

             (b) There are no liabilities of STC of any kind whatsoever, whether
        accrued, contingent, absolute, determined, determinable or otherwise, in
        each case,  that are required by GAAP to be set forth on a balance sheet
        of STC, other than:

                 (i) liabilities or obligations disclosed or provided for in the
             STC Balance Sheet or disclosed in the notes thereto;

                 (ii)  liabilities  or  obligations   under  this  Agreement  or
             incurred in connection with the transactions  contemplated  hereby;
             and

                 (iii) other  liabilities or obligations that individually or in
             the  aggregate,  would  not  be  reasonably  likely  to  have a STC
             Material Adverse Effect.

             (c) STC keeps  proper  accounting  records  in which  all  material
        assets  and  liabilities,  and  all  material  transactions,  of STC are
        recorded in conformity with GAAP. No part of STC's accounting  system or
        records,  or access thereto, is under the control of a Person who is not
        an employee of STC.

        SECTION 4.8. Information to be Supplied.

             (a) The  information  to be supplied by STC expressly for inclusion
        or  incorporation  by reference in the Joint Proxy  Statement/Prospectus
        will  (i) in the  case of the  Registration  Statement,  at the  time it
        becomes  effective,  not contain any untrue statement of a material fact
        or omit to state any  material  fact  required  to be stated  therein or
        necessary in order to make the  statements  therein not  misleading  and
        (ii)   in   the   case   of   the   remainder   of   the   Joint   Proxy
        Statement/Prospectus,  at the time of the  mailing  thereof,  and at the
        time of the Special  Meetings,  not contain  any untrue  statement  of a
        material  fact or omit to state any material  fact required to be stated
        therein or necessary in order to make the statements  therein,  in light
        of the  circumstances  under which they are made,  not  misleading.  The
        Joint  Proxy   Statement/Prospectus   will  comply   (with   respect  to
        information  relating to STC) as to form in all material  respects  with
        the provisions of the Securities Act and the Exchange Act.

             (b) Notwithstanding  the foregoing,  STC makes no representation or
        warranty  with  respect  to  any  statements  made  or  incorporated  by
        reference in the Joint Proxy  Statement/Prospectus  based on information
        supplied by Epitope.

        SECTION 4.9. Absence of Certain Changes. Since December 31, 1999, except
as otherwise  expressly  contemplated by this  Agreement,  STC has conducted its
business in the ordinary course  consistent with past practice and there has not
been (a) any damage,  destruction

                                      -30-
<PAGE>

or other  casualty  loss  (whether or not covered by  insurance)  affecting  the
business or assets of STC that,  individually  or in the  aggregate,  has had or
would be  reasonably  likely  to have a STC  Material  Adverse  Effect,  (b) any
action, event, occurrence,  development or state of circumstances or facts that,
individually or in the aggregate,  has had or would be reasonably likely to have
a STC Material Adverse Effect or (c) any incurrence,  assumption or guarantee by
STC of any material  indebtedness  for borrowed money other than in the ordinary
course and in amounts and on terms consistent with past practices.

        SECTION 4.10.  Litigation.  Section 4.10 of the STC Disclosure  Schedule
contains a list of each action, suit,  investigation,  arbitration or proceeding
pending against,  or to the Knowledge of STC threatened  against,  STC or any of
its assets or properties before any arbitrator or Governmental  Entity.  None of
such actions, suits, investigations,  arbitrations or proceedings,  individually
or in the aggregate,  would be reasonably  likely to have a STC Material Adverse
Effect.  There are no outstanding  judgments,  decrees,  injunctions,  awards or
orders against STC that would be reasonably  likely to have,  individually or in
the aggregate, a STC Material Adverse Effect.

        SECTION 4.11. Taxes.

             (a) All Tax returns,  statements,  reports and forms (collectively,
        the "STC Returns") required to be filed with any taxing authority by, or
        with respect to, STC have been filed in substantial  compliance with all
        applicable laws.

             (b) STC has timely  paid all Taxes  shown as due and payable on the
        STC Returns that have been so filed,  and all other Taxes not subject to
        reporting  obligations,  and as of the time of filing,  the STC  Returns
        correctly  reflected the facts regarding the income,  business,  assets,
        operations,  activities and the status of STC (other than Taxes that are
        being  contested  in good  faith and for  which  adequate  reserves  are
        reflected on the STC Balance Sheet).

             (c) STC has made  provision for all Taxes payable by them for which
        no STC Return has yet been filed.

             (d) The  charges,  accruals  and reserves for Taxes with respect to
        STC reflected on the STC Balance Sheet are adequate  under GAAP to cover
        the Tax liabilities accruing through the date thereof.

             (e)  There is no  action,  suit,  proceeding,  audit  or claim  now
        proposed or pending against or with respect to STC in respect of any Tax
        that would be reasonably likely to have a STC Material Adverse Effect.

             (f) STC has  not  been a  member  of an  affiliated,  consolidated,
        combined  or  unitary  group  other than one of which STC was the common
        parent.

             (g) STC does not hold any asset  subject to a consent under Section
        341(f) of the Code.

                                      -31-
<PAGE>

             (h)  The  representations  and  warranties  contained  in  the  STC
        Representation  Letter,  attached  hereto  as  Exhibit  J are  true  and
        correct.

        SECTION 4.12. Employee Benefits.

             (a)  Section  4.12(a)  of the STC  Disclosure  Schedule  contains a
        correct and complete list  identifying each material  "employee  benefit
        plan", as defined in Section 3(3) of ERISA,  each employment,  severance
        or similar contract,  plan, arrangement or policy and each other plan or
        arrangement  (written  or oral)  providing  for  compensation,  bonuses,
        profit-sharing,  stock  option or other  stock  related  rights or other
        forms  of  incentive  or  deferred   compensation,   vacation  benefits,
        insurance coverage (including any self-insured arrangements),  health or
        medical   benefits,    disability   benefits,   workers'   compensation,
        supplemental    unemployment    benefits,    severance    benefits   and
        post-employment or retirement benefits (including compensation, pension,
        health,   medical  or  life  insurance  benefits)  that  is  maintained,
        administered or contributed to by STC or any of its ERISA Affiliates and
        covers any  employee or former  employee  of STC or any STC  Subsidiary.
        Copies of such plans (and, if applicable,  related trust agreements) and
        all  amendments  thereto and written  interpretations  thereof have been
        furnished,  or will be made available upon request,  to Epitope together
        with the most recent annual report (Form 5500 including,  if applicable,
        Schedule B thereto) and summary plan description  prepared in connection
        with any such plan.  Such plans are referred to  collectively  herein as
        the "STC  Employee  Plans".  For purposes of this Section  4.12,  "ERISA
        Affiliate"  of any Person means any other Person  which,  together  with
        such Person,  would be treated as a single employer under Section 414 of
        the Code.

             (b) No STC Employee  Plan is now or at any time has been subject to
        Part 3, Subtitle B of Title I or ERISA or Title IV of ERISA.  At no time
        has STC or any of its ERISA Affiliates  contributed to, or been required
        to contribute to, any "multiemployer  plan," as defined in Section 3(37)
        of ERISA (a "Multiemployer  Plan"), and neither STC nor any of its ERISA
        Affiliates has, or ever has had, any liability (contingent or otherwise)
        relating to the withdrawal or partial  withdrawal  from a  Multiemployer
        Plan.  To the  Knowledge  of STC, no  condition  exists and no event has
        occurred  that would be  reasonably  likely to  constitute  grounds  for
        termination  of any STC Employee Plan that is a Retirement  Plan. To the
        Knowledge  of STC,  nothing  has been done or  omitted to be done and no
        transaction or holding of any asset under or in connection  with any STC
        Employee Plan has occurred that will make STC or any STC Subsidiary,  or
        any  officer or director  of STC or any STC  Subsidiary,  subject to any
        liability  under  Title I of ERISA or  liable  for any tax  pursuant  to
        Section  4975 of the  Code  (assuming  the  taxable  period  of any such
        transaction  expired as of the date  hereof)  that  would be  reasonably
        likely to have a STC Material Adverse Effect.

             (c) Each STC Employee  Plan that is intended to be qualified  under
        Section  401(a)  of the Code  now  meets,  and at all  times  since  its
        inception have met, the  requirements for such  qualification,  and each
        trust  forming  a part  thereof  is  now,  and at all  times  since  its
        inception  has been,  exempt from tax pursuant to Section  501(a) of the
        Code.  Each such  plan has  received  a  determination  letter  from the
        Internal  Revenue  Service to the effect that such plan is qualified and
        its  related  trust  is  exempt  from  federal

                                      -32-
<PAGE>

        income taxes. STC has furnished, or will make available upon request, to
        Epitope copies of the most recent Internal Revenue Service determination
        letters with respect to each such STC Employee  Plan.  Each STC Employee
        Plan has been maintained and administered in substantial compliance with
        its terms  (except  that in any case in which any STC  Employee  Plan is
        currently  required to comply with a provision  of ERISA or of the Code,
        but is not yet to be amended to reflect  such  provision,  such plan has
        been  maintained and  administered in accordance with the provision) and
        with the requirements prescribed by any and all statutes,  orders, rules
        and regulations,  including but not limited to ERISA and the Code, which
        are applicable to such STC Employee Plan. All material reports,  returns
        and similar documents with respect to each STC Employee Plan required to
        be filed with any governmental agency or distributed to any STC Employee
        Plan participant have been duly timely filed and distributed.

             (d) There is no contract, agreement, plan or arrangement that, as a
        result of the  Mergers,  would be  reasonably  likely to obligate STC to
        make any payment of any amount that would not be deductible  pursuant to
        the terms of Section 162(m) or Section 280G of the Code.

             (e) Except as  disclosed  in  writing to Epitope  prior to the date
        hereof,  there  has been no  amendment  to,  written  interpretation  or
        announcement (whether or not written) relating to, or change in employee
        participation  or  coverage  under,  any STC  Employee  Plan that  would
        increase  materially the expense of  maintaining  such STC Employee Plan
        above the level of the  expense  incurred  in  respect  thereof  for the
        fiscal year ended December 31, 1999.

             (f) No STC  Employee  Plan  promises  or  provides  post-retirement
        medical,  life  insurance or other  benefits due now or in the future to
        current, former or retired employees of STC or any Subsidiary.

        SECTION 4.13. Compliance with Laws; Licenses, Permits and Registrations.

             (a)  STC is  not  in  violation  of,  nor  has  STC  violated,  any
        applicable  provisions of any laws, statutes,  ordinances,  regulations,
        judgments,  injunctions,  orders or consent decrees, except for any such
        violations  that,  individually  or  in  the  aggregate,  would  not  be
        reasonably likely to have a STC Material Adverse Effect.

             (b) STC has all permits, licenses, approvals, authorizations of and
        registrations with and under all federal, state, local and foreign laws,
        and  from  all  Governmental  Entities  required  by STC to carry on its
        business as  currently  conducted,  except where the failure to have any
        such permits,  licenses,  approvals,  authorizations  or  registrations,
        individually or in the aggregate, would not be reasonably likely to have
        a STC Material Adverse Effect.

        SECTION 4.14. Title to Properties.

             (a) STC has good  and  marketable  title  to,  or  valid  leasehold
        interests  in, all its  properties  and assets except for such as are no
        longer  used or useful in the  conduct of its  business  or as have been
        disposed of in the ordinary course of business and except for

                                      -33-
<PAGE>

        defects in title,  easements,  restrictive  covenants and similar Liens,
        encumbrances  or impediments  that do not materially  interfere with the
        ability of STC to conduct its business as currently conducted.  All such
        assets and properties, other than assets and properties in which STC has
        leasehold  interests,  are free and clear of all Liens, except for Liens
        that do not and will not materially interfere with the ability of STC to
        conduct its business as currently conducted.

             (b) STC (i) is in  substantial  compliance  with  the  terms of all
        leases to which it is a party and under  which it is in  occupancy,  and
        all such  leases are in full force and effect and (ii)  enjoys  peaceful
        and undisturbed possession under all such leases.

        SECTION 4.15. Intellectual Property.

             (a) STC owns or has a valid license to use (i) all Marks;  (ii) all
        Patents;  (iii) all  Copyrights;  (iv) all Rights in Mask Works' and (v)
        all Trade  Secrets;  necessary  to (x) carry on the  business  of STC as
        currently  conducted  or as proposed to be  conducted  by the  Surviving
        Corporation,  to (y)  make,  have  made,  use,  distribute  and sell all
        products currently sold by STC and all products in development.

             (b) There are no outstanding and, to STC's Knowledge, no threatened
        disputes or disagreements  with respect to any agreement to which STC is
        a party, relating to any of STC's Marks, Patents, Copyrights,  Rights in
        Mask  Works,   or  Trade  Secrets   (collectively,   "STC   Intellectual
        Property").

             (c) STC is the owner of all right,  title,  and  interest in and to
        the STC  Intellectual  Property,  free and clear of all liens,  security
        interests, charges, encumbrances, equities, and other adverse claims.

             (d) All former and current  employees of STC have executed  written
        contracts  with STC that  assign to STC all  rights  to any  inventions,
        improvements,  discoveries,  or information  relating to the business of
        STC.  To  STC's  knowledge,  no  employee  of STC has  entered  into any
        contract  that  restricts or limits in any way the scope or type of work
        in which the  employee  may be  engaged  or  requires  the  employee  to
        transfer,  assign, or disclose information concerning his work to anyone
        other than STC.

             (e) All of the  Patents are  currently  in  compliance  with formal
        legal  requirements  (including  payment  of  filing,  examination,  and
        maintenance   fees  and  proofs  of  working  or  use),  are  valid  and
        enforceable,  and are not  subject to any  maintenance  fees or taxes or
        actions that have not been paid when due.

             (f) STC  uses  reasonable  procedures  to keep  its  Trade  Secrets
        confidential, STC's Trade Secrets have been disclosed only under written
        agreements  that  require  the  recipient  to hold  such  Trade  Secrets
        confidential.

             (g) No  Patent  has been or is now  involved  in any  interference,
        reissue,  reexamination,  or opposition proceeding.  To STC's Knowledge,
        there is no potentially  interfering patent or patent application of any
        third party.

                                      -34-
<PAGE>

             (h) No  Patent  is  infringed  or,  to  STC's  Knowledge,  has been
        challenged  or threatened  in any way. To STC's  knowledge,  none of the
        products  manufactured  and sold or proposed to be sold, nor any process
        or know-how  used, by STC infringes or is alleged to infringe any Patent
        or other proprietary right of any other Person.

             (i) STC is not required to make any  payments to any third  parties
        in connection with its use of the STC Intellectual Property.

             (j) All products  made,  used,  or sold under the Patents have been
        marked with the proper patent notice.

        SECTION 4.16. Environmental Matters.

             (a) To the  Knowledge  of STC,  there has not been,  as of the date
        hereof, any (i) "release" (as defined in 42 U.S.C.ss.9601(22)) or threat
        of  a  "release"  of  any  "hazardous  substances"  (as  defined  in  42
        U.S.C.ss.9601(14))  or oil or other  petroleum  related  products  on or
        about any of the real  property  owned,  operated or leased by STC ("STC
        Real  Property"),   or  (ii)  release  or  presence  of  any  pollutant,
        contaminant or condition giving rise to a cause of action under federal,
        state or local  statutory  or common law on or about any of the STC Real
        Property  other than such as would not reasonably be expected to have an
        STC Material Adverse Effect.

             (b) STC has no contract or agreement or has not otherwise  arranged
        for disposal or treatment,  or arranged with a transporter for transport
        for disposal or treatment, of hazardous substances at any "facility" (as
        defined in 42 U.S.C. ss.9601(9)) owned or operated by another Person.

             (c) STC has not accepted any hazardous  substances for transport to
        disposal or treatment facilities or sites selected by STC.

             (d) To the  Knowledge  of STC,  the STC Real  Property  and the use
        thereof is in material  compliance  with, and STC is in compliance with,
        all applicable laws, statutes,  ordinances, rules and regulations of any
        Governmental  Entity relating to environmental  protection,  underground
        storage tanks, toxic waste,  hazardous waste, oil or hazardous substance
        handling, treatment,  storage, disposal or transportation,  or arranging
        therefor, respecting any products or materials previously or now located
        on,  or in  transit  from  the  STC  Real  Property,  including  without
        limitation the Resource Conservation and Recovery Act, the Comprehensive
        Environmental   Response,   Compensation  and  Liability  Act,  and  the
        Superfund Amendments and Reauthorization Act of 1986.

             (e) The past disposal  practices  relating to hazardous  substances
        and  hazardous  wastes of STC (and its  predecessors,  if any) have been
        accomplished in accordance with all applicable  laws,  statutes,  rules,
        regulations and ordinances.

             (f) STC has not been  notified of nor, to the  Knowledge of STC, is
        there any basis for any  potential  liability of STC with respect to the
        clean-up of any waste  disposal  site or  facility.  STC has received no
        notification  to the effect  that any site at which STC

                                      -35-
<PAGE>

        has  disposed  of  hazardous  substances  or oil has  been  or is  under
        investigation by any Governmental Entity.

             (g) STC has not received any  notification of releases of hazardous
        substances or oil from any governmental or quasi-governmental agency.

        SECTION 4.17. Finders' Fees; Opinions of Financial Advisor.

             (a)  Except  for  BancBoston   Robertson  Stephens,   there  is  no
        investment  banker,  broker,  finder or other intermediary that has been
        retained by, or is  authorized  to act on behalf of, STC or who might be
        entitled to any fee or commission  from Epitope or any of its Affiliates
        upon consummation of the transactions contemplated by this Agreement.

             (b) STC has received the opinion of BancBoston  Robertson  Stephens
        dated as of the date hereof,  to the effect that,  as of such date,  the
        Exchange Ratio is fair,  from a financial  point of view, to STC and the
        holders  of shares of STC Common  Stock  (other  than  Merger  Sub,  any
        affiliates  of Epitope or Merger Sub, or any holders of STC Common Stock
        who are officers or directors  (or who have  representatives  serving as
        directors) of STC).

        SECTION 4.18. Required Vote and Waiver; Board Approval.

             (a) Assuming  satisfaction  of the  condition  set forth in Section
        9.3(g), the only vote or waiver of rights of the holders of any class or
        series of capital  stock of STC required by law,  rule or  regulation to
        approve and adopt this  Agreement  and/or any of the other  transactions
        contemplated  hereby,  including  the  Mergers  (collectively,  the "STC
        Stockholder  Approval") is the  affirmative  vote of the holders of more
        than fifty  percent  of the  outstanding  shares of STC Common  Stock in
        favor of the approval and adoption of this Agreement and approval of the
        STC Merger.

             (b) STC's Board of Directors has  unanimously  (i)  determined  and
        declared that this Agreement and the transactions  contemplated  hereby,
        including the Mergers,  are  advisable and in the best  interests of STC
        and its  stockholders,  (ii)  approved and adopted this  Agreement,  the
        Mergers  and  the  other  transactions  contemplated  hereby  and  (iii)
        resolved to  recommend to such  stockholders  that they vote in favor of
        adopting and approving this Agreement and the Mergers in accordance with
        the terms hereof at a special  meeting of the  stockholders  of STC duly
        held for such purpose (the "STC Stockholders Meeting").

        SECTION  4.19.  State  Takeover  Statutes.  STC has  taken  all  actions
required  to be  taken  by  it  in  order  to  exempt  this  Agreement  and  the
transactions  contemplated  hereby  from the  provisions  of Section  203 of the
Delaware Law, and accordingly, such Section does not apply to the Mergers or any
of  such  transactions.   No  other  "control  share   acquisition,"   "business
combination,"  "fair price" or other  anti-takeover laws or regulations  enacted
under state or federal laws in the United States apply to this  Agreement or any
of the transactions contemplated hereby.

                                      -36-
<PAGE>

        SECTION 4.20. Pooling Matters; Tax Treatment.

             (a) STC  intends  that the  Mergers  be  accounted  for  under  the
        "pooling of interests"  method under the  requirements of Opinion No. 16
        (Business  Combinations)  of  the  Accounting  Principles  Board  of the
        American  Institute  of  Certified  Public  Accountants,  the  Financial
        Accounting  Standards  Board,  and the rules and regulations of the SEC.
        STC will request a letter addressed to it from Arthur Andersen LLP dated
        as of the Closing Date,  and (if and when obtained) a copy of it will be
        delivered  to  Epitope.   Such  letter  (which  may  contain   customary
        qualifications  and  assumptions)  shall state that Arthur  Andersen LLP
        concurs with STC's management's conclusion that no conditions exist with
        respect  to STC that  would  preclude  the  Surviving  Corporation  from
        accounting  for the Mergers as a "pooling of  interests" as described in
        the first sentence of Section 4.20(a).

             (b)  Neither STC nor any of its  Affiliates  has taken or agreed to
        take, or will take,  any action or is aware of any fact or  circumstance
        that  would  prevent  or impede  the  Mergers  from  qualifying  (i) for
        "pooling of  interests"  accounting  treatment  as  described in Section
        4.20(a) above or (ii) as a 368  Reorganization or that would make untrue
        any representation or warranty  contained in the  Representation  Letter
        attached as Exhibit J.

        SECTION 4.21. Certain Agreements.  Neither STC nor any of its Affiliates
(i) are parties to or  otherwise  bound by any  agreement  or  arrangement  that
limits or otherwise  restricts  STC, the Surviving  Corporation  or any of their
respective  Affiliates  from engaging or competing in any line of business or in
any locations, and (ii) except in the ordinary course of business, have amended,
modified or terminated any material contract, agreement or arrangement of STC or
otherwise waived,  released or assigned any material rights,  claims or benefits
of STC thereunder.

        SECTION 4.22. Employment Agreements. There exists (i) no union, guild or
collective  bargaining  agreement to which STC is a party,  (ii) no  employment,
consulting  or  severance  agreement  between  STC and any  Person  (except  for
consulting agreements that individually,  and in the aggregate, are not material
to STC),  and (iii) no  employment,  consulting,  severance  or  indemnification
agreement  or other  agreement  or plan to which  STC is a party  that  would be
altered or result in any bonus, golden parachute,  severance or other payment or
obligation to any Person,  or result in any  acceleration of the time of payment
or in the provision or vesting of any benefits,  as a result of the execution or
performance  of this  Agreement  or as a  result  of the  Mergers  or the  other
transactions contemplated hereby.

        SECTION 4.23.  Transactions  With  Directors,  Officers and  Affiliates.
Except  for any of the  following  matters  which  would not be  required  to be
disclosed  pursuant to Item 402 or Item 404 of Regulation  S-K of the Commission
(assuming STC was subject to such Items),  since  December 31, 1999,  there have
been no transactions  between STC or any of its  Subsidiaries  and any director,
officer, employee, stockholder or "Affiliate" (as identified pursuant to Section
8.8 hereof) of STC, including, without limitation,  loans, guarantees or pledges
to, by or for STC,  from,  to, by or for any of such Persons.  Except for any of
the following  matters  which would not be required to be disclosed  pursuant to
Item 402 or Item 404 of Regulation S-K of the Commission  (assuming that STC was
subject to such  Items),  since  September  30,  1999,  none of the  officers or
directors of STC, and no spouse or relative of any of such  Persons,  has been a

                                      -37-
<PAGE>

director or officer of, or has had any material direct or indirect  interest in,
any Person which during such period has been a supplier, customer or sales agent
of STC or has  competed  with or been  engaged in any business of the kind being
conducted by STC.

        SECTION 4.24. Material Contracts.  Schedule 4.24 delivered to Epitope by
STC prior to the execution of this  Agreement  lists all material  contracts and
agreements  to which,  as of the date  hereof,  STC is a party or by which it is
bound or under which STC has or may acquire any rights,  which involve or relate
to (i)  obligations  of STC for borrowed money or other  indebtedness  where the
amount of such obligations exceeds $250,000 individually, (ii) the lease by STC,
as lessee or lessor,  of real property for rent of more than $250,000 per annum,
(iii) the  purchase or sale of goods (other than raw material to be purchased by
STC on terms that are customary and consistent with the past practice of STC and
in amounts and at prices substantially consistent with past practices of STC) or
services  with an aggregate  minimum  purchase  price of more than  $250,000 per
annum, (iv) rights to manufacture  and/or distribute any product which accounted
for more than  $250,000  of the  consolidated  revenues of STC during the fiscal
year ended  September  30, 1999 or under which STC  received or paid  license or
other fees in excess of $250,000  during any year,  (v) the  purchase or sale of
assets or properties  not in the ordinary  course of business  having a purchase
price  in  excess  of  $250,000,  (vi)  the  right  (whether  or  not  currently
exercisable)  to use,  license  (including any  "in-license"  or  "outlicense"),
sublicense  or  otherwise  exploit  any  intellectual  property  right  or other
proprietary  asset of STC or any other Person which,  when  considered  together
with all such other rights, is material to STC; (vii) any material collaboration
or joint venture or similar arrangement;  (viii) the restriction on the right or
ability of STC (A) to compete with any other Person,  (B) to acquire any product
or other asset or any services  from any other Person,  (C) to solicit,  hire or
retain any Person as an employee,  consultant or independent contractor,  (D) to
develop, sell, supply, distribute,  offer, support or service any product or any
technology  or other asset to or for any other Person,  (E) to perform  services
for any other  Person,  or (F) to transact  business or deal in any other manner
with any other Person;  (ix) any currency  hedging;  or (x)  individual  capital
expenditures  or  commitments  in excess of  $250,000.  All such  contracts  and
agreements  are duly  and  validly  executed  by STC and are in full  force  and
effect.  STC has not violated or breached,  or committed any default under,  any
contract  or  agreement,  and,  to the  Knowledge  of STC,  no other  Person has
violated or breached, or committed any default under, any contract or agreement,
which  violation,  breach  or  default  (alone  or  in  combination  with  other
violations, breaches or defaults under such contract or agreement or under other
contracts or  agreements)  has had or may  reasonably  be expected to have a STC
Material  Adverse  Effect.  No event has  occurred  which,  after  notice or the
passage of time or both, would constitute a default by STC under any contract or
agreement  or give any Person the right to (A) declare a default or exercise any
remedy  under any  contract  or  agreement,  (B)  receive  or  require a rebate,
chargeback,  penalty  or change in  delivery  schedule  under  any  contract  or
agreement,  (C)  accelerate  the  maturity  or  performance  of any  contract or
agreement, or (D) cancel, terminate or modify any contract or agreement, in each
case which,  together with all other events of the types  referred to in clauses
(A), (B), (C) and (D) of this sentence has had or may  reasonably be expected to
have a STC Material  Adverse  Effect.  All such  contracts and  agreements  will
continue,  after the Effective  Time, to be binding in all material  respects in
accordance with their respective terms until their respective expiration dates.

                                      -38-
<PAGE>

        SECTION  4.25.  Certain  Business  Practices.  Neither  STC  nor  to the
knowledge of STC any  director,  officer,  agent or employee of STC has (i) used
any funds for unlawful  contributions,  gifts,  entertainment  or other unlawful
expenses  relating to  political  activity,  (ii) made any  unlawful  payment to
foreign or domestic government  officials or employees or to foreign or domestic
political  parties or campaigns or violated any provision of the Foreign Corrupt
Practices Act of 1977,  as amended,  (assuming for purposes of this Section 4.25
that STC is subject to Section 30A of the Exchange  Act) or (iii) made any other
unlawful payment.

        SECTION  4.26.  Insurance.  The Company has made  available to Epitope a
summary of all  material  insurance  policies and all  material  self  insurance
programs and arrangements relating to the business, assets and operations of STC
 . Each of such  insurance  policies is in full force and effect.  Since December
31, 1999, STC has not received any notice or other  communication  regarding any
actual or possible (i)  cancellation or  invalidation of any material  insurance
policy,  (ii) refusal of any  coverage or rejection of any material  claim under
any insurance policy, or (iii) material adjustment in the amount of the premiums
payable  with  respect to any  insurance  policy.  There is no pending  workers'
compensation  or other  claim  under or based upon any  insurance  policy of STC
other than claims incurred in the ordinary course of business.

        SECTION 4.27. Product Information.

             (a)  Non-Exempt  Products.  The  products  of STC listed in Section
        4.27(a) of the Disclosure  Schedule (the "STC Non-Exempt  Products") are
        subject  to the  premarket  notification  (510(k))  requirements  of the
        Medical Device Amendments to the Federal Food, Drug and Cosmetic Act and
        all marketing  clearance/substantial  equivalence  letters received from
        the FDA are identified in Section 4.27(a) of the Disclosure Schedule.

                 (i) All  STC  Non-Exempt  Products  and  all  modifications  or
             changes to any Non-Exempt Product are in compliance in all material
             respects with the premarketing and postmarking  regulatory controls
             of the Medical  Device  Amendments  to the Federal  Food,  Drug and
             Cosmetic Act.

                 (ii)   All   pre-market   notification   submissions   and  any
             supplementary  materials  submitted  therewith  are accurate in all
             material  respects  and  each of the  STC  Non-Exempt  Products  is
             suitable for its intended use.

                 (iii)  During the  five-year  period  prior to the date hereof,
             there  have been no adverse  actions  taken by the FDA or any other
             Governmental   Entity  involving   Non-Exempt  Products  including,
             without limitation any recalls of any STC Non-Exempt  Product.  For
             STC Non-Exempt  Products,  STC maintains a system  designed to keep
             records of complaints.  There are no current  recalls or, to STC or
             STC's Knowledge, threatened recalls of any STC Non-Exempt Product.

                 (iv)  All  STC  Non-Exempt  Products  are  manufactured  in all
             material  respects  in  accordance  with  the  good   manufacturing
             practices  regulations of the Federal Food,  Drug and Cosmetic Act.
             All  contract  manufacturers  and contract  sterilizers  have been,
             during the five-year  period prior to the date hereof,  and are now
             registered with the Food and Drug Administration and all facilities
             used  in

                                      -39-
<PAGE>

             the manufacture and  sterilization of STC Non-Exempt  Products have
             been, during the five-year period prior to the date hereof, and are
             now in  compliance  in all material  respects  with the  applicable
             regulations of the Food and Drug Administration.

                 (v) No STC Non-Exempt  Products have been, during the five-year
             period  prior  to the date  hereof,  or are now  misbranded  in any
             material respect.

                 (vi) During the five-year period prior to the date hereof,  for
             all STC Non-Exempt  Products,  STC has either submitted to the Food
             and Drug Administration all written information disseminated on new
             uses in a supplemental  application or submitted an application for
             an exemption from submission of a supplemental application.

             (b) STC  has no  Knowledge  of any  current  investigations  by any
        Governmental  Entity including,  without  limitation,  the Food and Drug
        Administration regarding STC or any products of STC.

        SECTION 4.28.  Product  Liability  Claims.  During the three-year period
preceding  the date hereof,  STC has never been notified of or received a claim,
informally or in a legal action filed with a court, arbitrator, mediator or with
any other adjudicatory body or incurred any uninsured or insured  liability,  in
the form of a judgment,  settlement  or other  payment or  required  activity or
inactivity,  for or based upon breach of product  warranty  (other than warranty
service and repair  claims in the  ordinary  course of business  not material in
amount  of  significance),   strict  liability  in  tort,  negligent  design  or
manufacture  of  product,  negligent  provision  of  instructions,  warnings  or
services,  fraudulent  representations,  deceptive  trade practices or any other
allegation  of  liability,  concerning a personal  injury  (whether  physical or
emotional distress) or resulting in product recalls, arising from the materials,
design, testing,  manufacture,  packaging,  labeling (including instructions for
use) or sale of its  products  or from  the  provision  of  services  (hereafter
collectively  referred to as "Product  Liability").  To the Knowledge of STC, no
basis for any claim based upon alleged Product Liability exists which would have
an STC Material Adverse Effect.

                                   ARTICLE V

                  REPRESENTATIONS AND WARRANTIES OF MERGER SUB

        Merger Sub represents and warrants to STC as follows:

        SECTION   5.1.   Organization.   Merger  Sub  is  a   corporation   duly
incorporated,  validly existing and in good standing under the laws of Delaware.
Merger  Sub is a direct  wholly-owned  subsidiary  of  Epitope.  The  authorized
capital stock of Merger Sub consists of 120,000,000  shares of common stock, par
value $0.000001 per share and 25,000,000  shares of preferred  stock,  par value
$0.000001  per  share.  As of the date  hereof,  100 shares of Merger Sub common
stock  are  outstanding,  all of which  are held  beneficially  and of record by
Epitope.  There are not now, and  immediately  prior to the Sam Effective  Time,
there will be no, options,  warrants or other rights to purchase common stock of
Merger Sub.

                                      -40-
<PAGE>

        SECTION  5.2.  Corporate  Authorization.  Merger  Sub has all  requisite
corporate power and authority to enter into this agreement and to consummate the
transaction  contemplated  by  this  Agreement.  The  execution,   delivery  and
performance by each of Merger Sub of this Agreement and the  consummation of the
transactions  contemplated  by this Agreement  have been duly  authorized by all
necessary  corporate  action on the part of Merger Sub. This  Agreement has been
duly  executed and  delivered by Merger Sub and  constitutes a valid and binding
agreement of Merger Sub,  enforceable  against it in accordance  with its terms,
except  as  such  enforceability  may  be  limited  by  bankruptcy,  insolvency,
reorganization,  moratorium  and other  similar  laws  relating to or  affecting
creditors generally or by general equity principles.

        SECTION 5.3. Non-Contravention.  The execution, delivery and performance
by Merger  Sub of this  Agreement  and the  consummation  by  Merger  Sub of the
transactions  contemplated  by this  Agreement do not and will not contravene or
conflict with its certificate of incorporation or bylaws.

        SECTION 5.4. No Business  Activities.  Merger Sub has not  conducted any
activities  other than in connection  with the  organization  of Merger Sub, the
negotiation  and  execution  of  this  Agreement  and  the  consummation  of the
transactions contemplated by this Agreement. Merger Sub has no subsidiaries.

        SECTION 5.5. Taxes.

             (a) The representations and warranties  contained in the Merger Sub
        Representation Letter attached hereto as Exhibit O are true and correct.

             (b) Merger Sub has not taken or agreed to take,  will not take, and
        is not aware of any fact or  circumstance  that would  prevent or impede
        the Mergers from  qualifying as 368  Reorganizations  or that would make
        untrue  any  representation  or  warranty  contained  in  the  Officer's
        Certificate referred to in Section 5.5(a) hereof.

                                   ARTICLE VI

                              COVENANTS OF EPITOPE

        Epitope agrees that:

        SECTION   6.1.   Epitope   Interim   Operations.   Except  as  expressly
contemplated or permitted by this Agreement,  or as required by any Governmental
Entity of  competent  jurisdiction,  without  the prior  consent  of STC  (which
consent  shall not be  unreasonably  withheld or delayed),  from the date hereof
until the Effective  Time,  Epitope  shall,  and shall cause each of the Epitope
Subsidiaries to, conduct their business in all material respects in the ordinary
course  consistent  with past  practice  and shall use  commercially  reasonable
efforts to (i) preserve intact its present business organization,  (ii) maintain
in effect all material foreign, federal, state and local licenses, approvals and
authorizations, including, without limitation, all material licenses and permits
that are required for Epitope or any Epitope Subsidiary to carry on its business
and (iii) preserve existing relationships with its material customers,  lenders,
suppliers and others having  material  business  relationships  with it. Without
limiting the generality of the foregoing,  except as expressly  contemplated  or
permitted  by  this  Agreement,  or as  required  by a

                                      -41-
<PAGE>

Governmental  Entity of competent  jurisdiction,  from the date hereof until the
Effective  Time,  without the prior  consent of STC (which  consent shall not be
unreasonably  withheld or delayed),  Epitope  shall not, nor shall it permit any
Epitope Subsidiary to:

             (a) amend its articles of incorporation or by-laws;

             (b) split,  combine or  reclassify  any shares of capital  stock of
        Epitope or any less-than-wholly-owned Epitope Subsidiary or declare, set
        aside or pay any  dividend  (except for  dividends  by any  wholly-owned
        Epitope  Subsidiary) or other  distribution  (whether in cash,  stock or
        property or any combination thereof) in respect of its capital stock, or
        redeem, repurchase or otherwise acquire or offer to redeem,  repurchase,
        or otherwise  acquire any of its  securities  or any  securities  of any
        Epitope Subsidiary;

             (c) (i) issue, deliver or sell, or authorize the issuance, delivery
        or sale  of,  any  shares  of its  capital  stock  of any  class  or any
        securities convertible into or exercisable for, or any rights,  warrants
        or options to acquire,  any such capital  stock or any such  convertible
        securities,  other than (A) a number of shares of capital stock equal to
        that number of shares underlying  options forfeited prior to the Closing
        by former Epitope employees,  pursuant to the Epitope Employee Plans; or
        (B) Epitope  Common Stock upon the exercise of stock options or warrants
        in  accordance  with their  present  terms or upon  exercise  of options
        issued pursuant to clause (A) above of this Section  6.1(c)(i);  or (ii)
        amend in any respect any term of any outstanding  security of Epitope or
        any Epitope Subsidiary;

             (d) other than in connection  with  transactions  not prohibited by
        Section  6.1(e),  incur any capital  expenditures  or any obligations or
        liabilities in respect thereof, except for those (i) contemplated by the
        capital  expenditure  budgets for  Epitope and the Epitope  Subsidiaries
        made  available  to STC,  or (ii)  incurred  in the  ordinary  course of
        business of Epitope and the Epitope  Subsidiaries  and  consistent  with
        past practice;

             (e)  acquire  (whether  pursuant  to cash  merger,  stock  or asset
        purchase  or  otherwise)  in  one   transaction  or  series  of  related
        transactions (i) any assets  (including any equity  interests)  having a
        fair market  value in excess of $100,000,  or (ii) all or  substantially
        all of the equity interests of any Person or any business or division of
        any Person  having a fair market value in excess of $100,000,  but in no
        event shall the  expenditures,  commitments,  obligations or liabilities
        made,  incurred,  or  assumed,  as the case may be, by  Epitope  and the
        Epitope  Subsidiaries  pursuant  to Section  6.1(d)  and  6.1(e)  exceed
        $500,000 in the aggregate;

             (f) sell, lease, out-license,  encumber or otherwise dispose of any
        assets, other than (i) sales of finished goods in the ordinary course of
        business  consistent with past practice,  (ii) equipment and property no
        longer used in the  operation  of  Epitope's  business  and (iii) assets
        related to discontinued operations of Epitope or any Epitope Subsidiary;

             (g) (i) incur any  indebtedness for borrowed money or guarantee any
        such indebtedness, (ii) issue or sell any debt securities or warrants or
        rights  to  acquire  any  debt

                                      -42-
<PAGE>

        securities of Epitope or any Epitope  Subsidiary,  (iii) make any loans,
        advances  or  capital  contributions  to or  investments  in,  any other
        Person,  or (iv) except in the  ordinary  course of business  consistent
        with past practice (which shall include, without limitation,  borrowings
        under Epitope's existing credit agreements and overnight  borrowings and
        loans and advances to wholly-owned Epitope  Subsidiaries)  guarantee any
        debt securities or indebtedness of others, in any such case in an amount
        in excess of $100,000;

             (h) (i) enter into any  agreement  or  arrangement  that  limits or
        otherwise  restricts  Epitope,  any Epitope  Subsidiary  or any of their
        respective  Affiliates or any successor thereto or that would, after the
        Effective Time, limit or restrict Epitope, any Epitope Subsidiary or the
        Surviving  Corporation,  or any of  their  respective  Affiliates,  from
        engaging or  competing  in any line of business or in any  location,  or
        (ii) enter into,  amend,  modify or  terminate  any  material  contract,
        agreement  or  arrangement  of  Epitope  or any  Epitope  Subsidiary  or
        otherwise  waive,  release  or assign  any  material  rights,  claims or
        benefits  of Epitope or any  Epitope  Subsidiary  thereunder;  provided,
        however,  that this  Section  6.1(h)  shall  not  prevent  Epitope  from
        entering  into  material   contracts   with   customers,   suppliers  or
        distributors, so long as such contracts are entered into in the ordinary
        course and consistent with Epitope's past practice;

             (i) (i) except as required by law or a written  agreement  existing
        on or prior to the date hereof,  increase the amount of  compensation of
        any director or executive  officer or make any increase in or commitment
        to increase any employee benefits,  (ii) except as required by law, or a
        written  agreement  existing on or prior to the date hereof or a written
        Epitope  severance  policy  existing  as of the date  hereof,  grant any
        severance or  termination  pay to any  director,  officer or employee of
        Epitope or any Epitope  Subsidiary,  (iii) adopt any additional employee
        benefit plan or,  except in the ordinary  course of business  consistent
        with past practice and containing only normal and customary terms,  make
        any  contribution  to any such  existing  plan or (iv)  except as may be
        required by law or a written  agreement or written employee benefit plan
        existing  on or prior to the date  hereof,  or as  contemplated  by this
        Agreement,  enter into or amend in any respect or accelerate the vesting
        under any Epitope Employee Plan employment  agreement,  option,  license
        agreement or  retirement  agreements,  or (v) hire any employee  with an
        annual base salary in excess of $75,000;

             (j)  change  (x)  Epitope's  methods  of  accounting  in  effect at
        September  30,  1999,  except  as  required  by  changes  in  GAAP or by
        Regulation S-X of the Exchange Act, as concurred with by its independent
        public accountants,  (y) Epitope's fiscal year, or (z) make any material
        Tax election,  other than in the ordinary course of business  consistent
        with past practice and containing only normal and customary terms;

             (k) (i)  settle,  propose to settle,  or commence  any  litigation,
        investigation,  arbitration,  proceeding or other claim that is material
        to the  business  of Epitope and the  Epitope  Subsidiaries,  taken as a
        whole,  other  than  the  payment,  discharge  or  satisfaction,  in the
        ordinary course of business consistent with past practice of liabilities
        (x)  recognized or disclosed in the most recent  consolidated  financial
        statements (or the notes thereto) of Epitope included in the Epitope SEC
        Documents or (y) incurred since the date of such financial statements in
        the ordinary course of business  consistent with past


                                      -43-
<PAGE>

        practice,  or (ii) make any tax election or enter into any settlement or
        compromise of any tax liability; or

             (l)  Epitope  shall not,  and shall not  permit any of the  Epitope
        Subsidiaries to, enter into any new line of business;

             (m) except to the extent  required to comply  with its  obligations
        hereunder,  or required by law, Epitope shall not amend or propose to so
        amend  its  Articles  of   Incorporation,   Bylaws  or  other  governing
        documents;

             (n)  Epitope  shall  not  amend,  modify or waive  (other  than any
        amendment or waiver required to consummate the transactions contemplated
        by this  Agreement) any provision of the Epitope Rights  Agreement,  and
        shall not take any action to redeem the Epitope Stock Purchase Rights or
        render the Epitope Stock Purchase Rights inapplicable to any transaction
        (other than the transactions contemplated by this Agreement); or

             (o) agree, resolve or commit to do any of the foregoing.

        SECTION 6.2. Acquisition Proposals; Board Recommendation.

             (a)  Epitope  agrees  that it shall  not,  nor shall it permit  any
        Epitope  Subsidiary to, and it shall direct and use its reasonable  best
        efforts to cause any officer,  director,  employee,  investment  banker,
        attorney,  accountant,  agent  or other  advisor  or  representative  of
        Epitope or any Epitope  Subsidiary,  not to directly or indirectly,  (i)
        solicit, initiate or knowingly facilitate or encourage the submission of
        any  Acquisition   Proposal  for  Epitope,   (ii)   participate  in  any
        discussions  or  negotiations  regarding,  or  furnish to any Person any
        information  with  respect  to or take any  other  action  knowingly  to
        facilitate any inquiries or the making of any proposal that  constitutes
        an Acquisition  Proposal for Epitope,  (iii) grant any waiver or release
        under any  standstill or similar  agreement with respect to any class of
        Epitope's  equity  securities  or (iv)  enter  into any  agreement  with
        respect to an Acquisition Proposal for Epitope. Notwithstanding anything
        in this  Agreement  to the  contrary,  Epitope or its Board of Directors
        shall be  permitted  to (A) to the extent  applicable,  comply with Rule
        14d-9 and Rule 14e-2  promulgated  under the Exchange Act with regard to
        an Acquisition  Proposal for Epitope,  (B) in response to an unsolicited
        bona fide  written  Acquisition  Proposal  for  Epitope  by any  Person,
        recommend approval of such an unsolicited bona fide written  Acquisition
        Proposal for Epitope to its  stockholders or effect an Adverse Change in
        the  Epitope  Recommendation,  or  (C)  engage  in  any  discussions  or
        negotiations with, or provide any information to, any Person in response
        to an unsolicited bona fide Acquisition Proposal for Epitope by any such
        Person,  if and only to the  extent  that  Epitope  (including  for this
        purpose,  if  authorized  by Epitope,  all Epitope  Subsidiaries  or any
        officer, director,  employee,  investment banker, attorney,  accountant,
        agent or other  advisor or  representative  of  Epitope  or any  Epitope
        Subsidiaries)  have not  violated  in any  material  respect  any of the
        restrictions  contained  in Section  6.2(a)  and, in any such case as is
        referred to in clause (B) or (C), (i) the Epitope  Stockholders  Meeting
        shall not have occurred,  (ii) the Epitope Board of Directors (x) in the
        case of clause (B) above,  concludes  in good faith  after  consultation
        with its financial advisors and counsel, and

                                      -44-
<PAGE>

        taking  into  account,   among  other  things,  all  legal,   financial,
        regulatory  and other  aspects  of such  Acquisition  Proposal,  and the
        nature of the Person making the Acquisition Proposal,  that such written
        Acquisition  Proposal for Epitope  constitutes a Superior Proposal,  and
        provides  written notice of  termination  of this Agreement  pursuant to
        Section 10.1(e)  (provided that such termination  shall not be effective
        until such time as Epitope  makes the  payment  to STC  contemplated  by
        Section 10.2(b))or (y) in the case of clause (C) above concludes in good
        faith after  consultation with its financial  advisors and counsel,  and
        taking  into  account,   among  other  things,  all  legal,   financial,
        regulatory  and other  aspects  of such  Acquisition  Proposal,  and the
        nature  of  the  Person  making  the  Acquisition  Proposal,  that  such
        Acquisition  Proposal for Epitope would reasonably be expected to result
        in a Superior Proposal, (iii) prior to providing any information or data
        to any Person in connection with an Acquisition  Proposal for Epitope by
        any such  Person,  the Epitope  Board of  Directors  receives  from such
        Person an executed confidentiality agreement containing  confidentiality
        terms at least as  stringent as those  contained in the  confidentiality
        agreement  between  Epitope  and STC  dated as of March  23,  2000  (the
        "Confidentiality   Agreement"),   and  (iv)  prior  to   providing   any
        information  or data to any  Person  or  entering  into  discussions  or
        negotiations  with any Person,  Epitope  notifies  STC  promptly of such
        inquiries,  proposals  or  offers  received  by,  any  such  information
        requested  from, or any such  discussions or  negotiations  sought to be
        initiated  or  continued  with,  it,  its   subsidiaries,   its  or  its
        subsidiaries'   officers  or   directors,   or  any  of  its  agents  or
        representatives  indicating, in connection with such notice, the name of
        such Person and the  material  terms and  conditions  of any  inquiries,
        proposals or offers and shall furnish only information and data that has
        been previously  furnished to STC.  Epitope will provide STC with a copy
        of  any  written  Acquisition  Proposal  or  amendments  or  supplements
        thereto,  and  shall  thereafter  inform  STC on a  prompt  basis of any
        changes  to the  terms  and  conditions  of such  Acquisition  Proposal.
        Epitope will take the necessary steps to inform promptly the individuals
        or entities  referred to in the first sentence of this Section 6.2(a) of
        the obligations undertaken in this Section 6.2.

             (b) "Superior  Proposal" means a written  proposal made by a Person
        other   than  STC  which  is  for   (I)(i)  a  merger,   reorganization,
        consolidation,  share exchange, business combination,  recapitalization,
        liquidation,  dissolution or similar transaction  involving Epitope as a
        result  of  which  either  (A)  Epitope's  stockholders  prior  to  such
        transaction  (by virtue of their  ownership of Epitope's  shares) in the
        aggregate  cease to own at least  50% of the  voting  securities  of the
        entity  surviving or resulting from such  transaction (or if there is an
        ultimate  parent entity of such surviving or resulting  entity,  then of
        such ultimate parent entity) or (B) the individuals comprising the board
        of directors of Epitope prior to such  transaction  do not  constitute a
        majority of the board of directors of the surviving or resulting  entity
        (or,  if  there  is an  ultimate  parent  entity  of such  surviving  or
        resulting  entity,  then of such ultimate parent  entity),  (ii) a sale,
        lease,  exchange,  transfer or other  disposition of at least 50% of the
        assets of Epitope and its  Subsidiaries,  taken as a whole,  in a single
        transaction  or  a  series  of  related   transactions,   or  (iii)  the
        acquisition, directly or indirectly, by a Person of beneficial ownership
        of  50%  or  more  of  the  Epitope  Common  Stock  whether  by  merger,
        consolidation,  share exchange, business combination, tender or exchange
        offer or otherwise (other than a merger, consolidation,  share exchange,
        business combination, tender or exchange offer or other transaction upon
        the consummation of which Epitope's  stockholders would in the aggregate
        beneficially  own

                                      -45-
<PAGE>

        greater than 60% of the voting securities of such Person),  and which is
        (II)  otherwise on terms which the board of directors of Epitope in good
        faith  concludes  (after  consultation  with its financial  advisors and
        outside counsel and upon receipt of advice from its financial advisors),
        taking  into  account,   among  other  things,  all  legal,   financial,
        regulatory  and other  aspects  of the  proposal  and the  nature of the
        Person  making the  proposal,  (i) would,  if  consummated,  result in a
        transaction  that  is  more  favorable  to its  stockholders  (in  their
        capacities as  stockholders),  from a financial  point of view, than the
        transactions  contemplated by this Agreement  (after giving effect,  for
        purposes of clause (ii) of Section 10.1(e), to any revised proposal made
        by STC prior to the end of the three Business-Day  period referred to in
        Section  10.1(e)),  and (ii) is reasonably  capable of being  completed;
        provided,  however,  that any such  Acquisition  Proposal  shall  not be
        deemed a Superior  Proposal if any financing  required to consummate the
        transaction  contemplated by such Acquisition  Proposal is not committed
        in writing as of the time the Epitope Board makes its determination that
        it is a Superior Proposal.

                                  ARTICLE VII

                                COVENANTS OF STC

               STC agrees that:

        SECTION 7.1. STC Interim Operations. Except as expressly contemplated or
permitted  by this  Agreement,  or as  required  by any  Governmental  Entity of
competent  jurisdiction,  without the prior  consent of Epitope  (which  consent
shall not be unreasonably  withheld or delayed),  from the date hereof until the
Effective  Time, STC shall conduct its business in all material  respects in the
ordinary  course  consistent  with past  practice  and  shall  use  commercially
reasonable  efforts to (i) preserve  intact its present  business  organization,
(ii) maintain in effect all material foreign, federal, state and local licenses,
approvals  and  authorizations,  including,  without  limitation,  all  material
licenses  and permits  that are  required  for STC to carry on its  business and
(iii) preserve  existing  relationships  with its material  customers,  lenders,
suppliers and others having  material  business  relationships  with it. Without
limiting the generality of the foregoing,  except as expressly  contemplated  or
permitted  by  this  Agreement,  or as  required  by a  Governmental  Entity  of
competent  jurisdiction,  from the date hereof until the Effective Time, without
the prior consent of Epitope (which consent shall not be  unreasonably  withheld
or delayed), STC shall not:

             (a) amend its certificate of incorporation or by-laws;

             (b) split, combine or reclassify any shares of capital stock of STC
        or declare, set aside or pay any dividend or other distribution (whether
        in cash,  stock or property,  or any combination  thereof) in respect of
        its capital stock or redeem, repurchase or otherwise acquire or offer to
        redeem, repurchase, or otherwise acquire any of its securities;

             (c) (i) issue, deliver or sell, or authorize the issuance, delivery
        or sale  of,  any  shares  of its  capital  stock  of any  class  or any
        securities convertible into or exercisable for, or any rights,  warrants
        or options to acquire,  any such capital  stock or any such

                                      -46-
<PAGE>

        convertible  securities,  other  than (A) a number of shares of  capital
        stock equal to that number of shares underlying  options forfeited prior
        to the Closing by former STC  employees,  pursuant  to the STC  Employee
        Plans,  (B) STC  Common  Stock  upon the  exercise  of stock  options or
        warrants in  accordance  with their  present  terms or upon  exercise of
        options issued pursuant to clause (A) of this Section 7.1(c)(i);  or (C)
        STC Common Stock upon the conversion of the STC Notes;  or (ii) amend in
        any respect any term of any outstanding security of STC;

             (d) other than in connection  with  transactions  not prohibited by
        Section  7.1(e),  incur any capital  expenditures  or any obligations or
        liabilities in respect thereof, except for those (i) contemplated by the
        capital  expenditure  budgets for STC made available to Epitope, or (ii)
        incurred in the ordinary  course of business of STC and consistent  with
        past practice;

             (e)  acquire  (whether  pursuant  to cash  merger,  stock  or asset
        purchase  or  otherwise)  in  one   transaction  or  series  of  related
        transactions (i) any assets  (including any equity  interests)  having a
        fair market  value in excess of $100,000,  or (ii) all or  substantially
        all of the equity interests of any Person or any business or division of
        any Person  having a fair market value in excess of $100,000,  but in no
        event shall the  expenditures,  commitments,  obligations or liabilities
        made,  incurred  or  assumed,  as the case may be,  by STC  pursuant  to
        Sections 7.1(d) and 7.1(e) exceed $500,000 in the aggregate;

             (f) sell, lease, out-license,  encumber or otherwise dispose of any
        assets, other than (i) sales of finished goods in the ordinary course of
        business  consistent with past practice,  (ii) equipment and property no
        longer used in the operation of STC's  business and (iii) assets related
        to discontinued operations of STC or any STC Subsidiary;

             (g) (i) incur any  indebtedness for borrowed money or guarantee any
        such indebtedness, (ii) issue or sell any debt securities or warrants or
        rights to  acquire  any debt  securities  of STC,  (iii) make any loans,
        advances  or  capital  contributions  to or  investments  in,  any other
        Person,  or (iv) except in the  ordinary  course of business  consistent
        with past practice (which exception shall include,  without  limitation,
        borrowings   under  STC's  existing  credit   agreements  and  overnight
        borrowings)  guarantee any debt  securities or indebtedness of others in
        any such case in an amount in excess of $100,000;

             (h) (i) enter into any  agreement  or  arrangement  that  limits or
        otherwise  restricts  STC  or any of  its  Affiliates  or any  successor
        thereto or that would,  after the Effective Time,  limit or restrict STC
        or the Surviving  Corporation,  or any of their  respective  Affiliates,
        from  engaging or competing in any line of business or in any  location,
        or (ii) enter into,  amend,  modify or terminate any material  contract,
        agreement or  arrangement of STC or otherwise  waive,  release or assign
        any material  rights,  claims or benefits of STC  thereunder;  provided,
        however,  that this Section  7.1(h) shall not prevent STC from  entering
        into material  contracts with customers,  suppliers or distributors,  so
        long as such  contracts  are  entered  into in the  ordinary  course and
        consistent with STC's prior practice;

                                      -47-
<PAGE>

             (i) (i) except as required by law or a written  agreement  existing
        on or prior to the date hereof,  increase the amount of  compensation of
        any director or executive  officer or make any increase in or commitment
        to increase  any  employee  benefits,  (ii) except as required by law, a
        written agreement  existing on or prior to the date hereof, or a written
        STC severance policy existing as of the date hereof, grant any severance
        or termination pay to any director, officer or employee of STC or, (iii)
        adopt any  additional  employee  benefit plan or, except in the ordinary
        course of business  consistent  with past practice and  containing  only
        normal and customary  terms,  make any contribution to any existing such
        plan or (iv) except as may be required by law or a written  agreement or
        written  employee  benefit plan existing on or prior to the date hereof,
        or as contemplated by this Agreement,  enter into, amend in any respect,
        or  accelerate  the  vesting  under any STC  Employee  Plan,  employment
        agreement,  option, license agreement or retirement  agreements,  or (v)
        hire any employee with an annual base salary in excess of $75,000;

             (j) change (x) STC's  methods of  accounting  in effect at December
        31, 1999 except as required by changes in GAAP, as concurred with by its
        independent public  accountants,  (y) STC's fiscal year, or (z) make any
        material Tax  election,  other than in the  ordinary  course of business
        consistent  with past practice and containing  only normal and customary
        terms;

             (k) (i)  settle,  propose to settle or  commence,  any  litigation,
        investigation,  arbitration,  proceeding or other claim that is material
        to  the  business  of  STC,   other  than  the  payment,   discharge  or
        satisfaction,  in the ordinary  course of business  consistent with past
        practice of liabilities (x) recognized or disclosed in the STC Financial
        Statements (or the notes thereto) or (y) incurred since the date of such
        Financial  Statements in the ordinary course of business consistent with
        past  practice,  or (ii)  make  any  Tax  election  or  enter  into  any
        settlement or compromise of any Tax liability;

             (l) enter into any new material line of business;

             (m) except to the extent  required to comply  with its  obligations
        hereunder or required by law, STC shall not amend or propose to so amend
        its Certificate of Incorporation,  Bylaws or other governing  documents;
        or

             (n) agree, resolve or commit to do any of the foregoing.

        SECTION 7.2. Acquisition  Proposals;  Board  Recommendation.  STC agrees
that it shall not,  and it shall use its  reasonable  best  efforts to cause any
officer, director, employee,  investment banker, attorney,  accountant, agent or
other  advisor or  representative  of STC,  not to directly or  indirectly,  (i)
solicit,  initiate or knowingly  facilitate or encourage  the  submission of any
Acquisition   Proposal  for  STC,  (ii)   participate  in  any   discussions  or
negotiations  regarding,  or furnish to any Person any information  with respect
to, or take any other action knowingly to facilitate any inquiries or the making
of any proposal that  constitutes an  Acquisition  Proposal for STC, (iii) grant
any waiver or release under any standstill or similar  agreement with respect to
any class of STC equity securities or (iv) enter into any agreement with respect
to any Acquisition Proposal for STC.

                                      -48-
<PAGE>

                                  ARTICLE VIII

                          COVENANTS OF STC AND EPITOPE

               The parties hereto agree that:

        SECTION  8.1.  Reasonable  Best  Efforts.   Subject  to  the  terms  and
conditions hereof, each party will use reasonable best efforts to take, or cause
to be taken,  all actions and to do, or cause to be done, all things  necessary,
proper or advisable  under  applicable  laws and  regulations  to consummate the
transactions contemplated by this Agreement as promptly as practicable.

        SECTION  8.2.  Certain  Filings;  Cooperation  in Receipt  of  Consents;
Listing.  As promptly as reasonably  practicable after the date hereof,  STC and
Epitope  shall  prepare  and  Epitope  shall file with the SEC the  Registration
Statement,  in which the Joint  Proxy  Statement/Prospectus  will be included as
Epitope's  prospectus.  Each of STC and Epitope shall use all reasonable efforts
to have the Registration  Statement  declared effective under the Securities Act
as  promptly  as  reasonably  practicable  after  such  filing  and to keep  the
Registration  Statement  effective  as long as is necessary  to  consummate  the
Merger and the transactions  contemplated thereby. Each of STC and Epitope shall
mail the Joint Proxy  Statement/Prospectus  to their respective  stockholders as
promptly as reasonably  practicable after the Registration Statement is declared
effective  under the  Securities  Act and, if  necessary,  after the Joint Proxy
Statement/Prospectus  shall have been so  mailed,  promptly  circulate  amended,
supplemental  or  supplemented  proxy  material,  and, if required in connection
therewith,  resolicit proxies. Epitope and STC shall take any action (other than
qualifying  to do  business  in any  jurisdiction  in  which  it is  not  now so
qualified  or to file a general  consent to service of  process)  required to be
taken under any applicable  state securities or blue sky laws in connection with
the issuance of shares of Surviving Corporation Common Stock in the Mergers.

             (a)   No   amendment   or    supplement    to   the   Joint   Proxy
        Statement/Prospectus will be made by STC or Epitope without the approval
        of the other party, which will not be unreasonably  withheld or delayed.
        Each  party will  advise the other  party,  promptly  after it  receives
        notice  thereof,  of (i) the time when the  Registration  Statement  has
        become effective or any supplement or amendment has been filed, (ii) the
        issuance of any stop order, (iii) the suspension of the qualification of
        the shares of Surviving  Corporation Common Stock issuable in connection
        with the Mergers for offering or sale in any  jurisdiction,  or (iv) any
        request by the SEC for amendment of the Joint Proxy Statement/Prospectus
        or  comments  thereon and  responses  thereto or requests by the SEC for
        additional  information,  in each case, whether orally or in writing. If
        at any time prior to the Effective  Time,  STC or Epitope  discovers any
        information  relating  to  either  party,  or  any of  their  respective
        Affiliates,  officers  or  directors,  that  should  be set  forth in an
        amendment or supplement to the Joint Proxy Statement/Prospectus, so that
        such document would not include any  misstatement  of a material fact or
        omit to  state  any  material  fact  necessary  to make  the  statements
        therein,  in light of the circumstances  under which they were made, not
        misleading,  the party that  discovers such  information  shall promptly
        notify the other party hereto and an appropriate amendment or supplement
        describing  such  information  shall  be  promptly  filed  with  respect
        thereto, and with respect

                                      -49-
<PAGE>


        to the Registration  Statement, as the case may be, with the SEC and, to
        the  extent   required  by  law  or  regulation,   disseminated  to  the
        stockholders of STC or Epitope.

             (b) STC  and  Epitope  shall  cooperate  with  one  another  in (i)
        determining  whether  any other  action by or in  respect  of, or filing
        with, any  Governmental  Entity is required,  or any actions,  consents,
        approvals  or waivers are  required to be obtained  from  parties to any
        material   contracts,   in  connection  with  the  consummation  of  the
        transactions  contemplated  hereby, (ii) seeking any such other actions,
        consents,  approvals or waivers or making any such  filings,  furnishing
        information  required in connection  therewith  and seeking  promptly to
        obtain any such actions, consents, approvals or waivers, (iii) setting a
        mutually acceptable date for the Special Meetings,  so as to enable them
        to occur, to the extent  practicable,  on the same date, and (iv) taking
        all lawful action to call, give notice of, convene and hold a meeting of
        its  stockholders  for the purpose of obtaining the  requisite  votes to
        approve and adopt this  Agreement,  the  Mergers  and the other  matters
        contemplated by this Agreement. The Board of Directors of Epitope shall,
        subject to its  fiduciary  duties  under  applicable  law,  declare  the
        advisability  of and recommend  adoption and approval of this Agreement,
        the Merger and the other matters  contemplated  by this Agreement by the
        stockholders of Epitope,  and shall not, subject to its fiduciary duties
        under  applicable  law,  withdraw,  modify or materially  qualify in any
        manner adverse to STC such recommendation or take any action or make any
        statement in connection with the Epitope  Stockholder Meeting materially
        inconsistent   with   such    recommendation   (any   such   withdrawal,
        modification,  qualification or statement (whether or not required),  an
        "Adverse Change in the Epitope Recommendation").  The Board of Directors
        of STC shall,  subject to its  fiduciary  duties under  applicable  law,
        declare the advisability of and recommend  adoption and approval of this
        Agreement,  the  Merger  and  the  other  matters  contemplated  by this
        Agreement  by the  stockholders  of STC,  and shall not,  subject to its
        fiduciary  duties under applicable law,  withdraw,  modify or materially
        qualify in any manner adverse to Epitope to such  recommendation or take
        any action or make any statement in connection with the STC Stockholders
        Meeting  materially  inconsistent  with  such  recommendation  (any such
        withdrawal,  modification,  qualification  or statement  (whether or not
        required), an "Adverse Change in the STC Recommendation").

             (c)  Each  party  shall  permit  the  other  party  to  review  any
        communication  given by it to, and consult with each other in advance of
        any  meeting  or  conference  with,  any  Governmental   Entity  or,  in
        connection  with any  proceeding  by a  private  party,  with any  other
        Person,  and to the  extent  permitted  by the  applicable  Governmental
        Entity or other Person,  give the other party the  opportunity to attend
        and  participate  in such  meetings  and  conferences,  in each  case in
        connection with the transactions contemplated hereby.

             (d) Epitope and STC agree to use their  respective  reasonable best
        efforts to cause the shares of Surviving  Corporation Common Stock to be
        issued upon  conversion of shares of Epitope Common Stock and STC Common
        Stock in accordance with this Agreement,  the Articles of Merger and the
        Certificates  of Merger to be approved for listing upon  issuance on the
        Nasdaq Stock Market.

                                      -50-
<PAGE>

        SECTION 8.3. Headquarters.  The parties intend that, by January 1, 2001,
the Surviving  Corporation  shall maintain its principal  corporate  offices and
headquarters in Bethlehem, Pennsylvania.

        SECTION 8.4. Public Announcements.  Epitope and STC shall use reasonable
best  efforts to develop a joint  communications  plan and each party  shall use
reasonable  best efforts (i) to ensure that all press  releases and other public
statements  with  respect  to the  transactions  contemplated  hereby  shall  be
consistent  with such  joint  communications  plan,  and (ii)  unless  otherwise
required by applicable law or by obligations pursuant to any rules of the Nasdaq
Stock Market, to consult with each other before issuing any press release or, to
the extent practical, otherwise making any public statement with respect to this
Agreement or the transactions contemplated hereby.

        SECTION 8.5. Access to Information; Notification of Certain Matters.

             (a) From the date hereof  until the  Effective  Time and subject to
        applicable  law, STC and Epitope shall (i) give to the other party,  its
        counsel,    financial   advisors,    auditors   and   other   authorized
        representatives  reasonable  access during normal  business hours to the
        offices, properties,  books, records, contracts,  commitments,  officers
        and employees and all other information  concerning it and its business,
        properties,  assets,  condition (financial or otherwise) or prospects of
        such party, (ii) consistent with its legal obligations,  furnish or make
        available to the other party, its counsel, financial advisors,  auditors
        and other authorized  representatives  such financial and operating data
        and other  information as such Persons may reasonably  request and (iii)
        instruct its employees,  counsel, financial advisors, auditors and other
        authorized  representatives to cooperate with the reasonable requests of
        the other party in its investigation. Any investigation pursuant to this
        Section  8.5  shall be  conducted  in such  manner  as not to  interfere
        unreasonably with the conduct of the business of the other party. Unless
        otherwise  required by law, each of Epitope and STC will hold,  and will
        cause its respective officers,  employees,  counsel, financial advisors,
        auditors and other  authorized  representatives  to hold,  any nonpublic
        information   obtained  in  any  such  investigation  in  confidence  in
        accordance with Section 8.9. No information or knowledge obtained in any
        investigation  pursuant to this Section 8.5 shall affect or be deemed to
        modify any representation or warranty made by any party hereunder.

             (b) Each party hereto shall give prompt  notice to each other party
        hereto of:

                 (i)  the  receipt  by  such  party  or  any  of  such   party's
             Subsidiaries of any notice or other  communication  from any Person
             alleging  that the  consent of such Person is or may be required in
             connection with the transactions contemplated by this Agreement.

                 (ii)  the  receipt  by  such  party  or  any  of  such  party's
             Subsidiaries  of  any  notice  or  other   communication  from  any
             Governmental  Entity  in  connection  with any of the  transactions
             contemplated by this Agreement; and

                                      -51-
<PAGE>

                 (iii) such party's obtaining  Knowledge of any actions,  suits,
             claims,   investigations  or  proceedings   commenced,   threatened
             against, relating to or involving or otherwise affecting any of STC
             or  Epitope,  as the case may be, or any Epitope  Subsidiary  which
             relate to the consummation of the transactions contemplated by this
             Agreement; and

                 (iv) such party's  obtaining  Knowledge of the  occurrence,  or
             failure to occur, of any event which occurrence or failure to occur
             will  be  likely  to  cause  (A)  any  representation  or  warranty
             contained  in this  Agreement  o be  untrue  or  inaccurate  in any
             material  respect,  or (B) any  material  failure  of any  party to
             comply with or satisfy any  covenant,  condition  or agreement o be
             complied  with or satisfied by it under this  Agreement;  provided,
             however,  that no such notification shall limit or otherwise affect
             the  representations,  warranties,  obligations  or remedies of the
             parties  to the  conditions  to  the  obligations  of  the  parties
             hereunder.

        SECTION 8.6. Further Assurances.  At and after the STC Effective Time or
Epitope  Effective  Time,  as the case may be, the officers and directors of the
Surviving Corporation will be authorized to execute and deliver, in the name and
on behalf of Epitope,  STC or Merger Sub, any deeds, bills of sale,  assignments
or assurances  and to take and do, in the name and on behalf of Epitope,  STC or
Merger Sub, any other  actions and things to vest,  perfect or confirm of record
or otherwise in the Surviving  Corporation any and all right, title and interest
in, to and under any of the  rights,  properties  or assets of STC,  Epitope  or
Merger Sub acquired or to be acquired by the Surviving  Corporation  as a result
of, or in connection with the Mergers.

        SECTION 8.7. Tax and Accounting Treatment.

             (a) Prior to the Effective  Time,  each party shall  cooperate with
        the other party and shall use its  reasonable  best efforts to cause the
        Mergers to qualify as 368 Reorganizations,  and will not take any action
        reasonably likely to cause the Mergers not so to qualify.  The Surviving
        Corporation  shall not take any  action  after the  Effective  Time that
        would cause the Mergers not to qualify as 368 Reorganizations.

             (b) Each party shall  cooperate  with the other party and shall use
        its reasonable best efforts to cause the Mergers to qualify for "pooling
        of  interest"  accounting  treatment  as  described  in Section 3.21 and
        Section 4.20, and shall not take any action  reasonably  likely to cause
        the Mergers not so to qualify. Epitope shall use reasonable best efforts
        to cause to be delivered to STC two letters from  Epitope's  independent
        public  accountants,  one  dated  approximately  the date on  which  the
        Registration  Statement shall become effective and one dated the Closing
        Date,  each  addressed  to  Epitope  and  STC,  in  form  and  substance
        reasonably  satisfactory to STC and customary in scope and substance for
        comfort  letters   delivered  by  independent   public   accountants  in
        connection  with  registration  statements  similar to the  Registration
        Statement.  STC  shall  use  reasonable  best  efforts  to  cause  to be
        delivered  to  Epitope  two  letters  from  STC's   independent   public
        accountants,  one dated approximately the date on which the Registration
        Statement  shall become  effective and one dated the Closing Date,  each
        addressed  to  Epitope  and  STC,  in  form  and  substance   reasonably
        satisfactory to Epitope and customary in scope and

                                      -52-
<PAGE>

        substance  for  comfort   letters   delivered  by   independent   public
        accountants in connection with  registration  statements  similar to the
        Registration Statement.

             (c) Each party shall  cooperate  with the other party and shall use
        its  reasonable  best  efforts to obtain  the  opinions  referred  to in
        Sections 9.2(b) and 9.3(b) and in connection therewith, each of Epitope,
        STC  and  Merger   Sub  shall   deliver   to  such   counsel   customary
        representation  letters  substantially  in the forms attached  hereto as
        Exhibit I, Exhibit J and Exhibit O (the "Epitope Representation Letter",
        the "STC  Representation  Letter",  and the "Merger  Sub  Representation
        Letter"  respectively)  or  otherwise in form and  substance  reasonably
        satisfactory to such counsel.

        SECTION 8.8. Affiliates.

             (a) Not less than 45 days prior to the  Effective  Time,  STC shall
        deliver  to  Epitope  a  letter  identifying  all  persons  who,  in the
        reasonable  judgment of STC, may be deemed at the time this Agreement is
        submitted for adoption by the  stockholders of STC,  "affiliates" of STC
        for  purposes of Rule 145 under the  Securities  Act or for  purposes of
        qualifying  the Mergers for pooling of  interests  accounting  treatment
        under Opinion 16 of the Accounting  Principles  Board and applicable SEC
        rules and  regulations,  and such list shall be updated as  necessary to
        reflect  changes from the date  hereof.  STC shall use  reasonable  best
        efforts  to cause  each  Person  identified  on such list to  deliver to
        Epitope not less than 30 days prior to the STC Effective Time, a written
        agreement substantially in the form attached as Exhibit K hereto (a "STC
        Affiliate Agreement").

             (b) Not less  than 45 days  prior to the  Effective  Time,  Epitope
        shall  deliver  to STC a letter  identifying  all  persons  who,  in the
        reasonable judgment of Epitope, may be deemed at the time this Agreement
        is submitted for adoption by the  stockholders of Epitope,  "affiliates"
        of Epitope  for  purposes  of  qualifying  the  Mergers  for  pooling of
        interests  accounting  treatment  under  Opinion  16 of  the  Accounting
        Principles Board and applicable SEC rules and regulations, and such list
        shall be updated as necessary  to reflect  changes from the date hereof.
        Epitope  shall  use  reasonable   best  efforts  to  cause  each  person
        identified  on such list to  deliver  to  Epitope  not less than 30 days
        prior to the Effective Time, a written  agreement  substantially  in the
        form attached as Exhibit L (an "Epitope Affiliate Agreement").

             (c) The Surviving Corporation shall use its reasonable best efforts
        to publish no later than 90 days after the end of the first  month after
        the  Effective  Time in which  there  are at  least 30 days of  combined
        operations  following the Mergers (which month may be the month in which
        the Effective  Time occurs),  combined  sales and net income  figures as
        contemplated  by and in  accordance  with the  terms  of SEC  Accounting
        Series Release No. 135.

        SECTION 8.9. Confidentiality.

             (a) Prior to the Effective  Time and after any  termination of this
        Agreement each party hereto will hold, and will use its reasonable  best
        efforts  to  cause  its  officers,  directors,  employees,  accountants,
        counsel, consultants, advisors, affiliates (as such term

                                      -53-
<PAGE>

        is used in Rule  12b-2  under  the  Exchange  Act)  and  representatives
        (collectively,  the  "Representatives"),  to  hold,  in  confidence  all
        confidential  documents  and  information  concerning  the other parties
        hereto and its  Subsidiaries  furnished to such party in connection with
        the  transactions  contemplated  by this Agreement,  including,  without
        limitation, all analyses,  compilations,  studies or records prepared by
        the party receiving the information or by such party's  Representatives,
        that contain or otherwise reflect or are generated from such information
        (collectively,  the "Confidential  Material").  The party furnishing any
        Confidential  Material is herein referred to as the "Delivering Company"
        and the party receiving any Confidential  Material is herein referred to
        as the "Receiving Company."

             (b) The Receiving  Company  agrees that the  Confidential  Material
        will  not be  used  other  than  for  the  purpose  of the  transactions
        contemplated by this Agreement,  and that such  information will be kept
        confidential by the Receiving Company and its Representatives; provided,
        however,  that  (i)  any of such  information  may be  disclosed  to the
        Representatives  who  need  to know  such  information  for the  purpose
        described above (it being  understood that (a) each such  Representative
        shall be informed by the Receiving Company of the confidential nature of
        such  information,  shall be directed by the Receiving  Company to treat
        such  information  confidentially  and not to use it other  than for the
        purpose described above and shall agree to be bound by the terms of this
        Section  8.9,  and (b) in any  event,  the  Receiving  Company  shall be
        responsible   for  any   breach  of  this   Agreement   by  any  of  its
        Representatives),  and (ii) any other disclosure of such information may
        be made if the  Delivering  Company  has, in advance,  consented to such
        disclosure in writing.  The Receiving  Company will make all reasonable,
        necessary and appropriate efforts to safeguard the Confidential Material
        from disclosure to anyone other than as permitted hereby.

             (c) Notwithstanding the foregoing,  if the Receiving Company or any
        of its  Representatives  is requested  or required (by oral  question or
        request   for   information   or   documents   in   legal   proceedings,
        interrogatories,   subpoena,   civil  investigative  demand  or  similar
        process) to disclose any Confidential  Material,  the Receiving  Company
        will  promptly  notify  the  Delivering   Company  of  such  request  or
        requirement  so that the  Delivering  Company  may  seek an  appropriate
        protective  order and/or waive the Receiving  Company's  compliance with
        the  provisions  of this  Agreement.  If, in the absence of a protective
        order or the receipt of a waiver hereunder, the Receiving Company or any
        of its Representatives is nonetheless, in the reasonable written opinion
        of the Receiving Company's counsel,  compelled to disclose  Confidential
        Material to any tribunal,  the Receiving Company or such Representative,
        after notice to the Delivering Company, may disclose such information to
        such tribunal.  The Receiving Party shall exercise reasonable efforts to
        obtain reliable  assurance that confidential  treatment will be accorded
        the Confidential  Material so disclosed.  The Receiving  Company or such
        Representative  shall not be liable for the  disclosure of  Confidential
        Material hereunder to a tribunal  compelling such disclosure unless such
        disclosure  to such  tribunal was caused by or resulted  from a previous
        disclosure by the Receiving  Company or any of its  Representatives  not
        permitted by this Agreement.

                                      -54-
<PAGE>

             (d) This Section 8.9 shall be inoperative as to particular portions
        of the  Confidential  Material  if such  information  (i) is or  becomes
        generally available to the public other than as a result of a disclosure
        by the Receiving Company or its  Representatives,  (ii) was available to
        the  Receiving  Company  on  a  non-confidential   basis  prior  to  its
        disclosure to the  Receiving  Company by the  Delivering  Company or the
        Delivering Company's Representatives,  or (iii) becomes available to the
        Receiving Company on a  non-confidential  basis from a source other than
        the  Delivering  Company or the  Delivering  Company's  Representatives,
        provided that such source is not known by the Receiving  Company,  after
        reasonable inquiry, to be bound by a confidentiality  agreement with the
        Delivering Company or the Delivering  Company's  Representatives  and is
        not  otherwise  prohibited  from  transmitting  the  information  to the
        Receiving Company by a contractual,  legal or fiduciary obligation.  The
        fact  that  information  included  in the  Confidential  Material  is or
        becomes   otherwise   available   to  the   Receiving   Company  or  its
        Representatives  under clauses (i) through (iii) above shall not relieve
        the Receiving Company or its  Representatives of the prohibitions of the
        confidentiality  provisions  of this  Section  8.9 with  respect  to the
        balance of the Confidential Material.

             (e) If this  Agreement is  terminated,  each party hereto will, and
        will use its reasonable  best efforts to cause its officers,  directors,
        employees,  accountants,  counsel, consultants,  advisors and agents to,
        destroy or deliver to the party from whom such Confidential Material was
        obtained,  upon  request,  all documents  and other  materials,  and all
        copies  thereof,  obtained  by such party or on its behalf from any such
        other parties in connection with this Agreement that are subject to such
        confidence.

        SECTION  8.10.  Benefit  Matters.  Epitope and STC will work together to
design benefit plans to be adopted by the Surviving  Corporation for the benefit
of its  employees  as soon as  practicable  following  the  Mergers.  Until such
adoption,  the Surviving  Corporation shall cause all Epitope Employee Plans and
all STC Employee Plans to be maintained in full force and effect.

        SECTION 8.11. Antitrust Matters.

             (a)  The  parties  hereto  promptly  will  complete  all  documents
        required  to  be  filed  with  the  Federal  Trade  Commission  and  the
        Department of Justice in order to permit  stockholders  who will acquire
        Surviving Corporation Common Stock with a value in excess of $15 million
        as a result of the  Mergers and who do not have  exemption  from the HSR
        Act therefor to comply with the HSR Act and,  together  with the Persons
        who are  required to join in such  filings,  will file the same with the
        appropriate  Governmental  Entities.  The parties  hereto  promptly will
        furnish all  materials  thereafter  required by any of the  Governmental
        Entities  having  jurisdiction  over  such  filings  and  will  take all
        reasonable  actions  and file  and use all  reasonable  efforts  to have
        declared  effective or approved all documents and notifications with any
        such Governmental Entities, as may be required under the HSR Act for the
        consummation of the Mergers.

             (b) The parties  hereto will use their  reasonable  best efforts to
        resolve such objections,  if any, as may be asserted with respect to the
        transactions   contemplated  by  this  Agreement  under  any  antitrust,
        competition  or  trade  regulatory  laws,  rules or

                                      -55-
<PAGE>

        regulations of any domestic or foreign  Governmental  Entity ("Antitrust
        Laws"). If any suit is threatened or instituted  challenging the Mergers
        as violating any Antitrust Law, the parties hereto will take such action
        as may be reasonably required (i) by the applicable  Governmental Entity
        in order to resolve such objections as such Governmental Entity may have
        to such transaction  under such Antitrust Law or (ii) by any domestic or
        foreign  court or  similar  tribunal,  in any suit  brought by a private
        party or governmental  authority challenging the Merger as violating any
        Antitrust  Law,  in  order to avoid  the  entry  of,  or to  effect  the
        dissolution of, any  injunction,  temporary  restraining  order or other
        order that has the effect of preventing the  consummation of the Merger.
        Nothing in this  Section  8.11  shall  require  any of  Epitope  and its
        Subsidiaries  or STC to sell,  hold separate or otherwise  dispose of or
        conduct their  business in a specified  manner,  or agree to sell,  hold
        separate  or  otherwise  dispose  of  or  conduct  their  business  in a
        specified  manner,  or  permit  the  sale,  holding  separate  or  other
        disposition of, any assets of Epitope,  STC or any Epitope Subsidiary or
        the  conduct  of their  business  in a  specified  manner,  whether as a
        condition to obtaining  any approval from a  Governmental  Entity or any
        other Person or for any other reason, if such sale,  holding separate or
        other disposition or the conduct of their business in a specified manner
        is not  conditioned  on the Closing or would  reasonably  be expected to
        have a Material  Adverse  Effect on the  Surviving  Corporation  and its
        Subsidiaries, taken together, after giving effect to the Mergers.

             (c) Each party  promptly  will  inform  the others of any  material
        communication  from the Federal  Trade  Commission,  the  Department  of
        Justice or any other domestic or foreign  Governmental  Entity regarding
        any of the transactions  contemplated by this Agreement. If any party or
        any Affiliate  thereof receives a request for additional  information or
        documentary  material from any such government or authority with respect
        to the  transactions  contemplated  by this  Agreement,  such party will
        endeavor in good faith to make,  as soon as reasonably  practicable  and
        after  consultation with the other parties,  an appropriate  response to
        such request.  Each party hereto  promptly will advise the other parties
        hereto in  respect of any  understandings,  undertakings  or  agreements
        which the advising party proposes to make or enter into with the Federal
        Trade  Commission,  the  Department of Justice or any other  domestic or
        foreign   Governmental   Entity  in  connection  with  the  transactions
        contemplated by this Agreement.

        SECTION 8.12. Exemption From Liability Under Section 16(b).

             (a) Provided  that STC delivers to the  Surviving  Corporation  the
        Section 16 Information  with respect to STC prior to the Effective Time,
        the Board of Directors of the Surviving  Corporation,  or a committee of
        Non-Employee  Directors thereof (as such term is defined for purposes of
        Rule  16b-3(d)  under the Exchange  Act),  shall adopt a  resolution  in
        advance of the STC Effective  Time providing that the receipt by the STC
        Insiders of Surviving Corporation Common Stock in exchange for shares of
        STC  Common  Stock,  and of options to  purchase  Surviving  Corporation
        Common Stock upon assumption and conversion by the Surviving Corporation
        of options to purchase STC Common  Stock,  in each case  pursuant to the
        transactions  contemplated  hereby and to the extent such securities are
        listed in the  Section 16  Information,  are  intended to be exempt from
        liability pursuant to Rule 16b-3 under the Exchange Act.

                                      -56-
<PAGE>

             (b) "Section 16 Information" shall mean information accurate in all
        respects regarding the STC Insiders,  the number of shares of STC Common
        Stock, or other STC equity  securities,  deemed to be beneficially owned
        by each such STC Insider  and  expected to be  exchanged  for  Surviving
        Corporation Common Stock in connection with the Mergers.

             (c) "STC  Insiders"  shall mean those officers and directors of STC
        who are subject to the  reporting  requirements  of Section 16(a) of the
        Exchange Act who are listed in the Section 16 Information.

        SECTION 8.13. Indemnification and Insurance.

             (a) The  Surviving  Corporation  agrees  to assume  the  agreements
        listed in Exhibit M, which  agreements will survive the Mergers and will
        continue  in full force and effect for a period of not less than six (6)
        years from the  Effective  Time.  In the event any claim is  asserted or
        made within  such  six-year  period,  all rights to  indemnification  in
        respect of any such claim will continue until final disposition thereof.
        An  "Indemnified  Party"  shall mean any Person who is at the  Effective
        Time or prior thereto has been an employee,  agent,  director or officer
        of either STC or  Epitope  as  provided  in their  respective  charters,
        bylaws or resolutions.

             (b) From and after the Effective  Time,  the Surviving  Corporation
        shall indemnify all Indemnified  Parties to the fullest extent permitted
        by the Delaware Law with respect to all acts and  omissions  arising out
        of such  individuals'  services as  officers,  directors,  employees  or
        agents of either STC or Epitope or as  trustees  or  fiduciaries  of any
        plan for the benefit of employees, or otherwise on behalf of, either STC
        or Epitope,  occurring at or prior to the Effective Time,  including the
        transactions   contemplated  by  this   Agreement.   In  the  event  any
        Indemnified  Party is or becomes involved in any capacity in any action,
        proceeding or investigation in connection with any such matter occurring
        at or prior to the Effective Time, the Surviving Corporation will pay as
        incurred such  Indemnified  Party's legal and other expenses  (including
        the cost of any  investigation  and preparation)  incurred in connection
        therewith.  The Surviving  Corporation will pay all expenses,  including
        attorneys'  fees,  that  may be  incurred  by any  Indemnified  Party in
        enforcing  the  indemnity  and other  obligations  provided  for in this
        Section 8.13.

             (c) The Surviving Corporation will cause to be maintained in effect
        for not less than six (6) years from the Effective  Time  directors' and
        officers' liability insurance covering the directors and officers of STC
        and  Epitope  similar  in  scope  and  coverage  to the  directors'  and
        officers'  liability  insurance  maintained by STC and Epitope for their
        directors and officers.

             (d) The  provisions of this Section 8.13 are intended to be for the
        benefit of, and shall be enforceable by, each Indemnified  Party, his or
        her heirs and his or her personal  representatives  and shall be binding
        on all successors and assigns of the Surviving Corporation.

                                      -57-
<PAGE>

                                   ARTICLE IX

                            CONDITIONS TO THE MERGER

        SECTION 9.1. Conditions to the Obligations of Each Party. The respective
obligations of STC, Epitope and Merger Sub to consummate the Mergers are subject
to the  satisfaction  or waiver on or prior to the Closing Date of the following
conditions:

             (a) Stockholder Approval.  Each of the Epitope Stockholder Approval
        and the STC Stockholder Approval shall have been obtained;

             (b) Securities  Laws.  (i) The  Registration  Statement  shall have
        become  effective in accordance  with the  provisions of the  Securities
        Act, no stop order  suspending  the  effectiveness  of the  Registration
        Statement  shall have been issued by the SEC and no proceedings for that
        purpose  shall  have been  initiated  or  threatened  by the SEC and not
        concluded  or  withdrawn  and  (ii)  all  state  securities  or blue sky
        authorizations  necessary  to carry  out the  transactions  contemplated
        hereby shall have been obtained and be in effect;

             (c)  Nasdaq   Stock  Market   Listing.   The  shares  of  Surviving
        Corporation  Common  Stock to be issued in the  Mergers  shall have been
        approved for listing upon issuance on the Nasdaq Stock  Market,  subject
        to official notice of issuance;

             (d) Antitrust.  (i) Any applicable waiting period under the HSR Act
        contemplated  by Section  8.11 hereof shall have expired or been earlier
        terminated  and (ii) if required by  applicable  law, the parties  shall
        have received a decision from the Commission on the European Communities
        (the "European  Commission")  under Regulation  4064/89 (with or without
        the initiation of proceedings  under Article  6(1)(c)  thereof) that the
        proposed  Mergers and any matters  arising  therefrom fall within either
        Article  6.l(a) or Article 6. l(b) of such  Regulation  and that, in any
        event,  the Mergers will not be referred to any  competent  authority or
        dealt with by the  European  Commission  pursuant to Article 9.3 of such
        Regulation;

             (e) Other Regulatory Approvals. Other than the filings provided for
        by Article II, all authorizations,  consents, orders or approvals of, or
        declarations  or filings with, or expirations of waiting periods imposed
        by, any Governmental  Entity the failure of which to obtain would have a
        STC Material  Adverse Effect,  an Epitope  Material  Adverse Effect or a
        Surviving  Corporation  Material Adverse Effect,  shall have been filed,
        occurred or been obtained;

             (f) No Injunctions or  Restraints;  Illegality.  No Laws shall have
        been  adopted  or  promulgated,  and  no  temporary  restraining  order,
        preliminary or permanent  injunction or other order issued by a court or
        other Governmental Entity of competent  jurisdiction shall be in effect,
        (i)  having  the  effect of making  the  Mergers  illegal  or  otherwise
        prohibiting,  enjoining or  restraining  consummation  of the Mergers or
        (ii) which  otherwise  would  reasonably be expected to have a Surviving
        Corporation  Material Adverse Effect after giving effect to the Mergers;
        provided,  however, that the provisions of this

                                      -58-
<PAGE>

        Section  9.1(f)  shall not be  available  to any party whose  failure to
        fulfill its obligations pursuant to Sections 8.1 and 8.2 shall have been
        the cause of, or shall have resulted in, such order or injunction.

             (g) Pooling.  (i) Epitope  shall have  received a letter (which may
        contain customary  qualifications and assumptions) from  PriceWaterhouse
        Coopers  LLP dated as of the  Closing  Date and  addressed  to  Epitope,
        stating  that   PriceWaterhouse   Coopers  LLP  concurs  with  Epitope's
        management's conclusion that no conditions exist that would preclude the
        Surviving  Corporation  from accounting for the Mergers as a "pooling of
        interests" in conformity with GAAP as described in Accounting Principles
        Board Opinion No. 16 and applicable rules and regulations of the SEC and
        such letter  shall not have been  withdrawn  or modified in any material
        respect  and (ii) STC shall have  received a letter  (which may  contain
        customary  qualifications and assumption) from Arthur Andersen LLP dated
        as of the  Closing  Date  and  addressed  to STC,  stating  that  Arthur
        Andersen  LLP  concurs  with  STC's  management's   conclusion  that  no
        conditions  exist with respect to STC that would  preclude the Surviving
        Corporation  from accounting for the Mergers as a "pooling of interests"
        in  conformity  with GAAP as described in  Accounting  Principles  Board
        Opinion No. 16 and applicable  rules and regulations of the SEC and such
        letter  shall  not have  been  withdrawn  or  modified  in any  material
        respect.

        SECTION 9.2.  Conditions to the  Obligations  of Epitope and Merger Sub.
The  obligations of Epitope and Merger Sub to consummate the Mergers are subject
to the  satisfaction,  or waiver by Epitope  and Merger  Sub, on or prior to the
Closing Date, of the following further conditions:

             (a) Representations and Covenants.  (i) STC shall have performed in
        all material  respects all of its obligations  hereunder  required to be
        performed by it at or prior to the time of the filing of the Articles of
        Merger and the  Certificates  of Merger;  (ii) the  representations  and
        warranties  of  STC  in  this   Agreement   that  are  qualified  as  to
        materiality,  STC  Material  Adverse  Effect  or  Surviving  Corporation
        Material Adverse Effect shall be accurate,  and any such representations
        and  warranties  that are not so  qualified  shall be  accurate,  in all
        material  respects,  as of the  date  of  this  Agreement  and as of the
        Effective Time (except for  representations  and warranties that address
        matters only as of a specific  date, in which case such  representations
        and warranties qualified as to materiality,  STC Material Adverse Effect
        or  Surviving  Corporation  Material  Adverse  Effect  shall be true and
        correct,  and those not so  qualified  shall be true and  correct in all
        material  respects,  on and as of such earlier date);  and (iii) Epitope
        shall have received a certificate  signed by the Chief Executive Officer
        or Chief Financial Officer of STC to the foregoing effect;

             (b) Tax Opinion. Epitope shall have received an opinion of Stinson,
        Mag & Fizzell,  P.C. in form and substance  reasonably  satisfactory  to
        Epitope, on the basis of certain facts,  representations and assumptions
        set  forth in such  opinion,  dated as of the date of the  filing of the
        Articles of Merger and the  Certificates  of Merger,  to the effect that
        the  Mergers  will  qualify  for  federal  income  tax  purposes  as 368
        Reorganizations  and that each of Epitope,  STC and Merger Sub will be a
        party to a  reorganization  within the meaning of Section  368(b) of the
        Code. In rendering such opinion,  such counsel shall be entitled to rely
        upon representations of officers of Epitope, STC and Merger Sub;

                                      -59-
<PAGE>

             (c) Employment  Agreements.  The employees  identified in Exhibit N
        hereto shall have executed and  delivered to the  Surviving  Corporation
        employment  agreements in the respective  forms delivered to Epitope and
        Merger Sub on or prior to the date hereof;

             (d)  Affiliate  Agreements.  Epitope  shall have received from each
        Person  named in the letter  referred  to in Section  8.8(b) an executed
        copy of an Epitope  Affiliate  Agreement and a STC  Affiliate  Agreement
        substantially in the form of Exhibit L and Exhibit M,  respectively,  to
        this Agreement;

             (e) Fairness  Opinion.  The opinion  described  in Section  3.18(b)
        shall not have been  withdrawn  or  materially  modified  in an  adverse
        manner;

             (f) No  Material  Adverse  Change.  There  shall  have  been (i) no
        material  adverse  change  in  the  financial   condition,   results  of
        operations or cash flows or assets,  liabilities,  business or prospects
        of STC from the date of the STC Balance  Sheet  through the Closing Date
        and (ii) no  action  taken by the FDA with  respect  to STC's  products,
        operations or facilities that would be reasonably expected to have a STC
        Material Adverse Effect;

             (g) FDA Action.  There shall have been no adverse  action  taken by
        the Food and Drug  Administration  that  would,  or would be  reasonably
        expected to,  prohibit or  significantly  limit the  manufacture,  sale,
        promotion or  distribution  of any  products of STC or the  operation of
        STC; and

             (h) Epitope Rights  Agreement.  The Epitope Stock  Purchase  Rights
        shall not have become exercisable or been distributed or triggered.

        SECTION 9.3.  Conditions to the  Obligations of STC. The  obligations of
STC to consummate the Merger are subject to the satisfaction,  or waiver by STC,
on or prior to the Closing Date, of the following further conditions:

             (a) Representations and Covenants. (i) Epitope shall have performed
        in all material respects all of its obligations hereunder required to be
        performed by it at or prior to the time of the filing of the Articles of
        Merger and the  Certificates  of Merger;  (ii) the  representations  and
        warranties  of  Epitope  and  Merger  Sub in  this  Agreement  that  are
        qualified  as  to  materiality,   Epitope  Material  Adverse  Effect  or
        Surviving Corporation Material Adverse Effect shall be accurate, and any
        such  representations  and warranties that are not so qualified shall be
        accurate, in all material respects, as of the date of this Agreement and
        as of the  Effective  Time (except for  representations  and  warranties
        which  address  matters only as of a specific  date,  in which case such
        representations  and  warranties  qualified as to  materiality,  Epitope
        Material Adverse Effect or Surviving Corporation Material Adverse Effect
        shall be true and correct,  and those not so qualified shall be true and
        correct in all material  respects,  on and as of such earlier date); and
        (iii)  STC  shall  have  received  a  certificate  signed  by the  Chief
        Executive  Officer or Chief Financial  Officer of Epitope and Merger Sub
        to the foregoing effect;

                                      -60-
<PAGE>

             (b) Tax  Opinion.  STC shall  have  received  an  opinion of Pepper
        Hamilton LLP in form and substance  reasonably  satisfactory  to STC, on
        the basis of certain facts, representations and assumptions set forth in
        such  opinion,  dated as of the date of the  filing of the  Articles  of
        Merger and the  Certificates  of Merger,  to the effect that the Mergers
        will qualify for federal income tax purposes as 368  Reorganizations and
        that  each  of  Epitope,  STC  and  Merger  Sub  will  be a  party  to a
        reorganization  within the  meaning of  Section  368(b) of the Code.  In
        rendering  such  opinion,  such  counsel  shall be entitled to rely upon
        representations of officers of Epitope, STC and Merger Sub;

             (c) Employment  Agreements.  The employees  identified in Exhibit N
        hereto shall have executed and  delivered to the  Surviving  Corporation
        employment  agreements in the  respective  forms  delivered to STC on or
        prior to the date hereof;

             (d) No Material  Adverse Change.  There shall have been no material
        adverse change in the financial condition, results of operations or cash
        flows or assets, liabilities,  business or prospects of Epitope from the
        date of the Epitope Balance Sheet through the Closing Date;

             (e) FDA Action.  There shall have been no adverse  action  taken by
        the Food and Drug  Administration  that would,  or would  reasonably  be
        expected to,  prohibit or  significantly  limit the  manufacture,  sale,
        promotion or  distribution  of any products of Epitope or the operations
        of Epitope;

             (f) Epitope Rights  Agreement.  The Epitope Stock  Purchase  Rights
        shall not have become exercisable or been distributed or triggered; and

             (g) STC Preferred Stock. The holders of all shares of STC Preferred
        Stock shall have converted all of their shares into STC Common Stock.

                                   ARTICLE X

                                   TERMINATION

        SECTION 10.1. Termination.  This Agreement may be terminated at any time
prior to the Effective  Time by written notice by the  terminating  party to the
other  party  (except if such  termination  is  pursuant  to  Section  10.1(a)),
notwithstanding  approval thereof by the respective  stockholders of Epitope and
STC:

             (a) by mutual written agreement of Epitope and STC;

             (b) by either STC or Epitope, if

                 (i) the Mergers shall not have been  consummated by October 31,
             2000 (the "Expiration Date"); provided, however, that (x) the right
             to terminate this Agreement under this Section 10.1(b)(i) shall not
             be  available  to any party whose  breach of any  provision of this
             Agreement has resulted in the failure of the Mergers to occur on or
             before the  Expiration  Date,  and (y) such  termination  shall

                                      -61-
<PAGE>

             not limit  any  obligation  to make any  payment  or  reimbursement
             required under Section 10.2(b);

                 (ii)  there  shall be any Law that  makes  consummation  of the
             Mergers   illegal  or  otherwise   prohibited   or  any   judgment,
             injunction,  order or  decree  of any  Governmental  Entity  having
             competent  jurisdiction  enjoining  Epitope,  STC or the Merger Sub
             from  consummating  the  Mergers  is  entered  and  such  judgment,
             injunction,   judgment  or  order  shall  have  become   final  and
             nonappealable  and,  prior to such  termination,  the parties shall
             have used  reasonable  best efforts to resist,  resolve or lift, as
             applicable, such law, regulation,  judgment,  injunction,  order or
             decree; or

                 (iii) the holders of Epitope  Common  Stock do not approve this
             Agreement.

             (c) by Epitope,  (i) if there shall have occurred an Adverse Change
        in the STC  Recommendation  (or  the  Board  of  Directors  of STC  have
        resolved or publicly proposed to take such action);  (ii) if there shall
        have occurred a willful and material breach of Section 7.2 by STC or any
        of its officers,  directors,  employees,  advisors or agents; (iii) if a
        breach of any  representation,  warranty,  covenant or  agreement on the
        part of STC set forth in this  Agreement  shall have occurred that would
        cause the condition set forth in Section 9.2(a) not to be satisfied, and
        such condition  shall be incapable of being  satisfied or, if capable of
        being  satisfied,  shall not have been  satisfied  within 20 days  after
        written  notice  thereof shall have been received by STC; (iv) STC shall
        have failed to include in the Joint Proxy  Statement the  recommendation
        of the Board of  Directors  of STC in favor of the adoption and approval
        of this  Agreement  and the  approval  of the  Merger;  (v) the Board of
        Directors  of STC shall  have  approved,  endorsed  or  recommended  any
        Acquisition  Proposal;  (vi) a tender  or  exchange  offer  relating  to
        securities of STC shall have been  commenced and STC shall not have sent
        to its security holders, within ten business days after the commencement
        of such  tender or  exchange  offer,  a  statement  disclosing  that STC
        recommends  rejection of such tender or exchange  offer; or (vii) STC or
        STC's Board of Directors or any committee thereof shall have resolved to
        do or permit any of the foregoing;

             (d) by STC, (i) if there shall have  occurred an Adverse  Change in
        the Epitope  Recommendation  (or the Board of  Directors of Epitope have
        resolved or publicly proposed to take such action);  (ii) if there shall
        have  occurred a willful and material  breach of Section 6.2 by Epitope,
        any Epitope Subsidiary or any of their respective  officers,  directors,
        employees,   advisors   or   agents;   or  (iii)  if  a  breach  of  any
        representation,  warranty,  covenant or agreement on the part of Epitope
        set forth in this  Agreement  shall have  occurred  that would cause the
        condition  set forth in  Section  9.3(a) not to be  satisfied,  and such
        condition  is  incapable  of being  satisfied  or, if  capable  of being
        satisfied,  shall not have been  satisfied  within 20 days after written
        notice  thereof shall have been received by Epitope;  (iv) Epitope shall
        have failed to include in the Joint Proxy  Statement the  recommendation
        of the  Board of  Directors  of  Epitope  in favor of the  adoption  and
        approval of this Agreement and the approval of the Merger; (v) the Board
        of Directors of Epitope shall have approved, endorsed or recommended any
        Acquisition

                                      -62-
<PAGE>

        Proposal;  (vi) a tender or exchange  offer  relating to  securities  of
        Epitope shall have been commenced and Epitope shall not have sent to its
        security  holders,  within ten business days after the  commencement  of
        such  tender or exchange  offer,  a statement  disclosing  that  Epitope
        recommends  rejection of such tender or exchange offer; or (vii) Epitope
        or  Epitope's  Board of Directors or any  committee  thereof  shall have
        resolved to do or permit any of the foregoing;

             (e) by  Epitope  at any  time  prior to its  required  stockholders
        approval,  upon three Business Days' prior notice to STC, if the Epitope
        Board of Directors  shall have  determined as of the date of such notice
        that an Acquisition Proposal is a Superior Proposal and has entered into
        (subject to  termination of this  Agreement) a definitive  agreement for
        such Superior Proposal;  provided,  however, that (i) Epitope shall have
        complied  with Section 6.2, (ii) the Board of Directors of Epitope shall
        have  concluded  in  good  faith,  as of  the  effective  date  of  such
        termination,  after  taking into  account  any  revised  proposal by STC
        during such three Business Day period, that an Acquisition Proposal is a
        Superior  Proposal  and (iii)  Epitope  shall have made the  payment and
        reimbursement set forth in Section 10.2(b);

             (f)  automatically  if the  transactions  contemplated  herein  are
        enjoined by a court of  competent  jurisdiction  for a period  extending
        beyond 90 days;

             (g) by  STC,  if a  Share  Acquisition  Date  shall  have  occurred
        pursuant to the Epitope Rights Agreement;

             (h) by STC, if the Epitope  Average Price shall be less than $6.00;
        or

             (i) by STC, if the Epitope  meeting of  stockholders is canceled or
        is otherwise not held or if a final vote of Epitope's  stockholders  has
        not been taken with  respect to the Mergers  prior to October 31,  2000,
        except as a result  of a  judgment,  injunction,  order or decree of any
        competent  authority or events or  circumstances  beyond the  reasonable
        control of Epitope.

        SECTION 10.2. Effect of Termination.

             (a) If this Agreement is terminated  pursuant to Section 10.1, this
        Agreement shall forthwith become void and there shall be no liability or
        obligation on the part of Epitope or STC or their respective officers or
        directors  except with respect to the  provisions of Sections 8.9, 10.2,
        12.1,  12.4,  12.5,  12.10 and 12.11 of this Agreement which  provisions
        shall  remain in full force and effect and  survive any  termination  of
        this  Agreement,  and  except  that,  notwithstanding  anything  to  the
        contrary  contained in this Agreement,  neither Epitope nor STC shall be
        relieved or released from any  liabilities or damages arising out of its
        willful  material  breach of this  Agreement  or any  obligations  under
        Section 10.2(b).

             (b) Epitope  agrees to pay STC (A) a fee in  immediately  available
        funds equal to $3,000,000 in the event that this Agreement is terminated
        by STC  pursuant to clauses  (i),  (iv),  (v),  (vi) or (vii) of Section
        10.1(d) or pursuant to Section 10.1(i),  (B) together with an additional
        payment  of  $2,000,000  plus  reimbursement  to STC  of its  reasonable


<PAGE>

        Expenses  (as  defined  in  Section  10.3)  up to a  maximum  amount  of
        $1,000,000,  if (x) an  Acquisition  Proposal had been made prior to the
        actions  referenced in clauses (i), (iv),  (v), (vi) or (vii) of Section
        10.1(d) or Section 10.1(i),  and (y) within twelve months following such
        termination by STC, Epitope enters into a definitive  agreement with the
        party that made such Acquisition Proposal. Epitope agrees to (i) pay STC
        a fee in immediately  available  funds equal to $5,000,000,  and (ii) to
        reimburse STC for its  reasonable  Expenses (as defined in Section 10.3)
        up to a maximum  amount of  $1,000,000,  in the event this  Agreement is
        terminated  by Epitope  pursuant to Section  10.1(e),  which payment and
        reimbursement  shall be  reduced  by the  amount  of all  payments,  and
        reimbursements  made by Epitope  pursuant to the first  sentence of this
        Section 10.2(b).  The payment of the first $3,000,000 required by clause
        (A) of the first  sentence  of this  Section  10.2(b)  shall be made not
        later than the close of  business on the second  Business  Day after STC
        has terminated this Agreement pursuant to the provisions  referred to in
        such  sentence.  The  combined  payment  and  reimbursement  of up to an
        additional  $3,000,000  required by clause (B) of the first  sentence of
        this Section 10.2(b) shall be made  contemporaneously with entering into
        a definitive  agreement  with the third party that made the  Acquisition
        Proposal  referred  to  in  that  sentence.   The  termination  of  this
        Agreement,  and the  payment  and  reimbursement  required by the second
        sentence of this Section 10.2(b) shall be made  contemporaneously with a
        termination of this Agreement by Epitope.

             (c)  The  remedy  provided  for in  Section  10.2(b)  shall  be the
        exclusive remedy at law or in equity that STC shall have in the event of
        a  termination  of this  Agreement  (A) by STC  pursuant to clauses (i),
        (iv), (v), (vi) or (vii) of Section 10.1(d) or Section  10.1(i),  or (B)
        by Epitope pursuant to Section 10.1(e).

             (d) Epitope  acknowledges  that the  agreements  contained  in this
        Section 10.2 are an integral part of the  transactions  contemplated  by
        this Agreement,  and that,  without these  agreements STC would not have
        entered into this Agreement.

        SECTION  10.3.  Fees and  Expenses.  Except as set forth in this Section
10.2(b),  all  fees  and  expenses  incurred  in  connection  herewith  and  the
transactions  contemplated  hereby  shall be paid by the  party  incurring  such
expenses, whether or not the Mergers are consummated. As used in this Agreement,
"Expenses" includes all out-of-pocket  expenses (including,  without limitation,
all fees and expenses of counsel,  accountants,  investment bankers, experts and
consultants to a party hereto and its affiliates)  incurred by a party or on its
behalf  in  connection  with  or  related  to  the  authorization,  preparation,
negotiation,  execution and  performance of this Agreement and the  transactions
contemplated hereby, including the preparation,  printing, filing and mailing of
the  Joint  Proxy  Statement/Prospectus  and  the  solicitation  of  stockholder
approvals and all other matters related to the transactions contemplated hereby.

                                   ARTICLE XI

                                  MISCELLANEOUS

        SECTION 11.1. Notices.  All notices and other  communications  hereunder
shall be in writing  and shall be deemed  duly given (a) on the date of delivery
if delivered personally,  or by

                                      -64-
<PAGE>

telecopy or telefacsimile,  upon confirmation of receipt,  in each case, if on a
Business Day, and otherwise on the next Business Day, (b) on the first  service,
or (c) on the fifth  Business Day  following the date of mailing if delivered by
registered or certified mail,  return receipt  requested,  postage prepaid.  All
notices  hereunder  shall be delivered  as set forth below,  or pursuant to such
other  instructions as may be designated in writing by the party to receive such
notice:

               if to the Surviving  Corporation,  to the address set forth below
               for Epitope and STC, including copies;

                      if to Epitope, to:

                             Epitope, Inc.
                             8505 SW Creekside Place
                             Beaverton, OR 97008
                             Attention: Robert Thompson, President
                                        and Chief Executive Officer

                      with a copy to:

                             Stinson, Mag & Fizzell, P.C.
                             1201 Walnut Street, Suite 2800
                             Kansas City, MO 64106
                             Attention:  John A. Granda, Esq.

                      if to STC to:

                             STC Technologies, Inc.
                             1745 Eaton Avenue
                             Bethlehem, PA 18018
                             Attention: Mike Gausling, President
                                        and Chief Executive Officer

                      with a copy to:
                             Pepper Hamilton LLP
                             1235 Westlakes Drive, Suite 400
                             Berwyn, PA 19312
                             Attention:  Jeffrey P. Libson, Esq.

        SECTION  11.2.  Survival of  Representations,  Warranties  and Covenants
After the Effective Time. The representations,  warranties,  covenants and other
agreements contained herein and in any certificate or other instrument delivered
pursuant  hereto,  including  any  rights  arising  out of any  breach  of  such
representations,  warranties,  covenants and other agreements, shall not survive
the Effective Time.

                                      -65-
<PAGE>

SECTION 11.3.  Amendments; No Waivers.

             (a) Any provision of this  Agreement may be amended or waived prior
        to the  Effective  Time if, and only if, such  amendment or waiver is in
        writing and signed,  in the case of an amendment,  by Epitope and STC or
        in the case of a waiver,  by the party  against whom the waiver is to be
        effective;  provided that (i) after the Epitope Stockholder Approval, no
        such  amendment or waiver  shall,  without the further  approval of such
        stockholders,  be made  that  would  require  such  approval  under  any
        applicable  law, rule or regulation  and (ii) after the STC  Stockholder
        Approval,  no such  amendment  or  waiver  shall,  without  the  further
        approval of such stockholders,  be made that would require such approval
        under any applicable law, rule or regulation.

             (b) No failure or delay by any party in exercising any right, power
        or privilege  hereunder  shall operate as a waiver thereof nor shall any
        single  or  partial  exercise  thereof  preclude  any  other or  further
        exercise thereof or the exercise of any other right, power or privilege.
        The rights and remedies  herein  provided  shall be  cumulative  and not
        exclusive of any rights or remedies provided by law.

        SECTION 11.4. Assignment.  Neither this Agreement nor any of the rights,
interests  or  obligations  hereunder  shall be  assigned  by any of the parties
hereto, in whole or in part (whether by operation of law or otherwise),  without
the prior written  consent of the other party,  and any attempt to make any such
assignment without such consent shall be null and void. Subject to the preceding
sentence,  this Agreement  will be binding upon,  inure to the benefit of and be
enforceable by the parties and their respective successors and assigns.

        SECTION  11.5.  Governing  Law.  This  Agreement  shall be  construed in
accordance  with and  governed  by the  internal  laws of the State of  Delaware
without regard to any principles of conflicts or choice of law.

        SECTION  11.6.  Counterparts;   Effectiveness.  This  Agreement  may  be
executed in one or more  counterparts,  all of which shall be considered one and
the same agreement and shall become effective when one or more counterparts have
been signed by each of the parties and  delivered to the other  party,  it being
understood that both parties need not sign the same counterpart.  This Agreement
shall become  effective when each party hereto shall have received  counterparts
hereof signed by all of the other parties hereto.

        SECTION  11.7. No Third Party  Beneficiaries.  This  Agreement  shall be
binding upon and inure solely to the benefit of each party  hereto,  and nothing
in this Agreement,  express or implied,  is intended to or shall confer upon any
other Person any right,  benefit or remedy of any nature  whatsoever under or by
reason of this  Agreement,  other than Section 8.13 (which is intended to be for
the benefit of the Persons covered thereby and may be enforced by such Persons).

        SECTION 11.8. Interpretation. When a reference is made in this Agreement
to Sections,  Exhibits or Schedules,  such reference shall be to a Section of or
Exhibit or Schedule to this Agreement unless otherwise  indicated.  The table of
contents and headings  contained in this  Agreement are for  reference  purposes
only and  shall not  affect in any way the  meaning  or

                                      -66-
<PAGE>

interpretation  of this Agreement.  Whenever the words "include,"  "includes" or
"including" are used in this  Agreement,  they shall be deemed to be followed by
the words "without limitation."

        SECTION 11.9.  Enforcement.  The parties agree that  irreparable  damage
would occur in the event that any of the  provisions of this  Agreement were not
performed in accordance with their specific terms. It is accordingly agreed that
the parties shall be entitled to specific  performance of the terms hereof, this
being in  addition to any other  remedy to which they are  entitled at law or in
equity.

        SECTION  11.10.  Entire  Agreement.  This  Agreement  (together with the
exhibits and schedules  hereto)  constitutes  the entire  agreement  between the
parties  with  respect to the subject  matter  hereof and  supersedes  all prior
agreements and understandings,  both oral and written,  between the parties with
respect to the subject matter hereof.

        SECTION  11.11.  Severability.  If  any  term,  provision,  covenant  or
restriction  set  forth  in this  Agreement  is held  by a  court  of  competent
jurisdiction to be invalid, illegal, void or unenforceable, the remainder of the
terms, provisions,  covenants and restrictions set forth in this Agreement shall
remain in full  force and effect and shall in no way be  affected,  impaired  or
invalidated  so long as the  economic  or legal  substance  of the  transactions
contemplated  hereby is not  deemed by a party  (acting  reasonably  and in good
faith) to be materially  adverse to that party.  Upon such a determination,  the
parties shall  negotiate in good faith to modify this  Agreement so as to effect
the  original  intent of the  parties as closely as  possible  in order that the
transactions  contemplated hereby may be consummated as originally  contemplated
to the fullest extent possible.


                                      -67-
<PAGE>

        IN WITNESS WHEREOF,  the parties hereto have caused this Agreement to be
duly  executed by their  respective  authorized  officers as of the day and year
first above written.

                              EPITOPE, INC.


                              By:  /s/ Robert D. Thompson
                                  Name:  Robert D. Thompson
                                  Title: President and Chief Executive Officer


                              STC TECHNOLOGIES, INC.


                              By:  /s/ Michael J. Gausling
                                  Name:  Michael J. Gausling
                                  Title:  President and Chief Executive Officer
                                         -


                              EDWARD MERGER SUBSIDIARY, INC.


                              By:  /s/ Robert D. Thompson
                                  Name:  Robert D. Thompson
                                  Title: Chief Executive Officer


                                      -68-
<PAGE>

                                   APPENDIX I

                                   DEFINITIONS

        "Acquisition  Proposal  for  Epitope"  means any offer or proposal for a
merger,  consolidation,  share, exchange, business combination,  reorganization,
recapitalization,   issuance   of   securities,   acquisition   of   securities,
liquidation,  dissolution,  tender  offer or  exchange  offer  or other  similar
transaction or series of transactions  involving, or any purchase of 10% or more
of the assets,  or directly  or  indirectly  acquires  beneficial  ownership  of
securities representing,  or exchangeable for or convertible into, more than 10%
of the outstanding  securities of any class of voting  securities of, Epitope or
any  Significant  Subsidiary of Epitope or in which  Epitope or any  Significant
Subsidiary of Epitope  issues  securities  representing  10% of the  outstanding
securities  of any class of voting  securities  of  Epitope  or any  significant
subsidiary  of  Epitope,  other  than  the  transactions  contemplated  by  this
Agreement.

        "Acquisition Proposal for STC" means any offer or proposal for a merger,
consolidation,    share   exchange,   business   combination,    reorganization,
recapitalization, issuance of securities, liquidation, dissolution, tender offer
or  exchange  offer or other  similar  transaction  or  series  of  transactions
involving,  or any  purchase  of 10% or  more  of the  assets,  or  directly  or
indirectly  acquires  beneficial  ownership  of  securities   representing,   or
exchangeable  for  or  convertible  into,  more  than  10%  of  the  outstanding
securities  of any class of  voting  securities  of STC or in which  STC  issues
securities representing 10% of the outstanding securities of any class of voting
securities of STC, other than the transactions contemplated by this Agreement.

        "Action"  means any action,  suit,  proceeding  or  investigation  by or
before any Governmental Entity or arbitrator.

        "Affiliate"  means,  with  respect  to any  Person,  any  other  Person,
directly or  indirectly,  controlling,  controlled  by, or under common  control
with,  such  Person.  For  purposes  of  this  definition,  the  term  "control"
(including  the  correlative  terms  "controlling",  "controlled  by" and "under
common control with") means the possession,  direct or indirect, of the power to
direct  or cause the  direction  of the  management  and  policies  of a Person,
whether  through the ownership of voting  securities,  or  partnership  or other
ownership interests, by contract, or otherwise.

        "Articles  of Merger"  means the  Articles of Merger of Epitope with and
into Merger Sub, in substantially the form attached hereto as Exhibit D.

        "Average  Epitope  Stock Price"  means the average of the closing  sales
price per share of Epitope  Common Stock as reported by NASDAQ on each of the 20
consecutive  trading days  immediately  preceding the third trading day prior to
the Determination Date.

        "Business  Day"  means any day other than a  Saturday,  Sunday or one on
which banks are authorized by law to close in the City of New York.

        "Certificate  of Merger" means either (i) the  Certificate  of Merger of
STC with and into Merger  Sub,  in  substantially  the form  attached  hereto as
Exhibit C, or (ii) the  Certificate  of

                                      A-1
<PAGE>

Merger of Epitope with and into Merger Sub, in substantially the form of Exhibit
E, as the case may be.

        "Certificates of Merger" includes both of such Certificates.

        "Closing"  means  the  closing  of  the  Mergers  contemplated  in  this
Agreement.

        "Closing Date" means the date on which the Closing occurs.

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

        "Consequential Damages" means Damages arising out of any interruption of
business, loss of profits, loss of use of facilities,  claims of customers, loss
of goodwill or any indirect, incidental or special Damages.

        "Damages" means all losses, claims,  damages,  costs, fines,  penalties,
obligations,  payments  and  liabilities  (including  those  arising  out of any
Action),  together with all reasonable costs and expenses (including  reasonable
outside  attorneys'  fees and  reasonable  out-of-pocket  expenses)  incurred in
connection with any of the foregoing.

        "Determination  Date" means the date on which the last of the  following
occurs:  (i) the effective  date  (including  the  expiration of any  applicable
waiting period by law) of the last required consent or order of any Governmental
Entity having authority over and approving or exempting the Merger, and (ii) the
date on which the stockholders of both Epitope and STC have approved the Merger.

        "Epitope  Balance  Sheet" means  Epitope's  consolidated  balance  sheet
included in the Epitope 10-K  relating to its fiscal year ended on September 30,
1999.

        "Epitope  Common Stock" means the common stock of Epitope,  no par value
per share, including the associated rights (the "Epitope Stock Purchase Rights")
to purchase shares of Series A Junior  Participating  Cumulative Preferred Stock
of Epitope  (the  "Epitope  Series A  Preferred  Stock")  pursuant to the Rights
Agreement,  dated as of December  15,  1997,  between  Epitope  and  ChaseMellon
Shareholder  Services,  L.L.C.,  as Rights  Agent,  as proposed to be amended as
contemplated  by Section  3.23  hereof (the  "Epitope  Rights  Agreement").  All
references in this Agreement to Epitope Common Stock to be received  pursuant to
the Merger shall be deemed to include the Epitope Stock Purchase Rights.

        "Epitope  Disclosure  Schedule"  means the schedule  delivered to STC by
Epitope   pursuant  to  Article  III  hereof   containing   exceptions   to  the
representations and warranties of Epitope set forth in such Article III.

        "Epitope SEC Documents"  means (i) Epitope's  annual report on Form 10-K
for its  fiscal  year  ended  September  30,  1999 (the  "Epitope  10-K"),  (ii)
Epitope's  quarterly  report on Form 10-Q (the  "Epitope  10-Q")  for its fiscal
quarter ended December 31, 1999, (iii) Epitope's proxy or information statements
relating  to  meetings  of, or actions  taken  without a meeting  by,  Epitope's
stockholders held since September 30, 1999, and (iv) all other reports, filings,
registration  statements  and  other  documents  filed by it with the SEC  since
September 30, 1999.

                                      A-2
<PAGE>

        "Exchange  Act" means the  Securities  Exchange Act of 1934, as amended,
and the rules and regulations promulgated thereunder.

        "Exchange  Agent"  means the agent to be agreed  upon by Epitope and STC
and  engaged  by  the  Surviving  Corporation  to  effect  the  exchange  of the
Certificates pursuant to Section 2.3 of this Agreement.

        "Governmental  Entity"  means any federal,  state or local  governmental
authority,   any   transgovernmental   authority   or   any   court,   tribunal,
administrative  or  regulatory  agency  or  commission  or  other   governmental
authority or agency, domestic or foreign.

        "Joint    Proxy    Statement/Prospectus"    means   the   joint    proxy
statement/prospectus  included  in the  Registration  Statement  relating to the
Special Meetings, together with any amendments or supplements thereto.

        "Knowledge" means, with respect to the matter in question, if any of (i)
in the case of Epitope  or Merger  Sub,  Robert  Thompson,  President  and Chief
Executive Officer, Charles Bergeron, Vice President and Chief Financial Officer,
Andrew S. Goldstein,  Senior Vice President,  Richard George, Vice President and
Chief Science Officer,  William D. Block, Vice President of Marketing and Sales,
and Rob Ngungu, Vice President of Regulatory Affairs and Quality Assurance,  and
(ii) in the case of STC,  Michael J.  Gausling,  President  and Chief  Executive
Officer,  William  M.  Hinchey,  Executive  Vice  President,  R.  STC  Niedbala,
Executive Vice President,  and Richard D. Hooper,  Chief Financial Officer,  has
actual knowledge of such matter.

        "Law"   means   any   federal,   state,   local,   municipal,   foreign,
international,   multinational,  or  other  judicial  or  administrative  order,
judgment, decree, constitution,  statute, rule, regulation, treaty, ordinance or
principle of common law.

        "Lien" means,  with respect to any asset,  any mortgage,  lien,  pledge,
charge, security interest or encumbrance of any kind in respect of such asset.

        "Material  Adverse  Effect"  means  a  material  adverse  effect  on the
financial  condition,  business,  results of operations or prospects of a Person
and its  Subsidiaries,  taken as a whole, but shall exclude any material adverse
effect arising out of any change or  development  relating to (i) U.S. or global
economic or  industry  conditions  (including,  without  limitation,  conditions
applicable generally to the oral specimen collection business),  (ii) changes in
U.S. or global  financial  markets or  conditions,  and/or  (iii) any  generally
applicable  change in Law or GAAP or  interpretation  of any  thereof.  "Epitope
Material  Adverse Effect" means a Material Adverse Effect in respect of Epitope,
"STC Material  Adverse Effect" means a Material Adverse Effect in respect of STC
and "Surviving  Corporation  Material  Adverse Effect" means a Material  Adverse
Effect in respect of the Surviving Corporation.

        "Merger" or "Mergers" has the meaning  specified in the Recitals to this
Agreement.

        "Merger  Consideration"  means the total  number of shares of  Surviving
Corporation  Common  Stock  issued  pursuant  to the STC  Merger or the  Epitope
Merger,  as the case may be,

                                      A-3
<PAGE>

issued  pursuant to Article  II,  together  with any cash in lieu of  fractional
shares of  Surviving  Corporation  Common  Stock to be paid  pursuant to Section
2.1(d)(iv).

        "Person"  means  an  individual,  a  corporation,  a  limited  liability
company,  a  partnership,  an  association,  a  trust  or any  other  entity  or
organization, including any Governmental Entity.

        "Registration  Statement" means the  Registration  Statement on Form S-4
registering  under the  Securities  Act the Surviving  Corporation  Common Stock
issuable in connection with the Merger.

        "STC Balance  Sheet" means STC's audited  balance sheet  relating to its
fiscal year ended on December 31, 1999.

        "STC Common  Stock" means the common stock of STC,  $0.000001  par value
per share,  and all  references  in this  Agreement to STC Common Stock shall be
deemed to include  both the Class A Common Stock and the Class B Common Stock of
STC.

        "STC Common Stock  Equivalent"  means all rights and options to purchase
or acquire STC Common Stock.

        "STC Disclosure Schedule" means the schedule delivered to Epitope by STC
pursuant to Article IV hereof containing  exceptions to the  representations and
warranties of STC set forth in such Article IV.

        "STC Preferred Stock" means the Series A Convertible  Preferred Stock of
STC, $0.000001 par value per share.

        "SEC" means the Securities and Exchange Commission.

        "Securities  Act" means the Securities Act of 1933, as amended,  and the
rules and regulations promulgated thereunder.

        "Significant   Subsidiary"  means  any  Subsidiary  that  constitutes  a
"significant  subsidiary"  of such  Person  with  the  meaning  of Rule  1-02 of
Regulation S-X of the Exchange Act.

        "Subsidiary" means, with respect to any Person, any corporation or other
entity of which  securities or other ownership  interests having ordinary voting
power to elect a majority of the board of directors or other Persons  performing
similar  functions  are directly or  indirectly  owned by such Person.  "Epitope
Subsidiary" means a Subsidiary of Epitope.

        "Surviving  Corporation  Common  Stock" means the common stock of Merger
Sub,  $0.000001  par value per  share,  including  the  associated  rights  (the
"Surviving  Corporation  Stock Purchase  Rights") to purchase shares of Series A
Preferred Stock of the Surviving Corporation (the "Surviving  Corporation Series
A Preferred  Stock")  pursuant  to the Rights  Agreement  between the  Surviving
Corporation and ChaseMellon  Shareholder Services,  L.L.C., as Rights Agent (the
"Surviving  Corporation Rights Agreement").  All references in this Agreement to
Surviving  Corporation  Common Stock to be received pursuant to the Merger shall
be deemed to include the Surviving Corporation Stock Purchase Rights.

                                      A-4
<PAGE>

        "Tax" or "Taxes"  means any  federal,  state,  county,  local or foreign
taxes, charges, levies, imposts, duties, other assessments or similar charges of
any kind  whatsoever,  including  any interest,  penalties and addition  imposed
thereon or with respect thereto.

        In addition to the  definitions  set forth above,  each of the following
terms is defined in the Section set forth opposite such term:

         TERMS                                                        Section
         -----                                                        -------
         Adverse Change in the Epitope Recommendation                 8.2(b)
         Adverse Change in the STC Recommendation                     8.2(b)
         Certificates                                                 2.3(a)
         Confidentiality Agreement                                    6.2(a)
         Confidential Material                                        8.9(a)
         Delaware Law                                                 2.1(a)
         Delivering Company                                           8.9(a)
         Effective Time                                               2.2(b)
         Epitope                                                      Preamble
         Epitope Designees                                            2.4(d)
         Epitope Employee Plans                                       3.13(a)
         Epitope Intellectual Property                                3.16(b)
         Epitope Preferred Stock                                      3.5
         Epitope Representation Letter                                8.7(c)
         Epitope Returns                                              3.12
         Epitope Securities                                           3.5(b)
         Epitope Stockholder Approval                                 3.19(a)
         Epitope Stockholders Agreement                               Recitals
         Epitope Stockholders Meeting                                 3.19(b)
         Epitope Stock Options                                        3.5(a)
         Epitope Warrants                                             3.5(a)
         ERISA                                                        3.13(a)
         ERISA Affiliate                                              3.13(a)
         European Commission                                          9.1(d)
         Exchange Ratio                                               2.1(e)
         Expenses                                                     10.3
         Expiration Date                                              10.1(b)
         GAAP                                                         Recitals
         HSR Act                                                      3.3
         Mergers                                                      Recitals
         Merger Consideration                                         2.1(e)
         Multiemployer Plan                                           3.13(b)
         Oregon Law                                                   2.2(a)
         Receiving Company                                            8.9(a)
         Representatives                                              8.9(a)
         STC                                                          Preamble
         STC Designees                                                2.4(d)
         STC Financial Statements                                     4.7(a)
         STC Insiders                                                 8.12(c)

                                      A-5
<PAGE>
         TERMS                                                        Section
         -----                                                        -------
         STC Intellectual Property                                    4.15(b)
         STC Representation Letter                                    8.7(c)
         STC Returns                                                  4.11(a)
         STC Securities                                               4.5(b)
         STC Stockholder Approval                                     4.18(a)
         STC Stockholders Agreement                                   Recitals
         STC Stockholders Meeting                                     4.18(b)
         STC Stock Options                                            4.5(a)
         STC Warrants                                                 4.5(a)
         Section 16 Information                                       8.12(b)
         Stockholders Agreements                                      Recitals
         Superior Proposal                                            6.2(b)
         Surviving Corporation                                        2.1(a)
         368 Reorganization                                           Recitals



                                      A-6
<PAGE>
                                                                       EXHIBIT A


                              STOCKHOLDER AGREEMENT

                  STOCKHOLDER  AGREEMENT (this  "Agreement") dated as of May --,
2000 among  Epitope,  Inc.,  an Oregon  corporation  ("Epitope"),  Edward Merger
Subsidiary,  Inc.,  a Delaware  corporation  and a  wholly-owned  subsidiary  of
Epitope  ("Merger  Sub"),  and the  stockholders  of STC  Technologies,  Inc., a
Delaware  corporation  ("STC"  or the  "Company"),  named on  Schedule  I hereto
(individually, a "Stockholder" and collectively, the "Stockholders").

                  WHEREAS,  Epitope  and  Merger  Sub  propose  to enter into an
Agreement  and Plan of Merger  dated as of the date hereof (as amended from time
to time, the "Merger  Agreement";  capitalized terms used but not defined herein
shall  have the  meanings  set  forth in the  Merger  Agreement)  with STC which
provides,  among other things, that STC will merge with and into Merger Sub (the
"STC Merger") and immediately thereafter Epitope will merge with and into Merger
Sub (the "Epitope  Merger") (the STC Merger and the Epitope Merger are sometimes
collectively referred to herein as the "Mergers"); and

                  WHEREAS,  as of the  date  hereof,  each  Stockholder  owns of
record or beneficially  the respective  number of shares of STC Common Stock and
STC Preferred Stock set opposite such  Stockholder's  name on Schedule I hereto;
and

                  WHEREAS,  as an  essential  condition  to the  willingness  of
Epitope  and Merger Sub to enter into the Merger  Agreement,  Epitope and Merger
Sub have requested that each  Stockholder  agree, and in order to induce Epitope
and Merger Sub to enter into the Merger Agreement,  each Stockholder has agreed,
to enter into this  Agreement  with  respect to (i) all the shares of STC Common
Stock  and  STC  Preferred  Stock  owned  beneficially  and of  record  by  such
Stockholder  as of the date hereof or of which such  Stockholder  may  hereafter
acquire  record  or  beneficial  ownership  (the  "Shares")  and (ii) any  other
securities  owned of record or beneficially  by such  Stockholder as of the date
hereof or of which such Stockholder may hereafter acquire ownership of record or
beneficially  which  may be voted by or at the  direction  or on  behalf  of the
Stockholder at any meeting of STC  stockholders  or with respect to which action
taken without a meeting may be authorized by or at the direction or on behalf of
such Stockholder by written consent (the "Other Securities");

                  NOW,  THEREFORE,  in  consideration  of the  foregoing and the
mutual  covenants and  agreements  contained  herein and intending to be legally
bound hereby, the parties hereto agree as follows:

                                   ARTICLE I

                                VOTING AGREEMENT

                  SECTION 1.1 Voting Agreement.  Each Stockholder  hereby agrees
that, with respect to the STC Stockholders  Meeting and any other meeting of STC
stockholders or any action to be taken by written consent the Stockholder shall:

                  (a) appear in person or by proxy (or use its  reasonable  best
         efforts to cause the holder of record on any applicable  record date to
         appear in person or by proxy) for the

<PAGE>

         purpose of  obtaining a quorum at the STC  Stockholders  Meeting and at
         any adjournment or postponement thereof;

                  (b) vote (or  cause to be  voted)  the  Shares  and the  Other
         Securities  (or, as  applicable,  shall execute or cause to be executed
         written consents in respect of the Shares and the Other  Securities) in
         favor of the approval and adoption of the Merger Agreement, the Mergers
         and,  any other  transactions  or  matters  contemplated  by the Merger
         Agreement,  and any actions required in furtherance thereof and hereof;
         and

                  (c) not  encourage  any  holder of  securities  of STC to vote
         against the approval and adoption of the Merger Agreement,  the Mergers
         or any  other  transactions  or  matters  contemplated  by  the  Merger
         Agreement.

                  SECTION  1.2  Irrevocable  Proxy.  In order to ensure that the
voting  agreement  set forth in Section  1.1 and the other  obligations  of each
Stockholder  hereunder  will be carried out, each  Stockholder  hereby grants an
irrevocable  proxy,  coupled with an interest,  in the form  attached  hereto as
Exhibit A (the  "Irrevocable  Proxy") to, and hereby  constitutes  and  appoints
Epitope  and each of its  officers  as such  Stockholder's  sole  and  exclusive
attorney and proxy  pursuant to the  provisions of Section 212(c) of the General
Corporation Law of the State of Delaware,  with full power of substitution,  (a)
to vote and otherwise act (by written  consent or otherwise) with respect to the
Shares and the Other  Securities  which such  Stockholder is entitled to vote at
the STC  Stockholders  Meeting  and any other  meeting of STC  Stockholders,  or
pursuant to any written consent in lieu of a meeting of STC Stockholders, and at
any  adjournment  or  postponement  thereof  on the  matters  and in the  manner
specified in Section 1.1.  THIS PROXY AND POWER OF ATTORNEY IS  IRREVOCABLE  AND
COUPLED WITH AN INTEREST.  Such Stockholder hereby revokes all other proxies and
powers of attorney with respect to the Shares and the Other Securities that such
Stockholder  may have  heretofore  appointed or granted that would  prevent such
Stockholder  from performing its  obligations  hereunder.  All authority  herein
conferred or agreed to be conferred shall survive the death or incapacity of any
Stockholder and any obligation of such Stockholder under this Agreement shall be
binding upon the transferees,  heirs, personal  representatives,  successors and
assigns of such Stockholder.

                  SECTION 1.3 Evaluation of  Investment.  Each  Stockholder,  by
reason of such Stockholder's  knowledge and experience in financial and business
matters,  is capable of  evaluating  the merits and risks of the  investment  in
Epitope  Common  Stock to be received  pursuant to the STC Merger and the Common
Stock of Merger Sub following the Epitope Merger ("Surviving  Corporation Common
Stock"), contemplated by the Merger Agreement.

                  SECTION 1.4 Documents Delivered.  The Stockholder acknowledges
receipt of copies of the following documents:

                  (a) the  Merger  Agreement  and  all  schedules  and  exhibits
         thereto;

                  (b)  Epitope's  Annual report on Form 10-K for the fiscal year
         ended September 30, 1999;

                  (c) Epitope's Proxy Statement dated January 11, 2000;

                                      -2-
<PAGE>

                  (d)  each  report  filed  with  the  Securities  and  Exchange
         Commission  by Epitope on Forms 8-K and 10-Q since  September 30, 1999;
         and

                  (e)  any  other  information   requested  by  any  Stockholder
         concerning an  evaluation of an investment in Epitope  Common Stock and
         Surviving Corporation Common Stock.

Each Stockholder also acknowledges that it possesses the information relating to
STC which such  Stockholder  deems  relevant to its investment in Epitope Common
Stock  and  the  Surviving  Corporation  Common  Stock  should  the  Mergers  be
consummated.

                                   ARTICLE II

                         REPRESENTATIONS AND WARRANTIES

                  SECTION   2.1   Representations   and   Warranties   of   Each
Stockholder.  Except as set forth on the disclosure letter attached hereto, each
Stockholder represents and warrants to Epitope and Merger Sub as follows:

                  (a)  Each  Stockholder  (if it is a  corporation,  general  or
         limited  partnership,  limited liability company or other legal entity)
         is duly organized, validly existing and in good standing under the laws
         of  the  jurisdiction  of  its  incorporation  or  organization.   Such
         Stockholder  has the requisite  power and  authority  (and if a natural
         person,  the legal  capacity) to execute and deliver this Agreement and
         to perform its  obligations  hereunder.  The  execution and delivery of
         this Agreement and the  consummation of the  transactions  contemplated
         hereby  have  been duly  authorized  by such  Stockholder  and no other
         proceedings on the part of such  Stockholder are necessary to authorize
         this Agreement and the  consummation of the  transactions  contemplated
         hereby.  This  Agreement  has been duly  executed and delivered by such
         Stockholder and,  assuming that this Agreement  constitutes a valid and
         binding agreement of Epitope,  is a legal, valid and binding obligation
         of such Stockholder, enforceable against such Stockholder in accordance
         with  its  terms,  except  as such  enforceability  may be  limited  by
         bankruptcy,  insolvency,  reorganization,  moratorium and similar laws,
         now or  hereafter in effect,  relating to or  affecting  the rights and
         remedies of creditors  generally,  and to general  principles of equity
         (regardless  of  whether  such   enforceability   is  considered  in  a
         proceeding in equity or a law) and to general principles  governing the
         duties of fiduciaries.

                  (b) The  execution  and  delivery  of this  Agreement  by such
         Stockholder  do not,  and the  performance  of this  Agreement  by such
         Stockholder  will  not  conflict  with,  result  in  any  breach  of or
         constitute  a default (or an event that with notice or lapse of time or
         both  would  become a default)  under,  or give to others any rights of
         termination,  amendment,  acceleration or  cancellation  of, or require
         payment  under,  or  result in the  creation  of any  Encumbrances  (as
         defined below) on any of the assets of such Stockholder pursuant to any
         contract or other instrument to which such Stockholder is a party or by
         which such Stockholder or any of such  Stockholder's  assets are bound,
         except  for any  thereof  that  would not  reasonably  be  expected  to
         materially  impair the  ability  of

                                      -3-
<PAGE>

         such Stockholder to perform such Stockholder's obligations hereunder or
         to consummate the transactions contemplated hereby.

                  (c) The  execution  and  delivery  of this  Agreement  by such
         Stockholder  do not,  and the  performance  of this  Agreement  by such
         Stockholder  will not,  require such Stockholder to obtain any consent,
         approval,  authorization  or permit of, or to make any  filing  with or
         notification to, any Governmental  Entity based on any federal,  state,
         local or foreign law, statute,  ordinance,  rule,  regulation,  permit,
         injunction,  writ, judgment, decree or order (collectively,  "Laws") of
         any Governmental  Entity,  except (i) pursuant to the Exchange Act, the
         Securities  Act and the HSR Act;  and (ii) where the  failure to obtain
         such consents,  approvals,  authorizations or permits,  or to make such
         filings  or   notifications,   could  not  reasonably  be  expected  to
         materially  impair the  ability  of such  Stockholder  to perform  such
         Stockholder's  obligations  hereunder or to consummate the transactions
         contemplated hereby.

                  (d)  There is no suit,  action,  investigation  or  proceeding
         pending or, to the knowledge of such  Stockholder,  threatened  against
         such  Stockholder  at law or in equity  before  or by any  Governmental
         Entity  that would  reasonably  be expected  to  materially  impair the
         ability of such Stockholder to perform such  Stockholder's  obligations
         hereunder or to consummate the transactions contemplated hereby.

                  (e) Such  Stockholder  owns  beneficially  and of  record  the
         shares of STC Common Stock and STC Preferred  Stock set forth  opposite
         such Stockholder's  name on Schedule I hereto (the "Existing  Shares").
         The Existing  Shares  constitute all the shares of STC Common Stock and
         STC  Preferred   Stock  owned  of  record  or   beneficially   by  such
         Stockholder.  Such  Stockholder  has sole voting  power,  sole power of
         disposition  and all other  stockholder  rights with respect to all the
         Existing  Shares,   with  no  restrictions,   other  than  pursuant  to
         applicable securities laws, on such Stockholder's rights of disposition
         pertaining  thereto.  Such  Stockholder  owns  options or  warrants  to
         purchase  or  other  securities  convertible  or  exchangeable  into or
         exercisable  for the  number of shares of such  Common  Stock set forth
         opposite such  Stockholder's  name on Schedule I hereto  (collectively,
         the "Derivative Securities"). None of the Existing Shares or Derivative
         Securities is subject to (i) any right of first refusal or first offer,
         (ii) right to  purchase,  acquire or vote,  or (iii)  proxy or power of
         attorney, except in the case of clause (ii) or (iii) any rights created
         by this Agreement. Such Stockholder has good and valid title to all the
         Existing  Shares,  free and clear of all  Encumbrances  (other than any
         Encumbrance  created by this Agreement) except as disclosed on Schedule
         II hereto.

                  (f)  Such  Stockholder  (i) is not a party  to any  agreement,
         arrangement  or  understanding  with  respect  to  voting,  holding  or
         disposing of any Shares,  Other  Securities,  shares of Epitope  Common
         Stock or the shares of Surviving Corporation Common Stock, either as of
         the date  hereof or at any time  after the  Mergers,  and (ii) is not a
         member of a "group"  within  the  meaning of  Section  13(d)(3)  of the
         Exchange  Act and Rule  13d-5(b)  thereunder,  with  respect to Shares,
         Other  Securities,  shares of Epitope  Common  Stock,  or shares of STC
         Preferred Stock, except for this Agreement.

                                      -4-
<PAGE>

                                  ARTICLE III

                          COVENANTS OF THE STOCKHOLDER

                  SECTION  3.1  No   Solicitation.   Each  Stockholder  and  its
Representatives  shall immediately cease and cause to be terminated all existing
discussions or negotiations to which the Stockholder or its officers, directors,
employees, agents, accountants,  counsel, advisors or consultants (collectively,
"Representatives") are a part relating to an Acquisition Proposal for STC or any
transaction  referred  to in  Section  3.1 or 3.3  with  any  parties  conducted
heretofore.  From the date hereof until the Effective  Time or, if earlier,  the
termination  of the  Merger  Agreement  pursuant  to  Article  X  thereof,  each
Stockholder shall not, whether directly or indirectly through Representatives or
other intermediaries,  and will instruct such Stockholder's  Representatives not
to,   whether   directly  or  indirectly   through   Representatives   or  other
intermediaries,  initiate,  solicit or encourage (including by way of furnishing
information  or  assistance),  or take  any  other  action  to  facilitate,  any
inquiries  or the  making of any  proposal  regarding  a  potential  Acquisition
Proposal for STC or any transaction  referred to in Section 3.1 or 3.3, or agree
to or endorse any Acquisition Proposal for STC or any transaction referred to in
Section 3.1 or 3.3, or disclose any  non-public  information  relating to STC to
any  person  that has made or may  reasonably  be  expected  to make a  proposal
regarding  an  Acquisition  Proposal for STC or any  transaction  referred to in
Section 3.1 or 3.3 or that has advised  STC that it is or may be  interested  in
making a proposal  regarding an Acquisition  Proposal for STC or any transaction
referred  to in  Section  3.1 or  3.3,  or  authorize  or  permit  any  of  such
Stockholder's  Representatives  to take any such  action,  and each  Stockholder
shall use such Stockholder's reasonable best efforts to cause such Stockholder's
Representatives not to take any such action, and each Stockholder shall promptly
notify Epitope if any such inquiries or proposals are made regarding a potential
Acquisition  Proposal for STC or any  transaction  referred to in Section 3.1 or
3.3, and each  Stockholder  shall  promptly  inform  Epitope as to the terms and
details of any such  inquiry or  proposal  (including  the  identity of the true
party in interest making such inquiry or proposal) and, if in writing,  promptly
deliver or cause to be  delivered to Epitope a copy of such inquiry or proposal,
and each  Stockholder  shall keep Epitope  informed,  on a current basis, of the
status,  terms and details of any such inquiries or such proposals.  Anything in
this  Section 3.1 to the contrary  notwithstanding,  nothing in this Section 3.1
shall limit any  individual  Stockholder  who is also a director of the Company,
from exercising or performing any of such Stockholder's  rights or duties solely
in such Stockholder's capacity as a director of the Company.

                  SECTION 3.2  Pooling.  Each  Stockholder  agrees that from and
after the date hereof,  such Stockholder shall not knowingly take any action, or
knowingly fail to take any action, which action or inaction is reasonably likely
to  jeopardize  the  treatment of the Merger as a "pooling of  interests"  under
GAAP.

                  SECTION 3.3 Legend.  Each Stockholder will request the Company
to have the  certificates  evidencing  those shares which are owned of record or
beneficially by such Stockholder to bear  substantially the following legend and
to request the Company to instruct  its  transfer  agent to stop the transfer of
any  certificates  bearing such legend that is not made in accordance  with this
Agreement:

                                      -5-
<PAGE>

         THE VOTING OF THE SHARES  REPRESENTED BY THIS CERTIFICATE IS SUBJECT TO
         THE PRIOR RIGHTS AND LIMITATIONS  IMPOSED BY THE STOCKHOLDER  AGREEMENT
         DATED  AS  OF   -----------------,   2000  AMONG  EPITOPE,   AN  OREGON
         CORPORATION,  EPITOPE MERGER SUBSIDIARY,  INC., A DELAWARE CORPORATION,
         AND  CERTAIN   STOCKHOLDERS   WHO  ARE  SIGNATORIES   THERETO  AND  THE
         IRREVOCABLE  PROXY  ATTACHED  THERETO.  A COPY  OF SUCH  AGREEMENT  AND
         IRREVOCABLE  PROXY WILL BE FURNISHED BY THE  COMPANY'S  SECRETARY  UPON
         WRITTEN REQUEST AND WITHOUT CHARGE.

                                   ARTICLE IV

                        CONVERSION OF STC PREFERRED STOCK

                  SECTION  4.1   Conversion   of  STC  Preferred   Stock.   Each
Stockholder that is directly or indirectly the record or beneficial owner of any
shares of STC Preferred Stock agrees to convert,  or cause to be converted,  all
such shares into STC Common Stock prior to the Effective Time of the STC Merger.

                                   ARTICLE V

                                    SURVIVAL

                  SECTION 5.1 Survival.  All provisions of this Agreement  shall
survive any  termination of the Merger  Agreement and shall remain in full force
and effect,  except as otherwise  provided in Sections 5.2 and 5.3. In the event
that the Merger is consummated, only Section 3.2 of this Agreement shall survive
such consummation and shall remain in full force and effect.

                  SECTION 5.2  Termination.  Articles  I, II, III,  and IV shall
terminate  upon any  termination  of the Merger  Agreement  in  accordance  with
Article X thereof.

                  SECTION 5.3 Effect of Termination.  In the event that any part
of this Agreement shall terminate  pursuant to this Article V, such part of this
Agreement shall  thereafter be void and the parties hereto shall have no further
rights or  obligations  with  respect  thereto,  except as a result of any prior
breach thereof.

                                   ARTICLE VI

                                   DEFINITIONS

                  SECTION 6.1 Definitions. For purposes of this Agreement:


                  (a) "beneficially own" or "beneficial  ownership" with respect
         to any  securities  shall mean having  "beneficial  ownership"  of such
         securities  (as  determined  pursuant to Rule 13d-3 under the  Exchange
         Act),   including   pursuant   to   any   agreement,   arrangement   or
         understanding, whether or not in writing. Securities beneficially owned

                                      -6-
<PAGE>

         by one Person shall include securities  beneficially owned by all other
         Persons  with whom such Person would  constitute  a "group"  within the
         meaning of  Section  13(d)(3)  of the  Exchange  Act and Rule  13d-5(b)
         thereunder.

                  (b)   "Person"   shall   mean  an   individual,   corporation,
         partnership,   joint  venture,   association,   trust,   unincorporated
         organization or other entity.

                  (c) "Encumbrance" means any pledge,  security interest,  lien,
         claim, encumbrance,  mortgage, charge, hypothecation,  option, right of
         first refusal or offer,  community property right, other marital right,
         preemptive  right,  voting  agreement,  voting trust,  proxy,  power of
         attorney,  escrow,  option,  forfeiture,  penalty,  action at law or in
         equity,  security agreement,  shareholder agreement or other agreement,
         arrangement, contract, commitment,  understanding or obligation, or any
         other  restriction,  qualification or limitation on the use,  transfer,
         right to vote, right to dissent, and seek appraisal,  receipt of income
         or other exercise of any attribute of ownership, except for those which
         do not or could not reasonably be expected to,  individually  or in the
         aggregate,  impair the  ability  of such  Stockholder  to perform  such
         Stockholder's  obligations  hereunder or to consummate the transactions
         contemplated hereby.

                                  ARTICLE VII

                                  MISCELLANEOUS

                  SECTION 7.1  Severability.  If any term or other  provision of
this Agreement is invalid, illegal or incapable of being enforced by any rule of
law, or public  policy,  all other  conditions  and provisions of this Agreement
shall  nevertheless  remain in full force and effect so long as the  economic or
legal  substance  of this  Agreement  is not  affected in any manner  materially
adverse to any party. Upon such  determination  that any term or other provision
is invalid,  illegal or incapable of being  enforced,  the parties  hereto shall
negotiate  in good faith to modify this  Agreement  so as to effect the original
intent of the parties as closely as possible in a mutually  acceptable manner in
order that the terms of this Agreement remain as originally  contemplated to the
fullest extent possible.

                  SECTION 7.2 Entire Agreement.  This Agreement  constitutes the
entire agreement between Parent and each Stockholder with respect to the subject
matter hereof and  supersedes  all prior  agreements  and  understandings,  both
written and oral,  between  Epitope  and such  Stockholder  with  respect to the
subject matter hereof.

                  SECTION 7.3  Counterparts.  This Agreement may be executed and
delivered (including by facsimile transmission) in one or more counterparts, and
by the different  parties  hereto in separate  counterparts,  each of which when
executed and delivered  shall be deemed to be an original but all of which taken
together shall constitute one and the same instrument.

                  SECTION 7.4 Assignment.  Neither this Agreement nor any rights
or  interests  hereunder  shall  be  assigned  by any  Stockholder  (whether  by
operation of law or  otherwise)  without the prior  written  consent of Epitope,
except that any Stockholder may transfer the Shares or Other Securities  subject
to the  Voting  Agreement  set forth in Section  1.1 hereof and the

                                      -7-
<PAGE>

Irrevocable Proxy attached hereto as Exhibit A.  Epitope may assign, in its sole
discretion,  its  rights  hereunder  to any  direct  or  indirect  wholly  owned
subsidiary or affiliate of Epitope, but no such assignment shall relieve Epitope
of its obligations hereunder if such assignee does not perform such obligations.

                  SECTION 7.5  Amendments.  This  Agreement  may not be amended,
supplemented,  waived or  otherwise  modified  or  terminated,  except  upon the
execution and delivery of a written agreement executed by the parties hereto.

                  SECTION 7.6 Notices. All notices,  requests,  claims,  demands
and other  communications  hereunder shall be in writing and shall be given (and
shall be  deemed  to have been  duly  received  if so  given) by hand  delivery,
facsimile  transmission,  mail  (registered or certified mail,  postage prepaid,
return receipt requested),  or courier service providing proof of delivery.  All
communications  hereunder  shall be delivered to the  respective  parties at the
following addresses:

                  If to  Stockholder,  in accordance  with the  information  set
forth on Schedule I hereto.

                  If to Epitope:

                           Epitope, Inc.
                           8505 SW Creekside Place
                           Beaverton, OR 97008
                           Attention:  Robert Thompson, President
                               and Chief Executive Officer
                           Telephone: (503) 520-6215
                           Fax: (503) 520-6196

                  copies to:

                           Stinson, Mag & Fizzell, P.C.
                           1201 Walnut, Suite 2800
                           Kansas City, MO  64106
                           Attention: John A. Granda, Esq.
                           Telephone (816) 691-3188
                           Fax: (816) 691-3495

or to such  other  address  as the  person  to whom  notice  is  given  may have
previously furnished the others in writing in the manner set forth above.

                  SECTION 7.7 No Third Party  Beneficiaries.  This  Agreement is
not  intended  to be for the benefit  of, and shall not be  enforceable  by, any
person or entity not a party hereto.

                  SECTION 7.8 Specific  Performance.  Each of the parties hereto
acknowledges  that a breach by it of any agreement  contained in this  Agreement
may  cause  the  other  party to  sustain  damage  for  which it may not have an
adequate  remedy at law for money  damages,  and  therefore  each of the parties
hereto  agrees that in the event of any such breach the  aggrieved

                                      -8-
<PAGE>

party may be entitled to the remedy of specific  performance  of such  agreement
and  injunctive  and other  equitable  relief in addition to any other remedy to
which it may be entitled, at law or in equity.

                  SECTION  7.9  Remedies  Cumulative.  All  rights,  powers  and
remedies provided under this Agreement or otherwise  available in respect hereof
at law or in equity shall be cumulative and not alternative, and the exercise of
any thereof by any party shall not preclude the  simultaneous  or later exercise
of any other such right, power or remedy by such party.

                  SECTION  7.10 No Waiver.  The  failure of any party  hereto to
exercise any right,  power or remedy  provided under this Agreement or otherwise
available  in  respect  hereof at law or in  equity,  or to insist  upon  strict
compliance  by any other party hereto with its  obligations  hereunder,  and any
custom or practice of the parties at variance with the terms  hereof,  shall not
constitute  a waiver by such  party of its right to  exercise  any such or other
right, power or remedy or to demand such compliance.

                  SECTION 7.11 Governing Law.

                  (a) This  Agreement  shall be governed  by, and  construed  in
         accordance  with,  the laws of the State of  Delaware,  without  giving
         effect to the principles of conflicts of law thereof.

                  (b) Each party  hereby  irrevocably  submits to the  exclusive
         jurisdiction  of the Court of  Chancery in the State of Delaware in any
         action,  suit or proceeding  arising in connection with this Agreement,
         and agrees that any such action,  suit or  proceeding  shall be brought
         only in such  court  (and  waives  any  objection  based on  forum  non
         conveniens or any other objection to venue therein); provided, however,
         that such consent to jurisdiction is solely for the purpose referred to
         in  this  subsection  (b)  and  shall  not be  deemed  to be a  general
         submission  to the  jurisdiction  of  such  court  or in the  State  of
         Delaware other than for such purposes.

                  SECTION 7.12 Waiver of Jury Trial. EACH OF EPITOPE, MERGER SUB
AND EACH STOCKHOLDER HEREBY IRREVOCABLY WAIVES ALL RIGHT TO TRIAL BY JURY IN ANY
ACTION,   PROCEEDING  OR  COUNTERCLAIM  (WHETHER  BASED  ON  CONTRACT,  TORT  OR
OTHERWISE) ARISING OUT OF OR RELATING TO THIS AGREEMENT OR THE ACTIONS OF PARENT
OR  SUCH  STOCKHOLDER  IN  THE  NEGOTIATION,  ADMINISTRATION,   PERFORMANCE  AND
ENFORCEMENT THEREOF.


                      [This space left intentionally blank]

                                      -9-
<PAGE>

                  SECTION 7.13 Descriptive  Headings.  The descriptive  headings
used herein are inserted for  convenience of reference only and are not intended
to be part of or to affect the meaning or interpretation of this Agreement.

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


- -------------------------------------      EPITOPE, INC.
Stockholder


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


- -------------------------------------
Stockholder                                EDWARD MERGER SUBSIDIARY, INC.


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


- -------------------------------------
Stockholder



- -------------------------------------
Stockholder



- -------------------------------------
Stockholder


                                      -10-
<PAGE>

                                   SCHEDULE I



<TABLE>
                                     Shares Owned and        Derivative Securities
                                     ----------------        ---------------------
<S>                                <C>                             <C>                   <C>
     Name of Stockholder           Certificate Number(s)           Owned                  Address for Notices
     -------------------           ---------------------           -----                  -------------------
</TABLE>




                                      -11-
<PAGE>


                                   SCHEDULE II



Each of W. Hinchey, M. Gausling,  and S. Niedbala entered into Pledge Agreements
with Lafayette  Ambassador  Bank (the "Bank") on December 17, 1998,  pursuant to
which each pledged certain of the shares of STC stock to the Bank.


                                      -12-
<PAGE>
                                                                       EXHIBIT A



                   IRREVOCABLE PROXY COUPLED WITH AN INTEREST

        The undersigned hereby irrevocably  appoint(s) Epitope,  Inc., an Oregon
corporation ("Epitope"),  as the proxy of the undersigned and hereby grant(s) to
Epitope this irrevocable  proxy coupled with an interest  ("Irrevocable  Proxy")
with respect to ----------- shares (the "Shares"),  which term shall include any
and all other shares of capital stock or securities or rights issued or issuable
in respect  thereof on or after the date hereof) of the Common Stock,  par value
$0.000001 per share (the "Common Stock"), of STC Technologies,  Inc., a Delaware
corporation (the "Company"), that the undersigned own(s) of record, or otherwise
has the right to vote,  with all power and  authority to vote and to execute and
deliver  written  consents,  in each case,  in the name,  place and stead of the
undersigned,  and at any  annual  or  special  meeting  of  stockholders  of the
Company, or at any adjournment or postponement thereof, or as to any action that
can be taken by  written  consent,  in favor of  approval  and  adoption  of the
Agreement and Plan of Merger dated the date hereof among Epitope, STC and Edward
Merger  Subsidiary,  Inc.,  a Delaware  corporation  ("Merger  Sub"),  as may be
amended from time to time,  the  ("Merger  Agreement"),  the Mergers,  any other
transactions or matters  contemplated by the Merger  Agreement,  and any actions
required in furtherance  of any of the foregoing,  in such manner as Epitope may
determine in its sole and unlimited discretion,  in each case to the same extent
and  with the  same  effect  as the  undersigned  might  or  could do under  any
applicable law or regulation  governing the rights and powers of stockholders of
a Delaware  corporation,  irrespective  of whether the undersigned is present at
such meeting.

        This  Irrevocable  Proxy  constitutes a valid and effective  irrevocable
proxy  coupled with an interest of Epitope in the Shares,  within the meaning of
Section 212(e) of the Delaware  General  Corporation  Law, of the undersigned in
respect of the  foregoing  Shares of Common  Stock of the  Company;  revokes any
proxy or proxies heretofore given by the undersigned in respect of any Shares of
Common Stock of the Company;  this Irrevocable  Proxy shall remain in full force
and effect  until the  earlier of (i)  termination  of the Merger  Agreement  in
accordance  with  Article X thereof,  or (ii) the  consummation  of the Mergers.
Unless otherwise  defined herein,  all capitalized  terms shall have the meaning
set forth in the Merger Agreement.

        This  Irrevocable  Proxy  shall  continue  to  cover  the  Shares  sold,
transferred  or  otherwise  disposed of after the date  hereof  through the time
period referred to in the last clause of the immediately preceding paragraph.


Dated: ----------------------------, 2000    -----------------------------------
                                             Name: -----------------------------



<PAGE>


STATE OF --------------------)
                             )  ss.
COUNTY OF -------------------)

               Sworn to and subscribed before me this ---- day of -------------,
2000 and  acknowledged  before  me as being  the free act and deed of the  above
signatory.


                                          --------------------------------------
                                                      Notary Public

My Commission expires: ---------------




<PAGE>
                                                                       EXHIBIT B


                              STOCKHOLDER AGREEMENT

               STOCKHOLDER AGREEMENT (this "Agreement") dated as of May --, 2000
among  STC  Technologies,   Inc.,  a  Delaware   corporation  ("STC"),  and  the
stockholders  of Epitope,  Inc.,  an Oregon  corporation  ("Epitope"),  named on
Schedule  I  hereto  (individually,   a  "Stockholder"  and  collectively,   the
"Stockholders").

               WHEREAS,  Epitope and Edward Merger Subsidiary,  Inc., a Delaware
corporation and a wholly-owned  subsidiary of Epitope ("Merger Sub"), propose to
enter  into an  Agreement  and Plan of Merger  dated as of the date  hereof  (as
amended from time to time, the "Merger  Agreement";  capitalized  terms used but
not defined  herein shall have the  meanings set forth in the Merger  Agreement)
with STC which provides,  among other things,  that STC will merge with and into
Merger Sub (the "STC Merger") and immediately thereafter Epitope will merge with
and into  Merger Sub (the  "Epitope  Merger")  (the STC  Merger and the  Epitope
Merger are sometimes collectively referred to herein as the "Mergers"); and

               WHEREAS,  as of the date hereof,  each Stockholder owns of record
or  beneficially  the  respective  number of shares of Epitope  Common Stock set
opposite such Stockholder's name on Schedule I hereto; and

               WHEREAS,  as an essential  condition to the willingness of STC to
enter into the Merger Agreement,  STC has requested that each Stockholder agree,
and in order to induce STC to enter into the Merger Agreement,  each Stockholder
has agreed,  to enter into this  Agreement with respect to (i) all the shares of
Epitope Common Stock owned  beneficially and of record by such Stockholder as of
the date hereof or of which such  Stockholder  may hereafter  acquire  record or
beneficial  ownership  (the  "Shares")  and (ii) any other  securities  owned of
record or  beneficially  by such  Stockholder  as of the date hereof or of which
such Stockholder may hereafter acquire ownership of record or beneficially which
may be voted by or at the  direction  or on  behalf  of the  Stockholder  at any
meeting of Epitope  stockholders or with respect to which action taken without a
meeting  may  be  authorized  by or  at  the  direction  or on  behalf  of  such
Stockholder by written consent (the "Other Securities");

               NOW, THEREFORE,  in consideration of the foregoing and the mutual
covenants  and  agreements  contained  herein and  intending to be legally bound
hereby, the parties hereto agree as follows:

                                   ARTICLE I

                                VOTING AGREEMENT

               SECTION 1.1 Voting  Agreement.  Each  Stockholder  hereby  agrees
that, with respect to the Epitope  Stockholders Meeting and any other meeting of
Epitope  stockholders  or  any  action  to  be  taken  by  written  consent  the
Stockholder shall:

               (a)    appear in person or by proxy (or use its  reasonable  best
        efforts to cause the holder of record on any  applicable  record date to
        appear in person or by proxy) for the  purpose of  obtaining a quorum at
        the Epitope  Stockholders Meeting and at any adjournment or postponement
        thereof;


<PAGE>

               (b)    vote (or  cause to be  voted)  the  Shares  and the  Other
        Securities  (or, as  applicable,  shall  execute or cause to be executed
        written  consents in respect of the Shares and the Other  Securities) in
        favor of the approval and adoption of the Merger Agreement,  the Mergers
        and,  any other  transactions  or  matters  contemplated  by the  Merger
        Agreement,  and any actions required in furtherance  thereof and hereof;
        and

               (c)    not  encourage any holder of securities of Epitope to vote
        against the approval and adoption of the Merger  Agreement,  the Mergers
        or  any  other  transactions  or  matters  contemplated  by  the  Merger
        Agreement.

               SECTION 1.2 Irrevocable Proxy. In order to ensure that the voting
agreement set forth in Section 1.1 and the other obligations of each Stockholder
hereunder  will be carried out, each  Stockholder  hereby grants an  irrevocable
proxy,  coupled with an interest,  in the form attached hereto as Exhibit A (the
"Irrevocable Proxy") to, and hereby constitutes and appoints STC and each of its
officers as such  Stockholder's sole and exclusive attorney and proxy, with full
power of  substitution,  (a) to vote and  otherwise  act (by written  consent or
otherwise)  with  respect  to the  Shares  and the Other  Securities  which such
Stockholder  is  entitled to vote at the  Epitope  Stockholders  Meeting and any
other  meeting of Epitope  Stockholders,  or pursuant to any written  consent in
lieu  of  a  meeting  of  Epitope  Stockholders,   and  at  any  adjournment  or
postponement  thereof on the matters and in the manner specified in Section 1.1.
THIS PROXY AND POWER OF ATTORNEY IS  IRREVOCABLE  AND COUPLED  WITH AN INTEREST.
Such  Stockholder  hereby  revokes all other proxies and powers of attorney with
respect to the Shares and the Other  Securities  that such  Stockholder may have
heretofore  appointed  or  granted  that would  prevent  such  Stockholder  from
performing its obligations  hereunder.  All authority herein conferred or agreed
to be conferred shall survive the death or incapacity of any Stockholder and any
obligation of such  Stockholder  under this Agreement  shall be binding upon the
transferees,  heirs,  personal  representatives,  successors and assigns of such
Stockholder.

               SECTION 1.3 Evaluation of Investment. Each Stockholder, by reason
of such  Stockholder's  knowledge  and  experience  in  financial  and  business
matters,  is capable of evaluating the merits and risks of the investment in the
Common Stock of Merger Sub following the Epitope Merger ("Surviving  Corporation
Common Stock"), contemplated by the Merger Agreement.

               SECTION 1.4 Documents  Delivered.  The  Stockholder  acknowledges
receipt of copies of the following documents:

               (a)    the  Merger  Agreement  and  all  schedules  and  exhibits
        thereto;

               (b)    Epitope's  Annual  report on Form 10-K for the fiscal year
        ended September 30, 1999;

               (c)    Epitope's Proxy Statement dated January 11, 2000;

               (d)    each  report  filed  with  the   Securities  and  Exchange
        Commission  by Epitope on Forms 8-K and 10-Q since  September  30, 1999;
        and

                                      -2-
<PAGE>

               (e)    any  other   information   requested  by  any  Stockholder
        concerning  an  evaluation  of an  investment  in Surviving  Corporation
        Common Stock.

Each Stockholder also acknowledges that it possesses the information relating to
STC which such  Stockholder  deems  relevant to its  investment in the Surviving
Corporation Common Stock should the Mergers be consummated.

                                   ARTICLE II

                         REPRESENTATIONS AND WARRANTIES

               SECTION 2.1  Representations  and Warranties of Each Stockholder.
Except as set forth on the disclosure  letter attached hereto,  each Stockholder
represents and warrants to STC as follows:

               (a)    Each  Stockholder  (if  it is a  corporation,  general  or
        limited partnership, limited liability company or other legal entity) is
        duly organized,  validly existing and in good standing under the laws of
        the jurisdiction of its incorporation or organization.  Such Stockholder
        has the requisite  power and  authority  (and if a natural  person,  the
        legal capacity) to execute and deliver this Agreement and to perform its
        obligations hereunder.  The execution and delivery of this Agreement and
        the consummation of the transactions  contemplated hereby have been duly
        authorized by such  Stockholder and no other  proceedings on the part of
        such  Stockholder  are  necessary to authorize  this  Agreement  and the
        consummation of the transactions contemplated hereby. This Agreement has
        been duly executed and delivered by such Stockholder and,  assuming that
        this  Agreement  constitutes a valid and binding  agreement of STC, is a
        legal,  valid and binding  obligation of such  Stockholder,  enforceable
        against such  Stockholder in accordance  with its terms,  except as such
        enforceability may be limited by bankruptcy, insolvency, reorganization,
        moratorium and similar laws, now or hereafter in effect,  relating to or
        affecting the rights and remedies of creditors generally, and to general
        principles  of equity  (regardless  of whether  such  enforceability  is
        considered in a proceeding in equity or a law) and to general principles
        governing the duties of fiduciaries.

               (b)    The  execution  and  delivery  of this  Agreement  by such
        Stockholder  do not,  and the  performance  of  this  Agreement  by such
        Stockholder  will  not  conflict  with,  result  in  any  breach  of  or
        constitute  a default  (or an event that with notice or lapse of time or
        both  would  become a  default)  under,  or give to others any rights of
        termination,  amendment,  acceleration  or  cancellation  of, or require
        payment under, or result in the creation of any Encumbrances (as defined
        below) on any of the assets of such Stockholder pursuant to any contract
        or other  instrument  to which such  Stockholder  is a party or by which
        such Stockholder or any of such Stockholder's  assets are bound,  except
        for any thereof  that would not  reasonably  be  expected to  materially
        impair the ability of such  Stockholder  to perform  such  Stockholder's
        obligations  hereunder or to consummate  the  transactions  contemplated
        hereby.

               (c)    The  execution  and  delivery  of this  Agreement  by such
        Stockholder  do not,  and the  performance  of  this  Agreement  by such
        Stockholder  will not,  require such

                                      -3-
<PAGE>

        Stockholder to obtain any consent, approval, authorization or permit of,
        or to make any filing with or notification to, any  Governmental  Entity
        based on any federal,  state, local or foreign law, statute,  ordinance,
        rule, regulation,  permit,  injunction,  writ, judgment, decree or order
        (collectively,  "Laws") of any Governmental Entity,  except (i) pursuant
        to the Exchange Act, the  Securities Act and the HSR Act; and (ii) where
        the  failure  to obtain  such  consents,  approvals,  authorizations  or
        permits, or to make such filings or notifications,  could not reasonably
        be expected to  materially  impair the  ability of such  Stockholder  to
        perform such  Stockholder's  obligations  hereunder or to consummate the
        transactions contemplated hereby.

               (d)    There  is no suit,  action,  investigation  or  proceeding
        pending or, to the  knowledge of such  Stockholder,  threatened  against
        such  Stockholder  at law or in  equity  before  or by any  Governmental
        Entity  that would  reasonably  be  expected  to  materially  impair the
        ability of such  Stockholder to perform such  Stockholder's  obligations
        hereunder or to consummate the transactions contemplated hereby.

               (e)    Such  Stockholder  owns  beneficially  and of  record  the
        shares of Epitope  Common Stock set forth  opposite  such  Stockholder's
        name on Schedule I hereto (the "Existing  Shares").  The Existing Shares
        constitute  all the shares of Epitope  Common  Stock  owned of record or
        beneficially  by such  Stockholder.  Such  Stockholder  has sole  voting
        power, sole power of disposition and all other  stockholder  rights with
        respect to all the Existing  Shares,  with no  restrictions,  other than
        pursuant to applicable  securities laws, on such Stockholder's rights of
        disposition   pertaining  thereto.  Such  Stockholder  owns  options  or
        warrants to purchase or other  securities  convertible  or  exchangeable
        into or  exercisable  for the number of shares of such Common  Stock set
        forth   opposite   such   Stockholder's   name  on   Schedule  I  hereto
        (collectively, the "Derivative Securities"). None of the Existing Shares
        or Derivative Securities is subject to (i) any right of first refusal or
        first offer, (ii) right to purchase,  acquire or vote, or (iii) proxy or
        power of attorney, except in the case of clause (ii) or (iii) any rights
        created by this Agreement.  Such Stockholder has good and valid title to
        all the Existing Shares,  free and clear of all Encumbrances (other than
        any Encumbrance created by this Agreement).

               (f)    Such  Stockholder  (i) is not a  party  to any  agreement,
        arrangement  or  understanding  with  respect  to  voting,   holding  or
        disposing  of any Shares,  Other  Securities,  shares of Epitope  Common
        Stock or the shares of Surviving  Corporation Common Stock, either as of
        the date  hereof  or at any time  after the  Mergers,  and (ii) is not a
        member of a "group"  within  the  meaning  of  Section  13(d)(3)  of the
        Exchange Act and Rule 13d-5(b) thereunder, with respect to Shares, Other
        Securities, shares of Epitope Common Stock, except for this Agreement.

                                  ARTICLE III

                          COVENANTS OF THE STOCKHOLDER

               SECTION   3.1  No   Solicitation.   Each   Stockholder   and  its
Representatives  shall immediately cease and cause to be terminated all existing
discussions or negotiations to which the Stockholder or its officers, directors,
employees, agents, accountants,  counsel, advisors or

                                      -4-
<PAGE>

consultants  (collectively,   "Representatives")  are  a  part  relating  to  an
Acquisition  Proposal for Epitope or any transaction  referred to in Section 3.1
or 3.3 with any parties  conducted  heretofore.  From the date hereof  until the
Effective Time or, if earlier,  the termination of the Merger Agreement pursuant
to Article X thereof, each Stockholder shall not, whether directly or indirectly
through  Representatives  or  other  intermediaries,   and  will  instruct  such
Stockholder's  Representatives  not to, whether  directly or indirectly  through
Representatives  or  other  intermediaries,   initiate,   solicit  or  encourage
(including by way of furnishing  information or  assistance),  or take any other
action to  facilitate,  any inquiries or the making of any proposal  regarding a
potential  Acquisition  Proposal for Epitope or any  transaction  referred to in
Section 3.1 or 3.3, or agree to or endorse any Acquisition  Proposal for Epitope
or any transaction referred to in Section 3.1 or 3.3, or disclose any non-public
information relating to Epitope to any person that has made or may reasonably be
expected to make a proposal regarding an Acquisition Proposal for Epitope or any
transaction  referred to in Section 3.1 or 3.3 or that has advised  Epitope that
it is or may be  interested  in  making  a  proposal  regarding  an  Acquisition
Proposal  for Epitope or any  transaction  referred to in Section 3.1 or 3.3, or
authorize or permit any of such  Stockholder's  Representatives to take any such
action,  and each  Stockholder  shall  use such  Stockholder's  reasonable  best
efforts to cause such Stockholder's Representatives not to take any such action,
and  each  Stockholder  shall  promptly  notify  STC if any  such  inquiries  or
proposals are made regarding a potential Acquisition Proposal for Epitope or any
transaction  referred  to in  Section  3.1 or 3.3,  and each  Stockholder  shall
promptly  inform STC as to the terms and details of any such inquiry or proposal
(including  the  identity of the true party in interest  making such  inquiry or
proposal) and, if in writing, promptly deliver or cause to be delivered to STC a
copy of such inquiry or proposal,  and each Stockholder shall keep STC informed,
on a current  basis,  of the status,  terms and details of any such inquiries or
such  proposals.  Anything in this Section 3.1 to the contrary  notwithstanding,
nothing in this Section 3.1 shall limit any individual Stockholder who is also a
director of the Epitope, from exercising or performing any of such Stockholder's
rights or duties  solely in such  Stockholder's  capacity  as a director  of the
Epitope.

               SECTION 3.2 Pooling.  Each Stockholder agrees that from and after
the date  hereof,  such  Stockholder  shall not  knowingly  take any action,  or
knowingly fail to take any action, which action or inaction is reasonably likely
to  jeopardize  the  treatment of the Merger as a "pooling of  interests"  under
GAAP.

               SECTION 3.3 Legend.  Each Stockholder will request the Epitope to
have the  certificates  evidencing  those  shares  which  are owned of record or
beneficially by such Stockholder to bear  substantially the following legend and
to request the Company to instruct  its  transfer  agent to stop the transfer of
any  certificates  bearing such legend that is not made in accordance  with this
Agreement:

        THE VOTING OF THE SHARES  REPRESENTED BY THIS  CERTIFICATE IS SUBJECT TO
        THE PRIOR RIGHTS AND LIMITATIONS  IMPOSED BY THE  STOCKHOLDER  AGREEMENT
        DATED AS OF  -----------------,  2000 AMONG STC, A DELAWARE CORPORATION,
        EPITOPE MERGER  SUBSIDIARY,  INC., A DELAWARE  CORPORATION,  AND CERTAIN
        STOCKHOLDERS  WHO ARE  SIGNATORIES  THERETO  AND THE  IRREVOCABLE  PROXY
        ATTACHED THERETO. A COPY OF SUCH

                                      -5-
<PAGE>

        AGREEMENT  AND  IRREVOCABLE  PROXY WILL BE  FURNISHED  BY THE  COMPANY'S
        SECRETARY UPON WRITTEN REQUEST AND WITHOUT CHARGE.

                                   ARTICLE IV

                                    SURVIVAL

               SECTION 4.1  Survival.  All  provisions of this  Agreement  shall
survive any  termination of the Merger  Agreement and shall remain in full force
and effect,  except as otherwise  provided in Sections 4.2 and 4.3. In the event
that the Merger is consummated, only Section 3.2 of this Agreement shall survive
such consummation and shall remain in full force and effect.

               SECTION 4.2  Termination.  Articles I, II and III shall terminate
upon any  termination  of the Merger  Agreement  in  accordance  with  Article X
thereof.

               SECTION 4.3 Effect of Termination.  In the event that any part of
this Agreement  shall  terminate  pursuant to this Article IV, such part of this
Agreement shall  thereafter be void and the parties hereto shall have no further
rights or  obligations  with  respect  thereto,  except as a result of any prior
breach thereof.

                                    ARTICLE V

                                   DEFINITIONS

               SECTION 5.1 Definitions. For purposes of this Agreement:


               (a)    "beneficially own" or "beneficial  ownership" with respect
        to any  securities  shall mean  having  "beneficial  ownership"  of such
        securities  (as  determined  pursuant to Rule 13d-3  under the  Exchange
        Act), including pursuant to any agreement, arrangement or understanding,
        whether or not in writing.  Securities  beneficially owned by one Person
        shall include  securities  beneficially  owned by all other Persons with
        whom such  Person  would  constitute  a "group"  within  the  meaning of
        Section 13(d)(3) of the Exchange Act and Rule 13d-5(b) thereunder.

               (b)    "Person"   shall   mean   an   individual,    corporation,
        partnership,   joint   venture,   association,   trust,   unincorporated
        organization or other entity.

               (c)    "Encumbrance" means any pledge,  security interest,  lien,
        claim, encumbrance,  mortgage, charge,  hypothecation,  option, right of
        first refusal or offer,  community  property right, other marital right,
        preemptive  right,  voting  agreement,  voting  trust,  proxy,  power of
        attorney,  escrow,  option,  forfeiture,  penalty,  action  at law or in
        equity,  security agreement,  shareholder  agreement or other agreement,
        arrangement,  contract, commitment,  understanding or obligation, or any
        other  restriction,  qualification  or limitation on the use,  transfer,
        right to vote, right to dissent,  and seek appraisal,  receipt of income
        or other exercise of any attribute of ownership,  except for those which
        do not or could not  reasonably be expected to,  individually  or in the
        aggregate,  impair the  ability

                                      -6-
<PAGE>

        of such Stockholder to perform such Stockholder's  obligations hereunder
        or to consummate the transactions contemplated hereby.

                                   ARTICLE VI

                                  MISCELLANEOUS

               SECTION 6.1 Severability.  If any term or other provision of this
Agreement is invalid, illegal or incapable of being enforced by any rule of law,
or public policy,  all other  conditions and provisions of this Agreement  shall
nevertheless  remain in full force and effect so long as the  economic  or legal
substance of this Agreement is not affected in any manner materially  adverse to
any party. Upon such  determination that any term or other provision is invalid,
illegal or incapable of being  enforced,  the parties hereto shall  negotiate in
good faith to modify this  Agreement so as to effect the original  intent of the
parties as closely as possible in a mutually acceptable manner in order that the
terms of this Agreement remain as originally  contemplated to the fullest extent
possible.

               SECTION 6.2 Entire  Agreement.  This  Agreement  constitutes  the
entire agreement between Parent and each Stockholder with respect to the subject
matter hereof and  supersedes  all prior  agreements  and  understandings,  both
written and oral,  between STC and such  Stockholder with respect to the subject
matter hereof.

               SECTION 6.3  Counterparts.  This  Agreement  may be executed  and
delivered (including by facsimile transmission) in one or more counterparts, and
by the different  parties  hereto in separate  counterparts,  each of which when
executed and delivered  shall be deemed to be an original but all of which taken
together shall constitute one and the same instrument.

               SECTION 6.4 Assignment.  Neither this Agreement nor any rights or
interests  hereunder shall be assigned by any Stockholder  (whether by operation
of law or otherwise)  without the prior written  consent of STC, except that any
Stockholder  may transfer the Shares or Other  Securities  subject to the Voting
Agreement  set forth in Section 1.1 hereof and the  Irrevocable  Proxy  attached
hereto  as  Exhibit  A. STC may  assign,  in its  sole  discretion,  its  rights
hereunder to any direct or indirect wholly owned subsidiary or affiliate of STC,
but no such assignment  shall relieve STC of its  obligations  hereunder if such
assignee does not perform such obligations.

               SECTION  6.5  Amendments.  This  Agreement  may  not be  amended,
supplemented,  waived or  otherwise  modified  or  terminated,  except  upon the
execution and delivery of a written agreement executed by the parties hereto.

               SECTION 6.6 Notices. All notices,  requests,  claims, demands and
other communications hereunder shall be in writing and shall be given (and shall
be deemed to have been duly  received if so given) by hand  delivery,  facsimile
transmission,  mail  (registered  or certified  mail,  postage  prepaid,  return
receipt  requested),  or  courier  service  providing  proof  of  delivery.  All
communications  hereunder  shall be delivered to the  respective  parties at the
following addresses:

                                      -7-
<PAGE>

               If to  Stockholder,  in accordance with the information set forth
on Schedule I hereto.

               If to STC:

                      STC Technologies, Inc.
                      1745 Eaton Avenue
                      Bethlehem, PA 18018
                      Attention:  Mike Gausling
                      Telephone: (610) 882-1820 x 3039
                      Fax: (610) 882-2275

               copies to:

                      Pepper Hamilton LLP
                      1235 Westlake Drive, Suite 400
                      Berwyn, PA  19312
                      Attention: Jeffrey P. Libson, Esq.
                      Telephone (610) 640-7800
                      Fax: (610) 640-7835

or to such  other  address  as the  person  to whom  notice  is  given  may have
previously furnished the others in writing in the manner set forth above.

               SECTION 6.7 No Third Party  Beneficiaries.  This Agreement is not
intended to be for the benefit of, and shall not be  enforceable  by, any person
or entity not a party hereto.

               SECTION 6.8  Specific  Performance.  Each of the  parties  hereto
acknowledges  that a breach by it of any agreement  contained in this  Agreement
may  cause  the  other  party to  sustain  damage  for  which it may not have an
adequate  remedy at law for money  damages,  and  therefore  each of the parties
hereto  agrees that in the event of any such breach the  aggrieved  party may be
entitled to the remedy of specific  performance of such agreement and injunctive
and other  equitable  relief in addition to any other  remedy to which it may be
entitled, at law or in equity.

               SECTION 6.9 Remedies Cumulative.  All rights, powers and remedies
provided under this Agreement or otherwise available in respect hereof at law or
in equity  shall be  cumulative  and not  alternative,  and the  exercise of any
thereof by any party shall not preclude the  simultaneous  or later  exercise of
any other such right, power or remedy by such party.

               SECTION  6.10 No  Waiver.  The  failure  of any  party  hereto to
exercise any right,  power or remedy  provided under this Agreement or otherwise
available  in  respect  hereof at law or in  equity,  or to insist  upon  strict
compliance  by any other party hereto with its  obligations  hereunder,  and any
custom or practice of the parties at variance with the terms  hereof,  shall not
constitute  a waiver by such  party of its right to  exercise  any such or other
right, power or remedy or to demand such compliance.

                                      -8-
<PAGE>

               SECTION 6.11 Governing Law.

               (a)    This  Agreement  shall be governed  by, and  construed  in
        accordance  with,  the laws of the  State of  Delaware,  without  giving
        effect to the principles of conflicts of law thereof.

               (b)    Each party  hereby  irrevocably  submits to the  exclusive
        jurisdiction  of the Court of  Chancery  in the State of Delaware in any
        action,  suit or proceeding  arising in connection  with this Agreement,
        and agrees that any such  action,  suit or  proceeding  shall be brought
        only in such  court  (and  waives  any  objection  based  on  forum  non
        conveniens or any other objection to venue therein);  provided, however,
        that such consent to jurisdiction is solely for the purpose  referred to
        in  this  subsection  (b)  and  shall  not  be  deemed  to be a  general
        submission to the jurisdiction of such court or in the State of Delaware
        other than for such purposes.

               SECTION  6.12  Waiver  of  Jury  Trial.  EACH  OF  STC  AND  EACH
STOCKHOLDER  HEREBY IRREVOCABLY WAIVES ALL RIGHT TO TRIAL BY JURY IN ANY ACTION,
PROCEEDING  OR  COUNTERCLAIM  (WHETHER  BASED ON  CONTRACT,  TORT OR  OTHERWISE)
ARISING OUT OF OR RELATING  TO THIS  AGREEMENT  OR THE ACTIONS OF PARENT OR SUCH
STOCKHOLDER IN THE  NEGOTIATION,  ADMINISTRATION,  PERFORMANCE  AND  ENFORCEMENT
THEREOF.



                      [This space left intentionally blank]

                                      -9-
<PAGE>








                      [THIS PAGE LEFT INTENTIONALLY BLANK]



                                      -10-
<PAGE>

               SECTION 6.13 Descriptive Headings.  The descriptive headings used
herein are inserted for convenience of reference only and are not intended to be
part of or to affect the meaning or interpretation of this Agreement.

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


                                        STC TECHNOLOGIES, INC.



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



                                        ----------------------------------------
                                        Stockholder


                                        ----------------------------------------
                                        Stockholder


                                      -11-
<PAGE>


                                   SCHEDULE I



                            Shares Owned and      Derivative Securities
                            ----------------      ---------------------
<TABLE>
<S>                       <C>                             <C>              <C>
  Name of Stockholder     Certificate Number(s)           Owned            Address for Notices
  -------------------     ---------------------           -----            -------------------
</TABLE>

<PAGE>
                                                                       EXHIBIT A




                   IRREVOCABLE PROXY COUPLED WITH AN INTEREST

        The undersigned hereby irrevocably appoint(s) STC Technologies,  Inc., a
Delaware  corporation  ("STC"),  as the  proxy  of the  undersigned  and  hereby
grant(s) to STC this  irrevocable  proxy coupled with an interest  ("Irrevocable
Proxy")  with respect to  -----------  shares (the  "Shares"),  which term shall
include any and all other shares of capital stock or securities or rights issued
or issuable in respect thereof on or after the date hereof) of the Common Stock,
no par value  per share  (the  "Common  Stock"),  of  Epitope,  Inc.,  an Oregon
corporation (the "Company"), that the undersigned own(s) of record, or otherwise
has the right to vote,  with all power and  authority to vote and to execute and
deliver  written  consents,  in each case,  in the name,  place and stead of the
undersigned,  and at any  annual  or  special  meeting  of  stockholders  of the
Company, or at any adjournment or postponement thereof, or as to any action that
can be taken by  written  consent,  in favor of  approval  and  adoption  of the
Agreement and Plan of Merger dated the date hereof among Epitope, STC and Edward
Merger  Subsidiary,  Inc.,  a Delaware  corporation  ("Merger  Sub"),  as may be
amended from time to time,  the  ("Merger  Agreement"),  the Mergers,  any other
transactions or matters  contemplated by the Merger  Agreement,  and any actions
required in furtherance  of any of the foregoing,  in such manner as Epitope may
determine in its sole and unlimited discretion,  in each case to the same extent
and  with the  same  effect  as the  undersigned  might  or  could do under  any
applicable law or regulation  governing the rights and powers of stockholders of
an Oregon  corporation,  irrespective  of whether the  undersigned is present at
such meeting.

        This  Irrevocable  Proxy  constitutes a valid and effective  irrevocable
proxy  coupled with an interest of Epitope in the Shares of the  undersigned  in
respect of the  foregoing  Shares of Common  Stock of the  Company;  revokes any
proxy or proxies heretofore given by the undersigned in respect of any Shares of
Common Stock of the Company;  this Irrevocable  Proxy shall remain in full force
and effect  until the  earlier of (i)  termination  of the Merger  Agreement  in
accordance  with  Article X thereof,  or (ii) the  consummation  of the Mergers.
Unless otherwise  defined herein,  all capitalized  terms shall have the meaning
set forth in the Merger Agreement.

        This  Irrevocable  Proxy  shall  continue  to  cover  the  Shares  sold,
transferred  or  otherwise  disposed of after the date  hereof  through the time
period referred to in the last clause of the immediately preceding paragraph.


Dated:  -----------------------, 2000        -----------------------------------
                                             Name: -----------------------------


<PAGE>


STATE OF --------------------)
                             )  ss.
COUNTY OF -------------------)

               Sworn to and subscribed before me this ---- day of -------------,
2000 and  acknowledged  before  me as being  the free act and deed of the  above
signatory.


                                              ----------------------------------
                                                         Notary Public

My Commission expires: --------------------






                                      -12-
<PAGE>
                                                                       EXHIBIT C

                              CERTIFICATE OF MERGER
                                       OF

                             STC TECHNOLOGIES, INC.
                                      INTO

                           ORASURE TECHNOLOGIES, INC.

             (PURSUANT TO SECTION 251 OF THE GENERAL CORPORATION LAW
                            OF THE STATE OF DELAWARE)

        Pursuant to the provisions of the Delaware General  Corporation Law, the
undersigned corporation certifies as follows:

        1.     The constituent  corporations to the merger are STC Technologies,
Inc.,  a  Delaware  corporation,  and  OraSure  Technologies,  Inc.,  a Delaware
corporation.

        2.     STC  Technologies,  Inc.  and  OraSure  Technologies,  Inc.  have
entered  into an  Agreement  and Plan of  Merger,  dated as of May 6,  2000 (the
"Merger Agreement"),  which has been approved, adopted, certified,  executed and
acknowledged by STC  Technologies,  Inc. and Edward Merger  Subsidiary,  Inc. in
accordance with Section 251(c) of the Delaware General Corporation Law.

        3.     The surviving corporation is OraSure Technologies, Inc.

        4.     The Certificate of Incorporation of the surviving corporation, in
the  form  set  forth  as  Exhibit  A  hereto,   shall  be  its  certificate  of
incorporation.

        5.     The  executed  Merger  Agreement  is on file at the office of the
surviving  corporation located at 8505 S.W. Creekside Place,  Beaverton,  Oregon
97008.

        6.     A copy of the Merger Agreement will be furnished by the surviving
corporation,  on request and without cost, to any stockholder of any constituent
corporation.

        IN WITNESS  WHEREOF,  this  Certificate  of Merger has been  executed on
behalf of the surviving  corporation by its authorized  officer as of August --,
2000.

                                            OraSure Technologies, Inc.,
                                            a Delaware corporation


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

Attest:



- -----------------------------------
<PAGE>
                                                                       EXHIBIT D

                               ARTICLES OF MERGER

        OraSure  Technologies,  Inc.,  the  surviving  corporation  in a  merger
effected pursuant to ORS 60.481-60.501, submits the following articles of merger
for filing pursuant to ORS 60.494:

        1. The names of the constituent  corporations in the merger are Epitope,
Inc.,  an Oregon  corporation  (Oregon  Registry No.  ------------)  and OraSure
Technologies, Inc., a Delaware corporation.

        2. The surviving corporation in the merger is OraSure Technologies, Inc.

        3. A copy of the plan of merger is attached as Exhibit A.

        4. The plan of merger was  approved  by the  holders of common  stock of
OraSure Technologies,  Inc. voting as a single voting group, such approval being
the only shareholder approval required on the part of OraSure Technologies, Inc.
At the date of the  shareholder  vote,  there were 100 shares of common stock of
OraSure Technologies,  Inc.  outstanding,  all of which were entitled to be cast
with  respect to approval of the  merger.  ----------  shares were voted for the
plan of merger and ----------  shares were voted against approval of the plan of
merger.

        5. The plan of merger was  approved  by the  holders of common  stock of
Epitope,  Inc.  voting as a single  voting group,  such approval  being the only
shareholder  approval  required on the part of Epitope,  Inc. At the date of the
shareholder  vote,  there were -------- shares of common stock of Epitope,  Inc.
outstanding,  all of which were  entitled to be cast with respect to approval of
the merger.  ---------  shares  were voted for the plan of merger and  ---------
shares were voted against approval of the plan of merger.

        6. The merger shall be effective at the date and time of filing of these
articles of merger.

        IN  WITNESS  WHEREOF,  the  undersigned  constituent  corporations  have
executed these articles of merger on the ------- day of August, 2000.

Epitope, Inc.                                OraSure Technologies, Inc.


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


Person to contact about this filing:  Name: --------------------------
                                      Telephone: ---------------------

<PAGE>
                                                                       EXHIBIT E

                              CERTIFICATE OF MERGER
                                       OF

                                  EPITOPE, INC.
                                      INTO

                           ORASURE TECHNOLOGIES, INC.

             (PURSUANT TO SECTION 252 OF THE GENERAL CORPORATION LAW
                            OF THE STATE OF DELAWARE)

        Pursuant to the provisions of the Delaware General  Corporation Law, the
undersigned corporation certifies as follows:

        1. The  constituent  corporations  to the merger are Epitope,  Inc.,  an
Oregon corporation, and OraSure Technologies, Inc., a Delaware corporation.

        2.  Epitope,  Inc. and OraSure  Technologies,  Inc. have entered into an
Agreement and Plan of Merger,  dated as of May 6, 2000 (the "Merger Agreement"),
which has been  approved,  adopted,  certified,  executed  and  acknowledged  by
Epitope, Inc. and OraSure  Technologies,  Inc. in accordance with Section 252(c)
of the Delaware General Corporation Law.

        3. The surviving corporation is OraSure Technologies, Inc.

        4. The Certificate of Incorporation,  in the form set forth as Exhibit A
hereto, shall be its certificate of incorporation.

        5.  The  executed  Merger  Agreement  is on  file at the  office  of the
surviving  corporation located at 8505 S.W. Creekside Place,  Beaverton,  Oregon
97008.

        6. A copy of the Merger  Agreement  will be furnished  by the  surviving
corporation,  on request and without cost, to any stockholder of any constituent
corporation.

        7. The authorized capital stock of Epitope,  Inc. consists of 30,000,000
shares of common stock, no par value per share and 1,000,000 shares of preferred
stock, no par value per share.

        IN WITNESS  WHEREOF,  this  Certificate  of Merger has been  executed on
behalf of the surviving  corporation by its authorized officer as of August ---,
2000.

                                            OraSure Technologies, Inc.,
                                            a Delaware corporation


                                            By: --------------------------------
                                                 Name: -------------------------
                                                 Title: ------------------------
Attest:


- --------------------------------------
<PAGE>
                                                                       EXHIBIT F


                          CERTIFICATE OF INCORPORATION
                                       OF
                         EDWARD MERGER SUBSIDIARY, INC.


                                    ARTICLE I

        The name of this Corporation is: Edward Merger Subsidiary, Inc.

                                   ARTICLE II

        The  registered  office of the  Corporation  in the State of Delaware is
located at Corporation Trust Center, 1209 Orange Street,  Wilmington, New Castle
County,  Delaware 19801. The Registered Agent at such address is The Corporation
Trust Company.

                                   ARTICLE III

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

                                   ARTICLE IV

        A.     The total number of shares of capital stock which the Corporation
shall have authority to issue is  145,000,000,  of which (i)  25,000,000  shares
shall be preferred  stock,  of the par value of $.000001 per share  (hereinafter
referred to as "Preferred  Stock"),  and (ii) 120,000,000 shares shall be common
stock,  of the par value of  $.000001  per  share  (hereinafter  referred  to as
"Common  Stock").  All shares of Common Stock and Preferred Stock shall be fully
paid up when issued and shall be non-assessable.

        B.     The preferences,  limitations,  and relative rights of the shares
of each class of capital stock of the Corporation shall be as follows:

               1.     Preferred Stock.

                      a.     Division into Series.  The Board of Directors shall
               have authority to divide the Preferred  Stock into as many series
               as the Board of Directors shall from time to time determine,  and
               to  issue  the  Preferred  Stock  in such  series.  The  Board of
               Directors  shall  determine the number of shares  comprising each
               series,  which number may, unless otherwise provided by the Board
               of Directors in creating  such series,  be increased or decreased
               from  time to time by  action  of the  Board of  Directors.  Each
               series  shall  be so  designated  as to  distinguish  the  shares
               thereof from the shares of all other series.

                      b.     Authority   of  Board  of  Directors  to  Determine
               Preferences,  Limitations,  and  Relative  Rights.  The  Board of
               Directors shall have authority to determine,  except as otherwise
               prescribed  in  this  Article  IV or  by  law,  the  preferences,
               limitations, and relative rights, including voting rights, of the
               shares of  Preferred  Stock  before the issuance of any shares of
               such class or the


<PAGE>

               preferences,  limitations,  and relative rights, including voting
               rights, of the shares of any series of Preferred Stock before the
               issuance  of any  shares of such  series.  All shares of any such
               series shall have preferences,  limitations, and relative rights,
               including voting rights,  identical with those of other shares of
               the same series and, except to the extent  otherwise  provided in
               the  description of such series,  of those of other series of the
               Preferred Stock.

               2.     Common Stock.

               Subject to the preferences,  limitations,  and relative rights of
        the Preferred Stock, or any series thereof,  the holders of Common Stock
        shall have all rights of stockholders,  including,  without  limitation,
        (i) unlimited voting rights on all corporate matters on the basis of one
        vote per share,  except as such voting rights may be limited or required
        to be shared  together  with another class or series as provided by law,
        and (ii) the right to  receive  the net assets of the  corporation  upon
        dissolution.  Shares of Common  Stock may be issued from time to time as
        the Board of Directors  shall  determine  and on such terms and for such
        consideration as shall be fixed by the Board of Directors.

               3.     Denial of Preemptive Rights.

               No  stockholder  shall  have  any  preemptive  right  to  acquire
        additional  shares of this  Corporation,  whether  of shares  originally
        authorized or other shares which may subsequently be authorized.

                                    ARTICLE V

        A.     Any action required or permitted to be taken by the  stockholders
of the  Corporation  must be effected at a duly called annual or special meeting
of  stockholders,  and may not be  effected  by any  consent  in writing by such
stockholders, unless such consent is unanimous.

        B.     Except as otherwise required by law and subject to the rights, if
any, of the holders of Preferred Stock or any series thereof,  special  meetings
of the stockholders of the Corporation may be called only by the Chairman of the
Board of Directors,  the President of the  Corporation or the Board of Directors
pursuant to a resolution approved by a majority of the whole Board of Directors.

                                   ARTICLE VI

        A.     The Corporation shall indemnify and hold harmless, to the fullest
extent  permitted by applicable  law as it presently  exists or may hereafter be
amended, any person who was or is made or is threatened to be made a party or is
otherwise involved in any action, suit or proceeding,  whether civil,  criminal,
administrative  or  investigative (a "Proceeding") by reason of the fact that he
or she, or a person for whom he or she is the legal representative,  is or was a
director  or officer of the  Corporation  or is or was serving at the request of
the Corporation as a director,  officer,  partner, trustee, employee or agent of
another  corporation,  partnership,  limited liability  company,  joint venture,
trust,  enterprise  or  nonprofit  entity,  including  service  with  respect to
employee  benefit  plans  (an  "Indemnitee"),  against  all  liability  and loss
suffered and

                                       2
<PAGE>

expenses  (including  attorneys' fees) incurred by such person.  The Corporation
shall be required to indemnify a person in connection with a proceeding (or part
thereof)  initiated by such person only if the  proceeding (or part thereof) was
authorized by the Board of Directors of the Corporation.

        B.     The right to  indemnification  conferred by this ARTICLE VI shall
be presumed to have been relied upon by the  Indemnitee and shall be enforceable
as a  contract  right.  The  Corporation  may enter  into  contracts  to provide
individual  Indemnitees with specific rights of  indemnification  to the fullest
extent  permitted by applicable  law and may create trust funds,  grant security
interests,  obtain  letters of credit,  purchase and  maintain  insurance or use
other means to ensure the payment of such  amounts as may be necessary to effect
the rights  provided in this  ARTICLE VI or in any such  contract.  The right to
indemnification  conferred  by this ARTICLE VI shall be in addition to any other
similar rights to indemnification which may be provided by contract,  the Bylaws
of the Corporation or applicable law.

        C.     Upon making a request for  indemnification,  the Indemnitee shall
be  presumed to be entitled  to  indemnification  under this  ARTICLE VI and the
Corporation  shall  have the burden of proof to  overcome  that  presumption  in
reaching any contrary  determination.  Such  indemnification  shall  include the
right to receive  payment in advance of any expenses  incurred by the Indemnitee
in connection with any Proceeding,  consistent with the provisions of applicable
law.

                                   ARTICLE VII

        A.     The number of  Directors  of this  Corporation  shall not be less
than three nor more than  twelve as may be  determined  from time to time by the
affirmative vote of the majority of the Board of Directors.  The Directors shall
be divided into three classes,  designated Class I, Class II and Class III. Each
class shall  consist,  as nearly as may be  possible,  of one-third of the total
number  of  Directors  constituting  the  entire  Board  of  Directors.  At  the
organizational  meeting of the sole  incorporator of this  Corporation,  Class I
Directors  shall be elected for a one-year  term,  Class II  Directors  shall be
elected  for a two-year  term and Class III  Directors  shall be  elected  for a
three-year  term.  At each annual  meeting of  stockholders,  beginning in 2001,
successors to the class of Directors  whose term expires at that annual  meeting
shall be elected for a three-year  term. A Director  shall hold office until the
annual  meeting  for the year in which his or her term  expires and until his or
her successor  shall be elected and shall qualify,  subject,  however,  to prior
death, resignation, retirement, disqualification or removal from office.

        If the number of Directors is changed, any increase or decrease shall be
apportioned  among the classes so as to maintain the number of Directors in each
class as nearly  equal as  possible,  and any  additional  Director of any class
elected to fill a vacancy  resulting  from an  increase in such class shall hold
office for a term that shall coincide with the remaining term of that class, but
in no case will a decrease  in the number of  Directors  shorten the term of any
incumbent Director. Any Director elected to fill a vacancy not resulting from an
increase in the number of Directors  shall have the same  remaining term as that
of his or her  predecessor.  Any vacancy on the Board of Directors  that results
from an increase  in the number of  Directors  may be filled by the  affirmative
vote of a  majority  of the Board of  Directors  then in  office,  and any other
vacancy  occurring  on the Board of Directors  may be filled by the  affirmative
vote of a

                                       3
<PAGE>

majority of the Directors then in office,  although less than a quorum,  or by a
sole remaining Director.

        Notwithstanding  the foregoing,  whenever the holders of any one or more
classes or series of Preferred  Stock issued by the  Corporation  shall have the
right,  voting separately by class or series, to elect Directors at an annual or
special  meeting of  stockholders,  the  election,  term of  office,  filling of
vacancies  and other  features  of such  directorships  shall be governed by the
terms  of  this  Certificate  of  Incorporation  applicable  thereto,  and  such
Directors so elected shall not be divided into classes  pursuant to this ARTICLE
VII unless expressly provided by such terms.

        B.     There shall be no  qualifications  for  election as a Director of
the  Corporation;  except that no person shall be eligible to stand for election
as a  Director  if such  person  has been  convicted  of a felony  by a court of
competent  jurisdiction  where such  conviction  is no longer  subject to direct
appeal.

        C.     Except to the extent  prohibited  by law,  the Board of Directors
shall have the right  (which,  to the extent  exercised,  shall be exclusive) to
establish the rights,  powers,  duties,  rules and procedures  that from time to
time shall  govern the Board of  Directors  and each of its  members,  including
without  limitation  the vote required for any action by the Board of Directors,
and that from time to time  shall  affect  the  Directors'  power to manage  the
business  and  affairs  of the  Corporation;  and no Bylaw  shall be  adopted by
stockholders which shall impair or impede the implementation of the foregoing.

        D.     A  Director  may be  removed  only  for  cause,  and  only by the
affirmative  vote of the  holders of a majority  of shares of stock  entitled to
vote in an election of  Directors.  No Director so removed may be  reinstated so
long as the cause for removal continues to exist. For purposes of this Section D
of this ARTICLE VII,  "cause"  shall be limited to: (i)  conviction of a felony;
(ii) declaration of unsound mind by order of a court; (iii) gross dereliction of
duty; (iv) commission of a crime involving moral turpitude; or (v) commission of
an action which constitutes intentional misconduct or a knowing violation of law
if such action in either event results both in an improper  substantial personal
benefit to the Director and a material injury to the Corporation.

        E.     Advance  notice of  nominations  for the  election  of  Directors
otherthan  nominations made by the Board of Directors or a committee thereof, as
well as advance  notice of any proposals or other matters to be presented at any
meeting of the Corporation's stockholders,  shall be given to the Corporation in
the manner provided in the Bylaws.

                                  ARTICLE VIII

        In discharging the duties of their  respective  positions,  the Board of
Directors  and/or a  committee  or  committees  of the Board  and/or  individual
Directors  (collectively  or  individually,  as the case may be, a "Director" or
"Directors")  when  evaluating  any  Acquisition  Proposal (as defined below) or
presenting any related matter to the stockholders of the Corporation,  shall, in
connection with the exercise of such Directors'  judgment in determining what is
in the best interests of the  Corporation as a whole,  be authorized to give due
consideration  to  such  factors  as the  Directors  determine  to be  relevant,
including without limitation:

                                       4
<PAGE>

               1.     the   consideration   being  offered  in  the  Acquisition
        Proposal  in relation to such  Directors'  estimate  of: (i) the current
        value of the  Corporation  and/or its  equity  securities  (or  relevant
        portion of such  equity  securities)  and/or  its  assets  (or  relevant
        portion  of  its  assets)  in  a  freely   negotiated   or   independent
        transaction,  whether  in the form of a merger,  consolidation,  sale of
        assets  or   securities,   reorganization,   recapitalization,   or  any
        combination of the foregoing;  (ii) the current value of the Corporation
        and/or  its  equity  securities  (or  relevant  portion  of such  equity
        securities)  and/or its assets (or  relevant  portion of its  assets) if
        orderly  liquidated  in a  complete  or partial  liquidation;  (iii) the
        future  value  of the  Corporation  and/or  its  equity  securities  (or
        relevant  portion  of such  equity  securities)  and/or  its  assets (or
        relevant  portion  of  its  assets)  over  a  period  of  years  if  the
        Corporation  remained an independent  entity, in each case discounted to
        current  value at a discount  rate  reflective  of the relevant  risk or
        risks  involved;  (iv)  premiums  over  market  prices  for  the  equity
        securities of other corporations in similar transactions; (v) the future
        prospects of the Corporation, the earnings potential and growth in asset
        value of the  Corporation  over a period  of  years,  the  Corporation's
        short-term and/or long-term plans and/or the likelihood of increasing or
        enhancing  any or  all  of  the  foregoing  if  such  short-term  and/or
        long-term  plans  are  achieved;  (vi)  other  alternatives  that may be
        available to the  Corporation for increasing the current or future value
        of the Corporation  and/or its equity securities (or relevant portion of
        its equity  securities)  and/or its assets (or  relevant  portion of its
        assets);  and (vii) opinions or advice  rendered by investment  bankers,
        appraisers and other valuation professionals retained by the Corporation
        with  respect to such of the matters set forth in (i)-(vi)  above as may
        be relevant;

               2.     then  existing  political,   economic  and  other  factors
        bearing on  security  prices or asset  values  generally  or the current
        market value of the Corporation's securities or assets in particular;

               3.     whether the  Acquisition  Proposal might violate  federal,
        state or local laws;

               4.     social,  legal and  economic  effects on any or all groups
        affected,  including,  without  limitation,   stockholders,   employees,
        suppliers,  customers, creditors and others having similar relationships
        with the  Corporation,  and the  communities  in which  the  Corporation
        conducts its businesses;

               5.     the  financial  condition  and  earning  prospects  of the
        Person (as defined below) making the Acquisition Proposal including such
        Person's  ability  to  service  its debts and other  existing  or likely
        financial obligations;

               6.     the competence,  experience, integrity, intent and conduct
        (past, stated and potential) of the Person (as defined below) making the
        Acquisition Proposal;

               7.     the short-term and long-term interests of the Corporation,
        including without limitation benefits that may accrue to the Corporation
        from its short-term  and/or  long-term  plans and the  possibility  that
        these interests may be best served by the continued  independence of the
        Corporation; and

                                       5
<PAGE>

               8.     all other pertinent factors.

        In  considering  the foregoing  factors,  including any other  pertinent
factors not listed above,  such Directors shall not be required,  in considering
the best interests of the Corporation,  to regard any corporate  interest or the
interest of any  particular  group affected by such action,  including,  without
limitation,  the interests of stockholders of the Corporation,  as a dominant or
controlling interest or factor.

        For the purposes of this ARTICLE VIII, the term  "Acquisition  Proposal"
shall  mean a  proposal  or offer of any  Person  (it  being  understood  that a
"Person" shall mean any individual,  firm,  corporation or other entity): (a) to
make a tender offer,  exchange  offer or other  comparable  offer for any equity
security   of  the   Corporation;   (b)  to  effect  a  merger,   consolidation,
reorganization or recapitalization  with or involving another Person (as defined
above); (c) to effect any purchase,  sale, lease,  exchange,  mortgage,  pledge,
transfer or other  disposition (in one transaction or a series of  transactions)
of  all  or  substantially  all  of  the  assets  or  equity  securities  of the
Corporation with or involving another Person (as defined above); (d) to effect a
complete or partial  liquidation or dissolution  of the  Corporation;  or (e) to
effect a "business  combination" (as defined in Section 203(c)(3) of the General
Corporation Law of Delaware, as amended from time to time).

                                   ARTICLE IX

        No  Director  of the  Corporation  shall  be  personally  liable  to the
Corporation  or its  stockholders  for monetary  damages for breach of fiduciary
duty by such  Director as a Director;  provided,  however,  that this ARTICLE IX
shall not eliminate or limit the liability of a Director to the extent  provided
by applicable  law: (i) for any breach of the Director's  duty of loyalty to the
Corporation or its stockholders; (ii) for acts or omissions not in good faith or
which involve intentional  misconduct or a knowing violation of law; (iii) under
Section  174 of the  General  Corporation  Law of  Delaware;  or  (iv)  for  any
transaction from which the Director  derived an improper  personal  benefit.  No
amendment  to or repeal of this  ARTICLE IX 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 such
amendment or repeal.

                                    ARTICLE X

        Whenever  a  compromise  or   arrangement   is  proposed   between  this
Corporation  and  its  creditors  or any  class  of  them  and/or  between  this
Corporation  and its  stockholders  or any class of them, any court of equitable
jurisdiction  within the State of Delaware may, on the  application in a summary
way of this  Corporation  or of any  creditor or  stockholder  thereof or on the
application of any receiver or receivers  appointed for this  Corporation  under
the  provisions of Section 291 of Title 8 of the Delaware Code  (relating to the
General  Corporation  Law of the State of  Delaware)  or on the  application  of
trustees in  dissolution  or of any  receiver or  receivers  appointed  for this
Corporation  under the provisions of Section 279 of Title 8 of the Delaware Code
(relating  to the  General  Corporation  Law of the State of  Delaware)  order a
meeting of the creditors or class of creditors,  and/or of the  stockholders  or
class of stockholders of this Corporation, as the case may be, to be summoned in
such  manner  as such  court  directs.  If a  majority  in  number  representing
three-fourths  in value of the  creditors or class of  creditors,

                                       6
<PAGE>

and/or of the stockholders or class of stockholders of this Corporation,  as the
case may be, agree to any compromise or arrangement and to any reorganization of
this  Corporation  as a  consequence  of such  compromise or  arrangement,  such
compromise or arrangement  and such  reorganization  shall, if sanctioned by the
court to which such  application  has been made, be binding on all the creditors
or class of creditors,  and/or on all the stockholders or class of stockholders,
of this Corporation, as the case may be, and also on this Corporation.

                                   ARTICLE XI

        A.     The original Bylaws of this  Corporation  shall be adopted in any
manner provided by law.

        B.     In furtherance,  and not in limitation of the powers conferred by
statute,  the Board of Directors is expressly  authorized to make, adopt, alter,
amend or repeal  the  Bylaws of the  Corporation  by the vote of not less than a
majority of the whole Board of Directors.

        C.     Notwithstanding  any  other  provisions  in this  Certificate  of
Incorporation  or the Bylaws of the Corporation  (and  notwithstanding  the fact
that some lesser  percentage may be specified by law), the  stockholders  of the
Corporation  shall also have the power,  to the extent such power is at the time
in question conferred on them by applicable law, to make, adopt, alter, amend or
repeal  the  Bylaws  of the  Corporation  only  upon  the  affirmative  vote  of
two-thirds  (66.6%) or more of the combined voting power of the then outstanding
shares of stock of all  classes and series of the  Corporation  entitled to vote
generally in the election of directors  ("Voting  Stock"),  voting together as a
single class.

                                   ARTICLE XII

        A.     In addition to any  requirements of any other  provisions of this
Certificate  of  Incorporation  (and  notwithstanding  the  fact  that a  lesser
percentage may be specified by law or this  Certificate of  Incorporation),  the
affirmative  vote, at an annual or special meeting of the  stockholders,  of the
holders of two-thirds  (66.6%) or more of the combined  voting power of the then
outstanding  shares of Voting  Stock (as  defined in  Section C of ARTICLE  XI),
voting together as a single class,  shall be required to amend, alter or repeal,
or adopt any provision inconsistent with, ARTICLES V, VII, VIII and XI.

        B.     In addition to any  requirements of any other  provisions of this
Certificate  of  Incorporation  (and  notwithstanding  the  fact  that a  lesser
percentage may be specified by law or this  Certificate of  Incorporation),  the
affirmative  vote, at an annual or special meeting of the  stockholders,  of the
holders of two-thirds  (66.6%) or more of the combined  voting power of the then
outstanding  shares of Voting Stock  voting  together as a single class shall be
required to amend,  alter or repeal,  or adopt any provision in this Certificate
of Incorporation inconsistent with the Bylaws of the Corporation.

        C.     In addition to any  requirements of any other  provisions of this
Certificate  of  Incorporation  (and  notwithstanding  the  fact  that a  lesser
percentage may be specified by law or this Certificate of  Incorporation),  none
of Sections A or B of this ARTICLE XII may be amended,  altered or repealed, nor
may any  provision  inconsistent  therewith  be adopted,  unless the  respective
percentage  or  more of the  combined  voting  power  specified  therein  of the

                                       7
<PAGE>

outstanding shares of Voting Stock,  voting together as a single class, votes in
favor thereof, nor may this Section C of this ARTICLE XII be amended, altered or
repealed,  nor may any  provision  inconsistent  herewith be adopted  unless the
holders of two-thirds  (66.6%) or more of the combined  voting power of the then
outstanding  shares of Voting Stock,  voting together as a single class, vote in
favor thereof.

        IN WITNESS WHEREOF,  this Certificate of Incorporation has been executed
on behalf of the Corporation by its  Incorporator as of May 5, 2000, and each of
them does hereby affirm and acknowledge  that this  Certificate of Incorporation
is the act and deed of the  Corporation  and that the facts  stated  herein  are
true.


                                            ------------------------------------
                                            John A. Granda, Incorporator
                                            1201 Walnut, Suite 2800
                                            Kansas City, Missouri 64106


<PAGE>
                                                                       EXHIBIT G


                                     BYLAWS
                                       OF
                         EDWARD MERGER SUBSIDIARY, INC.


                                    ARTICLE I
                                NAME AND LOCATION

        SECTION 1. Name. The name of the Corporation shall be the name set forth
in the Certificate of Incorporation.

        SECTION 2. Principal Office.  The principal office of the Corporation is
located at 8505 S.W. Creekside Place, Beaverton, Oregon 97008.

        SECTION 3.  Additional  Offices.  Other offices for the  transaction  of
business of the  Corporation may be located at such place or places as the Board
of Directors may from time to time determine.

                                   ARTICLE II
                                  CAPITAL STOCK

        SECTION 1. Stock Certificates. All certificates of stock shall be signed
by the Chairman of the Board of Directors, the President or a Vice President and
the Secretary or an Assistant Secretary, and sealed with the corporate seal.

        SECTION  2. Stock  Transfers.  Transfers  of stock  shall be made on the
books of the  Corporation  upon the  surrender of the old  certificate  properly
endorsed, and said old certificate shall be canceled before a new certificate is
issued.

        SECTION 3. Lost or Destroyed  Stock  Certificates.  A new certificate of
stock may be issued in the place of any certificate  theretofore issued, alleged
to have been lost or  destroyed,  and the  Corporation  may, in its  discretion,
require  the  owner  of  the  lost  or  destroyed  certificate,   or  its  legal
representative,  to give a bond sufficient to indemnify the Corporation  against
any claim that may be made  against it on  account  of the  alleged  loss of any
certificate.

        SECTION 4. Preemptive Rights Denied. No holder of shares of any class of
the  Corporation,  or holder of any securities or obligations  convertible  into
shares  of any  class  of the  Corporation,  shall  have  any  preemptive  right
whatsoever  to  subscribe  for,  purchase  or  otherwise  acquire  shares of the
Corporation  of any  class,  whether  now  or  hereafter  authorized;  provided,
however,  that nothing in this SECTION 4 shall  prohibit  the  Corporation  from
granting,  contractually or otherwise, to any such holder, the right to purchase
additional securities of the Corporation.

                                   ARTICLE III
                             STOCKHOLDERS' MEETINGS

        SECTION 1. Annual Meeting. The annual meeting of the stockholders of the
Corporation  shall be held,  either within or without the State of Delaware,  on
such date and at


<PAGE>

such time as may from time to time be determined  by the Board of Directors.  At
such meeting the  stockholders  shall elect  directors in the manner provided in
the  Certificate of  Incorporation  of the  Corporation.  The  stockholders  may
transact such other business at such annual meetings as may properly come before
the meeting.

        SECTION 2. Special Meeting.  A special meeting of the holders of any one
or more classes of the capital  stock of the  Corporation  entitled to vote as a
class or classes with  respect to any matter,  as required by law or as provided
by the Certificate of Incorporation, may be called at any time and place, either
within or without the state of Delaware,  only by the Chairman of the Board, the
President or the Board of Directors.

        SECTION 3. Notice.  Notice of the time and place of all annual  meetings
and of the time,  place and purpose of all special  meetings  shall be mailed by
the Secretary to each  stockholder  at his or her last known post office address
as it appears on the  records of the  Corporation  at least ten (10) days before
the date set for such meeting.

        SECTION 4.  Nomination of Directors.  Nomination of persons for election
to the Board of Directors of the  Corporation  at a meeting of the  stockholders
may be made by or at the direction of the Board of Directors or may be made at a
meeting of stockholders  by any stockholder of the Corporation  entitled to vote
for the  election  of  Directors  at the meeting in  compliance  with the notice
procedures  set forth in this SECTION 4 of ARTICLE III. Such  nomination,  other
than those made by or at the  direction of the Board,  shall be made pursuant to
timely notice in writing to the Secretary of the  Corporation.  To be timely,  a
stockholder's  notice  shall be  delivered  to or  mailed  and  received  at the
principal executive offices of the Corporation not less than fifty (50) days nor
more than seventy-five (75) days prior to the meeting;  provided,  however, that
in the  event  that less  than  sixty-five  (65)  days'  notice or prior  public
disclosure of the date of the meeting is given or made to  stockholders,  notice
by the  stockholder  to be timely must be so received no later than the close of
business on the  fifteenth  (15th) day following the day on which such notice of
the date of the meeting was mailed or such public disclosure was made, whichever
first occurs. Such stockholder's notice to the Secretary shall set forth: (a) as
to each  person  whom the  stockholder  proposes  to  nominate  for  election or
re-election as a Director,  (i) the name,  age,  business  address and residence
address of the  person,  (ii) the  principal  occupation  or  employment  of the
person, (iii) the class and number of shares of capital stock of the Corporation
which are  beneficially  owned by the  person,  and (iv) any  other  information
relating to the person that is required to be  disclosed  in  solicitations  for
proxies  for  election  of  Directors  pursuant  to  Regulation  14A  under  the
Securities  Exchange Act of 1934, as amended (the "Exchange Act"); and (b) as to
the  stockholder  giving  the  notice;  (i) the name and  record  address of the
stockholder;  and (ii) the class and  number of shares of  capital  stock of the
Corporation which are beneficially owned by the stockholder. The Corporation may
require any proposed nominee to furnish such other information as may reasonably
be required by the  Corporation  to determine the  eligibility  of such proposed
nominee to serve as a Director of the  Corporation.  No person shall be eligible
for election as a Director of the  Corporation at a meeting of the  stockholders
unless such person has been  nominated in  accordance  with the  procedures  set
forth herein. If the facts warrant,  the Chairman of the meeting shall determine
and declare to the meeting that a nomination  does not satisfy the  requirements
set  forth in the  preceding  sentence  and the  defective  nomination  shall be
disregarded.  Nothing  in this  SECTION  4


                                       2
<PAGE>

shall be  construed  to affect  the  requirements  for proxy  statements  of the
Corporation under Regulation 14A of the Exchange Act.

        SECTION 5.  Presentation of Business at Stockholders'  Meetings.  At any
meeting of the stockholders, only such business shall be conducted as shall have
been  properly  brought  before the  meeting.  To be properly  brought  before a
meeting,  business  must be: (a)  specified  in the  notice of  meeting  (or any
supplement thereto) given by or at the direction of the Board of Directors,  (b)
otherwise  properly  brought  before the meeting by or at the  direction  of the
Board of Directors,  or (c) otherwise  properly  brought before the meeting by a
stockholder.  For  business  to  be  properly  brought  before  a  meeting  by a
stockholder, the stockholder must have given timely notice thereof in writing to
the Secretary of the Corporation.  To be timely, a stockholder's notice shall be
delivered to or mailed and received at the  principal  executive  offices of the
Corporation not less than fifty (50) days nor more than  seventy-five  (75) days
prior to the  meeting;  provided,  however,  that in the  event  that  less than
sixty-five  (65)  days'  notice or prior  public  disclosure  of the date of the
meeting is given or made to stockholders, notice by the stockholder to be timely
must be so received no later than the close of business on the fifteenth  (15th)
day following the day on which such notice of the date of the meeting was mailed
or such public disclosure was made,  whichever first occurs.  Such stockholder's
notice to the Secretary  shall set forth:  (a) as to each matter the stockholder
proposes  to bring  before the  meeting,  a brief  description  of the  business
desired to be brought  before the meeting and the  reasons for  conducting  such
business at the meeting,  and (b) as to the stockholder  giving the notice,  (i)
the name and  record  address of the  stockholder,  (ii) the class and number of
shares of capital stock of the Corporation  which are beneficially  owned by the
stockholder and (iii) any material interest of the stockholder in such business.
No business shall be conducted at a meeting of the stockholders  unless proposed
in accordance with the procedures set forth herein.  The Chairman of the meeting
shall, if the facts warrant,  determine and declare to the meeting that business
was not properly  brought  before the meeting in  accordance  with the foregoing
procedure and such business shall not be transacted.  To the extent this SECTION
5 shall be deemed by the  Board of  Directors  or the  Securities  and  Exchange
Commission,  or finally  adjudged by a court of  competent  jurisdiction,  to be
inconsistent  with the right of stockholders to request  inclusion of a proposal
in the  Corporation's  proxy statement  pursuant to Rule 14a-8 promulgated under
the Exchange Act, such rule shall prevail.

        SECTION 6. Presiding Officials.  The Chairman of the Board of Directors,
or in his or her absence or inability to act,  the  President,  or in his or her
absence  or  inability  to  act,  any  Vice  President,  shall  preside  at  all
stockholders' meetings.

        SECTION 7. Voting.  Except as otherwise  provided in the  Certificate of
Incorporation  of the  Corporation,  at each meeting of the  stockholders,  each
stockholder  shall be entitled  to cast one vote for each share of voting  stock
standing of record on the books of the Corporation,  in his or her name, and may
cast such vote either in person or by proxy. All proxies shall be in writing and
filed with the Secretary of the meeting.

        SECTION 8. Quorum;  Adjournment.  At any meeting held for the purpose of
electing  directors,  the  presence  in person or by proxy of the  holders of at
least a majority of the then outstanding  voting shares of the Corporation shall
be  required  and be  sufficient  to  constitute  a quorum for the  election  of
directors.  At a  meeting  held  for any  purpose  other  than the  election  of

                                       3
<PAGE>

directors,  shares  representing  a majority of the votes entitled to be cast on
such  matter,  present in person or  represented  by proxy,  shall  constitute a
quorum. In the absence of the required quorum at any meeting of stockholders,  a
majority of such  holders  present in person or by proxy shall have the power to
adjourn the meeting,  from time to time,  without  notice (except as required by
law) other than an announcement at the meeting, until a quorum shall be present.

        SECTION  9.  Annual  Statement  of  Business.  At  each  of  the  annual
stockholders'  meetings,  one of the executive officers of the Corporation shall
submit a statement of the business done during the preceding year, together with
a report of the general financial condition of the Corporation.

                                   ARTICLE IV
                                    DIRECTORS

        SECTION  1.  Powers of the  Board.  The  business  and  property  of the
Corporation  shall be managed by a Board  consisting of such number of Directors
as is  determined  from time to time in  accordance  with the  provisions of the
Certificate  of  Incorporation  of the  Corporation.  The Board of Directors may
elect one of their number to act as Chairman of the Board.

        SECTION 2.  Qualification.  Each Director upon his or her election shall
qualify  by  filing  his or her  written  acceptance  with the  Secretary  or an
Assistant Secretary and by fulfilling any prerequisite to qualification that may
be set forth in the Certificate of Incorporation of the Corporation.

        SECTION 3. Annual Meetings. The annual meeting of the Board of Directors
shall be held  immediately  after the  adjournment of each annual meeting of the
stockholders  and in the event a quorum is not present,  said  meeting  shall be
held within ten (10) days after  adjournment  upon proper notice by the Chairman
of the Board of Directors, the President or a Vice President.

        SECTION 4. Special Meetings.  Special meetings of the Board of Directors
may be  called  at any  time or  place by the  Chairman  of the  Board or by the
President, and in the absence or inability of either of them to act, by any Vice
President,  and may also be called by any two members of the Board of Directors.
By unanimous consent of the Directors, special meetings of the Board may be held
without notice, at any time and place.

        SECTION 5. Notice;  Telephonic Attendance;  Unanimous Consent. Notice of
all regular and special  meetings  of the Board of  Directors  or the  Executive
Committee or any  committee  established  pursuant to this ARTICLE IV (an "Other
Committee")  shall be sent to each Director or member of such committee,  as the
case may be, by the Secretary or any Assistant Secretary,  by a means reasonably
calculated  to be  received  at least seven (7) days prior to the time fixed for
such  meeting,  or notice of special  meetings of the Board of  Directors or the
Executive Committee or any Other Committee may be given by telephone, telegraph,
telefax or telex to each Director or member of such  committee,  as the case may
be, at least twenty-four (24) hours prior to the time fixed for such meeting, or
on such  shorter  notice as the  person  or  persons  calling  the  meeting  may
reasonably  deem necessary or appropriate  in the  circumstances.  To the extent
provided in the notice of the meeting or as otherwise determined by the Chairman
of the Board or the Board of Directors, Directors may participate in any regular
or special meeting by means

                                       4
<PAGE>

of conference  telephone,  videoconference or similar  communications  equipment
which allows all persons  participating  in such meeting to hear each other, and
participation  in such  meeting  by  means  of such a  device  shall  constitute
presence  in person at such  meeting.  Attendance  of a director  at any meeting
shall  constitute  a waiver of notice of such  meeting  except  where a director
attends a meeting for the express purpose of objecting to the transaction of any
business because the meeting is not lawfully called or convened.

        If all the directors shall severally or collectively  consent in writing
to any action to be taken by the  directors,  such consents  shall have the same
force and effect as a unanimous  vote of the  directors  at a meeting duly held.
The  Secretary  shall file such consents with the minutes of the meetings of the
Board of Directors.

        SECTION 6.  Quorum;  Adjournment.  Except as  otherwise  provided in the
Certificate of Incorporation of the Corporation, a quorum for the transaction of
business  at any  meeting of the  directors  shall  consist of a majority of the
members of the Board,  but the directors  present,  although less than a quorum,
shall have the power to adjourn the meeting  from time to time or to some future
date.

        SECTION 7. Election of Officers.  The directors shall elect the officers
of the Corporation and fix their salaries and other compensation.  Such election
shall be made at the  Directors'  meeting  following  each annual  stockholders'
meeting.

        SECTION 8.  Advisers to the Board of  Directors.  The Board of Directors
from time to time,  as they may deem proper,  shall have  authority to appoint a
general  manager,  counsel or attorneys  and other  employees for such length of
time  and  upon  such  terms  and  conditions  and at such  salaries  and  other
compensation as they may deem necessary and/or advisable.

        SECTION 9. Compensation;  Reimbursement of Expenses.  The members of the
Board of Directors shall receive  compensation for their services in such amount
as may be  reasonable  and  proper  and  consistent  with the  time and  service
rendered.  The members of the Board of Directors  shall  receive the  reasonable
expenses  necessarily  incurred  in  the  attendance  of  meetings  and  in  the
transaction of business for the Corporation.

        SECTION 10. Indemnification; Insurance.

        (a)    Indemnification.

               (1)  Actions  Other  than  Those  by  or  in  the  Right  of  the
        Corporation.  To the extent  permitted by Delaware law from time to time
        in effect and subject to the provisions of paragraph (c) of this Section
        10, the Corporation  shall indemnify any person who was or is a party or
        is threatened to be made a party to any threatened, pending or completed
        action, suit or proceeding,  whether civil, criminal,  administrative or
        investigative  (other  than  an  action  by  or  in  the  right  of  the
        Corporation)  by  reason  of  the  fact  that  such  person  is or was a
        director,  officer,  employee or agent of the Corporation,  or is or was
        serving  at the  request  of the  Corporation  as a  director,  officer,
        employee or agent of another  corporation,  partnership,  joint venture,
        trust or other enterprise, against expenses (including attorneys' fees),
        judgments,  fines and amounts paid in settlement actually and reasonably
        incurred  by  such  person  in  connection  with

                                       5
<PAGE>

        such action,  suit or  proceeding if such person acted in good faith and
        in a manner such person  reasonably  believed to be in or not opposed to
        the best  interests of the  Corporation  (or such other  corporation  or
        organization),  and, with respect to any criminal  action or proceeding,
        had no reasonable  cause to believe such person's  conduct was unlawful.
        The  termination of any action,  suit or proceeding by judgment,  order,
        settlement,  conviction,  or  upon  a plea  of  nolo  contendere  or its
        equivalent  shall not, of itself,  create a presumption  that the person
        did not act in good faith and in a manner  which such person  reasonably
        believed  to  be in  or  not  opposed  to  the  best  interests  of  the
        Corporation, and, with respect to any criminal action or proceeding, had
        reasonable cause to believe that such person's conduct was unlawful.

               (2) Action by or in the Right of the  Corporation.  To the extent
        permitted by Delaware law from time to time in effect and subject to the
        provisions  of paragraph (c) of this Section 10, the  Corporation  shall
        indemnify any person who was or is a party or is threatened to be made a
        party to any  threatened,  pending or completed  action or suit by or in
        the  right of the  Corporation  to  procure a  judgment  in its favor by
        reason  of the fact  that such  person  is or was a  director,  officer,
        employee or agent of the Corporation or is or was serving at the request
        of the Corporation as a director,  officer, employee or agent of another
        corporation,  partnership,  joint  venture,  trust or other  enterprise,
        against  expenses  (including  attorneys'  fees) actually and reasonably
        incurred by such person in connection  with the defense or settlement of
        such action or suit if such  person  acted in good faith and in a manner
        such  person  reasonably  believed  to be in or not  opposed to the best
        interests of the Corporation (or such other corporation or organization)
        and  except  that no  indemnification  shall be made in  respect  of any
        claim,  issue or matter as to which such person shall have been adjudged
        to  be  liable  to  the  Corporation  (or  such  other   corporation  or
        organization) unless and only to the extent that the court in which such
        action  or suit was  brought  shall  determine  upon  application  that,
        despite  the   adjudication   of  liability  but  in  view  of  all  the
        circumstances of the case, such person is fairly and reasonably entitled
        to indemnity for such expenses which such court shall deem proper.

               (3) Successful  Defense of Action.  Notwithstanding,  and without
        limitation  of, any other  provision  of this  SECTION 10, to the extent
        that a director,  officer, employee or agent of the Corporation has been
        successful on the merits or otherwise in defense of any action,  suit or
        proceeding  referred to in  sub-paragraph  (1) or (2) of this  paragraph
        (a), or in defense of any claim, issue or matter therein, such director,
        officer,  employee  or  agent  shall  be  indemnified  against  expenses
        (including  attorneys'  fees) actually and  reasonably  incurred by such
        person in connection therewith.

               (4)   Determination    Required.    Any   indemnification   under
        sub-paragraph  (1) or (2) of this  paragraph  (a)  (unless  ordered by a
        court)  shall  be made by the  Corporation  only  as  authorized  in the
        specific case upon a determination that indemnification of the director,
        officer,  employee or agent is proper in the circumstances  because such
        director,  officer, employee or agent has met the applicable standard of
        conduct set forth in said  sub-paragraph.  Such  determination  shall be
        made:  (i) by the  Board of  Directors  by a  majority  vote of a quorum
        consisting of directors who were not parties to the  particular  action,
        suit or proceeding, or (ii) if such a quorum is not obtainable, or, even
        if

                                       6
<PAGE>

        obtainable,   a  quorum  of  disinterested   directors  so  directs,  by
        independent  legal  counsel  in a  written  opinion,  or  (iii)  by  the
        stockholders.

        (b)  Insurance.  The  Corporation  may, when  authorized by the Board of
Directors, purchase and maintain insurance on behalf of any person who is or was
a director,  officer, employee or agent of the Corporation, or is or was serving
at the request of the Corporation as a director,  officer,  employee or agent of
another  corporation,  partnership,  joint  venture,  trust or other  enterprise
against any liability  asserted  against such person and incurred by such person
in any such capacity, or arising out of such person's status as such, whether or
not the Corporation would have the power to indemnify him against such liability
under the  provisions  of this SECTION 10. The risks insured under any insurance
policies  purchased  and  maintained  on behalf of any person as aforesaid or on
behalf of the  Corporation  shall not be limited in any way by the terms of this
SECTION 10 and to the extent  compatible  with the  provisions of such policies,
the risks insured shall extend to the fullest extent permitted by law, common or
statutory.

        (c)  Advancement  of  Expenses;   Nonexclusivity;   Duration.   Expenses
(including  attorneys' fees) incurred by an officer or director in defending any
civil,  criminal,  administrative  or investigative  action,  suit or proceeding
shall be paid by the  Corporation  in advance of the final  disposition  of such
action,  suit or proceeding  upon receipt of an  undertaking  by or on behalf of
such  officer  or  director  to repay  such  amount  if it shall  ultimately  be
determined that such person is not entitled to be indemnified by the Corporation
as  authorized  in this SECTION 10. Such expenses  (including  attorneys'  fees)
incurred by other  employees and agents may be so paid by the  Corporation  upon
such terms and conditions,  if any, as the Board of Directors deems appropriate.
The indemnifications, advancement of expenses and rights provided by, or granted
pursuant  to,  this  SECTION  10 shall  not be  deemed  exclusive  of any  other
indemnifications, advancement of expenses, rights or limitations of liability to
which any person  seeking  indemnification  or  advancement  of expenses  may be
entitled  under any Bylaw,  agreement,  vote of  stockholders  or  disinterested
directors, or otherwise,  either as to action in such person's official capacity
or as to action  in  another  capacity  while  holding  office,  and they  shall
continue although such person has ceased to be a director,  officer, employee or
agent and shall  inure to the  benefit of such  person's  heirs,  executors  and
administrators.  The authorization to purchase and maintain  insurance set forth
in paragraph (b) shall likewise not be deemed exclusive.

        SECTION 11.   Committees.

        (a) The Board of Directors may, by resolution or resolutions  adopted by
a  majority  of  the  whole  Board,  designate  two  or  more  directors  of the
Corporation to constitute one or more committees in addition to those committees
required by SECTIONS 12, 13 and 14 of this ARTICLE IV. Each such  committee,  to
the  extent  provided  in such  resolution  or  resolutions,  shall have and may
exercise all of the authority of the Board in the management of the Corporation;
provided,  however,  that  the  designation  of  each  such  committee  and  the
delegation  thereto of authority  shall not operate to relieve the Board, or any
member thereof, of any responsibility imposed upon it or such member by law.

        (b) Notwithstanding any other provision of these Bylaws, no committee of
the Board of  Directors  shall  have the power or  authority  of the Board  with
respect to (i) amending the  Certificate  of  Incorporation,  (ii)  approving or
recommending  to  stockholders  any type or form of

                                       7
<PAGE>

"business combination" (as defined in Section 203 of the General Corporation Law
of Delaware as in effect on January 1, 1996), (iii) approving or recommending to
the  stockholders  a  dissolution  of  the  Corporation  or  a  revocation  of a
dissolution,  (iv) amending these Bylaws, (v) declaring a dividend or making any
other  distribution to the stockholders,  (vi) authorizing the issuance of stock
otherwise  than  pursuant  to the  grant or  exercise  of a stock  option  under
employee  stock  options  of the  Corporation  or in  connection  with a  public
offering of securities  registered under the Securities Act of 1933, as amended,
or (vii) appointing any member of any committee of the Board.

        (c) Each such committee shall keep regular  minutes of its  proceedings,
which  minutes  shall be  recorded in the minute  book of the  Corporation.  The
Secretary or an Assistant  Secretary of the Corporation may act as Secretary for
each such committee if the committee so requests.

        SECTION 12.  Executive  Committee.  The Chief  Executive  Officer of the
Corporation,  together with no more than five additional  Directors  selected by
the Board shall constitute an Executive Committee of the Board of Directors. The
Executive  Committee  between  regular  meetings of the Board of Directors shall
manage the  business  and  property of the  Corporation  and shall have the same
power and authority as the Board of Directors;  provided, however, the Executive
Committee  shall not act (other  than to make a  recommendation)  in those cases
where  it is  provided  by law or by the  Certificate  of  Incorporation  of the
Corporation  that any vote or action in order to bind the  Corporation  shall be
taken by the Directors.  Members of the Executive  Committee may  participate in
any meeting of the  Executive  Committee  by means of  conference  telephone  or
videoconference  or similar  communications  equipment  which allows all persons
participating in the meeting to hear each other, and  participation in a meeting
by means of such a device shall constitute presence in person at such meeting.

        The Executive  Committee  shall keep a record of its proceedings and may
hold meetings upon one (1) day's written  notice or upon waiver of notice signed
by the members either before or after said Executive Committee meeting.

        A majority of the Executive  Committee shall constitute a quorum for the
transaction  of business  at any meeting for which  notice has been given to all
members in accordance  with ARTICLE IV, SECTION 5 hereof or for which notice has
been waived by all members.

        The  Executive  Committee  or any Other  Committee  may act by unanimous
written consent as provided in ARTICLE IV, SECTION 5.

        SECTION 13. Audit Committee. The Board of Directors at the annual or any
regular or special meeting of the directors  shall,  by resolution  adopted by a
majority of the whole Board,  designate  two or more  directors to constitute an
Audit  Committee  and appoint one of the directors so designated as the chairman
of the Audit Committee. Membership on the Audit Committee shall be restricted to
those directors who are independent of the management of the Corporation and are
free from any  relationship  that, in the opinion of the Board,  would interfere
with  the  exercise  of  independent  judgment  as a  member  of the  committee.
Vacancies in the  committee  may be filled by the Board at any meeting  thereof.
Each member of the  committee  shall hold office until such  committee  member's
successor has been duly elected and qualified,  or

                                       9
<PAGE>

until such committee member's resignation or removal from the Audit Committee by
the Board, or until such committee member otherwise ceases to be a director. Any
member of the Audit  Committee  may be removed from the  committee by resolution
adopted by a majority of the whole Board. The  compensation,  if any, of members
of the committee shall be established by resolution of the Board.

        The Audit Committee shall be responsible for:  recommending to the Board
the  appointment  or  discharge  of  independent  auditors;  reviewing  with the
management and the  independent  auditors the terms of engagement of independent
auditors,  including  the  fees,  scope  and  timing  of the audit and any other
services  rendered by the independent  auditors;  reviewing with the independent
auditors and management the  Corporation's  policies and procedures with respect
to internal  auditing,  accounting  and financial  controls;  reviewing with the
management  the  independent  statements,  audit  results  and  reports  and the
recommendations  made  by  any  of the  auditors  with  respect  to  changes  in
accounting procedures and internal controls; reviewing the results of studies of
the Corporation's  system of internal  accounting  controls;  and performing any
other duties or functions  deemed  appropriate by the Board. The Audit Committee
shall have the  powers  and  rights  necessary  or  desirable  to fulfill  these
responsibilities,  including  the power and right to consult with legal  counsel
and to rely upon the opinion of legal counsel. The Audit Committee is authorized
to communicate directly with the Corporation's financial officers and employees,
internal auditors and independent auditors as it deems desirable and to have the
internal auditors or independent  auditors perform any additional  procedures as
it deems appropriate.

        All actions of the Audit Committee shall be reported to the Board at the
next meeting of the Board.  The minute books of the Audit Committee shall at all
times be open to the inspection of any director.

        The Audit Committee shall meet at the call of its chairman or of any two
members of the Audit Committee (or if there shall be only one other member, then
at the call of that member).  A majority of the Audit Committee shall constitute
a quorum for the transaction of business (or if there shall only be two members,
then both must be  present),  and the act of a majority of those  present at any
meeting at which a quorum is  present  (or if there  shall be only two  members,
then they must act unanimously) shall constitute the act of the Audit Committee.

        SECTION 14. Compensation Committee. The Board of Directors at the annual
or any regular or special meeting shall, by resolution  adopted by a majority of
the whole Board,  designate two or more  directors to constitute a  Compensation
Committee.  Membership  on the  Compensation  Committee  shall be  restricted to
disinterested persons which for this purpose shall mean any director who, during
the  time  such  director  is a  member  of the  Compensation  Committee  is not
eligible,  and has not at any time within one year prior thereto been  eligible,
for  selection  to  participate  (other  than  in  a  manner  as  to  which  the
Compensation  Committee  has no  discretion)  in any of the  compensation  plans
administered by the  Compensation  Committee.  Vacancies in the committee may be
filled by the Board at any  meeting.  Each  member of the  committee  shall hold
office  until  such  committee  member's  successor  has been duly  elected  and
qualified,  or until such  committee  member's  resignation  or removal from the
Compensation  Committee by the Board, or until such committee  member  otherwise
ceases  to  be  a  director  or  a  disinterested  person.  Any  member  of  the
Compensation Committee may be removed by

                                       9
<PAGE>

resolution  adopted by a majority of the whole Board. The compensation,  if any,
of the members of the Compensation  Committee shall be established by resolution
of the Board.

        The Compensation  Committee shall,  from time to time,  recommend to the
Board  the  compensation   and  benefits  of  the  executive   officers  of  the
Corporation.  The  Compensation  Committee  shall  have the power and  authority
vested in the Board by any benefit  plan of the  Corporation.  The  Compensation
Committee  shall  also  make  recommendations  to the Board  with  regard to the
compensation  of the  Board  and  its  committees,  with  the  exception  of the
Compensation Committee.

        All actions of the Compensation Committee shall be reported to the Board
at the next meeting of the Board. The minute books of the Compensation Committee
shall at all times be open to the inspection of any director.

        The Compensation Committee shall meet at the call of the chairman of the
Compensation  Committee or of any two members of the Compensation  Committee (or
if there shall be only one other  member,  then at the call of that  member).  A
majority  of the  Compensation  Committee  shall  constitute  a  quorum  for the
transaction  of business (or if there shall be only two members,  then both must
be present),  and the act of a majority of those present at any meeting at which
a quorum is present (or if there shall be only two  members,  then they must act
unanimously) shall be the act of the Compensation Committee.

        SECTION 15.  Alternate  Committee  Members.  The Board of Directors,  by
resolution  adopted by a majority of the whole Board,  may designate one or more
additional directors as alternate members of any committee to replace any absent
or  disqualified  member at any meeting of that  committee,  and at any time may
change  the  membership  of any  committee  or amend or rescind  the  resolution
designating  the committee.  In the absence or  disqualification  of a member or
alternate  member of a committee,  the member or members  thereof present at any
meeting and not disqualified  from voting,  whether or not the member or members
constitute a quorum,  may  unanimously  appoint  another  director to act at the
meeting in the place of any such absent or  disqualified  member,  provided that
the director so appointed meets any qualifications stated in these Bylaws or the
resolution designating the committee or any amendment thereto.

        SECTION 16. Committee  Procedures.  Unless  otherwise  provided in these
Bylaws or in the resolution designating any committee, any committee may fix its
rules or  procedures,  fix the time and place of its  meetings  and specify what
notice of meetings, if any, shall be given.

                                    ARTICLE V
                                    OFFICERS

        SECTION 1.  Designations.  The officers of this  Corporation  shall be a
Chairman of the Board of Directors, a President,  as many Vice Presidents as the
Board of Directors may from time to time deem advisable and one or more of which
may  be  designated  Executive  Vice  President  or  Senior  Vice  President,  a
Secretary, a Treasurer,  and such Assistant Secretaries and Assistant Treasurers
as the Board of Directors may from time to time deem  advisable,  and such other
officers  as the Board of  Directors  may from time to time deem  advisable  and
designate.  The Chairman of the Board of  Directors  shall be a member of and be
elected by the Board of

                                       10
<PAGE>

Directors.  All other officers  shall be elected by the Board of Directors.  All
officers  shall hold office until their  respective  successors  are elected and
shall have  qualified.  Any two  offices  may be held by one  person  except the
office of President and Vice President.

        SECTION 2. Chairman of the Board. The Chairman of the Board of Directors
shall preside at all meetings of the Directors and  stockholders  at which he or
she is present and shall have such other  duties,  power and authority as may be
prescribed  by the Board of  Directors  from time to time or  elsewhere in these
Bylaws.  The Board of Directors  may  designate the Chairman of the Board as the
Chief  Executive  Officer of the  Corporation  with all of the powers  otherwise
conferred upon the President of the Corporation  under these Bylaws,  or it may,
from time to time,  divide the  responsibilities,  duties and  authority for the
general control and management of the Corporation's business and affairs between
the Chairman of the Board and the President.

        SECTION 3. President and Chief  Executive  Officer.  Unless the Board of
Directors otherwise provides, the President shall be the Chief Executive Officer
of the Corporation with such general  executive powers and duties of supervision
and management as are usually vested in such office and shall perform such other
duties as are authorized by the Board of Directors. The Chairman of the Board or
the President shall sign contracts,  certificates  and other  instruments of the
Corporation  as  authorized  by the Board of  Directors.  If the Chairman of the
Board is  designated  as the Chief  Executive  Officer of the  Corporation,  the
President  shall  perform  such duties as may be  delegated to him or her by the
Board of Directors  and as are  conferred by law  exclusively  upon such office.
Unless the Board of Directors otherwise provides,  the President,  or any person
designated in writing by the  President,  shall have full power and authority on
behalf of the  Corporation  to:  (i)  attend  and to vote or take  action at any
meeting of the holders of securities of  corporations  in which the  Corporation
may hold securities, and at such meetings shall possess and may exercise any and
all rights and powers  incident to being a holder of such  securities,  and (ii)
execute  and  deliver  waivers of notice and proxies for and in the name of this
Corporation  with respect to  securities  of any such  corporation  held by this
Corporation.

        SECTION 4. Vice  Presidents.  A Vice President  shall have the right and
power to perform all duties and exercise all authority of the President, in case
of the absence of the  President  or upon  vacancy in the office of President or
delegation  by the Board of  Directors,  until the Board of Directors  otherwise
provides,  and shall have all power and  authority  usually  enjoyed by a person
holding the office of Vice President.

        SECTION 5.  Secretary and  Assistant  Secretaries.  The Secretary  shall
issue notices of all directors' and stockholders' meetings, and shall attend and
keep the minutes of the same; shall have charge of all corporate books,  records
and papers;  shall be custodian of the corporate seal;  shall attest with his or
her signature,  which may be a facsimile signature if authorized by the Board of
Directors,  and impress with the  corporate  seal,  all stock  certificates  and
written contracts of the Corporation;  and shall perform all other duties as are
incident  to his or her  office.  Any  Assistant  Secretary,  in the  absence or
inability of the  Secretary,  shall perform all duties of the Secretary and such
other duties as may be required.

        SECTION 6. Treasurer and Assistant Treasurers.  The Treasurer shall have
custody of all money and  securities of the  Corporation  and shall give bond in
such sum and with such

                                       11
<PAGE>

sureties as the directors may specify, conditioned upon the faithful performance
of the  duties of his or her  office.  He or she  shall  keep  regular  books of
account and shall submit them, together with all of his or her records and other
papers,  to the  directors  for their  examination  and approval  annually;  and
quarterly  or as and when  directed by the Board of  Directors,  he or she shall
submit to each  director  a  statement  of the  condition  of the  business  and
accounts of the  Corporation;  and shall  perform  all such other  duties as are
incident  to his or her  office.  An  Assistant  Treasurer,  in the  absence  or
inability of the  Treasurer,  shall  perform all the duties of the Treasurer and
such other duties as may be required.

        SECTION 7.  Bonding.  Any officer or employee of the  Corporation  shall
give such bond for the faithful performance of his or her duties in such sum, as
and when the Board of Directors may direct.

                                   ARTICLE VI
                                    DIVIDENDS

        SECTION  1.  Dividends  shall be paid out of the net  income  or  earned
surplus  of the  Corporation,  determined  after  making  proper  provision  for
required  sinking fund deposits for debt  obligations and proper  provisions for
working  capital and such  reserves  as may be  required  by good and  generally
accepted accounting  practice,  when declared from time to time by resolution of
the Board of Directors.  No such dividends  shall be declared or paid which will
impair the capital of the Corporation.

                                   ARTICLE VII
                                   AMENDMENTS

        SECTION  1.  Except  as  otherwise   provided  in  the   Certificate  of
Incorporation  of the  Corporation,  these  Bylaws  may be  amended,  altered or
repealed  by the  affirmative  vote of a  majority  of the  Board of  Directors,
subject to the power of stockholders to amend, alter or repeal the Bylaws, or as
otherwise  may  from  time to time be  authorized  by the  laws of the  State of
Delaware.

                                  ARTICLE VIII
                                 CORPORATE SEAL

        SECTION 1. The corporate seal of this  Corporation  shall have inscribed
thereon the name of the Corporation and its state of incorporation.





                                        ----------------------------------------
                                        ----------------------, Secretary

<PAGE>
                                                                       EXHIBIT H




                   PRINCIPAL OFFICERS OF SURVIVING CORPORATION



                      Name                            Title
                      ----                            -----

                 Robert D. Thompson        Chief Executive Officer

                Michael J. Gausling        President and Chief Operating Officer

                    R. Sam Niedbala        Executive Vice President and Chief
                                           Scientific Officer

           J. Richard George, Ph.D.        Senior Vice President of Research and
                                           Development, Infectious Disease

                   William D. Block        Senior Vice President of Sales

                    William Hinchey        Senior Vice President of Marketing

                Charles E. Bergeron        Vice President and Chief Financial
                                           Officer

                Andrew S. Goldstein        Vice President of Product Support and
                                           Development

             Philip Michael Formica        Vice President of Operations

                      Robert Ngungu        Vice President of Regulatory Affairs
                                           and Quality Assurance




<PAGE>
                                                                       EXHIBIT I


                  [To be typed on letterhead of Epitope, Inc.]

                                    D R A F T

                                 [Closing Date]

Stinson, Mag & Fizzell, P.C.
1201 Walnut, Suite 2800
Kansas City, MO  64106

                       RE:    Tax Opinion in Connection with Mergers of  STC
                              Technologies, Inc. and Epitope, Inc. with and into
                              OraSure Technologies, Inc.


Ladies and Gentlemen:

               This letter is provided to you in connection with the tax opinion
you are rendering with respect to the proposed  merger (the "Sam Merger") of STC
Technologies,  Inc. ("STC") with and into OraSure  Technologies,  Inc.  ("Merger
Sub") and the proposed merger (the "Edward Merger") of Epitope, Inc. ("Epitope")
with and into Merger Sub pursuant to the  Agreement  and Plan of Merger dated as
of May 6, 2000 among Epitope,  Merger Sub (hereinafter referred to as "Surviving
Corporation") and STC (the "Agreement").  Recognizing that you will rely on this
letter and the  representations  herein in rendering your tax opinion, we hereby
make and certify the following representations:

               1.  The facts  concerning  the Sam Merger  and the Edward  Merger
                   described  in the  Proxy  Statement  included  as part of the
                   Registration  Statement  on Form S-4 are  true,  correct  and
                   complete in all material respects as of the date hereof.

               2.  The Sam Merger and the Edward Merger will be  consummated  in
                   compliance  with  the  terms  of the  Agreement  and  will be
                   statutory  mergers in accordance  with the applicable laws of
                   the State of Delaware and the State of Oregon.

               3.  None of the terms and  conditions of the Agreement  have been
                   waived or modified,  and  Surviving  Corporation  and Epitope
                   have no plan or intention to waive or modify any such term or
                   condition.

               4.  Valid business purposes exist for both the Sam Merger and the
                   Edward Merger.

               5.  The fair market  value of the  Surviving  Corporation  Common
                   Stock, par value $0.000001 per share ("Surviving  Corporation
                   Common Stock"), and other consideration  received by each STC
                   shareholder


<PAGE>

                   will be  approximately  equal to the fair market value of the
                   STC Common Stock,  par value $0.000001 per share ("STC Common
                   Stock"),  surrendered  in the  exchange,  and the fair market
                   value of the  Surviving  Corporation  Common  Stock and other
                   consideration  received by each Epitope  shareholder  will be
                   approximately  equal to the fair market  value of the Epitope
                   Common  Stock,  no  par  value  per  share  ("Epitope  Common
                   Stock"), surrendered in the exchange.

               6.  Neither  Surviving   Corporation  nor  a  person  related  to
                   Surviving   Corporation   within  the   meaning  of  Treasury
                   Regulation ss.  1.368-1(e)(3) has acquired or has any plan or
                   intention  to acquire  any STC Common  Stock  prior to and in
                   connection  with the Sam Merger or any Epitope  Common  Stock
                   prior to and in connection with the Edward Merger.

               7.  Surviving  Corporation  has no plan or intention to reacquire
                   any of its  stock  issued  in the Sam  Merger  or the  Edward
                   Merger.

               8.  A person related to Surviving  Corporation within the meaning
                   of  Treasury  Regulation  ss.  1.368-1(e)(3)  has no  plan or
                   intention to acquire any Surviving  Corporation  Common Stock
                   issued in the Sam Merger or the Edward Merger.

               9.  Surviving  Corporation  has no plan or  intention  to sell or
                   otherwise  dispose  of any of the  assets  of STC or  Epitope
                   acquired in the transaction,  except for dispositions made in
                   the  ordinary  course of business or  transfers  described in
                   section 368(a)(2)(C) of the Internal Revenue Code.

               10. The liabilities of Epitope  assumed by Surviving  Corporation
                   and the  liabilities  to  which  the  transferred  assets  of
                   Epitope are subject were  incurred by Epitope in the ordinary
                   course of its business.

               11. Following  the Sam Merger and the  Edward  Merger,  Surviving
                   Corporation will continue the historic  businesses of STC and
                   Epitope or use a  significant  portion  of STC and  Epitope's
                   historic business assets in a business.

               12. Surviving  Corporation,  STC, Epitope and the shareholders of
                   STC and Epitope will pay their respective  expenses,  if any,
                   incurred  in  connection  with the Sam  Merger and the Edward
                   Merger.

               13. There  is no  intercorporate  indebtedness  existing  between
                   Surviving   Corporation   and   STC  or   between   Surviving
                   Corporation and Epitope that was issued, acquired, or will be
                   settled at a discount.

                                       2
<PAGE>

               14. Neither  Surviving  Corporation  nor Epitope  are  investment
                   companies as defined in section  368(a)(2)(F) of the Internal
                   Revenue Code.

               15. Epitope is not under the  jurisdiction  of a court in a Title
                   11 or similar case within the meaning of section 368(a)(3)(A)
                   of the Internal Revenue Code.

               16. The fair market value of the assets of STC to be  transferred
                   to Surviving  Corporation will equal or exceed the sum of the
                   liabilities assumed by Surviving Corporation, plus the amount
                   of liabilities,  if any, to which the transferred  assets are
                   subject,  and the fair market  value of the assets of Epitope
                   to be  transferred  to  Surviving  Corporation  will equal or
                   exceed  the  sum  of the  liabilities  assumed  by  Surviving
                   Corporation, plus the amount of liabilities, if any, to which
                   the transferred assets are subject.

               17. None    of    the     compensation     received     by    any
                   shareholder-employees  of STC or  Epitope  will  be  separate
                   consideration  for, or  allocable  to, any of their shares of
                   STC Common Stock or Epitope  Common Stock  surrendered in the
                   exchanges,    and    the    compensation    paid    to   such
                   shareholder-employees  will be for services actually rendered
                   and will be  commensurate  with amounts paid to third parties
                   bargaining at arms-length for similar  services.  None of the
                   Surviving Corporation Common Stock received in the Sam Merger
                   or  Edward  Merger  by  any  shareholder-employees  of STC or
                   Epitope will be separate  consideration for, or allocable to,
                   any compensation owed to such employee.

               18. The payment of cash in lieu of fractional shares of Surviving
                   Corporation  Common Stock with respect to both the Sam Merger
                   and the Edward  Merger is solely for the  purpose of avoiding
                   the expense and  inconvenience  to Surviving  Corporation  of
                   issuing  fractional shares and does not represent  separately
                   bargained-for  consideration.  The total  cash  consideration
                   that will be paid in the Sam  Merger to the  shareholders  of
                   STC  instead  of  issuing   fractional  shares  of  Surviving
                   Corporation  Common  Stock will not exceed one percent of the
                   total  consideration that will be issued in the Sam Merger to
                   the  shareholders  of Sam in exchange for their shares of STC
                   Common Stock, and the total cash  consideration  that will be
                   paid in the  Edward  Merger to the  shareholders  of  Epitope
                   instead of issuing fractional shares of Surviving Corporation
                   Common  Stock  will  not  exceed  one  percent  of the  total
                   consideration that will be issued in the Edward Merger to the
                   shareholders  of  Epitope  in  exchange  for their  shares of
                   Epitope Common Stock.  The fractional share interests of each
                   shareholder  of STC and Epitope  will be  aggregated,  and no
                   shareholder   of  STC  or  Epitope   will  receive  cash  for
                   fractional  shares in an amount  equal to or

                                       3
<PAGE>

                   greater  than  the  value  of one  full  share  of  Surviving
                   Corporation Common Stock.

               19. After the Sam Merger and the Edward  Merger,  no dividends or
                   distributions  will be made to the former STC shareholders or
                   the former  Epitope  shareholders  by Surviving  Corporation,
                   other than regular or normal dividend distributions made with
                   regard to all shares of Surviving Corporation Common Stock.

To the best of his  knowledge and belief,  the  undersigned  certifies  that the
above  representations  are correct and that the factual  statements  upon which
they are based are true, correct and complete.

                                         Very truly yours,

                                         EPITOPE, INC.


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


                                       4
<PAGE>
                                                                       EXHIBIT J

              [To be typed on letterhead of STC Technologies, Inc.]

                                    D R A F T

                                 [Closing Date]

Stinson, Mag & Fizzell, P.C.
1201 Walnut, Suite 2800
Kansas City, MO  64106

                                RE:     Tax Opinion in Connection with Merger
                                        of  STC Technologies, Inc. with and into
                                        OraSure Technologies, Inc.


Ladies and Gentlemen:

               This letter is provided to you in connection with the tax opinion
you are rendering with respect to the proposed  merger (the "Sam Merger") of STC
Technologies,  Inc. ("STC") with and into OraSure  Technologies,  Inc.  ("Merger
Sub") pursuant to the Agreement and Plan of Merger dated as of May 6, 2000 among
Epitope,  Inc.  ("Epitope"),  Merger Sub, (hereinafter referred to as "Surviving
Corporation") and STC (the "Agreement").  Recognizing that you will rely on this
letter and the  representations  herein in rendering your tax opinion, we hereby
make and certify the following representations:

               1.  The facts  concerning  the Sam Merger  described in the Proxy
                   Statement  included as part of the Registration  Statement on
                   Form S-4 are  true,  correct  and  complete  in all  material
                   respects as of the date hereof.

               2.  The Sam Merger will be  consummated  in  compliance  with the
                   terms of the  Agreement  and will be a  statutory  merger  in
                   accordance with the applicable laws of the State of Delaware.

               3.  None of the terms and  conditions of the Agreement  have been
                   waived or modified, and STC has no plan or intention to waive
                   or modify any such term or condition.

               4.  A valid business purpose exists for the Sam Merger.

               5.  The fair market  value of the  Surviving  Corporation  Common
                   Stock, par value $0.000001 per share ("Surviving  Corporation
                   Common Stock"), and other consideration  received by each STC
                   shareholder  will be  approximately  equal to the fair market
                   value of the STC Common Stock,  par value $0.000001 per share
                   ("STC Common

<PAGE>

                   Stock"), surrendered in the exchange.

               6.  The  liabilities of STC assumed by Surviving  Corporation and
                   the  liabilities to which the  transferred  assets of STC are
                   subject were  incurred by STC in the  ordinary  course of its
                   business.

               7.  Surviving  Corporation,  STC and the shareholders of STC will
                   pay their respective expenses, if any, incurred in connection
                   with the Sam Merger.

               8.  There  is no  intercorporate  indebtedness  existing  between
                   Surviving  Corporation and STC that was issued,  acquired, or
                   will be settled at a discount.

               9.  STC  is not an  investment  company  as  defined  in  section
                   368(a)(2)(F) of the Internal Revenue Code.

               10. STC is not under the jurisdiction of a court in a Title 11 or
                   similar  case within the meaning of section  368(a)(3)(A)  of
                   the Internal Revenue Code.

               11. The fair market value of the assets of STC to be  transferred
                   to Surviving  Corporation will equal or exceed the sum of the
                   liabilities assumed by Surviving Corporation, plus the amount
                   of liabilities,  if any, to which the transferred  assets are
                   subject.

               12. None    of    the     compensation     received     by    any
                   shareholder-employees  of STC will be separate  consideration
                   for, or allocable to, any of their shares of STC Common Stock
                   surrendered  in the exchange,  and the  compensation  paid to
                   such  shareholder-employees  will  be for  services  actually
                   rendered and will be commensurate  with amounts paid to third
                   parties bargaining at arms-length for similar services.  None
                   of the Surviving Corporation Common Stock received in the Sam
                   Merger by any  shareholder-employees  of STC will be separate
                   consideration  for, or allocable to, any compensation owed to
                   such employee.

               13. The payment of cash in lieu of fractional shares of Surviving
                   Corporation  Common  Stock  is  solely  for  the  purpose  of
                   avoiding   the  expense  and   inconvenience   to   Surviving
                   Corporation  of  issuing   fractional  shares  and  does  not
                   represent separately bargained-for  consideration.  The total
                   cash consideration that will be paid in the Sam Merger to the
                   shareholders of STC instead of issuing  fractional  shares of
                   Surviving  Corporation  Common  Stock  will  not  exceed  one
                   percent of the total consideration that will be issued in the
                   Sam Merger to the  shareholders  of STC in exchange for their
                   shares of STC Common Stock. The fractional share interests of
                   each   shareholder  of


                                       2
<PAGE>

                   STC  will  be  aggregated,  and no  shareholder  of STC  will
                   receive cash for  fractional  shares in an amount equal to or
                   greater  than  the  value  of one  full  share  of  Surviving
                   Corporation Common Stock.

               14. No dividends or  distributions,  other than regular or normal
                   dividends  or  distributions,  have been made or will be made
                   with  respect  to  any  STC  Common  Stock  prior  to  and in
                   connection with the Sam Merger.

               15. STC has no redeemed  and has no plan or  intention  to redeem
                   any STC Common Stock prior to and in connection  with the Sam
                   Merger.

               16. A person  related  to STC  within  the  meaning  of  Treasury
                   Regulation  ss.1.368-1(e)(3) has not acquired and has no plan
                   or  intention to acquire any STC Common Stock prior to and in
                   connection with the Sam Merger.

To the best of his  knowledge and belief,  the  undersigned  certifies  that the
above  representations  are correct and that the factual  statements  upon which
they are based are true, correct and complete.

                                                   Very truly yours,

                                                   STC TECHNOLOGIES, INC.

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

                                       3
<PAGE>
                                                                       EXHIBIT K

                 FORM OF STC TECHNOLOGIES, INC. AFFILIATE LETTER


Ladies and Gentlemen:

               I have been  advised  that as of the date of this letter I may be
deemed to be an "Affiliate" of STC  Technologies,  Inc., a Delaware  corporation
("STC" or the "Company"), as the term "Affiliate" is (i) defined for purposes of
paragraphs (c) and (d) of Rule 145 of the rules and regulations  (the "Rules and
Regulations")  of the Securities  and Exchange  Commission  ("the  "Commission")
under the  Securities  Act of 1933, as amended (the "Act"),  and/or (ii) used in
and for purposes of Accounting  Series Releases 130 and 135, as amended,  of the
Commission.  Pursuant to the terms of the  Agreement and Plan of Merger dated as
of May  ---,  2000,  as it  may be  amended  from  time  to  time  (the  "Merger
Agreement"),  among STC, Epitope, Inc., an Oregon corporation  ("Epitope"),  and
Edward  Merger  Subsidiary,  Inc.,  a  Delaware  corporation  ("Merger  Sub"  or
following the Mergers (as defined below) the "Surviving Corporation").  STC will
be merged with and into Merger Sub ("STC  Merger")  and  immediately  thereafter
Epitope  will be merged with and into  Merger Sub  ("Epitope  Merger")  (the STC
Merger  and the  Epitope  Merger  are  referred  to  collectively  herein as the
"Mergers").

               As a result of the  Mergers,  the  shares of Common  Stock of STC
("STC Common Stock") which I own would be converted into shares of common stock,
par  value  $0.000001  per  share,  of  the  Surviving  Corporation  ("Surviving
Corporation Common Stock").

               I represent,  warrant and covenant to Epitope and Merger Sub that
in the event I receive any Surviving Corporation Common Stock as a result of the
Mergers:

               A.     I will not make any sale, transfer or other disposition of
the Surviving  Corporation Common Stock in violation of the Act or the Rules and
Regulations.

               B.     I have carefully read this letter and the Merger Agreement
and  discussed  the   requirements  of  such  documents  and  other   applicable
limitations upon my ability to sell,  transfer or otherwise dispose of Surviving
Corporation  Common Stock,  to the extent I felt  necessary,  with my counsel or
counsel for STC.

               C.     I  have  been  advised  that  the  issuance  of  Surviving
Corporation  Common  Stock to me  pursuant  to the  Mergers  has been or will be
registered with the Commission under the Act on a Registration Statement on Form
S-4.  However,  I have also been advised  that,  because I may be deemed to have
been an Affiliate of STC at the time the Mergers  were  submitted  for a vote of
the  stockholders of STC, I may not sell,  transfer or otherwise  dispose of the
Surviving  Corporation  Common Stock issued to me in the Mergers unless (i) such
sale, transfer or other disposition has been registered under the Act, (ii) such
sale,  transfer or other  disposition is made in conformity  with the volume and
other  limitations of Rule 145  promulgated by the Commission  under the Act, or
(iii)  in  the  opinion  of  counsel  reasonably  acceptable  to  the  Surviving
Corporation,  such sale,  transfer or other disposition is otherwise exempt from
registration under the Act.

               D.     I agree that during the Pooling  Period (as defined below)
I will not sell, transfer, or otherwise dispose of my interests in, or reduce my
risk relative to, any of the


<PAGE>

(i) shares of STC Common Stock or shares of Surviving  Corporation  Common Stock
over  which I have or  share  voting  or  dispositive  power  or  other  form of
Beneficial Ownership (as defined in Rule 13d-3 under the Securities Exchange Act
of 1934,  as amended (the  "Exchange  Act") with  respect  thereto or (ii) other
securities  which are  converted  upon  consummation  of the Mergers or upon the
exercise of any options or other rights to acquire STC Common Stock or Surviving
Corporation  Common  Stock  which  I  Beneficially  Own.  For  purposes  of this
Affiliate Letter,  "Pooling Period" shall mean the period commencing thirty (30)
days prior to the  Effective  Time and ending on the date which is one  business
day after publication by the Surviving  Corporation of its results of operations
following the Mergers for the period which includes at least thirty (30) days of
combined operations of Epitope and STC following the Mergers whether by issuance
of a quarterly  earnings report on Form 10-Q or other public issuance (such as a
press release) that includes such  information.  Epitope and Merger Sub agree to
make such filing or announcement as soon as reasonably  practical  following the
Effective  Time of the Merger.  I understand  that  reducing my risk relative to
such STC Common Stock or Surviving Corporation Common Stock includes, but is not
limited to, using such shares to secure a loan,  purchasing a put option to sell
such shares or otherwise entering a put agreement with respect to such shares.

               E.     Except as set forth in the Stockholders' Agreement,  dated
March 30, 1999, among the Company and certain stockholders thereto, I understand
that the  Surviving  Corporation  is under no  obligation  to register the sale,
transfer or other disposition of the Surviving Corporation Common Stock by me or
on my behalf  under the Act or to take any other  action  necessary  in order to
make compliance with an exemption from such registration available.

               F.     I also understand that stop transfer  instructions will be
given  to the  Surviving  Corporation's  transfer  agents  with  respect  to the
Surviving  Corporation  Common  Stock  and  that  there  will be  placed  on the
certificates  for the  Surviving  Corporation  Common Stock issued to me, or any
substitutions therefor, a legend stating in substance:

               "THE  SHARES  EVIDENCED  BY THIS  CERTIFICATE  WERE  ISSUED  IN A
               TRANSACTION  TO WHICH RULE 145  PROMULGATED  UNDER THE SECURITIES
               ACT OF 1933 APPLIES. THE SHARES EVIDENCED BY THIS CERTIFICATE MAY
               ONLY BE TRANSFERRED IN ACCORDANCE  WITH THE TERMS OF AN AGREEMENT
               DATED  -------------------,  2000 BETWEEN THE  REGISTERED  HOLDER
               HEREOF AND ---------------,  A COPY OF WHICH AGREEMENT IS ON FILE
               AT THE PRINCIPAL OFFICES OF THE ISSUER."

               G.     I also  understand  that  unless the  transfer by me of my
Surviving  Corporation  Common Stock has been  registered  under the Act or is a
sale  made in  conformity  with  the  provisions  of  Rule  145,  the  Surviving
Corporation  reserves  the right to place the same legend set forth in paragraph
F. above on the certificates issued to my transferee.

               The undersigned understands and agrees that the legends set forth
in  paragraphs  F and G  above  shall  be  removed  by  delivery  of  substitute
certificates  without such legend if the undersigned shall have delivered to the
Surviving Corporation a copy of a letter from the staff of

                                      -2-
<PAGE>

the  Commission,  or an  opinion of  counsel  in form and  substance  reasonably
satisfactory to the Surviving Corporation, to the effect that such legend is not
required for purposes of the Act.

               H.     The shares of STC Common  Stock which I  Beneficially  Own
are free  and  clear of all  Encumbrances  (as  defined  below;  other  than any
Encumbrance created by this Agreement). The term "Encumbrance" means any pledge,
security interest, lien, claim, encumbrance,  mortgage,  charge,  hypothecation,
option, right of first refusal or offer, community property right, other marital
right,  preemptive  right,  voting  agreement,  voting  trust,  proxy,  power of
attorney,  escrow,  option,  forfeiture,  penalty,  action at law or in  equity,
security  agreement,  stockholder  agreement  or other  agreement,  arrangement,
contract,  commitment,  understanding or obligation,  or any other  restriction,
qualification  or  limitation  on the use,  transfer,  right  to vote,  right to
dissent,  and  seek  appraisal,  receipt  of  income  or other  exercise  of any
attribute of ownership.

               Execution of this letter should not be considered an admission on
my part that I am an "Affiliate"  of STC as described in the first  paragraph of
this letter, or as a waiver of any rights I may have to object to any claim that
I am such an Affiliate on or after the date of this letter.

               By Epitope's  acceptance  of this letter,  Epitope and Merger Sub
hereby agree with me as follows:

                      (i) For so long as and to the extent  necessary  to permit
me to sell the Surviving  Corporation  Common Stock pursuant to Rule 145 and, to
the extent applicable,  Rule 144 under the Act, the Surviving  Corporation shall
(A) use its reasonable  efforts to (1) file, on a timely basis,  all reports and
data  required to be filed with the  Commission  by it pursuant to Section 13 of
the  Exchange  Act,  and (2)  furnish  to me upon  reasonable  request a written
statement  as to  whether  the  Surviving  Corporation  has  complied  with such
reporting requirements during the twelve (12) months preceding any proposed sale
of the  Surviving  Corporation  Common  Stock  by me  under  Rule  145,  and (B)
otherwise use its  reasonable  efforts to permit such sales pursuant to Rule 145
and Rule 144.  Epitope  hereby  represents  to me that it has filed all  reports
required to be filed with the Commission under Section 13 of the 1934 Act during
the preceding twelve (12) months.

                      (ii) It is understood  and agreed that  certificates  with
the  legends  set  forth in  paragraphs  F and G above  will be  substituted  by
delivery of certificates without such legends if (A) one year shall have elapsed
from the date the undersigned  acquired the Surviving  Corporation  Common Stock
received in the Mergers and the  provisions of Rule 145(d)(2) are then available
to the  undersigned,  (B) two  years  shall  have  elapsed  from  the  date  the
undersigned  acquired the  Surviving  Corporation  Common Stock  received in the
Mergers  and the  provisions  of  Rule  145(d)(3)  are  then  applicable  to the
undersigned,  or (C) the Surviving Corporation has received either an opinion of
counsel,  which  opinion and counsel  shall be  reasonably  satisfactory  to the
Surviving Corporation,  or a "no-action" letter obtained by the undersigned from
the staff of the Commission, to the effect that the restrictions imposed by Rule
145 under the Act no longer apply to the undersigned.


                                      -3-
<PAGE>

               Notwithstanding  the foregoing  provisions of this letter, if the
undersigned is a corporation, limited partnership or another form of entity, the
shares  of  Surviving  Corporation  Common  Stock may be  distributed  after the
expiration of the Pooling Period to stockholders,  partners or other owners,  as
the case may be, thereof (collectively,  the "Distributees"),  provided that (i)
such shares shall remain subject to any applicable requirements of Rule 145, and
(ii)  the  Surviving   Corporation  reserves  the  right  to  place  the  legend
contemplated  by  paragraph G of this letter on the  certificates  issued to the
Distributees.

                                            Very truly yours,


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

                                            Name: ------------------------------


Accepted this ---- day of
- ----------------, 2000 by

EPITOPE, INC.


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


EDWARD MERGER SUBSIDIARY, INC.


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


                                      -4-
<PAGE>
                                                                       EXHIBIT L

                     FORM OF EPITOPE, INC. AFFILIATE LETTER


Ladies and Gentlemen:

               I have been  advised  that as of the date of this letter I may be
deemed to be an "Affiliate" of Epitope,  Inc., an Oregon corporation  ("Epitope"
or the  "Company"),  as the  term  "Affiliate"  is used in and for  purposes  of
Accounting  Series  Releases  130 and 135, as  amended,  of the  Securities  and
Exchange Commission  ("Commission").  Pursuant to the terms of the Agreement and
Plan of Merger dated as of May --, 2000,  as it may be amended from time to time
(the "Merger Agreement"),  among STC Technologies,  Inc., a Delaware corporation
("STC"),  Epitope and Edward  Merger  Subsidiary,  Inc., a Delaware  corporation
("Merger  Sub" or  following  the  Mergers  (as  defined  below) the  "Surviving
Corporation").  STC will be merged with and into Merger Sub ("STC  Merger")  and
immediately thereafter Epitope will be merged with and into Merger Sub ("Epitope
Merger")  (the STC Merger and the Epitope  Merger are  referred to  collectively
herein as the "Mergers").

               As a result of the Mergers, the shares of Common Stock of Epitope
("Epitope  Common  Stock") which I own would be converted  into shares of common
stock, par value $0.000001 per share, of the Surviving  Corporation  ("Surviving
Corporation Common Stock").

               I represent,  warrant and covenant to Epitope and Merger Sub that
in the event I receive any Surviving Corporation Common Stock as a result of the
Mergers:

               A.     I agree that during the Pooling  Period (as defined below)
I will not sell, transfer, or otherwise dispose of my interests in, or reduce my
risk  relative  to, any of the (i) shares of Epitope  Common  Stock or shares of
Surviving  Corporation  Common  Stock  over  which I have  or  share  voting  or
dispositive  power or other form of  Beneficial  Ownership  (as  defined in Rule
13d-3 under the Securities Exchange Act of 1934, as amended (the "Exchange Act")
with  respect  thereto  or  (ii)  other  securities  which  are  converted  upon
consummation  of the Mergers or upon the exercise of any options or other rights
to acquire  Epitope Common Stock or Surviving  Corporation  Common Stock which I
Beneficially Own. For purposes of this Affiliate Letter,  "Pooling Period" shall
mean the period  commencing  thirty  (30) days prior to the  Effective  Time and
ending on the date which is one business day after  publication by the Surviving
Corporation  of its results of  operations  following the Mergers for the period
which  includes at least thirty (30) days of combined  operations of Epitope and
STC following the Mergers whether by issuance of a quarterly  earnings report on
Form 10-Q or other public  issuance (such as a press release) that includes such
information. Epitope and Merger Sub agree to make such filing or announcement as
soon as  reasonably  practical  following the  Effective  Time of the Merger.  I
understand  that  reducing my risk  relative  to such  Epitope  Common  Stock or
Surviving  Corporation Common Stock includes,  but is not limited to, using such
shares  to  secure a loan,  purchasing  a put  option  to sell  such  shares  or
otherwise entering a put agreement with respect to such shares.

               B.     I also understand that stop transfer  instructions will be
given  to the  Surviving  Corporation's  transfer  agents  with  respect  to the
Surviving Corporation Common


<PAGE>

Stock  and that  there  will be  placed on the  certificates  for the  Surviving
Corporation Common Stock issued to me, or any substitutions  therefor,  a legend
stating in substance:

               "THE SHARES EVIDENCED BY THIS CERTIFICATE MAY ONLY BE TRANSFERRED
               IN   ACCORDANCE   WITH   THE   TERMS   OF  AN   AGREEMENT   DATED
               -------------------,  2000 BETWEEN THE  REGISTERED  HOLDER HEREOF
               AND ---------------,  A COPY OF WHICH AGREEMENT IS ON FILE AT THE
               PRINCIPAL OFFICES OF THE ISSUER."

               C.     The undersigned understands and agrees that the legend set
forth  in  paragraph  B  above  shall  be  removed  by  delivery  of  substitute
certificates without such legend following the expiration of the Pooling Period

               D.     The shares of Epitope  Common  Stock which I  Beneficially
Own are free and clear of all  Encumbrances  (as defined  below;  other than any
Encumbrance created by this Agreement). The term "Encumbrance" means any pledge,
security interest, lien, claim, encumbrance,  mortgage,  charge,  hypothecation,
option, right of first refusal or offer, community property right, other marital
right,  preemptive  right,  voting  agreement,  voting  trust,  proxy,  power of
attorney,  escrow,  option,  forfeiture,  penalty,  action at law or in  equity,
security  agreement,  stockholder  agreement  or other  agreement,  arrangement,
contract,  commitment,  understanding or obligation,  or any other  restriction,
qualification  or  limitation  on the use,  transfer,  right  to vote,  right to
dissent,  and  seek  appraisal,  receipt  of  income  or other  exercise  of any
attribute of ownership.

               Execution of this letter should not be considered an admission on
my part that I am an "Affiliate" of Epitope as described in the first  paragraph
of this  letter,  or as a waiver of any rights I may have to object to any claim
that I am such an Affiliate on or after the date of this letter.

                                            Very truly yours,

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

                                            Name: ------------------------------

                                      -2-
<PAGE>

Accepted this ---- day of
- ----------------, 2000 by


EPITOPE, INC.


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


EDWARD MERGER SUBSIDIARY, INC.


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

                                      -3-
<PAGE>
                                                                       EXHIBIT M


                            INDEMNIFICATION AGREEMENT

        THIS AGREEMENT is made this ---- day of ---------, 2000, between OraSure
Technologies,    Inc.,   a   Delaware    corporation   (the   "Company"),    and
- ------------------------- ("Indemnitee").

        WHEREAS,  it is  important  to the  Company  to  attract  and  retain as
directors and officers the most capable persons available; and

        WHEREAS,  the  Bylaws of the  Company  (the  "Bylaws")  provide  for the
indemnification of the directors,  officers, employees and agents of the Company
as  authorized  by  Delaware  General  Corporation  Law  Section 145 (the "State
Statute"); and

        WHEREAS,  such Bylaws and the State  Statute  specifically  provide that
they are not exclusive,  and thereby  contemplate  that contracts may be entered
into  between  the  Company  and its  directors  and  officers  with  respect to
indemnification of such directors and officers; and

        WHEREAS,  in  accordance  with the  authorization  provided by the State
Statute  and the  Bylaws,  the  Company  may  purchase a policy or  policies  of
Directors and Officers Liability  Insurance ("D&O Insurance"),  covering certain
liabilities  which  may  be  incurred  by  its  directors  and  officers  in the
performance of their services for the Company; and

        WHEREAS,  recent developments with respect to the terms and availability
of D&O Insurance and with respect to the application,  amendment and enforcement
of  statutory  and  bylaw  indemnification   provisions  generally  have  raised
questions  concerning the adequacy and reliability of the protection afforded to
directors and officers thereby; and

        WHEREAS,   in  order  to  resolve  such  questions  and  thereby  induce
Indemnitee to agree to serve or continue to serve as a director  and/or  officer
of the  Company,  the  Company  has  determined  and  agreed to enter  into this
contract with Indemnitee;

        NOW,  THEREFORE,  in  consideration  of the premises and of Indemnitee's
agreeing to serve or  continuing  to serve as a director  and/or  officer of the
Company, the parties hereto agree as follows:

        1.     Indemnity.  The  Company  hereby  agrees  to  hold  harmless  and
indemnify Indemnitee to the full extent permitted by law:

               (a) Against any and all  expenses  (including  attorneys'  fees),
        judgments,  fines,  penalties and amounts paid in settlement (including,
        without limitation, all interest,  assessments and other charges paid or
        payable in connection  therewith)  actually and  reasonably  incurred by
        Indemnitee  in  connection  with any  threatened,  pending or  completed
        action,  suit or proceeding,  whether  brought by or in the right of the
        Company or otherwise  and whether  civil,  criminal,  administrative  or
        investigative,  to which  Indemnitee  is,  was or at any time  becomes a
        party,  or is threatened to be made a party,  by reason of the fact that
        Indemnitee is, was or at any time becomes a director, officer, employee,
        agent or fiduciary  of the Company,  or is or was serving at the request
        of the Company as a director,  officer,  employee, agent or fiduciary of
        another corporation,

<PAGE>

        partnership, joint venture, employee benefit plan, trust or other entity
        or  enterprise,  or by reason of anything done or not done by Indemnitee
        in any such capacity, whether prior to or subsequent to the date of this
        Agreement; and

               (b)  Against any and all  expenses  (including  attorneys'  fees)
        actually and  reasonably  incurred by Indemnitee in serving or preparing
        to serve as a witness or other participant in any threatened, pending or
        completed action, suit or proceeding, whether brought by or in the right
        of the Company or otherwise and whether civil, criminal,  administrative
        or  investigative,  if  Indemnitee is such a witness or  participant  by
        reason  of the fact that  Indemnitee  is,  was or at any time  becomes a
        director,  officer, employee, agent or fiduciary of the Company or is or
        was  serving at the  request  of the  Company  as a  director,  officer,
        employee, agent or fiduciary of another corporation,  partnership, joint
        venture, employee benefit plan, trust or other entity or enterprise.

        2.     Specific  Limitations  on  Indemnity.  Indemnitee  shall  not  be
entitled to indemnification under this Agreement:

               (a)    In respect to remuneration  paid to or advantage gained by
        Indemnitee if it shall be determined by a final  judgment or other final
        adjudication   that   Indemnitee  was  not  legally   entitled  to  such
        remuneration or advantage;

               (b)    On account of Indemnitee's  conduct which is determined by
        a final  judgment or other  final  adjudication  to have been  knowingly
        fraudulent, deliberately dishonest or willful misconduct;

               (c)    Prior to a Change in Control (as defined in Section 4(e)),
        in respect of any action,  suit or  proceeding  initiated by  Indemnitee
        against  the Company or any  director or officer of the Company  (unless
        the Company has joined in or consented to the initiation of such action,
        suit or  proceeding),  except (i) as set forth in Section  12(b) hereof,
        (ii) in respect of any counterclaims made against Indemnitee in any such
        action,  suit or proceeding,  and (iii) to the extent  Indemnitee  seeks
        contribution  or  apportionment  of  an  award  or  settlement   against
        Indemnitee  and against the Company and/or any other director or officer
        of the Company;

               (d)    On account of any matter determined by a final judgment or
        other  final  adjudication  to  be a  violation  by  Indemnitee  of  the
        provisions  of Section 16 of the  Securities  Exchange  Act of 1934,  as
        amended  (the  "Act"),   or  the  rules  and   regulations   promulgated
        thereunder, as amended from time to time; or

               (e)    With respect to any matter if it shall be  determined by a
        final judgment or other final adjudication that such  indemnification is
        not lawful.

        3.     Advance of  Expenses  and  Payment of  Indemnification.  Upon the
written  request of  Indemnitee,  expenses  that are subject to  indemnification
under this  Agreement  shall be advanced by the Company within five (5) business
days of receipt of such request. Subject to Section 4(a),  indemnification shall
be made under this  Agreement no later than sixty (60) days after receipt by the
Company of the  written  request of  Indemnitee,  which  written  request  shall
identify the judgments, fines, penalties and amounts paid in settlement that are
subject to

                                       2
<PAGE>

indemnification under this Agreement and for which indemnification is requested.
Written request shall be deemed received three days after the date postmarked if
sent by prepaid mail properly  addressed to the Company at the address set forth
in Section 11 hereof.

        4.     Determination of Indemnification.

        (a)    Notwithstanding  any other  provision of this  Agreement  (i) the
obligations  of the Company  under  Section 1 shall be subject to the  condition
that the Reviewing  Party (as defined in Section 4(f)) shall have determined (in
a  written  opinion,  in any case in which the  Independent  Legal  Counsel  (as
defined in Section 4(g)) is involved) that  Indemnitee  would be permitted to be
indemnified under this Agreement,  (ii) the obligation of the Company to make an
expense  advance  pursuant to Section 3 shall be subject to the condition  that,
if, when and to the extent that it is finally  determined that Indemnitee  would
not be permitted to be indemnified for such expenses under this  Agreement,  the
Company shall be entitled to be reimbursed by Indemnitee  (who hereby agrees and
undertakes to reimburse the Company) for all such amounts  theretofore paid, and
(iii) the  obligation  of the  Company to make an expense  advance  pursuant  to
Section 3 shall be made  without  regard to  Indemnitee's  ability  to repay the
amount  advanced and without  regard to  Indemnitee's  ultimate  entitlement  to
indemnification  under this Agreement or otherwise.  Indemnitee's  obligation to
reimburse  the Company for expense  advances  shall be unsecured and no interest
shall be charged thereon.

        (b)    The Reviewing  Party shall be selected by the Board of Directors,
provided,  however,  that if there has been a Change in  Control  (other  than a
Change in Control which has been  approved by a majority of the Company's  Board
of Directors who were directors immediately prior to such Change in Control) the
Reviewing  Party shall be the  Independent  Legal Counsel.  If there has been no
determination  by the Reviewing  Party within the sixty (60) day period referred
to  in  Section  3,  the  Reviewing  Party  shall  be  deemed  to  have  made  a
determination  that  it  is  permissible  to  indemnify  Indemnitee  under  this
Agreement.

        (c)    The  Company  agrees  that if there is a Change in Control of the
Company (other than a Change in Control which has been approved by a majority of
the Company's  Board of Directors who were directors  immediately  prior to such
Change  in  Control)  then  Independent  Legal  Counsel  shall  be  selected  by
Indemnitee and approved by the Company (which approval shall not unreasonably be
withheld)  and such  Independent  Legal  Counsel  shall  determine  whether  the
director or officer is  entitled to  indemnification  for  expenses,  judgments,
fines, penalties and amounts paid in settlement (including,  without limitation,
all  interest,  assessments  and other  charges  paid or payable  in  connection
therewith)  under this  Agreement or any other  agreement or the  Certificate of
Incorporation  or Bylaws of the Company now or hereafter  in effect  relating to
indemnification. Such Independent Legal Counsel shall render its written opinion
to the Company and Indemnitee as to whether and to what extent  Indemnitee  will
be permitted to be indemnified  for expenses,  judgments,  fines,  penalties and
amounts  paid  in  settlement  (including,  without  limitation,  all  interest,
assessments  and other  charges paid or payable in  connection  therewith).  The
Company agrees to pay the reasonable fees of the  Independent  Legal Counsel and
to indemnify fully such  Independent  Legal Counsel against any and all expenses
(including  attorneys' fees), claims,  liabilities and damages arising out of or
relating to this  Agreement  or the  engagement  of  Independent  Legal  Counsel
pursuant hereto.

                                       3
<PAGE>

        (d)    If a  determination  denying  Indemnitee's  claim  is  made  by a
Reviewing  Party  (other  than  Independent  Legal  Counsel),   notice  of  such
determination   shall   disclose  with   particularity   the  reasons  for  such
determination.  If  a  determination  denying  Indemnitee's  claim  is  made  by
Independent Legal Counsel,  the notice shall include a copy of the related legal
opinion of such counsel.

        (e)    "Change in Control"  shall be deemed to have  occurred if (i) any
"person"  (as such term is used in Sections  13(d) and 14(d) of the Act),  other
than a trustee or other fiduciary  holding  securities under an employee benefit
plan of the  Company  or a  corporation  owned  directly  or  indirectly  by the
stockholders  of the  Company in  substantially  the same  proportions  as their
ownership  of stock of the  Company,  is or becomes the  "beneficial  owner" (as
defined in Rule 13d-3 under the Act),  directly or indirectly,  of securities of
the Company  representing  15% or more of the total voting power  represented by
the Company's then outstanding  Voting  Securities (as defined in Section 4(h)),
or (ii)  during  any period of two  consecutive  years,  individuals  who at the
beginning  of such period  constitute  the Board of Directors of the Company and
any new director  whose  election by the Board of Directors  or  nomination  for
election  by the  Company's  stockholders  was  approved  by a vote of at  least
two-thirds (2/3) of the directors then still in office who either were directors
at the beginning of the period or whose  election or nomination for election was
previously so approved,  cease for any reason to constitute a majority  thereof,
or (iii) the  stockholders of the Company approve a merger or  consolidation  of
the Company  with any other  corporation,  other than a merger or  consolidation
which  would  result  in  the  Voting  Securities  of  the  Company  outstanding
immediately   prior  thereto   continuing  to  represent  (either  by  remaining
outstanding  or by being  converted  into  Voting  Securities  of the  surviving
entity)  at least  85% of the  total  voting  power  represented  by the  Voting
Securities of the Company or such surviving entity outstanding immediately after
such merger or consolidation,  or the stockholders of the Company approve a plan
of  complete  liquidation  of the  Company  or an  agreement  for  the  sale  or
disposition by the Company (in one transaction or a series of  transactions)  of
all or substantially all of the assets of the Company.

        (f)    "Reviewing  Party"  shall  mean any  appropriate  person  or body
consisting  of a member or members of the Board of  Directors  of the Company or
any  other  person  or body  appointed  by the  Board  who is not a party to the
particular  action,  suit or  proceeding  with  respect to which  Indemnitee  is
seeking indemnification, or Independent Legal Counsel.

        (g)    "Independent  Legal Counsel" shall mean an attorney,  selected in
accordance  with the  provisions of Section 4(c),  who shall not have  otherwise
performed  services  for the  Company or  Indemnitee  within the last five years
(other than in connection with seeking  indemnification  under this  Agreement).
Independent  Legal  Counsel  shall not be any person who,  under the  applicable
standards  of  professional  conduct then  prevailing,  would have a conflict of
interest  in  representing  either  the  Company or  Indemnitee  in an action to
determine Indemnitee's rights under this Agreement,  nor shall Independent Legal
Counsel be any person who has been sanctioned or censured for ethical violations
of applicable standards of professional conduct.

        (h)    "Voting  Securities"  shall mean any  securities  of the  Company
which vote generally in the election of directors.

                                       4
<PAGE>

        5.     Partial Indemnity.  If Indemnitee is entitled under any provision
of this Agreement to indemnification by the Company for some or a portion of the
expenses, judgments, fines, penalties and amounts paid in settlement (including,
without limitation, all interest,  assessments and other charges paid or payable
in connection  therewith)  incurred by Indemnitee,  but not for the total amount
thereof, the Company shall indemnify Indemnitee for the portion thereof to which
Indemnitee is entitled.  Notwithstanding  any other provision of this Agreement,
to the extent that  Indemnitee  has been  successful  on merits or  otherwise in
defense of any or all actions, suits or proceedings relating in whole or in part
to an event subject to  indemnification  hereunder or in defense of any issue or
matter therein,  including  dismissal  without  prejudice,  Indemnitee  shall be
indemnified  against  expenses  incurred in connection  with such action,  suit,
proceeding, issue or matter, as the case may be.

        6.     Non-exclusivity.  The rights of Indemnitee  under this  Agreement
shall  be in  addition  to any  other  rights  Indemnitee  may  have  under  the
Certificate of  Incorporation,  the Bylaws,  any other agreement of the Company,
the Delaware General  Corporation Law ("DGCL"),  D&O Insurance or otherwise.  To
the extent that any change in the DGCL (whether by statute or judicial decision)
permits greater  indemnification  by agreement than would be afforded  currently
under the  Certificate of  Incorporation  and the Bylaws of the Company and this
Agreement,  it is the intent of the parties hereto that Indemnitee shall by this
Agreement be entitled to the greater benefits so afforded by such change.

        7.     Liability  Insurance.  To the extent the  Company  maintains  D&O
Insurance,  the Company shall maintain coverage for Indemnitee under such policy
or policies, in accordance with its or their terms, to the maximum extent of the
coverage provided under such policy or policies in effect for any other director
or officer of the Company.

        8.     No Duplication of Payments. The Company shall not be liable under
this  Agreement  to make  any  payment  in  connection  with any  claim  against
Indemnitee to the extent  Indemnitee  has otherwise  actually  received  payment
(under any  insurance  policy,  Bylaw or  otherwise)  of the  amounts  otherwise
indemnifiable  hereunder  or to the extent  that  Indemnitee  is  entitled to be
indemnified  directly by any insurance  company under the individual  directors'
and  officers'  liability  provisions  of any D&O  Insurance  maintained  by the
Company.

        9.     No Presumption.  For purposes of this Agreement,  the termination
of any  claim,  actions,  suit or  proceeding  by  judgment,  order,  settlement
(whether with or without court  approval) or conviction,  or upon a plea of nolo
contendere,  or its  equivalent,  shall not of itself create a presumption  that
Indemnitee  did not  meet  any  particular  standard  of  conduct  or  have  any
particular  belief or that a court has determined  that  indemnification  is not
permitted by applicable law.

        10.    Continuation of Indemnity.  All agreements and obligations of the
Company  contained  herein  shall  continue  during the period  Indemnitee  is a
director, officer, employee, agent or fiduciary of the Company, or is serving at
the request of the Company as a director,  officer, employee, agent or fiduciary
of another  corporation,  partnership,  joint venture,  trust or other entity or
enterprise, and shall continue thereafter so long as Indemnitee shall be subject
to any  possible  claim or  threatened,  pending or  completed  action,  suit or
proceeding, whether civil,

                                       5
<PAGE>

criminal or investigative,  by reason of the fact that Indemnitee was a director
or officer of the Company or serving in any other capacity referred to herein.

        11.    Notification of Proceedings; Consent to Settlements; Defense.

        (a)    Promptly   after   receipt  by   Indemnitee   of  notice  of  the
commencement of any action, suit or proceeding,  Indemnitee shall, if a claim in
respect thereof is to be made against the Company under this  Agreement,  notify
the Company of the commencement thereof. Notice shall be in writing and shall be
addressed as follows:

                              OraSure Technologies, Inc.
                              8505 S.W. Creekside Place
                              Beaverton, OR 97008
                              Attention: President

        Such notice shall be deemed  received if sent by prepaid  mail  properly
addressed.  Indemnitee and the Company shall  cooperate fully with each other in
the defense of any such action,  suit or  proceeding  and each shall provide the
other with such  information  as the other may reasonably  require.  The Company
shall not be liable to indemnify Indemnitee under this Agreement for any amounts
paid in settlement of any action,  suit or proceeding effected without its prior
written consent (which consent shall not unreasonably be withheld).

        (b)    The Company shall be entitled to participate in the action,  suit
or proceeding at its own expense.

        (c)    Except as  otherwise  provided  below,  the  Company  may, at its
option, assume the defense of such action, suit or proceeding with legal counsel
reasonably  satisfactory  to  Indemnitee.  After  notice  from  the  Company  to
Indemnitee  of its  election  to  assume  the  defense  of an  action,  suit  or
proceeding,  the Company will not be liable to Indemnitee for expenses  incurred
by  Indemnitee  in connection  with such action,  suit or proceeding  under this
Agreement,  including Section 3 hereof, other than Indemnitee's reasonable costs
of investigation or participation in such action, suit or proceeding (including,
without  limitation,  travel expenses) and except as provided below.  Indemnitee
shall have the right to employ Indemnitee's own counsel in any such action, suit
or proceeding,  but the fees and expenses of such counsel  incurred after notice
from the  Company  of its  assumption  of the  defense of such  action,  suit or
proceeding  shall be at the expense of Indemnitee,  unless (i) the employment of
counsel by Indemnitee has been authorized by the Company,  (ii) Indemnitee shall
have reasonably  concluded that there may be a conflict of interest  between the
Company and  Indemnitee  in the conduct of the defense of such  action,  suit or
proceeding,  or (iii) the  Company  shall not in fact have  employed  counsel to
assume the defense of such action,  suit or  proceeding,  in each of which cases
the fees and expenses of  Indemnitee's  counsel shall be advanced by the Company
as provided in Section 3 hereof. The Company shall not be entitled to assume the
defense of any such action,  suit or  proceeding  brought by or on behalf of the
Company.

        (d)    If two or more persons,  including Indemnitee, may be entitled to
indemnification  from the Company as parties to any action,  suit or proceeding,
the Company may require  Indemnitee  to use the same legal  counsel as the other
parties.  Indemnitee  shall have the right to

                                       6
<PAGE>

use separate legal counsel in such action,  suit or proceeding,  but the Company
shall not be liable to  Indemnitee  under this  Agreement,  including  Section 3
hereof,  for the fees and  expenses of separate  legal  counsel  incurred  after
notice from the Company of the  requirement to use the same legal counsel as the
other  parties,  unless  Indemnitee  reasonably  concludes  that  there may be a
conflict of interest between Indemnitee and any of the other parties required by
the Company to be represented by the same legal counsel.

        (e)    Indemnitee shall permit the Company to settle any action, suit or
proceeding  that the Company  assumes  the  defense of,  except that the Company
shall not,  without  Indemnitee's  written consent,  settle any action,  suit or
proceeding  unless such settlement  includes a provision  whereby the parties to
the settlement unconditionally release Indemnitee from all liabilities, damages,
fines,  penalties,  costs and  expenses  in  respect  of claims by reason of the
settlement or release of the parties in such action, suit or proceeding.

        12.    Enforcement.

        (a)    The  Company  expressly  confirms  and agrees that it has entered
into this Agreement and assumed the obligations imposed on it hereby in order to
induce Indemnitee to agree to serve or to continue to serve as a director and/or
officer of the Company and  acknowledges  that  Indemnitee  is relying upon this
Agreement in agreeing to serve or continuing to serve in such capacity.

        (b)    The right to indemnification  provided by this Agreement shall be
enforceable  by Indemnitee in any court in the State of Delaware  having subject
matter jurisdiction thereof and in which venue is proper.  Indemnitee shall have
the right to commence litigation in any such court challenging any determination
by the  Reviewing  Party or any aspect  thereof,  or the legal or factual  bases
therefor.  The Company shall  reimburse  Indemnitee  for any and all  reasonable
expenses  (including  attorneys' fees) incurred by Indemnitee in connection with
any claim  asserted  or action  brought by  Indemnitee  to enforce  rights or to
collect moneys due under this Agreement, the Certificate of Incorporation or the
Bylaws of the Company or any other  agreement  with the Company nor or hereafter
in effect  relating  to  indemnification,  or any D&O  Insurance  purchased  and
maintained  by the  Company,  regardless  of whether  Indemnitee  ultimately  is
determined to be entitled to such  indemnification,  advance  expense payment or
insurance  coverage,  as the case may be, unless the court  determines  that the
claim or action is frivolous or that  assertions  made therein were made with no
reasonable basis.

        (c)    In connection  with any  determination  by the Reviewing Party or
otherwise as to whether Indemnitee is entitled to be indemnified hereunder,  the
burden of proof shall be on the Company to establish  that  Indemnitee is not so
entitled.

        13.    Separability.  Each  of the  provisions  of this  Agreement  is a
separate and distinct  agreement and  independent of the others,  so that if any
provision  hereof shall be held to be invalid or  unenforceable  for any reason,
such   invalidity  or   unenforceability   shall  not  affect  the  validity  or
enforceability of the other provisions hereof.

                                       7
<PAGE>

        14.    Governing Law; Binding Effect; Amendment and Termination.

        (a)    This Agreement  shall be  interpreted  and enforced in accordance
with the laws of the State of Delaware  without  giving effect to the principles
of conflicts of laws thereof.

        (b)    This  Agreement  shall be binding  upon  Indemnitee  and upon the
Company,  its  successors  and  assigns  (including  any  transferee  of  all or
substantially  all of the assets of the Company and any  successor  by merger or
operation  of law),  and shall  inure to the benefit of  Indemnitee,  his or her
heirs,  personal  representatives and assigns and to the benefit of the Company,
its successors and assigns. The Company shall require and cause any successor to
all or  substantially  all of its  assets,  by  written  agreement  in form  and
substance  satisfactory to Indemnitee,  expressly to assume and agree to perform
this  Agreement in the same manner and to the same extent that the Company would
be required to perform if no succession had taken place.

        (c)    No amendment,  modification,  termination or cancellation of this
Agreement shall be effective unless in writing signed by both parties hereto. No
waiver of any provision of this Agreement shall be deemed or shall  constitute a
waiver of any other  provision  hereof,  and no such waiver  shall  constitute a
continuing waiver.

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

        16.    Change in Other Rights.  The Company will not adopt any amendment
to the Certificate of Incorporation or Bylaws of the Company the effect of which
would be to deny,  diminish or encumber  Indemnitee's rights to indemnification,
advancement  of  expenses,  exculpation  or  maintenance  of the D & O Insurance
hereunder, under such other documents or under applicable law, as applied to any
act or failure to act occurring in whole or in part prior to the date upon which
any such  amendment was approved by the Board of Directors or the  stockholders,
as the case may be.  Notwithstanding  the  foregoing,  if the Company adopts any
amendment to the Certificate of  Incorporation  or Bylaws the effect of which is
to so deny,  diminish or encumber such rights, such amendment will apply only to
acts or failures to act occurring entirely after the effective date thereof.

        17.    Savings  Clause.  If this  Agreement or any  provision  hereof is
invalidated  on any ground by any court of competent  jurisdiction,  the Company
shall nevertheless  indemnify Indemnitee as to any expenses,  judgments,  fines,
penalties and amounts paid in  settlement  actually and  reasonably  incurred by
Indemnitee  in  connection  with any action,  suit or  proceeding to the fullest
extent permitted by any applicable provision of this Agreement that has not been
invalidated and to the fullest extent permitted by Delaware law.

        18.    Deposit of Funds in Trust.  In the event that the Company decides
to  voluntarily  dissolve  or to file a  voluntary  petition  for  relief  under
applicable bankruptcy,  moratorium or similar laws, then not later than ten (10)
days prior to such dissolution or filing, the Company shall deposit in trust for
the  exclusive  benefit  of  Indemnitee  a cash  amount  equal  to  all  amounts

                                       8
<PAGE>

previously  authorized  to be paid to Indemnitee  hereunder,  such amounts to be
used to discharge the Company's obligations to Indemnitee hereunder.  Any amount
in such trust not required for such purpose shall be returned to the Company.

        19.    Counterparts.  This  Agreement  may be  executed  in one or  more
counterparts,  all of which shall be considered  one and the same  agreement and
shall become  effective when one or more  counterparts  have been signed by each
party and delivered to the other.


        IN WITNESS  WHEREOF,  the parties hereto have executed this Agreement as
of the day and year first above written.

                                            ORASURE TECHNOLOGIES, INC.


                                            By: --------------------------------
                                                President

                                            -----------------------------------
                                            [NAME]


                                       9
<PAGE>


           LIST OF PARTIES WHO WILL EXECUTE INDEMNIFICATION AGREEMENTS


                 Name                                      Title
                 ----                                      -----




                                       10
<PAGE>
                                                                       EXHIBIT N




            LIST OF EMPLOYEES REQUIRED TO ENTER EMPLOYMENT AGREEMENTS



                    Name                            Title
                    ----                            -----

                Robert D. Thompson        Chief Executive Officer

               Michael J. Gausling        President and Chief Operating Officer

                   R. Sam Niedbala        Executive Vice President and Chief
                                          Scientific Officer

          J. Richard George, Ph.D.        Senior Vice President of Research and
                                          Development, Infectious Disease

                  William D. Block        Senior Vice President of Sales

                   William Hinchey        Senior Vice President of Marketing

            Philip Michael Formica        Vice President of Operations




<PAGE>
                                                                       EXHIBIT O


            [To be typed on letterhead of OraSure Technologies, Inc.]

                                    D R A F T

                                 [Closing Date]

Stinson, Mag & Fizzell, P.C.
1201 Walnut, Suite 2800
Kansas City, MO  64106

                      RE:    Tax Opinion in Connection with Mergers of  STC
                             Technologies, Inc. and Epitope, Inc. with and into
                             OraSure Technologies, Inc.


Ladies and Gentlemen:

               This letter is provided to you in connection with the tax opinion
you are rendering with respect to the proposed  merger (the "Sam Merger") of STC
Technologies,  Inc. ("STC") with and into OraSure  Technologies,  Inc.  ("Merger
Sub") and the proposed merger (the "Edward Merger") of Epitope, Inc. ("Epitope")
with and into Merger Sub pursuant to the  Agreement  and Plan of Merger dated as
of May 6, 2000 among Epitope,  Merger Sub (hereinafter referred to as "Surviving
Corporation") and STC (the "Agreement").  Recognizing that you will rely on this
letter and the  representations  herein in rendering your tax opinion, we hereby
make and certify the following representations:

               1.  The facts  concerning  the Sam Merger  and the Edward  Merger
                   described  in the  Proxy  Statement  included  as part of the
                   Registration  Statement  on Form S-4 are  true,  correct  and
                   complete in all material respects as of the date hereof.

               2.  The Sam Merger and the Edward Merger will be  consummated  in
                   compliance  with  the  terms  of the  Agreement  and  will be
                   statutory  mergers in accordance  with the applicable laws of
                   the State of Delaware and the State of Oregon.

               3.  None of the terms and  conditions of the Agreement  have been
                   waived or modified,  and  Surviving  Corporation  and Epitope
                   have no plan or intention to waive or modify any such term or
                   condition.

               4.  Valid business purposes exist for both the Sam Merger and the
                   Edward Merger.

               5.  The fair market  value of the  Surviving  Corporation  Common
                   Stock, par value $0.000001 per share ("Surviving  Corporation
                   Common Stock"), and other consideration  received by each STC
                   shareholder


<PAGE>

                   will be  approximately  equal to the fair market value of the
                   STC Common Stock,  par value $0.000001 per share ("STC Common
                   Stock"),  surrendered  in the  exchange,  and the fair market
                   value of the  Surviving  Corporation  Common  Stock and other
                   consideration  received by each Epitope  shareholder  will be
                   approximately  equal to the fair market  value of the Epitope
                   Common  Stock,  no  par  value  per  share  ("Epitope  Common
                   Stock"), surrendered in the exchange.

               6.  Neither  Surviving   Corporation  nor  a  person  related  to
                   Surviving   Corporation   within  the   meaning  of  Treasury
                   Regulation ss.  1.368-1(e)(3) has acquired or has any plan or
                   intention  to acquire  any STC Common  Stock  prior to and in
                   connection  with the Sam Merger or any Epitope  Common  Stock
                   prior to and in connection with the Edward Merger.

               7.  Surviving  Corporation  has no plan or intention to reacquire
                   any of its  stock  issued  in the Sam  Merger  or the  Edward
                   Merger.

               8.  A person related to Surviving  Corporation within the meaning
                   of  Treasury  Regulation  ss.  1.368-1(e)(3)  has no  plan or
                   intention to acquire any Surviving  Corporation  Common Stock
                   issued in the Sam Merger or the Edward Merger.

               9.  Surviving  Corporation  has no plan or  intention  to sell or
                   otherwise  dispose  of any of the  assets  of STC or  Epitope
                   acquired in the transaction,  except for dispositions made in
                   the  ordinary  course of business or  transfers  described in
                   section 368(a)(2)(C) of the Internal Revenue Code.

               10. The liabilities of Epitope  assumed by Surviving  Corporation
                   and the  liabilities  to  which  the  transferred  assets  of
                   Epitope are subject were  incurred by Epitope in the ordinary
                   course of its business.

               11. Following  the Sam Merger and the  Edward  Merger,  Surviving
                   Corporation will continue the historic  businesses of STC and
                   Epitope or use a  significant  portion  of STC and  Epitope's
                   historic business assets in a business.

               12. Surviving  Corporation,  STC, Epitope and the shareholders of
                   STC and Epitope will pay their respective  expenses,  if any,
                   incurred  in  connection  with the Sam  Merger and the Edward
                   Merger.

               13. There  is no  intercorporate  indebtedness  existing  between
                   Surviving   Corporation   and   STC  or   between   Surviving
                   Corporation and Epitope that was issued, acquired, or will be
                   settled at a discount.

                                       2
<PAGE>

               14. Neither  Surviving  Corporation  nor Epitope  are  investment
                   companies as defined in section  368(a)(2)(F) of the Internal
                   Revenue Code.

               15. Epitope is not under the  jurisdiction  of a court in a Title
                   11 or similar case within the meaning of section 368(a)(3)(A)
                   of the Internal Revenue Code.

               16. The fair market value of the assets of STC to be  transferred
                   to Surviving  Corporation will equal or exceed the sum of the
                   liabilities assumed by Surviving Corporation, plus the amount
                   of liabilities,  if any, to which the transferred  assets are
                   subject,  and the fair market  value of the assets of Epitope
                   to be  transferred  to  Surviving  Corporation  will equal or
                   exceed  the  sum  of the  liabilities  assumed  by  Surviving
                   Corporation, plus the amount of liabilities, if any, to which
                   the transferred assets are subject.

               17. None    of    the     compensation     received     by    any
                   shareholder-employees  of STC or  Epitope  will  be  separate
                   consideration  for, or  allocable  to, any of their shares of
                   STC Common Stock or Epitope  Common Stock  surrendered in the
                   exchanges,    and    the    compensation    paid    to   such
                   shareholder-employees  will be for services actually rendered
                   and will be  commensurate  with amounts paid to third parties
                   bargaining at arms-length for similar  services.  None of the
                   Surviving Corporation Common Stock received in the Sam Merger
                   or  Edward  Merger  by  any  shareholder-employees  of STC or
                   Epitope will be separate  consideration for, or allocable to,
                   any compensation owed to such employee.

               18. The payment of cash in lieu of fractional shares of Surviving
                   Corporation  Common Stock with respect to both the Sam Merger
                   and the Edward  Merger is solely for the  purpose of avoiding
                   the expense and  inconvenience  to Surviving  Corporation  of
                   issuing  fractional shares and does not represent  separately
                   bargained-for  consideration.  The total  cash  consideration
                   that will be paid in the Sam  Merger to the  shareholders  of
                   STC  instead  of  issuing   fractional  shares  of  Surviving
                   Corporation  Common  Stock will not exceed one percent of the
                   total  consideration that will be issued in the Sam Merger to
                   the  shareholders  of Sam in exchange for their shares of STC
                   Common Stock, and the total cash  consideration  that will be
                   paid in the  Edward  Merger to the  shareholders  of  Epitope
                   instead of issuing fractional shares of Surviving Corporation
                   Common  Stock  will  not  exceed  one  percent  of the  total
                   consideration that will be issued in the Edward Merger to the
                   shareholders  of  Epitope  in  exchange  for their  shares of
                   Epitope Common Stock.  The fractional share interests of each
                   shareholder  of STC and Epitope  will be  aggregated,  and no
                   shareholder   of  STC  or  Epitope   will  receive  cash  for
                   fractional  shares in an amount  equal to or

                                       3
<PAGE>

                   greater  than  the  value  of one  full  share  of  Surviving
                   Corporation Common Stock.

               19. After the Sam Merger and the Edward  Merger,  no dividends or
                   distributions  will be made to the former STC shareholders or
                   the former  Epitope  shareholders  by Surviving  Corporation,
                   other than regular or normal dividend distributions made with
                   regard to all shares of Surviving Corporation Common Stock.

To the best of his  knowledge and belief,  the  undersigned  certifies  that the
above  representations  are correct and that the factual  statements  upon which
they are based are true, correct and complete.

                                                   Very truly yours,

                                                   ORASURE TECHNOLOGIES, INC.


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


                                       4


[Logo] EPITOPE                           [Logo] STC Technologies Inc.




COMPANY CONTACTS:                           REPRESENTING EPITOPE:
Epitope, Inc.                               Lippert/Heilshorn & Associates
<TABLE>
<S>                                         <C>                          <C>                <C>
Charles E. Bergeron                         Bruce Voss                   310-575-4848       [email protected]
Chief Financial Officer                     Kim Sutton Golodetz          212-838-3777       [email protected]
503-641-6115                                Keith Lippert                212-838-3777       [email protected]
www.epitope.com                             MEDIA CONTACT:
                                            Pamela Rigler                212-838-3777       [email protected]
                                                                                            www.lhai.com
</TABLE>

                         STC Technologies, Inc.
Mike Gausling                      Rich Hooper
([email protected])            ([email protected])
Chief Executive Officer            Chief Financial Officer
610-882-1820                       610-882-1820
www.stctech.com



                      EPITOPE AND STC TECHNOLOGIES TO MERGE

               $200 MILLION ALL-STOCK DEAL CREATES ORAL FLUID AND
                    POINT-OF-CARE MEDICAL DIAGNOSTICS LEADER


BEAVERTON,  ORE. (MAY 8, 2000) - EPITOPE, INC. (NASDAQ NM: EPTO) today announced
that the Company has signed a definitive merger agreement with STC Technologies,
Inc., a privately-held company based in Bethlehem, Pennsylvania, under which the
two  companies  will  become  a  leader  in  the  fast-growing  oral  fluid  and
point-of-care medical diagnostics  industry.  The agreement has been approved by
the Board of  Directors  of each  company,  and is subject to typical  terms and
conditions,  including a vote of Epitope and STC  shareholders  expected to take
place in August  2000.  The  holders  of  approximately  52 percent of the STC's
shares have given irrevocable proxies to vote in favor of the merger.

STC  shareholders  will receive  Epitope  common stock in the merger.  The total
number of Epitope shares to be issued will be based on the average closing price
of Epitope common stock over a 20 trading-day  period prior to the completion of
the merger. At the current stock price, it is estimated that Epitope would issue
a total of 20 million shares to holders of STC's outstanding shares and options.

On a proforma  basis,  the new company  will have more than $20 million in cash,
trailing  12-month  revenues of $26.3 million,  a gross margin of 65%, and a net
loss of $4.1 million. Combining

                                     -more-
<PAGE>


operations  is  expected to result in at least $2 million in savings due to cost
synergies from the  consolidation  of duplicate  overhead and  consolidation  of
certain  manufacturing  operations.  For the 12 months ended March 31, 2000, STC
Technologies posted revenues of $14.8 million and a net loss of $1.0 million.

The  combined  company  will be  renamed  OraSure  Technologies,  Inc.,  will be
incorporated  under  Delaware  law,  and  will be  headquartered  in  Bethlehem,
Pennsylvania.  Robert D.  Thompson,  Epitope's  president  and  chief  executive
officer,  will be chief executive officer at the new company.  Michael Gausling,
STC's  president  and  chief  executive  officer,  will be  president  and chief
operating  officer.  The Epitope facility in Beaverton,  Oregon will continue to
focus on its current activities in the field of infectious disease.

Together,   Epitope  and  STC  will  leverage  their  expertise  in  oral  fluid
technology,  infectious disease testing and substance abuse testing.  The merger
combines the  developers  of the premier oral fluid  collection  device with the
leaders in oral fluid  assay  development.  Epitope's  OraQuick(R)  rapid  assay
platform and STC's Up-Converting Phosphor Technology (UPT(TM)),  which are under
development for a broad range of medical diagnostic applications, will provide a
substantial product pipeline for the combined company.

"Merging  these two great  companies  hits  dead-center on our shared mission to
become  the  world's  pre-eminent  oral  fluid  diagnostic  company,"  said  Mr.
Thompson.  "OraSure  Technologies  will have the  intellectual  capital  and the
technology  platforms  to  extend  the  reach of oral  fluid  testing,  touching
millions of lives. With our three platform technologies-  OraSure(R),  OraQuick,
and  UPlink(TM),  - we will be extremely  well  positioned  to  commercialize  a
variety of oral fluid testing  platforms for new and existing-use  applications.
The combination of laboratory  accuracy,  point-of-care  speed and  convenience,
non-invasive  anytime-anywhere  collection,  and competitive economics ensures a
prominent  place  for  rapid  oral  fluid  testing  in the  future  of  in-vitro
diagnostics. We intend to be the company that makes it happen."

"Over the past several  years,  Epitope and STC pioneered  oral fluid testing in
the  life  insurance  market.  Most  recently,  the  companies  collaborated  to
commercialize  Intercept(TM),  the first  laboratory  based  oral fluid test for
drugs of abuse, using the OraSure platform technology," said Mr. Gausling. "This
heritage gives us a great foundation for  commercializing  exciting new products
and technologies with a broad range of licensing opportunities."

OraQuick HIV is under development as the first product in the OraQuick line. The
product is a visually  read,  oral fluid  testing  device,  which can detect HIV
antibodies  within  20  minutes.  The  company  expects  to launch  the  product
internationally  in July 2000 and is preparing to enter  clinical  trials in the
United States.  The company plans to expand the OraQuick product line to include
tests for a variety of medical diagnostic applications.

UPT is a proprietary  label  detection  technology  being developed by STC. This
enabling  technology utilizes submicron phosphor particles that convert infrared
light to visible  light.  When used in conjunction  with  antibodies or DNA as a
probe  label,  UPT  assays  produce no  background  signal,  which  dramatically
increases  the  sensitivity  of the test  system.  In  addition  to  eliminating
background  signal,  these  particles allow  simultaneous  detection of multiple
biological  markers by the use of  different  UPT  particle  colors,  as well as
miniaturization  of the test platform and a permanent record of the test results
because of the stability of the UPT particles.  STC has demonstrated the utility
of UPT  labels in a lateral  flow  format  for use in a  variety  of  diagnostic
applications  under the  UPlinktrademark.  The first  UPlink  product  will be a
point-of-care  system  used to detect  drugs of abuse in oral  fluids,  which is
expected to be launched in the second half of 2001. STC has

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<PAGE>

collaborated with SRI International,  Menlo Park, CA, and Leiden University, the
Netherlands,  on the  development of the UPT  technology.  The Company has broad
patent protection for the use of UPT for biological applications.

The actual  number of shares to be issued in the merger is subject to adjustment
as follows: (i) issuance of 25 million shares if the average Epitope stock price
is between $6 and $8 per  share,  (ii)  issuance  of  Epitope  stock  worth $200
million  if the  average  Epitope  stock  price is between $8 and $10 per share,
(iii)  issuance  of 20 million  shares if the  average  Epitope  stock  price is
between $10 and $13 per share,  and (iv)  issuance  of Epitope  stock worth $260
million  if the  average  Epitope  stock  price is above  $13 per  share.  It is
anticipated  that  Epitope  shareholders  will own,  on a fully  diluted  basis,
approximately  50% of the  combined  company at the time the merger is affected,
subject to the average Epitope stock price prior to the merger.  The merger will
be tax  free  to the  stockholders  of  both  companies  and is  expected  to be
accounted for as a pooling of interests.

Deutsche Banc Alex. Brown advised Epitope in this  transaction,  while Robertson
Stephens advised STC  Technologies.  Robert Thompson,  Mike Gausling and Dr. Sam
Niedbala, chief science officer of STC, will be presenting at the DB Alex. Brown
healthcare conference on May 11, 2000.

The company will hold a conference call to discuss this  announcement  beginning
at 11:00 a.m. Eastern Time today.  Individual investors are invited to listen to
the conference  call over the Internet  through Vcall, a service of the Investor
Broadcast  Network,  at www.vcall.com.  To listen to the live call, please go to
the Web site at least 15  minutes  prior to the  start of the call to  register,
download and install any necessary  audio software.  In addition,  a replay will
begin shortly after the call has ended and will be available for 90 days.

STC Technologies,  Inc. develops,  manufactures and markets proprietary in vitro
diagnostic  products  and  medical  devices  for use in  clinical  laboratories,
physician  offices and workplace  testing.  STC is the leading  supplier of oral
fluid  assays  to  the  insurance  risk  assessment   testing  market  and  also
manufactures and markets other substance abuse testing products.  Epitope,  Inc.
develops,  manufactures  and markets  medical  devices and  diagnostic  products
utilizing  its  proprietary  oral fluid  technologies  for sale to  public-  and
private-sector  clients  worldwide.  The  Company's  primary  focus  is  on  the
detection of HIV antibodies, with emphasis in the U.S. life insurance and global
public health markets, and on the use of oral fluid testing for the detection of
drugs of abuse and other analytes.

This press release contains forward-looking statements.  Actual results could be
significantly  different.  Factors  that  could  affect  results  include  those
relating  to  the  proposed  merger,   including  failure  to  achieve  expected
synergies,  failure to obtain required regulatory or shareholder  approval,  and
unexpected  liabilities resulting from the two companies' operations prior to or
after the merger occurs. Other factors that could affect results include loss of
key personnel; failure to comply with regulations of the FDA or other regulatory
agencies;  obstacles to international  marketing of products; loss or impairment
of sources of capital; ability to develop product distribution channels; ability
to develop new products; development of competing products; market acceptance of
oral fluid testing products; and changes in international, federal or state laws
or regulations.  Although  forward-looking  statements help to provide  complete
information   about  future   prospects,   readers  should  keep  in  mind  that
forward-looking statements are much less reliable than historical information.

ADDITIONAL INFORMATION AND WHERE TO FIND IT:

EPITOPE  PLANS TO FILE A  REGISTRATION  STATEMENT ON SEC FORM S-4 IN  CONNECTION
WITH THE MERGER  AND TO MAIL A PROXY  STATEMENT/PROSPECTUS  TO  EPITOPE  AND STC
SHAREHOLDERS  CONTAINING  INFORMATION  ABOUT THE MERGER.  INVESTORS AND SECURITY
HOLDERS   ARE  URGED  TO  READ  THE   REGISTRATION   STATEMENT   AND  THE  PROXY
STATEMENT/PROSPECTUS   CAREFULLY  WHEN  THEY  ARE  AVAILABLE.  THE  REGISTRATION
STATEMENT AND THE PROXY  STATEMENT/PROSPECTUS WILL CONTAIN IMPORTANT INFORMATION
ABOUT  EPITOPE,  STC,  THE MERGER AND RELATED  MATTERS.  INVESTORS  AND SECURITY
HOLDERS  WILL BE ABLE TO OBTAIN FREE COPIES OF THESE  DOCUMENTS  THROUGH THE WEB
SITE   MAINTAINED   BY  THE  U.S.   SECURITIES   AND  EXCHANGE   COMMISSION   AT
HTTP//WWW.SEC.GOV.

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<PAGE>

EPITOPE FILES ANNUAL,  QUARTERLY AND SPECIAL REPORTS, PROXY STATEMENTS AND OTHER
INFORMATION WITH THE SECURITIES AND EXCHANGE  COMMISSION.  YOU MAY READ AND COPY
ANY REPORTS, STATEMENTS AND OTHER INFORMATION FILED BY EPITOPE AT THE SEC PUBLIC
REFERENCE  ROOMS  AT 450  FIFTH  ST.,  N.W.,  WASHINGTON,  D.C.  20549 OR AT THE
COMMISSION'S  OTHER PUBLIC REFERENCE ROOMS IN NEW YORK AND CHICAGO.  PLEASE CALL
THE  COMMISSION AT  800/SEC-0330  FOR FURTHER  INFORMATION  ON PUBLIC  REFERENCE
ROOMS. COPIES OF EPITOPE'S FILINGS WITH THE COMMISSION ALSO ARE AVAILABLE TO THE
PUBLIC FROM COMMERCIAL  DOCUMENT-RETRIEVAL SERVICES AND MAY BE OBTAINED FOR FREE
AT THE WEB SITE MAINTAINED BY THE COMMISSION AT HTTP//WWW.SEC.GOV, OR BY WRITING
EPITOPE AT: EPITOPE  INVESTOR  RELATIONS,  8505 SW CREEKSIDE  PLACE,  BEAVERTON,
OREGON 97008.

EPITOPE, ITS DIRECTORS, EXECUTIVE OFFICERS AND CERTAIN MEMBERS OF MANAGEMENT AND
EMPLOYEES MAY BE SOLICITING  PROXIES FROM EPITOPE  SHAREHOLDERS  IN FAVOR OF THE
APPROVAL OF THE MERGER  AGREEMENT.  A DESCRIPTION  OF ANY  INTERESTS,  DIRECT OR
INDIRECT,  THAT  EPITOPE'S  DIRECTORS AND EXECUTIVE  OFFICERS HAVE IN THE MERGER
WILL BE INCLUDED IN THE PROXY STATEMENT/PROSPECTUS.

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