<PAGE>

                                                                     EXHIBIT 4.2

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


                               RIGHTS AGREEMENT

                                    between

                          ORASURE TECHNOLOGIES, INC.

                                      and

                   CHASEMELLON SHAREHOLDER SERVICES, L.L.C.

                                as Rights Agent



                            Dated as of May 6, 2000


================================================================================
<PAGE>

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                                      Page
                                                                                                      ----
<S>                                                                                                   <C>
Section 1.    Definitions...........................................................................    1
Section 2.    Appointment of Rights Agent...........................................................    7
Section 3.    Evidence of Rights; Issuance of Rights Certificates...................................    7
Section 4.    Form of Rights Certificates...........................................................    9
Section 5.    Execution, Countersignature and Registration of Rights Certificates...................   10
Section 6.    Transfer, Split Up, Combination and Exchange of Rights Certificates; Lost,
              Stolen, Destroyed or Mutilated Rights Certificates....................................   11
Section 7.    Exercise of Rights; Expiration Date of Rights; Purchase Price.........................   12
Section 8.    Cancellation and Destruction of Rights Certificates...................................   14
Section 9.    Reservation and Availability of Capital Stock.........................................   15
Section 10.   Preferred Stock Record Date...........................................................   16
Section 11.   Adjustment of Purchase Price, Number and Kind of Shares and Number of Rights..........   17
Section 12.   Certificate of Adjusted Purchase Price or Number of Shares............................   25
Section 13.   Consolidation, Merger or Sale or Transfer of Assets or Earning Power..................   26
Section 14.   Fractional Rights and Fractional Shares...............................................   29
Section 15.   Rights of Action......................................................................   31
Section 16.   Agreement of Rights Holders...........................................................   31
Section 17.   Rights Certificate Holder Not Deemed a Stockholder....................................   32
Section 18.   Concerning the Rights Agent...........................................................   32
Section 19.   Merger or Consolidation or Change of Name of Rights Agent.............................   33
Section 20.   Duties of Rights Agent................................................................   33
</TABLE>

                                       i
<PAGE>

                              TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                                      PAGE
                                                                                                      ----
<S>                                                                                                   <C>
Section 21.   Change of Rights Agent................................................................  36
Section 22.   Issuance of New Rights Certificates...................................................  37
Section 23.   Redemption and Termination............................................................  37
Section 24.   Exchange..............................................................................  38
Section 25.   Notice of Certain Events..............................................................  39
Section 26.   Notices...............................................................................  40
Section 27.   Supplements and Amendments............................................................  41
Section 28.   Successors............................................................................  41
Section 29.   Determinations and Actions by the Board of Directors..................................  41
Section 30.   Benefits of this Agreement............................................................  42
Section 31.   Severability..........................................................................  42
Section 32.   Governing Law.........................................................................  42
Section 33.   Counterparts..........................................................................  42
Section 34.   Descriptive Headings..................................................................  43
</TABLE>

Exhibit A - Form of Certificate of Designation, Preferences and Rights

Exhibit B - Form of Rights Certificate

Exhibit C - Form of Summary of Rights

                                      ii
<PAGE>

                               RIGHTS AGREEMENT
                               ----------------

     THIS RIGHTS AGREEMENT (this "Agreement") is entered into as of May 6, 2000
                                  ---------
between OraSure Technologies, Inc., a Delaware corporation (the "Company"), and
                                                                 -------
ChaseMellon Shareholder Services, L.L.C., a New Jersey limited company, as
rights agent (the "Rights Agent").
                   ------------

     WHEREAS, on May 6, 2000 (the "Rights Distribution Declaration Date"), the
                                   ------------------------------------
Board of Directors of the Company authorized the distribution of one Right for
each share of Common Stock of the Company outstanding immediately after the
Effective Time of the Mergers (as such terms are defined in that certain Merger
Agreement, dated as of May 6, 2000 among Epitope, Inc., STC Technologies, Inc.
and the Company) (the "Record Date"), and has authorized the issuance of one (as
                       -----------
such number may hereinafter be adjusted pursuant to the provisions of Section
11(p) hereof) Right for each share of Common Stock issued between the Record
Date (whether originally issued or delivered from the Company's treasury) and
the Distribution Date, and, in certain circumstances provided in Section 22 of
this Agreement, after the Distribution Date, each Right initially representing
the right to purchase one one-thousandth of a share of Preferred Stock of the
Company having the rights, powers and preferences set forth in the form of
Certificate of Designation attached hereto as Exhibit A, upon the terms and
                                              ---------
subject to the conditions hereinafter set forth ("Rights"); and
                                                  ------

     NOW, THEREFORE, in consideration of the premises and the mutual agreements
herein set forth, the parties hereby agree as follows:

     Section 1.  Definitions.  For purposes of this Agreement, the following
                 -----------
terms have the meanings indicated:

           (a)   "Acquiring Person" shall mean collectively any Person who or
                  ----------------
     which, together with all Affiliates and Associates of such Person, shall be
     the Beneficial Owner of 15% or more of the shares of Common Stock then
     outstanding (other than as a result of a Qualifying Offer) or was such a
     Beneficial Owner at any time after the date hereof, whether or not such
     Person together with all Affiliates or Associates of such Person continues
     to be the Beneficial Owner of 15% or more of the then outstanding Common
     Stock.  Notwithstanding the foregoing, (A) the term "Acquiring Person"
     shall not include (i) the Company, (ii) any Subsidiary of the Company
     (including with respect to any shares of Common Stock held in trust), (iii)
     any employee benefit plan of the Company or of any Subsidiary of the
     Company, (iv) any Person or entity organized, appointed or established by
     the Company for or pursuant to the terms of any such plan, and (v) any
     Person together with all Affiliates and Associates of such Person who or
     which becomes the Beneficial Owner of 15% or more of the then outstanding
     shares of Common Stock as a result of the acquisition of Common Stock
     directly from the Company (each of (i) through (v), an "Exempted Person");
                                                             ---------------
     (B) no Person shall become an "Acquiring Person" as a result of an
     acquisition of Common Stock by the Company which, by reducing the number of
     such shares then outstanding, increases the proportionate number of shares
     beneficially owned by such Person  together with all Affiliates and
     Associates of such Person to 15% or more of the outstanding Common Stock,
     except that if such Person, after such share purchases by the Company,
     becomes the Beneficial Owner of additional
<PAGE>

     shares of Common Stock constituting 1% or more of the then outstanding
     shares of Common Stock other than pursuant to a Qualifying Offer, such
     Person shall be deemed to be an "Acquiring Person"; and (C) if the Board of
     Directors of the Company determines in good faith that a Person, together
     with all Affiliates and Associates of such Person, who would otherwise be
     an "Acquiring Person" has become such inadvertently, and such Person,
     together with all Affiliates and Associates of such Person, divests as
     promptly as practicable a sufficient number of shares of Common Stock so
     that such Person, together with all Affiliates and Associates of such
     Person, would no longer be an Acquiring Person, then such Person shall not
     be deemed to be an "Acquiring Person." The term "outstanding," when used
                                                      -----------
     with reference to a Person's Beneficial Ownership of securities of the
     Company, shall mean the number of such securities then issued and
     outstanding together with the number of such securities not then actually
     issued and outstanding which such Person would be deemed to beneficially
     own hereunder.

          (b)  "Act" shall mean the Securities Act of 1933, as amended and in
                ---
     effect on the date hereof.

          (c)  "Adjustment Shares" shall have the meaning set forth in Section
                -----------------
     11(a)(ii) of this Agreement.

          (d)  "Affiliate" shall have the meaning set forth in Rule 12b-2 of the
                ---------
     General Rules and Regulations under the Exchange Act, as amended and in
     effect on the date hereof.

          (e)  "Associate" shall have the meaning set forth in Rule 12b-2 of the
                ---------
     General Rules and Regulations under the Exchange Act, as amended and in
     effect on the date hereof.

          (f)  A Person shall be deemed the "Beneficial Owner" of, and shall be
                                             ----------------
     deemed to "beneficially own," any securities:
                ----------------

               (i) that such Person or any of such Person's Affiliates or
          Associates, directly or indirectly, has the right to acquire (whether
          such right is exercisable immediately or only after the passage of
          time) pursuant to any agreement, arrangement or understanding (whether
          or not in writing) or upon the exercise of conversion rights, exchange
          rights, rights (other than the Rights), warrants or options, or
          otherwise; provided, however, that a Person shall not be deemed the
                     --------  -------
          "Beneficial Owner" of, or to "beneficially own," (A) securities
          tendered pursuant to a tender or exchange offer made by or on behalf
          of such Person or any of such Person's Affiliates or Associates until
          such tendered securities are accepted for purchase or exchange, or (B)
          securities issuable upon exercise of Rights at any time prior to the
          occurrence of a Triggering Event, or (C) securities issuable upon
          exercise of Rights from and after the occurrence of a Triggering Event
          to the extent such Rights were acquired by such Person or any of such
          Person's Affiliates or Associates prior to the Distribution Date or
          pursuant to Section 22 hereof ("Original Rights") or pursuant to
                                          ---------------
          Section 11(i) hereof in connection with an adjustment made with
          respect to any Original Rights;

                                       2
<PAGE>

               (ii)   that such Person or any of such Person's Affiliates or
          Associates, directly or indirectly, has the right to vote or dispose
          of or has "beneficial ownership" of (as determined pursuant to Rule
          13d-3 of the General Rules and Regulations under the Exchange Act, as
          amended and in effect on the date hereof), including pursuant to any
          agreement, arrangement or understanding (whether or not in writing);
          provided, however, that a Person shall not be deemed the "Beneficial
          --------  -------
          Owner" of, or to "beneficially own," any security under this
          subparagraph (ii) as a result of an agreement, arrangement or
          understanding to vote such security if such agreement, arrangement or
          understanding: (A) arises solely from a revocable proxy given in
          response to a public proxy or consent solicitation made pursuant to,
          and in accordance with, the applicable provisions of the General Rules
          and Regulations under the Exchange Act, as amended and in effect on
          the date hereof, and (B) is not also then reportable by such Person on
          Schedule 13D under the Exchange Act (or any comparable or successor
          report); or

               (iii)  that are beneficially owned, directly or indirectly, by
          any other Person (or any Affiliate or Associate thereof) with which
          such Person (or any of such Person's Affiliates or Associates) has any
          agreement, arrangement or understanding (whether or not in writing),
          for the purpose of acquiring, holding, voting (except pursuant to a
          revocable proxy as described in the proviso to subparagraph (ii) of
          this paragraph (f)) or disposing of any voting securities of the
          Company;

     provided, however, that nothing in this paragraph (f) shall cause a Person
     --------  -------
     engaged in business as an underwriter of securities to be the "Beneficial
     Owner" of, or to "beneficially own," any securities acquired through such
     Person's participation in good faith in a bona fide firm commitment
     underwriting until the expiration of forty days after the date of such
     acquisition.  Notwithstanding anything in this definition of Beneficial
     Owner to the contrary, a Person who, prior to the Distribution Date, is a
     member of the Board of Directors or an officer of the Company or who is an
     Affiliate or Associate of a member of the Board of Directors or officer of
     the Company (each, an "Excluded Person") shall not be deemed to
                            ---------------
     "beneficially own" shares of Common Stock held by another Excluded Person
     solely by reason of any agreement, arrangement or understanding (whether or
     not in writing), entered into in opposition to any transaction or in
     support of a Qualifying Offer.

          (g)  "Board of Directors" shall mean the Board of Directors of the
                ------------------
     Company as constituted from time to time.

          (h)  "Business Day" shall mean any day other than a Saturday, Sunday
                ------------
     or a day on which banking institutions in the State of Pennsylvania or the
     State of New Jersey is located are authorized or obligated by law or
     executive order to close.

          (i)  "Close of Business" on any given date shall mean 5:00 p.m., New
                -----------------
     York City time, on such date; provided, however, that if such date is not a
                                   --------  -------
     Business Day it shall mean 5:00 p.m., New York City time, on the next
     succeeding Business Day.

                                       3
<PAGE>

          (j)  "Common Stock" shall mean the common stock, par value $0.000001
                ------------
     per share, of the Company (or in the event of a subdivision, combination or
     reclassification with respect to such shares of common stock, the shares of
     common stock resulting from such subdivision, combination or
     reclassification), except, subject to the proviso in Section 13(b) of this
     Agreement, that "Common Stock" when used with reference to any Person other
     than the Company shall mean the capital stock (or other equity securities
     or equity interests) of such Person with the greatest voting power to
     control or direct the management of such Person, or if such Person is a
     Subsidiary of another Person, the Person or Persons that ultimately control
     such first-mentioned Person.

          (k)  "Common Stock Equivalents" shall have the meaning set forth in
                ------------------------
     Section 11(a)(iii) of this Agreement.

          (l)  "Company" shall have the meaning set forth in the introductory
                -------
     paragraph of this Agreement, subject to Section 13(a) hereof.

          (m)  "Current Market Price" shall have the meaning set forth in
                --------------------
     Section 11(d).

          (n)  "Current Value" shall have the meaning set forth in Section
                -------------
     11(a)(iii) of this Agreement.

          (o)  "Distribution Date" shall have the meaning set forth in Section
                -----------------
     3(a) of this Agreement.

          (p)  "Equivalent Preferred Stock" shall have the meaning set forth in
                --------------------------
     Section 11(b) of this Agreement.

          (q)  "Exchange Act" shall mean the Securities Exchange Act of 1934, as
                ------------
     amended and in effect on the date hereof.

          (r)  "Exchange Ratio" shall have the meaning set forth in Section
                --------------
     24(a) hereof.

          (s)  "Excluded Person" shall have the meaning set forth in Section
                ---------------
     1(f) of this Agreement.

          (t)  "Exempted Person" shall have the meaning set forth in Section
                ---------------
     1(a) of this Agreement.

          (u)  "Expiration Date" shall have the meaning set forth in Section
                ---------------
     7(a) of this Agreement.

          (v)  "Final Expiration Date" shall have the meaning set forth in
                ---------------------
     Section 7(a) of this Agreement.

          (w)  "NASDAQ" shall have the meaning set forth in Section 4(a) of this
                ------
     Agreement.

          (x)  "Original Rights" shall have the meaning set forth in Section
                ---------------
     1(f)(i) of this

                                       4
<PAGE>

     Agreement.

          (y)  "Person" shall mean any individual, firm, corporation,
                ------
     partnership, limited liability company or other entity.

          (z)  "Preferred Stock" shall mean shares of Series A Preferred Stock,
                ---------------
     $0.000001 par value per share, of the Company (or in the event of a
     subdivision, combination or reclassification with respect to such shares of
     Series A Preferred Stock, the shares of preferred stock resulting from such
     subdivision, combination or reclassification), and, to the extent that
     there is not a sufficient number of shares of Series A Preferred Stock
     authorized to permit the full exercise of the Rights, any other series of
     preferred stock of the Company designated for such purpose containing terms
     substantially similar to the terms of the Series A Preferred Stock.

          (aa) "Principal Party" shall have the meaning set forth in Section
                ---------------
     13(b) of this Agreement.

          (bb) "Purchase Price" shall have the meaning set forth in Section
                --------------
     4(a) of this Agreement, subject to Section 11(a)(ii) hereof.

          (cc) "Qualifying Offer" shall mean an acquisition of shares of Common
                ----------------
     Stock pursuant to a tender offer or an exchange offer for all outstanding
     shares of Common Stock at a price and on terms determined by at least a
     majority of the members of the Board of Directors, after receiving advice
     from one or more nationally recognized investment banking firms selected by
     the Board of Directors, to be (a) fair to stockholders (taking into account
     all factors that the Board of Directors may deem relevant including,
     without limitation, prices that could reasonably be achieved if the Company
     or its assets were sold on an orderly basis designed to realize maximum
     value) and (b) otherwise in the best interests of the Company and its
     stockholders (other than the Person or any Affiliate or Associate thereof
     on whose behalf the offer is being made) taking into account all factors
     that the Board of Directors may deem relevant; provided, however, that (i)
                                                    --------  -------
     such determination is made by the Board of Directors prior to the purchase
     of shares under such tender offer or exchange offer, and (ii) a  majority
     of the members of the Board of Directors are not Acquiring Persons or
     Affiliates, Associates, nominees or representatives of an Acquiring Person.

          (dd) "Record Date" shall have the meaning set forth in the first
                -----------
     "WHEREAS" clause at the beginning of this Agreement.

          (ee) "Redemption Date" shall have the meaning set forth in Section
                ---------------
     7(a) of this Agreement.

          (ff) "Redemption Price" shall have the meaning set forth in Section 23
                ----------------
     of this Agreement.

          (gg) "Rights" shall have the meaning set forth in the first "WHEREAS"
                ------
     clause at the beginning of this Agreement.

                                       5
<PAGE>

          (hh) "Rights Agent" shall have the meaning set forth in the
                ------------
     introductory paragraph of this Agreement.

          (ii) "Rights Certificates" shall have the meaning set forth in Section
                -------------------
     3(d) of this Agreement.

          (jj) "Rights Distribution Declaration Date" shall have the meaning set
                ------------------------------------
     forth in the first "WHEREAS" clause at the beginning of this Agreement.

          (kk) "Section 11(a)(ii) Event" shall have the meaning set forth in
                -----------------------
     Section 11(a)(ii) of this Agreement.

          (ll) "Section 11(a)(ii) Trigger Date" shall have the meaning set forth
                ------------------------------
     in Section 11(a)(iii) of this Agreement.

          (mm) "Section 13 Event" shall mean any event described in clauses (x),
                ----------------
     (y) or (z) of Section 13(a) of this Agreement.

          (nn) "Spread" shall have the meaning set forth in Section 11(a)(iii)
                ------
     of this Agreement.

          (oo) "Stock Acquisition Date" shall mean the earlier of the date of
                ----------------------
     (i) the public announcement (which, for purposes of this definition, shall
     include, without limitation, a report filed under the Exchange Act) by the
     Company or an Acquiring Person that an Acquiring Person has become such or
     (ii) the public disclosure of facts by the Company or an Acquiring Person
     indicating that an Acquiring Person has become an Acquiring Person;
     provided, however, that if such Person is determined not to have become an
     --------  -------
     Acquiring Person pursuant to Section 1(a)(C) hereof, then no Stock
     Acquisition Date shall be deemed to have occurred.

          (pp) "Subsidiary" shall mean, with reference to any Person, any
                ----------
     corporation or other Person of which an amount of voting securities
     sufficient to elect at least a majority of the directors or others having
     similar authority over such corporation or other Person is beneficially
     owned, directly or indirectly, by such first-named Person, or otherwise
     controlled by such first-named Person.

          (qq) "Substitution Period" shall have the meaning set forth in Section
                -------------------
     11(a)(iii) of this Agreement.

          (rr) "Summary of Rights" shall have the meaning set forth in Section
                -----------------
     3(b) of this Agreement.

          (ss) "Trading Day" shall have the meaning set forth in Section
                -----------
     11(d)(i) of this Agreement.

          (tt) "Transaction" shall mean any merger, consolidation or sale of
                -----------
     assets or earning power described in Section 13(a) hereof or any
     acquisition of Common Stock which, without regard to any required approval
     of the Company, would result in a Person

                                       6
<PAGE>

becoming an Acquiring Person.

          (uu) "Triggering Event" shall mean any Section 11(a)(ii) Event or any
                ----------------
     Section 13 Event.

          (vv) "Vote" shall mean, with respect to any entity, the ability to
                ----
     cast a vote at a stockholders', members' or comparable meeting of such
     entity with respect to the election of directors, managers or other members
     of such entity's governing body, or the ability to cast a general
     partnership or comparable vote.

          (ww) "Voting Power" shall mean, with respect to any entity as of any
                ------------
     date, the aggregate number of Votes outstanding as of such date in respect
     of such entity.

          (xx) "Voting Securities" shall mean the Common Stock and any other
                -----------------
     securities of the Company the holders of which are ordinarily, in the
     absence of contingencies, entitled to Vote, even if the right to such Vote
     has been suspended by the happening of such a contingency.

     Section 2.  Appointment of Rights Agent.  The Company hereby appoints the
                 ---------------------------
Rights Agent to act as agent for the Company in accordance with the terms and
conditions hereof, and the Rights Agent hereby accepts such appointment.  The
Company may from time to time appoint such co-Rights Agents as it may deem
necessary or desirable.  The Rights Agent shall have no duty to supervise, and
in no event shall be liable for, the acts or omissions of any such co-Rights
Agent.

     Section 3.  Evidence of Rights; Issuance of Rights Certificates.
                 ---------------------------------------------------

            (a)  Evidence of Rights Prior to Distribution Date. Until the
                 ---------------------------------------------
     earlier of (i) the Close of Business on the tenth Business Day after the
     Stock Acquisition Date (or, if the tenth Business Day after the Stock
     Acquisition Date occurs before the Record Date, the Close of Business on
     the Record Date), or (ii) the Close of Business on the tenth Business Day
     (or such later date as the Board of Directors shall determine) after the
     date of the earlier of commencement by any Person (other than an Exempted
     Person) of, or the first public announcement of the intention of any Person
     (other than an Exempted Person) to commence, a tender or exchange offer the
     consummation of which would result in any Person becoming an Acquiring
     Person (the earlier of (i) and (ii) being herein referred to as the
     "Distribution Date"), (x) the Rights will be evidenced (subject to the
     ------------------
     provisions of Section 3(d) of this Agreement) by the certificates for the
     Common Stock registered in the names of the record holders of the Common
     Stock (which certificates for Common Stock shall be deemed also to be
     certificates for Rights) and not by separate certificates, and (y) the
     Rights will be transferable only in connection with the transfer of the
     underlying shares of Common Stock (including a transfer to the Company);
     provided, however, that if a tender or exchange offer is terminated prior
     --------  -------
     to the occurrence of a Distribution Date, then no Distribution Date shall
     occur as a result of such tender or exchange offer.  The Board of Directors
     may defer the date set forth in clause (ii) of the preceding sentence to a
     specified later date or to an unspecified later date, each to be

                                       7
<PAGE>

     determined by action of the Board of Directors. The Company shall provide
     the Rights Agent with prompt notice of any such deferral.

          (b)  Common Stock Outstanding as of the Record Date.  With respect to
               ----------------------------------------------
     the Common Stock outstanding as of the Record Date, until the earlier of
     the Distribution Date or the Expiration Date, the Rights will be evidenced
     by the certificates for such Common Stock and the record holders of the
     Common Stock shall also be the record holders of the associated Rights, and
     the transfer of any of such certificates shall also constitute the transfer
     of the Rights associated with such shares of Common Stock.  As promptly as
     practicable following the Record Date, the Company will send a copy of a
     Summary of Rights to Purchase Preferred Stock, in substantially the form
     attached hereto as Exhibit C (the "Summary of Rights"), which Summary of
                        ---------       -----------------
     Rights will be included as a part of the proxy statement being distributed
     to stockholders in connection with the merger of Epitope with and into the
     Company, to each record holder of the Common Stock as of the Close of
     Business on the Record Date, at the address of such holder shown on the
     records of the Company.

          (c)  Common Stock Issued After the Record Date. Rights shall be issued
               -----------------------------------------
     in respect of all shares of Common Stock that are issued (whether
     originally issued or from the Company's treasury) after the Record Date but
     prior to the earlier of the Distribution Date or the Expiration Date, and,
     in certain circumstances provided in Section 22 of this Agreement, after
     the Distribution Date.  Certificates representing such shares of Common
     Stock shall also be deemed to be certificates for Rights and shall bear the
     following legend:

          This certificate also evidences and entitles the holder hereof to
          certain Rights as set forth in the Rights Agreement between
          OraSure Technologies, Inc. (the "Company") and ChaseMellon
          Shareholder Services, L.L.C. (the "Rights Agent"), dated as of
          May 6, 2000 (the "Rights Agreement"), the terms of which are
          hereby incorporated herein by reference and a copy of which is on
          file at the principal offices of the Company. Under certain
          circumstances, as set forth in the Rights Agreement, such Rights
          will be evidenced by separate certificates and will no longer be
          evidenced by this certificate. The Company will mail to the
          holder of this certificate a copy of the Rights Agreement, as in
          effect on the date of mailing, without charge, promptly after
          receipt of a written request therefor. Under certain
          circumstances set forth in the Rights Agreement, Rights issued
          to, or held by, any Person who is, was or becomes an Acquiring
          Person or any Affiliate or Associate thereof (as such terms are
          defined in the Rights Agreement), whether currently held by or on
          behalf of such Person or by any subsequent holder, may become
          null and void.

     With respect to such certificates containing the foregoing legend, until
     the earlier of the Distribution Date or the Expiration Date, the Rights
     associated with the Common Stock represented by such certificates shall be
     evidenced by such certificates alone and record holders of Common Stock
     shall also be the record holders of the associated Rights, and

                                       8
<PAGE>

     the transfer of any of such certificates shall also constitute the transfer
     of the Rights associated with the Common Stock represented by such
     certificates. In the event the Company purchases or acquires any Common
     Stock after the Record Date but prior to the Distribution Date, any Rights
     associated with such Common Stock shall be deemed canceled and retired so
     that the Company shall not be entitled to exercise any Rights associated
     with Common Stock that is no longer outstanding. Notwithstanding the
     provisions of this Section 3(c), the omission of a legend shall not affect
     the enforceability of any part of this Agreement or the rights of any
     holder of the Rights.

          (d)  Issuance of Rights Certificates. As soon as practicable after the
               -------------------------------
     Distribution Date, the Company shall prepare and execute, and the Rights
     Agent will countersign and, at the Company's expense and provided the
     Rights Agent has been provided with all necessary information, send by
     first-class, insured, postage prepaid mail, to each record holder of the
     Common Stock as of the Close of Business on the Distribution Date, at the
     address of such holder shown on the registry books for the Common Stock of
     the Company, one or more rights certificates, in substantially the form of
     Exhibit B hereto (the "Rights Certificates"), evidencing one Right for each
     ---------              -------------------
     share of Common Stock so held, subject to adjustment as provided herein.
     In the event that an adjustment in the number of Rights per share of Common
     Stock has been made pursuant to Section 11(p) hereof, at the time of
     distribution of the Rights Certificates, the Company shall make the
     necessary and appropriate rounding adjustments (in accordance with Section
     14(a) hereof) so that Rights Certificates representing only whole numbers
     of Rights are distributed and cash is paid in lieu of any fractional
     Rights.  As of and after the Distribution Date, the Rights will be
     evidenced solely by such Rights Certificates.

     Section 4. Form of Rights Certificates.
                ---------------------------

           (a)  Form of Rights Certificates.  The Rights Certificates (and the
                ---------------------------
     form of election to purchase and form of assignment to be printed on the
     reverse thereof) shall each be substantially in the form set forth in
     Exhibit B hereto and may have such marks of identification or designation
     ---------
     and such legends, summaries or endorsements printed thereon as the Company
     may deem appropriate (but which do not affect the rights, duties or
     responsibilities of the Rights Agent) and as are not inconsistent with the
     provisions of this Agreement, or as may be required to comply with any
     applicable law or with any rule or regulation made pursuant thereto, or
     with any rule or regulation of any stock exchange or the National
     Association of Securities Dealers, Inc. Automated Quotation System
     ("NASDAQ") on which or with whom the Rights may from time to time be listed
       ------
     or quoted, or to conform to usage.  Subject to the provisions of Section 11
     and Section 22 hereof, the Rights Certificates, whenever distributed, shall
     entitle the record holders thereof to purchase such number of one one-
     thousandths of a share of Preferred Stock as shall be set forth therein at
     the exercise price set forth therein (such exercise price per one one-
     thousandth of a share, the "Purchase Price"), but the amount and the type
                                 --------------
     of securities purchasable upon the exercise of each Right and the Purchase
     Price thereof shall be subject to adjustment as provided herein.

           (b)  Legend to be Included in Certain Rights Certificates. Any Rights
                ----------------------------------------------------
     Certificate issued pursuant to Section 3(d) or Section 22 hereof that
     represents Rights

                                       9
<PAGE>

     beneficially owned by: (i) an Acquiring Person or any Associate or
     Affiliate of an Acquiring Person, (ii) a transferee of an Acquiring Person
     (or of any such Associate or Affiliate) who becomes a transferee after the
     Acquiring Person becomes such, or (iii) a transferee of an Acquiring Person
     (or of any such Associate or Affiliate) who becomes a transferee prior to
     or concurrently with the Acquiring Person becoming such and receives such
     Rights pursuant to either (A) a transfer (whether or not for consideration)
     from the Acquiring Person to holders of equity interests in such Acquiring
     Person or to any Person with whom such Acquiring Person has any continuing
     agreement, arrangement or understanding regarding the transferred Rights or
     (B) a transfer that the Board of Directors of the Company has determined is
     part of a plan, arrangement or understanding which has as a primary purpose
     or effect avoidance of Section 7(e) hereof, and any Rights Certificate
     issued pursuant to Section 6 or Section 11 hereof upon transfer, exchange,
     replacement or adjustment of any other Rights Certificate referred to in
     this sentence, shall contain (to the extent feasible and to the extent the
     Rights Agent has knowledge of the applicability of this Section) the
     following legend:

               The Rights represented by this Rights Certificate are or
               were beneficially owned by a Person who is or was an
               Acquiring Person or an Affiliate or Associate of an
               Acquiring Person (as such terms are defined in the Rights
               Agreement between OraSure Technologies, Inc. and ChaseMellon
               Shareholder Services, L.L.C., dated as of May 6, 2000 (the
               "Rights Agreement")). Accordingly, this Rights Certificate
               and the Rights represented hereby may become, or may have
               already become, null and void in the circumstances specified
               in Section 7(e) of the Rights Agreement.

     The provisions of Section 7(e) of this Agreement shall be operative whether
     or not the foregoing legend is contained in any such Rights Certificate.

     Section 5.  Execution, Countersignature and Registration of Rights
                 ------------------------------------------------------
Certificates.
------------

            (a)  Execution and Countersignature. The Rights Certificates shall
                 ------------------------------
     be executed on behalf of the Company by its Chairman of the Board, its
     President or any Vice President, either manually or by facsimile signature,
     and shall have affixed thereto the Company's seal or a facsimile thereof,
     which shall be attested by the Secretary or an Assistant Secretary of the
     Company, either manually or by facsimile signature. The Rights
     Certificates shall be countersigned by an authorized signatory of the
     Rights Agent, either manually or by facsimile signature, and shall not be
     valid for any purpose unless so countersigned.  In case any officer of the
     Company who shall have signed any of the Rights Certificates shall cease to
     be such officer of the Company before countersignature by the Rights Agent
     and issuance and delivery by the Company, such Rights Certificates,
     nevertheless, may be countersigned by an authorized signatory of the Rights
     Agent and issued and delivered by the Company with the same force and
     effect as though the person who signed such Rights Certificates had not
     ceased to be such officer of the Company.  Any Rights Certificates may be
     signed on behalf of the Company by any person who, at the actual date of
     the execution of such Rights Certificate, shall be a proper officer of the
     Company to sign such Rights Certificate, although at the date of the
     execution of this

                                       10
<PAGE>

     Agreement any such person was not such an officer.

            (b)  Registration. Following the Distribution Date and receipt by
                 ------------
     the Rights Agent of all relevant information, the Rights Agent will keep or
     cause to be kept, at its offices designated as the appropriate place for
     surrender of Rights Certificates upon exercise or transfer, books for
     registration and transfer of the Rights Certificates issued hereunder. Such
     books shall show the names and addresses of the respective record holders
     of the Rights Certificates, the number of Rights evidenced on its face by
     each of the Rights Certificates and the date of each of the Rights
     Certificates. The Company and Rights Agent may deem and treat the person in
     whose name any Rights Certificate (or prior to the Distribution Date, the
     associated certificate of Common Stock) is recorded on the books for the
     registration and transfer of Rights (or, prior to the Distribution Date,
     Common Stock) as the absolute owner thereof, for all purposes whatsoever,
     and neither the Company nor the Rights Agent shall be affected by any
     notice to the contrary.

     Section 6.  Transfer, Split Up, Combination and Exchange of Rights
                 ------------------------------------------------------
                 Certificates; Lost, Stolen, Destroyed or Mutilated Rights
                 ---------------------------------------------------------
                 Certificates.
                 ------------

           (a)   Transfer, Split Up, Combination and Exchange of Rights
                 ------------------------------------------------------
     Certificates.  Subject to the provisions of Section 4(b), Section 7(e) and
     ------------
     Section 14 hereof, at any time after the Close of Business on the
     Distribution Date, and at or prior to the Close of Business on the
     Expiration Date, any Rights Certificate or Certificates may be transferred,
     split up, combined or exchanged for another Rights Certificate or
     Certificates, entitling the record holder to purchase a like number of one
     one-thousandths of a share of Preferred Stock (or, following a Triggering
     Event, Common Stock, other securities, cash or other assets, as the case
     may be) as the Rights Certificate or Certificates surrendered then entitles
     such holder (or former holder in the case of a transfer) to purchase.  Any
     record holder desiring to transfer, split up, combine or exchange any
     Rights Certificate or Certificates shall make such request in writing to
     the Rights Agent in a form acceptable to the Rights Agent, and shall
     surrender the Rights Certificate or Certificates to be transferred, split
     up, combined or exchanged at the office or offices of the Rights Agent
     designated for such purpose.  Neither the Rights Agent nor the Company
     shall be obligated to take any action whatsoever with respect to the
     transfer of any such surrendered Rights Certificate until the record holder
     shall have properly completed and signed the certificate contained in the
     form of assignment on the reverse side of such Rights Certificate and shall
     have provided such additional evidence of the identity of the Beneficial
     Owner (or former Beneficial Owner) or Affiliates or Associates thereof as
     the Company or the Rights Agent shall reasonably request.  Thereupon the
     Rights Agent shall, subject to Section 4(b), Section 7(e) and Section 14
     hereof, countersign and deliver to the Person entitled thereto a Rights
     Certificate or Certificates, as the case may be, as so requested.  The
     Company may require payment by the record holder of a Rights Certificate of
     a sum sufficient to cover any U.S. federal or state transfer tax or
     governmental charge that may be imposed in connection with any transfer,
     split up, combination or exchange of Rights Certificates.  The Rights Agent
     shall have no duty or obligation to take any action under any Section of
     this Agreement which requires the payment by a Rights holder of applicable
     U.S. federal or state transfer taxes and

                                       11
<PAGE>

     governmental charges unless and until the Rights Agent is satisfied that
     all such taxes and/or charges have been paid.

          (b)  Lost, Stolen, Destroyed or Mutilated Rights Certificates. Subject
               --------------------------------------------------------
     to the provisions of Section 4(b), Section 7(e) and Section 14 hereof, upon
     receipt by the Rights Agent of (i) evidence reasonably satisfactory to it
     of the loss, theft, destruction or mutilation of a Rights Certificate, (ii)
     in the case of loss, theft or destruction of a Rights Certificate,
     indemnity or security to the Rights Agent and the Company reasonably
     satisfactory to the Rights Agent and (iii) reimbursement to the Company and
     the Rights Agent of all reasonable expenses incidental thereto, and in the
     case of mutilation of a Rights Certificate, upon surrender of the Rights
     Certificate to the Rights Agent and cancellation of the Rights Certificate,
     the Company will execute and deliver a new Rights Certificate of like tenor
     to the Rights Agent for countersignature and delivery to the record holder
     in lieu of the Rights Certificate so lost, stolen, destroyed or mutilated.

     Section 7.  Exercise of Rights; Expiration Date of Rights; Purchase Price.
                 -------------------------------------------------------------

            (a)  Exercise of Rights; Expiration Date of Rights. Subject to
                 ---------------------------------------------
     Section 7(e) hereof, the record holder of any Rights Certificate may
     exercise the Rights evidenced thereby (except as otherwise provided herein
     including, without limitation, the restrictions on exercisability set forth
     in Section 9(c), Section 11(a)(iii), Section 23(a) and Section 24(b)
     hereof) in whole or in part at any time after the Distribution Date upon
     surrender of the Rights Certificate, with the form of election to purchase
     and the related certification set forth on the reverse side thereof duly
     executed, to the Rights Agent at the office or offices of the Rights Agent
     designated for such purpose, along with a signature guarantee and such
     other and further documentation as the Rights Agent may reasonably request,
     together with payment of the aggregate Purchase Price with respect to the
     total number of one one-thousandths of a share of Preferred Stock (or,
     following the occurrence of a Triggering Event, Common Stock or other
     securities, cash or other assets, as the case may be) as to which such
     surrendered Rights are then exercisable, at or prior to the earlier of (i)
     the Close of Business on May 6, 2010 (the "Final Expiration Date"), (ii)
                                                ---------------------
     the time at which the Rights are redeemed as provided in Section 23 hereof
     (the "Redemption Date"), (iii) the time at which such Rights are exchanged
           ---------------
     as provided in Section 24 hereof, or (iv) the consummation of a transaction
     contemplated by Section 13(d) hereof (the earliest of (i), (ii), (iii) and
     (iv) being herein referred to as the "Expiration Date").
                                           ---------------

          (b)  Purchase Price. The Purchase Price for each one one-thousandth of
               --------------
     a share of Preferred Stock to be purchased pursuant to the exercise of a
     Right shall initially be $85.00, and shall be subject to adjustment from
     time to time as provided in Sections 11 and 13(a) hereof and shall be
     payable in accordance with Section 7(c).

          (c)  Deliveries Upon Exercise of Rights.  Upon receipt of a Rights
               ----------------------------------
     Certificate representing exercisable Rights, with the form of election to
     purchase and the related certification set forth on the reverse side
     thereof  duly executed along with a signature guarantee and such other and
     further documentation as the Rights Agent may reasonably request, together
     with payment of the aggregate Purchase Price with respect to the total


                                       12
<PAGE>

     number of one one-thousandths of a share of Preferred Stock (or, following
     the occurrence of a Triggering Event, Common Stock or other securities,
     cash or other assets, as the case may be) to be purchased and an amount
     equal to any applicable U.S. federal or state transfer tax or governmental
     charge required to be paid by the holder of such Rights Certificate in
     accordance with Section 9(e) hereof, the Rights Agent shall, subject to
     Section 20(k) hereof, thereupon promptly (i) (A) requisition from any
     transfer agent of the shares of Preferred Stock (or make available, if the
     Rights Agent is the transfer agent for such shares) certificates for the
     total number of one one-thousandths of a share of Preferred Stock to be
     purchased, and the Company hereby irrevocably authorizes its transfer agent
     to comply with all such requests, or (B) if the Company shall have elected
     to deposit the total number of shares of Preferred Stock issuable upon
     exercise of the Rights hereunder with a depositary agent, requisition from
     the depositary agent depositary receipts representing such number of one
     one-thousandths of a share of Preferred Stock as are to be purchased (in
     which case certificates for the shares of Preferred Stock represented by
     such receipts shall be deposited by the transfer agent with the depositary
     agent), and the Company will direct the depositary agent to comply with
     such request, (ii) requisition from the Company the amount of cash, if any,
     to be paid in lieu of fractional shares in accordance with Section 14
     hereof, (iii) promptly after receipt of such aforementioned certificates or
     depositary receipts, cause the same to be delivered to or upon the order of
     the record holder of such Rights Certificate, registered in such name or
     names as may be designated by such holder, and (iv) after receipt thereof,
     promptly deliver such aforementioned cash, if any, to or upon the order of
     the record holder of such Rights Certificate. The payment of the Purchase
     Price (as such amount may be reduced pursuant to Section 11(a)(iii) hereof)
     shall be made in cash or by certified bank check or bank draft payable to
     the order of the Company. In the event that the Company is obligated to
     issue other securities (including Common Stock) of the Company, pay cash
     and/or distribute other property upon exercise of the Rights pursuant to
     Section 11(a) hereof, the Company will make all arrangements necessary so
     that such other securities, cash and/or other property are available for
     distribution by the Rights Agent, if and when necessary to comply with this
     Agreement. The Company reserves the right to require, prior to the
     occurrence of a Triggering Event that, upon any exercise of Rights, a
     number of Rights be exercised so that only whole shares of Preferred Stock
     would be issued.

          (d)  New Rights Certificate Issued for Unexercised Rights. In case the
               ----------------------------------------------------
     record holder of any Rights Certificate shall exercise less than all the
     Rights evidenced thereby, a new Rights Certificate evidencing Rights
     equivalent to the Rights remaining unexercised shall be issued by the
     Rights Agent and delivered to, or upon the order of, the record holder of
     such Rights Certificate, registered in such name or names as may be
     designated by such holder, subject to the provisions of Section 6 and
     Section 14 hereof.

          (e)  Rights Owned by an Acquiring Person To Become Null and Void.
               -----------------------------------------------------------
     Notwithstanding anything in this Agreement to the contrary, from and after
     the first occurrence of a Section 11(a)(ii) Event, any Rights beneficially
     owned by (i) an Acquiring Person or an Affiliate or Associate of an
     Acquiring Person, (ii) a transferee of an Acquiring Person (or of any such
     Associate or Affiliate) who becomes a transferee after the Acquiring Person
     becomes such, or (iii) a transferee of an Acquiring Person (or

                                       13
<PAGE>

     of any such Associate or Affiliate) who becomes a transferee prior to or
     concurrently with the Acquiring Person becoming such and receives such
     Rights pursuant to either (A) a transfer (whether or not for consideration)
     from the Acquiring Person to holders of equity interests in such Acquiring
     Person or to any Person with whom the Acquiring Person has any continuing
     agreement, arrangement or understanding regarding the transferred Rights or
     (B) a transfer that the Board of Directors has determined is part of a
     plan, arrangement or understanding which has as a primary purpose or effect
     the avoidance of this Section 7(e), shall become null and void without any
     further action, and no record holder of such Rights shall have any rights
     whatsoever with respect to such Rights, whether under any provision of this
     Agreement or otherwise. The Company shall notify the Rights Agent as soon
     as practicable after the Company obtains knowledge that this Section 7(e)
     has become applicable and shall use all reasonable efforts to ensure that
     the provisions of this Section 7(e) and Section 4(b) hereof are complied
     with, but neither the Rights Agent nor the Company shall have any liability
     to any record holder of Rights Certificates or other Person as a result of
     the Company's failure to make any determinations with respect to an
     Acquiring Person or its Affiliates, Associates or transferees hereunder.
     The Company may require (or cause the Rights Agent or any transfer agent of
     the Company to require) any Person who submits a Rights Certificate (or a
     certificate representing shares of Common Stock that evidences, or but for
     the provisions of this Section 7(e) would evidence, Rights) for transfer on
     the registry books or to exercise the Rights represented thereby, to
     establish to the satisfaction of the Company in its sole discretion that
     such Rights have not become null and void pursuant to the provisions of
     this Section 7(e).

            (f)  Certification and Evidence of Identity Required.
                 -----------------------------------------------
     Notwithstanding anything in this Agreement to the contrary, neither the
     Rights Agent nor the Company shall be obligated to undertake any action
     with respect to a record holder upon the occurrence of any purported
     exercise as set forth in this Section 7 unless such holder shall have (i)
     properly completed and signed the certification contained in the form of
     election to purchase set forth on the reverse side of the Rights
     Certificate surrendered for such exercise, and (ii) provided such
     additional evidence of the identity of the Beneficial Owner (or former
     Beneficial Owner) or Affiliates or Associates thereof as the Company or the
     Rights Agent shall reasonably request.

     Section 8.  Cancellation and Destruction of Rights Certificates.  All
                 ---------------------------------------------------
Rights Certificates surrendered for the purpose of exercise, transfer, split up,
combination or exchange shall, if surrendered to the Company or any of its
agents, be delivered to the Rights Agent for cancellation or in canceled form,
or, if surrendered to the Rights Agent, shall be canceled by it, and no Rights
Certificates shall be issued in lieu thereof except as expressly permitted by
the provisions of this Agreement.  The Company shall deliver to the Rights Agent
for cancellation and retirement, and the Rights Agent shall so cancel and
retire, any Rights Certificates purchased or acquired by the Company.  The
Rights Agent shall deliver a certificate of cancellation to the Company with
respect to each canceled Rights Certificate and shall destroy such canceled
Rights Certificates in accordance with applicable law and regulations.

                                       14
<PAGE>

     Section 9.  Reservation and Availability of Capital Stock.
                 ---------------------------------------------

            (a)  Reservation and Availability of Capital Stock.  The Company
                 ---------------------------------------------
     covenants and agrees that it will cause to be reserved and kept available
     out of its authorized and unissued shares of Preferred Stock (and,
     following the occurrence of a Triggering Event, out of its authorized and
     unissued shares of Common Stock and/or other securities or out of its
     authorized and issued shares of Common Stock and/or other securities held
     in its treasury), the number of shares of Preferred Stock (and, following
     the occurrence of a Triggering Event, Common Stock and/or other securities)
     that, as provided in this Agreement, including Section 11(a)(iii) hereof,
     will be sufficient to permit the exercise in full of all outstanding
     Rights.

            (b)  Reserved Shares To Be Listed Upon Issuance. So long as the
                 -------------------------------------------
     shares of Preferred Stock (and, following the occurrence of a Triggering
     Event, Common Stock and/or other securities) issuable and deliverable upon
     the exercise of the Rights may be listed on any national securities
     exchange or national automated quotation system, the Company shall use its
     best efforts to cause, from and after such time as the Rights become
     exercisable (but only to the extent that it is reasonably likely that the
     Rights will be exercised), all shares reserved for such issuance to be
     listed on such exchange or authorized to be quoted on such quotation system
     upon official notice of issuance upon such exercise.

            (c)  Registration of Securities to be Acquired Upon Exercise of
                 ----------------------------------------------------------
     Rights. The Company shall use its best efforts to (i) file, as soon as
     ------
     practicable following the earliest date after the first occurrence of a
     Section 11(a)(ii) Event on which the consideration to be delivered by the
     Company upon exercise of the Rights has been determined in accordance with
     Section 11(a)(ii) and 11(a)(iii) hereof, a registration statement under the
     Act with respect to the securities purchasable upon exercise of the Rights
     on an appropriate form, (ii) cause such registration statement to become
     effective as soon as practicable after such filing, and (iii) cause such
     registration statement to remain effective (with a prospectus at all times
     meeting the requirements of the Act) until the earlier of (A) the date as
     of which the Rights are no longer exercisable for such securities, and (B)
     the Expiration Date. The Company also will take such action as may be
     appropriate under, or to ensure compliance with, the securities or "blue
     sky" laws of the various states in connection with the exercisability of
     the Rights. The Company may temporarily suspend, for a period of time not
     to exceed ninety (90) days after the date set forth in clause (i) of the
     first sentence of this Section 9(c), the exercisability of the Rights in
     order to prepare and file such registration statement and permit it to
     become effective. Upon any such suspension, the Company shall make a public
     announcement, and shall give simultaneous written notice to the Rights
     Agent, stating that the exercisability of the Rights has been temporarily
     suspended, as well as a public announcement at such time as the suspension
     is no longer in effect. The Company shall promptly provide the Rights Agent
     with copies of such announcements. In addition, if the Company shall
     determine that a registration statement is required following the
     Distribution Date, the Company may temporarily suspend the exercisability
     of the Rights (with prompt notice of such suspension to the Rights Agent)
     until such time as a registration statement has been declared effective.
     Notwithstanding any provision of this Agreement to the contrary, the

                                       15
<PAGE>

     Rights shall not be exercisable in any jurisdiction if the requisite
     qualification in such jurisdiction shall not have been obtained, the
     exercise thereof shall not be permitted under applicable law or a
     registration statement shall not have been declared effective.

          (d) Stock To Be Validly Issued.  The Company covenants and agrees that
              --------------------------
     it will take all such action as may be necessary to ensure that all one
     one-thousandths of a share of Preferred Stock (and, following the
     occurrence of a Triggering Event, Common Stock and/or other securities, as
     the case may be) delivered upon exercise of Rights shall, at the time of
     delivery of the certificates for such Preferred Stock, Common Stock, or
     other securities, as the case may be (subject to payment of the Purchase
     Price), be duly and validly authorized and issued, and fully paid and
     nonassessable including, without limitation, effecting such changes to the
     accounts of the Company as may be necessary to accomplish the foregoing
     purposes.

          (e) Transfer Taxes.  The Company covenants and agrees that it will pay
              --------------
     when due and payable any and all U.S. federal and state transfer taxes and
     governmental charges that may be payable in respect of the issuance or
     delivery of the Rights Certificates and any certificates for a number of
     one one-thousandths of a share of Preferred Stock (or Common Stock and/or
     other securities, as the case may be) upon the exercise of the Rights.  The
     Company shall not, however, be required to pay any U.S. federal or state
     transfer tax or governmental charge that may be payable in respect of any
     transfer or delivery of Rights Certificates to a Person other than, or the
     issuance or delivery of certificates or depositary receipts for a number of
     one one-thousandths of a share of Preferred Stock (or Common Stock and/or
     other securities, as the case may be) in respect of a name other than that
     of, the record holder of the Rights Certificates evidencing Rights
     surrendered for exercise or to issue or deliver any certificates for a
     number of one one-thousandths of a share of Preferred Stock (or, following
     the occurrence of a Triggering Event, Common Stock and/or other securities,
     as the case may be) in a name other than that of the record holder upon the
     exercise of any Rights until such U.S. federal or state transfer tax or
     governmental charge shall have been paid (any such U.S. federal or state
     transfer tax or governmental charge being payable by the holder of such
     Rights Certificate at the time of surrender) or until it has been
     established to the Company's satisfaction that no such U.S. federal or
     state transfer tax or governmental charge is due.

     SECTION 10.    Preferred Stock Record Date.  Each Person in whose name any
                    ---------------------------
certificate for a number of one one-thousandths of a share of Preferred Stock
(or Common Stock and/or other securities, as the case may be) is issued upon the
exercise of Rights shall for all purposes be deemed to have become the holder of
record of such fractional shares of Preferred Stock (or Common Stock and/or
other securities, as the case may be) represented thereby on, and such
certificate shall be dated, the date upon which the Rights Certificate
evidencing such Rights was duly surrendered and payment of the aggregate
Purchase Price (and all applicable U.S. federal or state transfer taxes or
governmental charges) was made; provided, however, that if the date of such
                                --------  -------
surrender and payment is a date upon which the Preferred Stock (or Common Stock
and/or other securities, as the case may be) transfer books of the Company are
closed, such Person shall be deemed to have become the record holder of such
shares (fractional or otherwise) on, and such certificate shall be dated, the
next succeeding Business Day on which the Preferred

                                       16
<PAGE>

Stock (or Common Stock and/or other securities, as the case may be) transfer
books of the Company are open. Prior to the exercise of the Rights evidenced
thereby, the record holder of a Rights Certificate shall not be entitled to any
rights of a stockholder of the Company with respect to shares for which the
Rights shall be exercisable, including, without limitation, the right to vote,
to receive dividends or other distributions or to exercise any preemptive
rights, and shall not be entitled to receive any notice of any proceedings of
the Company, except as provided herein.

     SECTION 11.    Adjustment of Purchase Price, Number and Kind of Shares and
                    -----------------------------------------------------------
Number of Rights.  The Purchase Price, the number and kind of shares covered by
----------------
each Right and the number of Rights outstanding are subject to adjustment from
time to time as provided in this Section 11.

          (a) Adjustment of Purchase Price Upon Declaration of Stock Dividend or
              ------------------------------------------------------------------
     Subdivision, Combination or Reclassification of Preferred Stock; Adjustment
     ---------------------------------------------------------------------------
     of Number and Kind of Shares Upon Person Becoming an Acquiring Person;
     ----------------------------------------------------------------------
     Substitution for Adjustment Shares.
     ----------------------------------

               (i) In the event the Company shall at any time after the date of
          this Agreement (A) declare a dividend on the Preferred Stock payable
          in shares of Preferred Stock, (B) subdivide the outstanding Preferred
          Stock, (C) combine the outstanding Preferred Stock into a smaller
          number of shares, or (D) issue any shares of its capital stock in a
          reclassification of the Preferred Stock (including any such
          reclassification in connection with a consolidation or merger in which
          the Company is the continuing or surviving corporation), except as
          otherwise provided in this Section 11(a) and Section 7(e) hereof, the
          Purchase Price in effect at the time of the record date for such
          dividend or of the effective date of such subdivision, combination or
          reclassification, and the number and kind of shares of Preferred Stock
          or capital stock, as the case may be, issuable on such date, shall be
          proportionately adjusted so that the record holder of any Right
          exercised after such time shall be entitled to receive, upon payment
          of the Purchase Price then in effect, the aggregate number and kind of
          shares of Preferred Stock (or Common Stock and/or other securities, as
          the case may be), which, if such Right had been exercised immediately
          prior to such date and at a time when the Preferred Stock transfer
          books of the Company were open, such record holder would have owned
          upon such exercise and been entitled to receive by virtue of such
          dividend, subdivision, combination or reclassification.  If an event
          occurs which would require an adjustment under both this Section
          11(a)(i) and Section 11(a)(ii) hereof, the adjustment provided for in
          this Section 11(a)(i) shall be in addition to, and shall be made prior
          to, any adjustment required pursuant to Section 11(a)(ii) hereof.

               (ii) Subject to Section 24 hereof, in the event any Person, alone
          or together with its Affiliates and Associates, shall, at any time
          after the Rights Distribution Declaration Date, become an Acquiring
          Person (such an event being referred to herein as a "Section 11(a)(ii)
                                                               -----------------
          Event"), then, promptly following the occurrence of such Section
          -----
          11(a)(ii) Event, proper provision shall be made by the

                                       17
<PAGE>

          Company so that each holder of a Right (except as provided below and
          in Section 7(e) hereof) shall thereafter have the right to receive,
          upon exercise thereof at the then current Purchase Price in accordance
          with the terms of this Agreement, in lieu of a number of one one-
          thousandths of a share of Preferred Stock, such number of shares of
          Common Stock of the Company as shall equal the result obtained by (x)
          multiplying the then current Purchase Price by the then number of one
          one-thousandths of a share of Preferred Stock for which a Right was
          exercisable immediately prior to the first occurrence of a Section
          11(a)(ii) Event, and (y) dividing that product (which, following such
          first occurrence, shall thereafter be referred to as the "Purchase
                                                                    --------
          Price" for each Right and for all purposes of this Agreement) by 50%
          -----
          of the Current Market Price (determined pursuant to Section 11(d)(i)
          hereof) per share of Common Stock on the date of such first occurrence
          (such number of shares being referred to as the "Adjustment Shares");
                                                           -----------------
          provided, however, that if the transaction that would otherwise give
          --------  -------
          rise to the foregoing adjustment is also subject to the provisions of
          Section 13 hereof, then only the provisions of Section 13 hereof shall
          apply and no adjustment shall be made pursuant to this Section
          11(a)(ii).

               (iii)  Subject to such limitations existing as of the date hereof
          as are necessary to prevent a default under any agreement to which the
          Company is a party, in the event that the number of shares of Common
          Stock that are authorized by the Company's certificate of
          incorporation but not outstanding or reserved for issuance for
          purposes other than upon exercise of the Rights are not sufficient to
          permit the exercise in full of the Rights in accordance with Section
          11(a)(ii), the Company, acting by resolution of its Board of Directors
          shall (A) determine the excess of (x) the value of the Adjustment
          Shares issuable upon the exercise of a Right determined as set forth
          below (the "Current Value"), over (y) the Purchase Price (such excess,
                      -------------
          the "Spread"), and (B) with respect to each Right (subject to Section
               ------
          7(e) hereof), make adequate provision to substitute for the Adjustment
          Shares, upon the exercise of a Right and payment of the applicable
          Purchase Price, (1) cash, (2) a reduction in the Purchase Price, (3)
          Common Stock or other equity securities of the Company (including,
          without limitation, shares or units of shares of preferred stock, such
          as the Preferred Stock, which the Board of Directors has deemed to
          have essentially the same value or economic rights as shares of Common
          Stock (such shares of preferred stock or other equity securities being
          referred to as "Common Stock Equivalents")), (4) debt securities of
                          ------------------------
          the Company, (5) other assets, or (6) any combination of the
          foregoing, having an aggregate value equal to the Current Value, where
          such aggregate value has been determined by the Board of Directors
          based upon the advice of a nationally recognized investment banking
          firm selected by the Board of Directors; provided, however, that if
                                                   --------  -------
          the Company shall not have made adequate provision to deliver value
          pursuant to clause (B) above within thirty (30) days following the
          date on which the Company's right of redemption pursuant to Section
          23(a) expires (such date being referred to herein as the "Section
                                                                    -------
          11(a)(ii) Trigger Date"), then the Company shall be obligated to
          -----------------------
          deliver, upon the surrender for exercise of a Right and without
          requiring payment of the Purchase Price (other than an amount equal to
          the par value of the shares of Common Stock to be issued), shares of
          Common

                                       18
<PAGE>

          Stock (to the extent available) and then, if necessary, cash, which
          shares and/or cash have an aggregate value equal to the Spread. If the
          Board of Directors determines in good faith that it is likely that
          sufficient additional shares of Common Stock could be authorized for
          issuance upon exercise in full of the Rights, the thirty (30) day
          period set forth above may be extended to the extent necessary, but
          not more than ninety (90) days after the Section 11(a)(ii) Trigger
          Date, in order that the Company may seek stockholder approval for the
          authorization of such additional shares (such thirty (30) day period,
          as it may be extended, is herein called the "Substitution Period").
                                                       -------------------
          To the extent that action is to be taken pursuant to the first and/or
          second sentences of this Section 11(a)(iii), the Company (1) shall
          provide, subject to Section 7(e) hereof, that such action shall apply
          uniformly to all outstanding Rights, and (2) may suspend the
          exercisability of the Rights until the expiration of the Substitution
          Period in order to seek such stockholder approval for such
          authorization of additional shares and/or to decide the appropriate
          form of distribution to be made pursuant to such first sentence and to
          determine the value thereof.  In the event of any such suspension, the
          Company shall make a public announcement and shall give simultaneous
          written notice to the Rights Agent stating that the exercisability of
          the Rights has been temporarily suspended, as well as a public
          announcement at such time as the suspension is no longer in effect.
          For purposes of this Section 11(a)(iii), the Current Value of each
          Adjustment Share shall be the Current Market Price per share of the
          Common Stock on the Section 11(a)(ii) Trigger Date, and the per share
          or per unit value of any Common Stock Equivalent shall be deemed to
          equal the Current Market Price per share of the Common Stock on such
          date.

          (b) Adjustment of Purchase Price Upon Issuance of Rights, Options or
              ----------------------------------------------------------------
     Warrants to Holders of Preferred Stock.  In case the Company shall fix a
     --------------------------------------
     record date for the issuance of rights, options or warrants to all record
     holders of Preferred Stock entitling them to subscribe for or purchase (for
     a period expiring within forty-five (45) calendar days after such record
     date) Preferred Stock (or shares having the same rights, privileges and
     preferences as the shares of Preferred Stock ("Equivalent Preferred
                                                    --------------------
     Stock")) or securities convertible into Preferred Stock or Equivalent
     -----
     Preferred Stock at a price per share of Preferred Stock or per share of
     Equivalent Preferred Stock (or having a conversion price per share, if a
     security convertible into Preferred Stock or Equivalent Preferred Stock)
     less than the Current Market Price (determined pursuant to Section
     11(d)(ii) hereof) per share of Preferred Stock on such record date, the
     Purchase Price to be in effect after such record date shall be determined
     by multiplying the Purchase Price in effect immediately prior to such
     record date by a fraction, the numerator of which shall be the number of
     shares of Preferred Stock and Equivalent Preferred Stock outstanding on
     such record date plus the number of shares of Preferred Stock and
     Equivalent Preferred Stock which the aggregate offering price of the total
     number of shares of Preferred Stock and/or Equivalent Preferred Stock so to
     be offered (and/or the aggregate initial conversion price of the
     convertible securities so to be offered) would purchase at such Current
     Market Price, and the denominator of which shall be the number of shares of
     Preferred Stock and Equivalent Preferred Stock outstanding on such record
     date plus the number of additional shares of Preferred Stock and/or
     Equivalent Preferred Stock to

                                       19
<PAGE>

     be offered for subscription or purchase (or into which the convertible
     securities so to be offered are initially convertible). In case such
     subscription price may be paid by delivery of consideration part or all of
     which may be in a form other than cash, the value of such consideration
     shall be as determined in good faith by the Board of Directors, whose
     determination shall be described in a statement filed with the Rights Agent
     and shall be binding on the Rights Agent and the holders of the Rights.
     Shares of Preferred Stock and Equivalent Preferred Stock owned by or held
     for the account of the Company shall not be deemed outstanding for the
     purpose of any such computation. Such adjustment shall be made successively
     whenever such a record date is fixed, and in the event that such rights or
     warrants are not so issued, the Purchase Price shall be adjusted to be the
     Purchase Price which would then be in effect if such record date had not
     been fixed.

          (c) Adjustment of Purchase Price Upon Distributions to Holders of
              -------------------------------------------------------------
     Preferred Stock.  In case the Company shall fix a record date for a
     ---------------
     distribution to all record holders of Preferred Stock (including any such
     distribution made in connection with a consolidation or merger in which the
     Company is the continuing or surviving corporation) of evidences of
     indebtedness, cash (other than a regular quarterly cash dividend out of the
     earnings or retained earnings of the Company), assets (other than a
     dividend payable in Preferred Stock, but including any dividend payable in
     stock other than Preferred Stock) or subscription rights or warrants
     (excluding those referred to in Section 11(b) hereof), the Purchase Price
     to be in effect after such record date shall be determined by multiplying
     the Purchase Price in effect immediately prior to such record date by a
     fraction, the numerator of which shall be the Current Market Price per
     share of Preferred Stock on such record date less the fair market value (as
     determined in good faith by the Board of Directors, whose determination
     shall be described in a statement filed with the Rights Agent and shall be
     binding on the Rights Agent and the holders of the Rights) of the portion
     of the cash, assets or evidences of indebtedness so to be distributed or of
     such subscription rights or warrants applicable to a share of Preferred
     Stock, and the denominator of which shall be the Current Market Price per
     share of Preferred Stock on such record date.  Such adjustments shall be
     made successively whenever such a record date is fixed, and in the event
     that such distribution is not so made, the Purchase Price shall be adjusted
     to be the Purchase Price which would have been in effect if such record
     date had not been fixed.

          (d) Definition of Current Market Price.
              ----------------------------------

               (i) For the purpose of any computation hereunder other than
          computations made pursuant to Section 11(a)(iii) hereof, the "Current
                                                                        -------
          Market Price" per share of Common Stock on any date shall be deemed to
          ------------
          be the average of the daily closing prices per share of such Common
          Stock for the thirty (30) consecutive Trading Days immediately prior
          to but not including such date, and for purposes of computations made
          pursuant to Section 11(a)(iii) hereof, the Current Market Price per
          share of Common Stock on any date shall be deemed to be the average of
          the daily closing prices per share of such Common Stock for the ten
          (10) consecutive Trading Days immediately following but not including
          such date; provided, however, that in the event that the Current
                     --------  -------
          Market Price per share of Common Stock is determined during a period
          following the announcement by

                                       20
<PAGE>

          the issuer of such Common Stock of (A) a dividend or distribution on
          such Common Stock payable in shares of such Common Stock or securities
          convertible into shares of such Common Stock (other than the Rights),
          or (B) any subdivision, combination or reclassification of such Common
          Stock, and the ex-dividend or ex-distribution date for such dividend
          or distribution, or the record date for such subdivision, combination
          or reclassification shall not have occurred prior to the commencement
          of the requisite thirty (30) Trading Day or ten (10) Trading Day
          period, as set forth above, then, and in each such case, the Current
          Market Price shall be properly adjusted to reflect the current market
          per share equivalent. The closing price for each day shall be the last
          sale price, regular way, or, in case no such sale takes place on such
          day, the average of the closing bid and asked prices, regular way, in
          either case as reported in the principal consolidated transaction
          reporting system with respect to securities listed or admitted to
          trading on the New York Stock Exchange or, if the shares of Common
          Stock are not listed or admitted to trading on the New York Stock
          Exchange, as reported in the principal consolidated transaction
          reporting system with respect to securities listed on the principal
          national securities exchange on which the shares of Common Stock are
          listed or admitted to trading or, if the shares of Common Stock are
          not listed or admitted to trading on any national securities exchange,
          the last sale price, regular way, or, if such last sale price is not
          reported, the average of the high bid and low asked prices in the
          over-the-counter market, as reported by NASDAQ or such other system
          then in use, or, if on any such date the shares of Common Stock are
          not quoted by any such organization, the average of the closing bid
          and asked prices as furnished by a professional market maker making a
          market in the Common Stock selected by the Board of Directors. If on
          any such date no market maker is making a market in the Common Stock,
          the fair value of such shares on such date as determined in good faith
          by the Board of Directors shall be used. The term "Trading Day" shall
                                                             -----------
          mean a day on which the principal national securities exchange on
          which the shares of Common Stock are listed or admitted to trading is
          open for the transaction of business or, if the shares of Common Stock
          are not listed or admitted to trading on any national securities
          exchange, a Business Day. Notwithstanding the first sentence of this
          Section 11(d)(i), if the Common Stock is not publicly held or not so
          listed or traded, Current Market Price per share of the Common Stock
          shall mean the fair value per share as determined in good faith by the
          Board of Directors, whose determination shall be described in a
          statement filed with the Rights Agent and shall be conclusive for all
          purposes.

               (ii) For the purpose of any computation hereunder, the Current
          Market Price per share of Preferred Stock shall be determined in the
          same manner as set forth for the Common Stock in Section 11(d)(i)
          (other than the last sentence thereof).  If the Current Market Price
          per share of Preferred Stock cannot be determined in the manner
          provided above or if the Preferred Stock is not publicly held or
          listed or traded in a manner described in Section 11(d)(i), the
          Current Market Price per share of Preferred Stock shall be
          conclusively deemed to be an amount equal to 1000 (as such number may
          be appropriately adjusted for such events as stock splits, stock
          dividends and recapitalizations with respect to the

                                       21
<PAGE>

          Common Stock occurring after the date of this Agreement) multiplied by
          the Current Market Price per share of the Common Stock. If neither the
          Common Stock nor the Preferred Stock is publicly held or so listed or
          traded, Current Market Price per share of the Preferred Stock shall
          mean the fair value per share as determined in good faith by the Board
          of Directors, whose determination shall be described in a statement
          filed with the Rights Agent and shall be conclusive for all purposes.
          For all purposes of this Agreement, the Current Market Price of one
          one-thousandth of a share of Preferred Stock shall be equal to the
          Current Market Price of one share of Preferred Stock divided by 1000.

          (e) Limitation on Adjustments to Purchase Price.  Anything herein to
              -------------------------------------------
     the contrary notwithstanding, no adjustment in the Purchase Price shall be
     required unless such adjustment would require an increase or decrease of at
     least one percent (1%) in the Purchase Price; provided, however, that any
                                                   --------  -------
     adjustments which by reason of this Section 11(e) are not required to be
     made shall be carried forward and taken into account in any subsequent
     adjustment.  All calculations under this Section 11 shall be made to the
     nearest cent or to the nearest hundred-thousandth of a share of Common
     Stock or other share or one-millionth of a share of Preferred Stock, as the
     case may be.  Notwithstanding the first sentence of this Section 11(e), any
     adjustment required by this Section 11 shall be made no later than the
     earlier of (i) three (3) years from the date of the transaction which
     mandates such adjustment, or (ii) the Expiration Date.

          (f) Applicability of Certain Provisions to Shares of Capital Stock
              --------------------------------------------------------------
     Other Than Preferred Stock.  If as a result of an adjustment made pursuant
     --------------------------
     to Section 11(a)(ii) or Section 13(a) hereof the holder of any Right
     thereafter exercised shall become entitled to receive any shares of capital
     stock other than Preferred Stock, thereafter the number of such other
     shares so receivable upon exercise of any Right and the Purchase Price
     thereof shall be subject to adjustment from time to time in a manner and on
     terms as nearly equivalent as practicable to the provisions with respect to
     the Preferred Stock contained in Sections 11(a), (b), (c), (e), (g), (h),
     (i), (j), (k) and (m), and the provisions of Sections 7, 9, 10, 13 and 14
     hereof with respect to the Preferred Stock shall apply on like terms to any
     such other shares.

          (g) Purchase Price for Rights Issued After Adjustment to Purchase
              -------------------------------------------------------------
     Price.  All Rights originally issued by the Company subsequent to any
     -----
     adjustment made to the Purchase Price hereunder shall evidence the right to
     purchase, at the adjusted Purchase Price, the number of one one-thousandths
     of a share of Preferred Stock purchasable from time to time hereunder upon
     exercise of the Rights, all subject to further adjustment as provided
     herein.

          (h) Adjustment of Number of Shares of Preferred Stock Covered By a
              --------------------------------------------------------------
     Right.  Unless the Company shall have exercised its election to adjust the
     -----
     number of Rights as provided in Section 11(i), upon each adjustment of the
     Purchase Price as a result of the calculations made in Sections 11(b) and
     (c), each Right outstanding immediately prior to the making of such
     adjustment shall thereafter evidence the right to purchase, at the adjusted
     Purchase Price, that number of one one-thousandths of a share of Preferred
     Stock (calculated to the nearest one-millionth) obtained by (i) multiplying
     (x) the number

                                       22
<PAGE>

     of one one-thousandths of a share covered by a Right immediately prior to
     this adjustment, by (y) the Purchase Price in effect immediately prior to
     such adjustment of the Purchase Price, and (ii) dividing the product so
     obtained by the Purchase Price in effect immediately after such adjustment
     of the Purchase Price.

          (i) Election To Adjust the Number of Rights.  The Company may elect on
              ---------------------------------------
     or after the date of any adjustment of the Purchase Price to adjust the
     number of Rights in lieu of any adjustment in the number of one one-
     thousandths of a share of Preferred Stock purchasable upon the exercise of
     a Right.  Each of the Rights outstanding after the adjustment in the number
     of Rights shall be exercisable for the number of one one-thousandths of a
     share of Preferred Stock for which a Right was exercisable immediately
     prior to such adjustment.  Each Right held of record prior to such
     adjustment of the number of Rights shall become that number of Rights
     (calculated to the nearest one-millionth) obtained by dividing the Purchase
     Price in effect immediately prior to adjustment of the Purchase Price by
     the Purchase Price in effect immediately after adjustment of the Purchase
     Price.  The Company shall make a public announcement and shall give
     simultaneous written notice to the Rights Agent of its election to adjust
     the number of Rights, indicating the record date for the adjustment, and,
     if known at the time, the amount of the adjustment to be made.  This record
     date may be the date on which the Purchase Price is adjusted or any day
     thereafter, but, if the Rights Certificates have been issued, shall be at
     least ten (10) days later than the date of the public announcement.  If
     Rights Certificates have been issued, upon each adjustment of the number of
     Rights pursuant to this Section 11(i), the Company shall, as promptly as
     practicable, cause to be distributed to holders of Rights Certificates on
     such record date Rights Certificates evidencing, subject to Section 14
     hereof, the additional Rights to which such holders shall be entitled as a
     result of such adjustment, or, at the option of the Company, shall cause to
     be distributed to such holders in substitution and replacement for the
     Rights Certificates held by such holders prior to the date of adjustment,
     and upon surrender thereof, if required by the Company, new Rights
     Certificates evidencing all the Rights to which such holders shall be
     entitled after such adjustment.  Rights Certificates so to be distributed
     shall be issued, executed and countersigned in the manner provided for
     herein (and may bear, at the option of the Company, the adjusted Purchase
     Price) and shall be registered in the names of the holders of record of
     Rights Certificates on the record date specified in the public
     announcement.

          (j) Rights Certificates Need Not Reflect Certain Adjustments.
              --------------------------------------------------------
     Irrespective of any adjustment or change in the Purchase Price or the
     number by one one-thousandths of a share of Preferred Stock issuable upon
     the exercise of the Rights, the Rights Certificates theretofore and
     thereafter issued may continue to express the Purchase Price per one one-
     thousandths of a share and the number of one one-thousandths of a share
     which were expressed in the initial Rights Certificates issued hereunder.

          (k) Stock To Be Fully Paid and Non-Assessable.  Before taking any
              -----------------------------------------
     action that would cause an adjustment reducing the Purchase Price below the
     then par value, if any, of the one one-thousandths of a share of Preferred
     Stock issuable upon exercise of the Rights, or the par value, if any, of
     any shares of any other capital stock issuable upon exercise of the Rights,
     the Company shall take any corporate action which may, in the

                                       23
<PAGE>

     opinion of its counsel, be necessary in order that the Company may validly
     and legally issue fully paid and non-assessable one one-thousandths of a
     share of Preferred Stock, or other shares of capital stock, as the case may
     be, at such adjusted Purchase Price. If upon any exercise of the Rights, a
     holder is to receive a combination of Common Stock and Common Stock
     Equivalents, a portion of the consideration paid upon such exercise, equal
     to at least the then par value of a share of Common Stock, shall be
     allocated as the payment for each share of Common Stock so received.

          (l) Election to Defer Issuance of Certain Shares Until After Record
              ---------------------------------------------------------------
     Date for Adjustment Event.  In any case in which this Section 11 shall
     -------------------------
     require that an adjustment in the Purchase Price be made effective as of a
     record date for a specified event, the Company may elect to defer (with
     prompt notice of such election to the Rights Agent), until the occurrence
     of such event, the issuance to the record holder of any Right exercised
     after such record date the number of one one-thousandths of a share of
     Preferred Stock and other capital stock or securities of the Company, if
     any, issuable upon such exercise over and above the number of one one-
     thousandths of a share of Preferred Stock, and other capital stock or
     securities of the Company, if any, issuable upon such exercise on the basis
     of the Purchase Price in effect prior to such adjustment; provided,
                                                               --------
     however, that the Company shall deliver to such holder a due bill or other
     -------
     appropriate instrument evidencing such holder's right to receive such
     additional shares (fractional or otherwise) or securities upon the
     occurrence of the event requiring such adjustment.

          (m) Reductions in Purchase Price to Avoid Taxable Events.  Anything in
              ----------------------------------------------------
     this Section 11 to the contrary notwithstanding, the Company shall be
     entitled to make such reductions in the Purchase Price, in addition to
     those adjustments expressly required by this Section 11, as and to the
     extent that in their good faith judgment the Board of Directors shall
     determine to be advisable in order that any (i) consolidation or
     subdivision of the Preferred Stock, (ii) issuance wholly for cash of any
     shares of Preferred Stock at less than the Current Market Price thereof,
     (iii) issuance wholly for cash of shares of Preferred Stock or securities
     which by their terms are convertible into or exchangeable for shares of
     Preferred Stock, (iv) stock dividends, or (v) issuance of rights, options
     or warrants referred to in this Section 11, hereafter made by the Company
     to holders of its Preferred Stock shall not be taxable to such holders.

          (n) No Consolidation, Merger or Sale of More Than 50% of Assets or
              --------------------------------------------------------------
     Earning Power.  The Company covenants and agrees that it shall not, at any
     -------------
     time after the Distribution Date and so long as the Rights have not been
     redeemed pursuant to Section 23 hereof or exchanged pursuant to Section 24
     hereof, (i) consolidate with any other Person (other than a Subsidiary of
     the Company in a transaction that complies with Section 11(o) hereof), (ii)
     merge with or into any other Person (other than a Subsidiary of the Company
     in a transaction that complies with Section 11(o) hereof), or (iii) sell or
     transfer (or permit any Subsidiary to sell or transfer), in one
     transaction, or a series of related transactions, assets or earning power
     aggregating more than 50% of the assets or earning power of the Company and
     its Subsidiaries (taken as a whole) to any other Person or Persons (other
     than the Company and/or any of its Subsidiaries in one or more
     transactions, each of which complies with Section 11(o) hereof), if (x) at
     the time of or

                                       24
<PAGE>

     immediately after such consolidation, merger or sale there are any
     certificate of incorporation or bylaw provisions or any rights, warrants or
     other instruments or securities outstanding or agreements in effect or
     other actions taken which would substantially diminish or otherwise
     eliminate the benefits intended to be afforded by the Rights or (y) prior
     to, simultaneously with or immediately after such consolidation, merger or
     sale, the stockholders of the Person who constitutes, or would constitute,
     the Principal Party for purposes of Section 13(a) hereof shall have
     received a distribution of Rights previously owned by such Person or any of
     its Affiliates and Associates. The Company shall not consummate any such
     consolidation, merger, sale or transfer unless prior thereto the Company
     and such other Person shall have executed and delivered to the Rights Agent
     a supplemental agreement evidencing compliance with this Section 11(n).

          (o) No Actions That Diminish Benefits of Rights.  The Company
              -------------------------------------------
     covenants and agrees that, after the Distribution Date, it will not, except
     as permitted by Section 23, Section 24 or Section 27 hereof, take (or
     permit any Subsidiary to take) any action if at the time such action is
     taken it is reasonably foreseeable that such action will diminish
     substantially or otherwise eliminate the benefits intended to be afforded
     by the Rights.

          (p) Adjustment in Number of Rights Associated With Each Share of
              ------------------------------------------------------------
     Common Stock.  Anything in this Agreement to the contrary notwithstanding,
     ------------
     in the event that the Company shall at any time after the Rights
     Distribution Declaration Date and prior to the Distribution Date (i)
     declare or pay any dividend on the outstanding shares of Common Stock
     payable in shares of Common Stock, (ii) subdivide or split the outstanding
     shares of Common Stock into a greater number of shares, or (iii) combine or
     consolidate the outstanding shares of Common Stock into a smaller number of
     shares or effect a reverse split of the outstanding shares of Common Stock,
     then, and in each such event, the number of Rights associated with each
     share of Common Stock then outstanding, or issued or delivered thereafter
     but prior to the Distribution Date, shall be proportionately adjusted so
     that the number of Rights thereafter associated with each share of Common
     Stock following any such event shall equal the result obtained by
     multiplying the number of Rights associated with each share of Common Stock
     immediately prior to such event by a fraction the numerator of which shall
     be the total number of shares of Common Stock outstanding immediately prior
     to the occurrence of the event and the denominator of which shall be the
     total number of shares of Common Stock outstanding immediately following
     the occurrence of such event.

     SECTION 12.    Certificate of Adjusted Purchase Price or Number of Shares.
                    ----------------------------------------------------------
Whenever an adjustment is made as provided in Section 11 or Section 13 hereof,
the Company shall (a) promptly prepare a certificate setting forth such
adjustment and a brief statement of the facts and computations accounting for
such adjustment, (b) promptly file with the Rights Agent, and with each transfer
agent for the Preferred Stock and the Common Stock, a copy of such certificate,
and (c) mail a brief summary thereof to each record holder of a Rights
Certificate (or, if prior to the Distribution Date, to each record holder of a
certificate representing shares of Common Stock) in accordance with Section 26
hereof.  The Rights Agent shall be fully protected in relying on any such
certificate and on any adjustment therein contained and shall have no duty with
respect to and shall not be deemed to have knowledge of such adjustment unless
and until it shall have received such certificate.

                                       25
<PAGE>

     SECTION 13.    Consolidation, Merger or Sale or Transfer of Assets or
                    ------------------------------------------------------
Earning Power.
-------------

          (a) Section 13 Events.  In the event that, following the Stock
              -----------------
     Acquisition Date (which for purposes of this Section 13(a) only shall also
     include the date of the first public announcement (including, without
     limitation, a report filed pursuant to Section 13(d) under the Exchange
     Act) that any Person (other than the Company, any Subsidiary of the
     Company, any employee benefit plan of the Company or of any Subsidiary of
     the Company, or any Person or entity organized, appointed or established by
     the Company for or pursuant to the terms of any such plan), together with
     any of such Person's Affiliates and Associates, has become the Beneficial
     Owner of 15% or more of the shares of Common Stock then outstanding
     pursuant to a Qualifying Offer), directly or indirectly, (x) the Company
     shall consolidate with, or merge with and into, any other Person (other
     than a Subsidiary of the Company in a transaction that complies with
     Section 11(o) hereof), and the Company shall not be the continuing or
     surviving corporation of such consolidation or merger, (y) any Person
     (other than a Subsidiary of the Company in a transaction that complies with
     Section 11(o) hereof) shall consolidate with, or merge with or into, the
     Company, and the Company shall be the continuing or surviving corporation
     of such consolidation or merger and, in connection with such consolidation
     or merger, all or part of the outstanding shares of Common Stock shall be
     changed into or exchanged for stock or other securities of any other Person
     or cash or any other property, or (z) the Company shall sell or otherwise
     transfer (or one or more of its Subsidiaries shall sell or otherwise
     transfer), in one transaction or a series of related transactions, assets
     or earning power aggregating more than 50% of the assets or earning power
     of the Company and its Subsidiaries (taken as a whole) to any  Person or
     Persons (other than the Company or any Subsidiary of the Company in one or
     more transactions each of which complies with Section 11(o) hereof), then,
     upon the first occurrence of such event (except as may be contemplated by
     Section 13(d) hereof), proper provision shall be made so that:  (i) each
     holder of a Right, except as provided in Section 7(e) hereof, shall
     thereafter have the right to receive, upon the exercise thereof at the then
     current Purchase Price, in accordance with the terms of this Agreement,
     such number of validly authorized and issued, fully paid, non-assessable
     and freely tradable shares of Common Stock of the Principal Party (as such
     term is hereinafter defined), not subject to any liens, encumbrances,
     rights of first refusal or other adverse claims, as shall be equal to the
     result obtained by (1) multiplying the then current Purchase Price by the
     number of one one-thousandths of a share of Preferred Stock for which a
     Right is exercisable immediately prior to the first occurrence of a Section
     13 Event (or, if a Section 11(a)(ii) Event has occurred prior to the first
     occurrence of a Section 13 Event, multiplying the number of such one one-
     thousandths of a share for which a Right was exercisable immediately prior
     to the first occurrence of a Section 11(a)(ii) Event by the Purchase Price
     in effect immediately prior to such first occurrence), and (2) dividing
     that product (which, following the first occurrence of a Section 13 Event,
     shall be referred to as the "Purchase Price" for each Right and for all
     purposes of this Agreement) by 50% of the Current Market Price (determined
     pursuant to Section 11(d)(i) hereof) per share of the Common Stock of such
     Principal Party on the date of consummation, provided that the Purchase
     Price and the number of shares of Common Stock of such Principal Party
     issuable upon exercise of each Right shall be further adjusted as provided
     in Section 11(f) of this Agreement to

                                       26
<PAGE>

     reflect any events occurring in respect of such Principal Party after the
     date of such Section 13 Event; (ii) such Principal Party shall thereafter
     be liable for, and shall assume, by virtue of such Section 13 Event, all
     the obligations and duties of the Company pursuant to this Agreement; (iii)
     the term "Company" shall thereafter be deemed to refer to such Principal
               -------
     Party, it being specifically intended that the provisions of Section 11
     hereof shall apply only to such Principal Party following the first
     occurrence of a Section 13 Event; (iv) such Principal Party shall take such
     steps (including, but not limited to, the reservation of a sufficient
     number of shares of its Common Stock) in connection with the consummation
     of any such transaction as may be necessary to assure that the provisions
     hereof shall thereafter be applicable, as nearly as reasonably may be, in
     relation to its shares of Common Stock thereafter deliverable upon the
     exercise of the Rights; and (v) the provisions of Section 11(a)(ii) hereof
     shall be of no effect following the first occurrence of any Section 13
     Event.

          (b) Definition of Principal Party.  "Principal Party" shall mean:
              -----------------------------    ---------------

               (i) in the case of any transaction described in clause (x) or (y)
          of the first sentence of Section 13(a):  (A) the Person that is the
          issuer of any securities into which shares of Common Stock of the
          Company are converted in such merger or consolidation, or if there is
          more than one such issuer, the issuer that has the greatest aggregate
          market value of shares of its Common Stock outstanding, or (B) if no
          securities are so issued, (1) the Person that is the other party to
          the merger, if such Person survives said merger, or, if there is more
          than one such Person, the Person that has the greatest aggregate
          market value of shares of its Common Stock outstanding or (2) if the
          Person that is the other party to the merger does not survive the
          merger, the Person that does survive the merger (including the Company
          if it survives) or (3) the Person resulting from the consolidation;
          and

               (ii) in the case of any transaction described in clause (z) of
          the first sentence of Section 13(a), the Person that is the party
          receiving the greatest portion of the assets or earning power
          transferred pursuant to such transaction or transactions or, if each
          Person that is a party to such transaction or transactions receives
          the same portion of the assets or earning power so transferred or if
          the Person receiving the greatest portion of the assets or earning
          power cannot be determined, whichever of such Persons has the greatest
          aggregate market value of shares of its Common Stock outstanding;

     provided, however, that in any such case, (1) if the Common Stock of such
     --------  -------
     Person is not at such time and has not been continuously over the preceding
     twelve (12) month period registered under Section 12 of the Exchange Act,
     and such Person is a direct or indirect Subsidiary of another Person the
     Common Stock of which is and has been so registered, "Principal Party"
                                                           ---------------
     shall refer to such other Person; (2) in case such Person is a Subsidiary,
     directly or indirectly, of more than one Person, the Common Stocks of two
     or more of which are and have been so registered, "Principal Party" shall
                                                        ---------------
     refer to whichever of such Persons is the issuer having the greatest
     aggregate market value of shares of its Common Stock outstanding; and (3)
     in case such Person is owned, directly or indirectly, by a joint

                                       27
<PAGE>

     venture formed by two or more Persons that are not owned, directly or
     indirectly, by the same Person, the rules set forth in (1) and (2) above
     shall apply to each of the chains of ownership having an interest in such
     joint venture as if such party were a "Subsidiary" of both or all of such
     joint venturers and the Principal Parties in each such chain shall bear the
     obligations set forth in this Section 13 in the same ratio as their direct
     or indirect interests in such Person bear to the total of such interests.

          (c) Obligations of Principal Party.  The Company shall not consummate
              ------------------------------
     any consolidation, merger, sale or transfer described in Section 13(a)
     unless the Principal Party covenants and agrees that it will cause to be
     reserved and kept available out of its authorized and unissued shares of
     Common Stock or out of its authorized and issued shares of Common Stock
     held in its treasury, the number of shares of its Common Stock that will be
     sufficient to permit the exercise in full of all outstanding Rights under
     this Section 13 and unless prior thereto the Company and such Principal
     Party shall have executed and delivered to the Rights Agent a supplemental
     agreement confirming that the requirements set forth in paragraphs (a) and
     (b) of this Section 13 shall be promptly performed in accordance with their
     terms and further providing that, as soon as practicable after executing
     such agreement pursuant to this Section 13, the Principal Party will:

               (i)   prepare and file a registration statement under the Act,
          with respect to the Rights and the securities purchasable upon
          exercise of the Rights on an appropriate form, and will use its best
          efforts to cause such registration statement to (A) become effective
          as soon as practicable after such filing and (B) remain effective
          (with a prospectus at all times meeting the requirements of the Act)
          until the Expiration Date and similarly comply with applicable state
          securities laws;

               (ii)  use its best efforts, if the shares of Common Stock of the
          Principal Party shall be listed or admitted to trading on a national
          securities exchange or NASDAQ to list or admit to trading (or continue
          the listing of) the Rights and the securities purchasable upon
          exercise of the Rights on such securities exchange or NASDAQ and, if
          the shares of Common Stock of the Principal Party shall not be listed
          or admitted to trading on a national securities exchange or NASDAQ, to
          cause the Rights and the securities purchasable upon exercise of the
          Rights to be reported by such other system then in use;

               (iii) deliver to record holders of the Rights historical
          financial statements for the Principal Party and each of its
          Affiliates that comply in all respects with the requirements for
          registration on Form 10 under the Exchange Act; and

               (iv)  obtain waivers of any rights of first refusal or preemptive
          rights in respect of the shares of Common Stock of the Principal Party
          subject to purchase upon exercise of outstanding Rights.

     The provisions of this Section 13 shall similarly apply to successive
     mergers or consolidations or sales or other transfers.  In the event that a
     Section 13 Event shall occur

                                       28
<PAGE>

     at any time after the occurrence of a Section 11(a)(ii) Event, the Rights
     that have not theretofore been exercised shall thereafter become
     exercisable in the manner described in Section 13(a). If, for any reason,
     the Rights cannot be exercised for Common Stock of the Company or such
     Principal Party, then a holder of Rights will have the right to exchange
     such Rights for cash from the Company or such Principal Party in an amount
     equal to the number of shares of such Common Stock such holder would
     otherwise be entitled to purchase times 50% of the then Current Market
     Price, as determined pursuant to Section 11(d)(i) hereof, of such stock of
     such Principal Party or the Company. If, for any reason, including, without
     limitation, such Principal Party is an individual, private partnership or
     private company, the foregoing formulation cannot be applied to determine
     the cash amount into which the Rights are exchangeable, then the Board of
     Directors, based upon advice from one or more nationally recognized
     investment banking firms, shall determine such amount reasonably and with
     utmost good faith to the holders of Rights. Any such determination shall be
     binding and final.

          (d)    Section 13 Not Applicable to Certain Transactions Following a
                 -------------------------------------------------------------
     Qualifying Offer.  Notwithstanding anything in this Agreement to the
     ----------------
     contrary, Section 13 shall not be applicable to a transaction described in
     subparagraphs (x) and (y) of Section 13(a) if (i) such transaction is
     consummated with a Person or Persons who acquired shares of Common Stock
     pursuant to a Qualifying Offer (or a wholly owned Subsidiary of any such
     Person or Persons), (ii) the price per share of Common Stock offered in
     such transaction is not less than the price per share of Common Stock paid
     to all record holders of shares of Common Stock whose shares were purchased
     pursuant to such Qualifying Offer, and (iii) the form of consideration
     being offered to the remaining record holders of shares of Common Stock
     pursuant to such transaction is the same as the form of consideration paid
     pursuant to such Qualifying Offer. Upon consummation of any such
     transaction contemplated by this Section 13(d), all Rights hereunder shall
     expire.

     SECTION 14. Fractional Rights and Fractional Shares.
                 ---------------------------------------

          (a)    Fractional Rights.  The Company shall not be required to issue
                 -----------------
     fractions of Rights, except prior to the Distribution Date as provided in
     Section 11(p) hereof, or to distribute Rights Certificates that evidence
     fractional Rights.  In lieu of such fractional Rights, the Company may pay
     to the record holders of the Rights Certificates with regard to which such
     fractional Rights would otherwise be issuable, an amount in cash equal to
     the same fraction of the current market value of a whole Right.  For
     purposes of this Section 14(a), the current market value of a whole Right
     shall be the closing price of the Rights for the Trading Day immediately
     prior to the date on which such fractional Rights would have been otherwise
     issuable.  The closing price of the Rights for any day shall be the last
     sale price, regular way, or, in case no such sale takes place on such day,
     the average of the closing bid and asked prices, regular way, in either
     case as reported in the principal consolidated transaction reporting system
     with respect to securities listed or admitted to trading on the New York
     Stock Exchange or, if the Rights are not listed or admitted to trading on
     the New York Stock Exchange, as reported in the principal consolidated
     transaction reporting system with respect to securities listed on the
     principal national securities exchange on which the Rights are listed or
     admitted to trading, or if the Rights are not listed or admitted to trading
     on any national securities exchange, the

                                       29
<PAGE>

     last sale price or, if such last sale price is not reported, the average of
     the high bid and low asked prices in the over-the-counter market, as
     reported by NASDAQ or such other system then in use or, if on any such date
     the Rights are not quoted by any such organization, the average of the
     closing bid and asked prices as furnished by a professional market maker
     making a market in the Rights selected by the Board of Directors. If on any
     such date no such market maker is making a market in the Rights, the fair
     value of the Rights on such date as determined in good faith by the Board
     of Directors shall be used to determine the current market value of the
     whole Right.

          (b) Fractional Shares of Preferred Stock.  The Company shall not
              ------------------------------------
     issue fractions of shares of Preferred Stock (other than, except as
     provided in Section 7(c), fractions that are integral multiples of one one-
     thousandth of a share of Preferred Stock) upon exercise of the Rights or to
     distribute certificates that evidence fractional shares of Preferred Stock
     (other than fractions that are integral multiples of one one-thousandth of
     a share of Preferred Stock). Fractions of shares of Preferred Stock in
     integral
     multiples of one one-thousandth of a share of Preferred Stock may, at the
     election of the Company, be evidenced by depositary receipts, pursuant to
     an appropriate agreement between the Company and a depositary selected by
     it; provided, however, that such agreement shall provide that the holders
         --------  -------
     of such depositary receipts shall have the rights, privileges and
     preferences to which they are entitled as beneficial owners of the shares
     of Preferred Stock represented by such depositary receipts.  In lieu of
     fractional shares of Preferred Stock that are not integral multiples of one
     one-thousandth of a share of Preferred Stock, the Company shall pay to the
     record holders of Rights Certificates at the time such Rights are exercised
     as herein provided an amount in cash equal to the same fraction of the
     Current Market Price per share of Preferred Stock as of the Trading Day
     immediately prior to the date of such exercise.

          (c) Fractional Shares of Common Stock.  The Company shall not issue
              ---------------------------------
     fractions of shares of Common Stock or distribute certificates that
     evidence fractional shares of Common Stock upon the exercise of Rights by
     any record holder thereof following the occurrence of a Triggering Event.
     In lieu of fractional shares of Common Stock, the Company shall pay to the
     record holders of Rights Certificates at the time such Rights are exercised
     as herein provided an amount in cash equal to the same fraction of the
     Current Market Price per share of Common Stock as of the Trading Day
     immediately prior to the date of such exercise.

          (d) Waiver by Record Holder of Rights.  The record holder of a Right
              ---------------------------------
     by the acceptance of the Rights expressly waives his right to receive any
     fractional Rights or any fractional shares upon exercise of a Right, except
     as permitted by this Section 14.

          (e) Rights Agent's Duties.  The Rights Agent shall have no duty or
              ---------------------
     obligation with respect to this Section 14 and any other Section of this
     Agreement relating to fractional shares of Common Stock unless and until it
     has received specific instructions (and sufficient cash, if required) from
     the Company with respect to its duties and obligations under such Sections.

                                       30
<PAGE>

     SECTION 15. Rights of Action.  All rights of action in respect of this
                 ----------------
Agreement, excepting the rights of action given to the Rights Agent, are vested
in the respective record holders of the Rights Certificates (and, prior to the
Distribution Date, the record holders of the Common Stock); and any record
holder of any Rights Certificate (or, prior to the Distribution Date, of the
Common Stock), without the consent of the Rights Agent or of the record holder
of any other Rights Certificate (or, prior to the Distribution Date, of the
Common Stock), may, in his own behalf and for his own benefit, enforce, and may
institute and maintain any suit, action or proceeding against the Company to
enforce, or otherwise act in respect of, his right to exercise the Rights
evidenced by such Rights Certificate in the manner provided in such Rights
Certificate and in this Agreement.  Without limiting the foregoing or any
remedies available to the record holders of Rights, it is specifically
acknowledged that such holders of Rights would not have an adequate remedy at
law for any breach of this Agreement and shall be entitled to specific
performance of the obligations hereunder and injunctive relief against actual or
threatened violations of the obligations hereunder of any Person subject to this
Agreement.

     SECTION 16. Agreement of Rights Holders.  Every holder of a Right, by
                 ---------------------------
accepting the same, consents and agrees with the Company and the Rights Agent
and with every other holder of a Right that:

          (a)    prior to the Distribution Date, the Rights will be transferable
     only in connection with the transfer of Common Stock;

          (b)    after the Distribution Date, the Rights Certificates are
     transferable only on the transfer books of the Rights Agent if surrendered
     at the offices of the Rights Agent designated for such purposes, duly
     endorsed or accompanied by a proper instrument of transfer and with the
     appropriate forms and certificates fully executed;

          (c)    subject to Section 6(a) and Section 7(f) hereof, the Company
     and the Rights Agent may deem and treat the Person in whose name a Rights
     Certificate (or, prior to the Distribution Date, the associated Common
     Stock certificate) is registered on the transfer books of the Rights Agent
     as the absolute owner thereof and of the Rights evidenced thereby
     (notwithstanding any notations of ownership or writing on the Rights
     Certificates or the associated Common Stock certificate made by anyone
     other than the Company or the Rights Agent) for all purposes whatsoever,
     and neither the Company nor the Rights Agent, subject to the last sentence
     of Section 7(e) hereof, shall be required to be affected by any notice to
     the contrary; and

          (d)    notwithstanding anything in this Agreement to the contrary,
     neither the Company nor the Rights Agent shall have any liability to any
     holder of a Right or other Person as a result of its inability to perform
     any of its obligations under this Agreement by reason of any preliminary or
     permanent injunction or other order, decree, judgment or ruling issued by a
     court of competent jurisdiction or by a governmental, regulatory or
     administrative  agency or commission, or any statute, rule, regulation or
     executive order promulgated or enacted by any governmental authority,
     prohibiting or otherwise restraining performance of such obligations;
     provided, however, the Company must use its reasonable efforts to have any
     --------  -------
     such order, judgment, decree or ruling lifted or otherwise overturned as
     soon as possible.

                                       31
<PAGE>

     Section 17. Rights Certificate Holder Not Deemed a Stockholder.  No
                 --------------------------------------------------
holder, as such, of any Rights Certificate shall be entitled to vote, receive
dividends or be deemed for any purpose the holder of the number of one one-
thousandths of a share of Preferred Stock or any other securities of the Company
which may at any time be issuable on the exercise of the Rights represented
thereby, nor shall anything contained herein or in any Rights Certificate be
construed to confer upon the holder of any Rights Certificate, as such, any of
the rights of a stockholder of the Company or any right to vote for the election
of directors or upon any matter submitted to stockholders at any meeting
thereof, or to give or withhold consent to any corporate action, or to receive
notice of meetings or other actions affecting stockholders (except as provided
in Section 25 hereof), or to receive dividends or subscription rights, or
otherwise, until the Right or Rights evidenced by such Rights Certificate shall
have been exercised in accordance with the provisions hereof.

     Section 18. Concerning the Rights Agent.
                 ---------------------------

           (a)   Compensation and Indemnification.  The Company agrees to pay to
                 --------------------------------
     the Rights Agent such compensation as shall be agreed to in writing between
     the Company and the Rights Agent for all services rendered by it hereunder
     and, from time to time, on demand of the Rights Agent, its reasonable
     expenses and counsel fees and disbursements and other disbursements
     incurred in the preparation, execution, delivery, amendment and
     administration of this Agreement and the exercise and performance of its
     duties hereunder.  The Company also agrees to indemnify the Rights Agent,
     including its members, directors, officers, employees, stockholders and
     agents, for, and to hold it harmless against, any loss, liability, damage,
     judgment, fine, penalty, claim, demand, settlement, cost or expense
     incurred without gross negligence, bad faith or willful misconduct (each as
     may be finally determined by a court of competent jurisdiction) on the part
     of the Rights Agent, for any action, taken, suffered, or omitted by the
     Rights Agent in connection with the acceptance and administration of this
     Agreement, including, without limitation, the costs and expenses of
     defending against any claim of liability in the premises (including
     reasonable counsel fees and expenses).  The indemnity provided for herein
     shall survive the expiration of the Rights and the termination of this
     Agreement.  The costs and expenses incurred by the Rights Agent in
     enforcing this right of indemnification shall be paid by the Company.

           (b)   Limitation of Liability. The Rights Agent shall be authorized
                 -----------------------
     and protected and shall incur no liability for or in respect of any action
     taken, suffered or omitted by it in connection with its acceptance, insofar
     as it relates to the Company, and administration of this Agreement in
     reliance upon any Rights Certificate or certificate for Common Stock or for
     other securities of the Company, instrument of assignment or transfer,
     power of attorney, endorsement, affidavit, letter, notice, direction,
     consent, certificate, statement, or other paper or document believed by it
     to be genuine and to be signed, executed, and where necessary, verified,
     guaranteed or acknowledged, by the proper Person or Persons.

                                       32
<PAGE>

     Section 19.  Merger or Consolidation or Change of Name of Rights Agent.
                  ---------------------------------------------------------

             (a)  Merger or Consolidation of Rights Agent. Any Person into which
                  ---------------------------------------
     the Rights Agent or any successor Rights Agent may be merged or with which
     it may be consolidated, or any Person resulting from any merger or
     consolidation to which the Rights Agent or any successor Rights Agent shall
     be a party, or any Person succeeding to the stockholder services business
     of the Rights Agent or any successor Rights Agent, shall be the successor
     to the Rights Agent under this Agreement without the execution or filing of
     any paper or any further act on the part of any of the parties hereto,
     provided, that such Person would be eligible for appointment as a successor
     --------
     Rights Agent under the provisions of Section 21 hereof.  In case at the
     time such successor Rights Agent shall succeed to the agency created by
     this Agreement, any of the Rights Certificates shall have been
     countersigned but not delivered, any such successor Rights Agent may adopt
     the countersignature of a predecessor Rights Agent and deliver such Rights
     Certificates so countersigned; and in case at that time any of the Rights
     Certificates shall not have been countersigned, any successor Rights Agent
     may countersign such Rights Certificates in the name of the successor
     Rights Agent; and in all such cases such Rights Certificates shall have the
     full force provided in the Rights Certificates and in this Agreement.

             (b)  Change of Name of Rights Agent. In case at any time the name
                  ------------------------------
     of the Rights Agent shall be changed and at such time any of the Rights
     Certificates shall have been countersigned but not delivered, the Rights
     Agent may adopt the countersignature under its prior name and deliver
     Rights Certificates so countersigned; and in case at that time any of the
     Rights Certificates shall not have been countersigned, the Rights Agent may
     countersign such Rights Certificates either in its prior name or in its
     changed name; and in all such cases such Rights Certificates shall have the
     full force provided in the Rights Certificates and in this Agreement.

     Section 20.  Duties of Rights Agent.  The Rights Agent undertakes only
                  ----------------------
the specific duties and obligations expressly imposed by this Agreement, and no
implied duties or obligations shall be read into this Agreement against the
Rights Agent, upon the following terms and conditions, by which the Company and
the holders of Rights Certificates, by their acceptance thereof, shall be bound:

            (a)   The Rights Agent may consult with legal counsel (who may be
     legal counsel for the Company), and the advice or opinion of such counsel
     shall be full and complete authorization and protection to the Rights Agent
     as to, and the Rights Agent shall incur no liability for or in respect of,
     any action taken, suffered or omitted by it in good faith and in accordance
     with such advice or opinion.

            (b)   Whenever in the performance of its duties under this Agreement
     the Rights Agent shall deem it necessary or desirable that any fact or
     matter (including, without limitation, the identity of any Acquiring Person
     and the determination of "Current Market Price") be proved or established
     by the Company prior to taking, suffering or omitting to take any action
     hereunder, such fact or matter (unless other evidence in respect thereof be
     herein specifically prescribed) may be deemed to be

                                       33
<PAGE>

     conclusively proved and established by a certificate signed by the Chairman
     of the Board, the President, any Vice President, the Treasurer, any
     Assistant Treasurer, the Secretary or any Assistant Secretary of the
     Company and delivered to the Rights Agent; and such certificate shall be
     full authorization and protection to the Rights Agent, and the Rights Agent
     shall incur no liability for or in respect of, any action taken, suffered
     or omitted to be taken in good faith by it under the provisions of this
     Agreement in reliance upon such certificate.

          (c)  The Rights Agent shall be liable hereunder only for its own gross
     negligence, bad faith or willful misconduct, each as may be finally
     determined by a court of competent jurisdiction.  Anything to the contrary
     notwithstanding, in no event shall the Rights Agent be liable for special,
     punitive, indirect, consequential or incidental loss or damage of any kind
     whatsoever (including but not limited to lost profits), even if the Rights
     Agent has been advised of the likelihood of such loss or damage.  Any
     liability of the Rights Agent under this Rights Agreement will be limited
     to the amount of fees paid by the Company to the Rights Agent.

          (d)  The Rights Agent shall not be liable for or by reason of any of
     the statements of fact or recitals contained in this Agreement or in the
     Rights Certificates or be required to verify the same (except as to its
     countersignature on such Rights Certificates), but all such statements and
     recitals are and shall be deemed to have been made by the Company only.

          (e)  The Rights Agent shall not have any liability for or be under any
     responsibility in respect of the validity of this Agreement or the
     execution and delivery hereof (except the due execution hereof by the
     Rights Agent) or in respect of the validity or execution of any Rights
     Certificate (except its countersignature thereof); nor shall it be
     responsible for any breach by the Company of any covenant or condition
     contained in this Agreement or in any Rights Certificate; nor shall it be
     responsible for any adjustment required under the provisions of Section 11
     or Section 13 hereof or responsible for the manner, method or amount of any
     such adjustment or the ascertaining of the existence of facts that would
     require any such adjustment (except with respect to the exercise of Rights
     evidenced by Rights Certificates after actual notice of any such
     adjustment); nor shall it by any act hereunder be deemed to make any
     representation or warranty as to the authorization or reservation of any
     shares of Common Stock or Preferred Stock to be issued pursuant to this
     Agreement or any Rights Certificate or as to whether any shares of Common
     Stock, Preferred Stock or other securities, will when so issued, be validly
     authorized and issued, fully paid and nonassessable.

          (f)  The Company agrees that it will perform, execute, acknowledge and
     deliver or cause to be performed, executed, acknowledged and delivered all
     such further and other acts, instruments and assurances as may reasonably
     be required by the Rights Agent for the carrying out or performing by the
     Rights Agent of the provisions of this Agreement.

          (g)  The Rights Agent is hereby authorized and directed to accept
     instructions with respect to the performance of its duties hereunder from
     the Chairman of the Board,

                                       34
<PAGE>

     the President, any Vice President, the Secretary, any Assistant Secretary,
     the Treasurer or any Assistant Treasurer of the Company, and to apply to
     such officers for advice or instructions in connection with its duties, and
     it shall be full authorization to the Rights Agent and the Rights Agent
     shall not be liable for any action taken, suffered or omitted to be taken
     by it in good faith in accordance with instructions of any such officer or
     for any delay in acting while waiting for those instructions.

          (h)  The Rights Agent and any stockholder, affiliate, director,
     officer or employee of the Rights Agent may buy, sell or deal in any of the
     Rights or other securities of the Company or become pecuniarily interested
     in any transaction in which the Company may be interested, or contract with
     or lend money to the Company or otherwise act as fully and freely as though
     it were not Rights Agent under this Agreement. Nothing herein shall
     preclude the Rights Agent from acting in any other capacity for the Company
     or for any other Person.

          (i)  The Rights Agent may execute and exercise any of the rights or
     powers hereby vested in it or perform any duty hereunder either itself or
     by or through its attorneys or agents, and the Rights Agent shall not be
     answerable or accountable for any act, default, neglect or misconduct of
     any such attorneys or agents or for any loss to the Company or any other
     Person resulting from any such act, default, neglect or misconduct, absent
     gross negligence, willful misconduct or bad faith (each as may be finally
     determined by a court of competent jurisdiction) in the selection and
     continued employment thereof.

          (j)  No provision of this Agreement shall require the Rights Agent to
     expend or risk its own funds or otherwise incur any financial liability in
     the performance of any of its duties hereunder or in the exercise of its
     rights if it believes that repayment of such funds or adequate
     indemnification against such risk or liability is not reasonably assured to
     it.

          (k)  If, with respect to any Rights Certificate surrendered to the
     Rights Agent for exercise or transfer, the certificate attached to the form
     of assignment or form of election to purchase, as the case may be, has
     either not been completed or indicates an affirmative response to clause 1
     and/or 2 thereof, the Rights Agent shall not take any further action with
     respect to such requested exercise or transfer without first consulting
     with the Company.

          (l)  The Rights Agent shall have no responsibility to the Company, any
     holders of Rights or any holders of shares of Common Stock for interest or
     earnings on any moneys held by the Rights Agent pursuant to this Agreement.

          (m)  The Rights Agent shall not be required to take notice or be
     deemed to have notice of any event or condition hereunder, including, but
     not limited to, a Distribution Date, a Redemption Date, any adjustment of
     the Purchase Price of the Common Stock, and adjustment to the Purchase
     Price of the Preferred Stock, the existence of an Acquiring Person or any
     other event or condition that may require action by the Rights Agent,
     unless the Rights Agent shall be specifically notified in writing of such
     event or

                                       35
<PAGE>

     condition by the Company, and all notices or other instruments required by
     this Agreement to be delivered to the Rights Agent must, in order to be
     effective, be received by the Rights Agent as specified in Section 26
     hereof, and in the absence of such notice so delivered, the Rights Agent
     may conclusively assume no such event or condition exists.

     Section 21.    Change of Rights Agent.  The Rights Agent or any successor
                    ----------------------
Rights Agent may resign and be discharged from its duties under this Agreement
upon thirty (30) days' notice in writing to the Company and shall provide notice
thereof to each transfer agent of the Common Stock or Preferred Stock by
registered or certified mail and to the holders of the Rights Certificates in
accordance with Section 26 hereof, (or if prior to the Distribution Date, to the
holders of Rights through any filing made by the Company pursuant to the
Exchange Act). The Company may remove the Rights Agent or any successor Rights
Agent upon thirty (30) days' notice in writing to the Rights Agent or successor
Rights Agent, as the case may be, and shall provide notice thereof to each
transfer agent of the Common Stock and Preferred Stock by registered or
certified mail and to the holders of the Rights Certificates in accordance with
Section 26 hereof (or, if prior to the Distribution Date, to the holders of
Rights through any filing made by the Company pursuant to the Exchange Act). If
the Rights Agent shall resign or be removed or shall otherwise become incapable
of acting, the Company shall appoint a successor to the Rights Agent. If the
Company shall fail to make such appointment within a period of thirty (30) days
after giving notice of such removal or after it has been notified in writing of
such resignation or incapacity by the resigning or incapacitated Rights Agent or
by the record holder of a Rights Certificate (who shall, with such notice,
submit his Rights Certificate for inspection by the Company), then the Company
shall become the Rights Agent until a successor Rights Agent has been appointed,
and any record holder of any Rights Certificate or the Rights Agent may apply to
any court of competent jurisdiction for the appointment of a new Rights Agent.
Any successor Rights Agent, whether appointed by the Company or by such a court,
shall be either (a) a Person organized and doing business under the laws of the
United States or of the State of New York (or of any other state of the United
States so long as such Person is authorized to do business in the State of New
York), in good standing, which is subject to supervision or examination by
federal or state authority and which has at the time of its appointment as
Rights Agent a combined capital and surplus of at least $25,000,000, or (b) an
Affiliate of such Person. After appointment, the successor Rights Agent shall be
vested with the same powers, rights, duties and responsibilities as if it had
been originally named as Rights Agent without further act or deed and the rights
and obligations of the predecessor shall cease and terminate, but the
predecessor Rights Agent shall deliver and transfer to the successor Rights
Agent any property at the time held by it hereunder, and execute and deliver any
further assurance, conveyance, act or deed necessary for the purpose. Not later
than the effective date of any such appointment, the Company shall file notice
thereof in writing with the predecessor Rights Agent and each transfer agent of
the Common Stock and the Preferred Stock, and mail a notice thereof in writing
to the holders of the Rights Certificates in accordance with Section 26 hereof
(or, if prior to the Distribution Date, give notice to the holders of Rights
through any filing made by the Company pursuant to the Exchange Act). Failure to
give any notice provided for in this Section 21, however, or any defect therein,
shall not affect the legality or validity of the resignation or removal of the
Rights Agent or the appointment of the successor Rights Agent, as the case may
be.

                                       36
<PAGE>

     Section 22.  Issuance of New Rights Certificates.  Notwithstanding any of
                  -----------------------------------
the provisions of this Agreement or of the Rights to the contrary, the Company
may, at its option, issue new Rights Certificates evidencing Rights in such form
as may be approved by its Board of Directors to reflect any adjustment or change
in the Purchase Price or the number or kind or class of shares or other
securities or property purchasable under the Rights Certificates made in
accordance with the provisions of this Agreement.  In addition, in connection
with the issuance or sale of shares of Common Stock following the Distribution
Date and prior to the redemption or expiration of the Rights, the Company (a)
shall, with respect to shares of Common Stock so issued or sold pursuant to the
exercise of stock options or under any employee plan or arrangement, granted or
awarded as of the Distribution Date, or upon the exercise, conversion or
exchange of securities hereinafter issued by the Company, and (b) may, in any
other case, if deemed necessary or appropriate by the Board of Directors, issue
Rights Certificates representing the appropriate number of Rights in connection
with such issuance or sale; provided, however, that (i) no such Rights
                            --------  -------
Certificates shall be issued and this sentence shall be null and void ab initio
if, and to the extent that, the Company shall be advised by counsel that such
issuance would create a significant risk of material adverse tax consequences to
the Company or the Person to whom such Rights Certificate would be issued, and
(ii) no such Rights Certificate shall be issued if, and to the extent that,
appropriate adjustment shall otherwise have been made in lieu of the issuance
thereof.

     Section 23.  Redemption and Termination.
                  --------------------------

             (a)  Redemption of Rights. The Board of Directors, at its option,
                  --------------------
     at any time prior to the earlier of (i) the Close of Business on the tenth
     Business Day following the Stock Acquisition Date (or, if the Stock
     Acquisition Date shall have occurred prior to the Record Date, the Close of
     Business on the tenth Business Day following the Record Date), or (ii) the
     Close of Business on the Final Expiration Date, redeem all but not less
     than all of the then outstanding Rights at a redemption price of $.01 per
     Right (such redemption price being hereinafter referred to as the
     "Redemption Price").  Notwithstanding anything contained in this Agreement
     -----------------
     to the contrary, the Rights shall not be exercisable after the first
     occurrence of a Section 11(a)(ii) Event until such time as the Company's
     right of redemption hereunder has expired.  The Company may, at its option,
     pay the Redemption Price in cash, shares of Common Stock (based on the
     Current Market Price of the Common Stock at the time of redemption) or any
     other form of consideration deemed appropriate by the Board of Directors.
     The redemption of the Rights may be made effective at such time, on such
     basis and with such conditions as the Board of Directors in its sole
     discretion may establish.

             (b)  Termination of Exercise Rights; Notice of Redemption.
                  ----------------------------------------------------
     Immediately upon the action of the Board of Directors ordering the
     redemption of the Rights pursuant to Section 23(a) hereof (or at such later
     time as the Board of Directors may establish for the effectiveness of such
     redemption) and without any further action and without any notice, the
     right to exercise the Rights will terminate and the only right thereafter
     of the holders of Rights shall be to receive the Redemption Price for each
     Right so held. Promptly after the action by the Board of Directors ordering
     the redemption of the Rights becoming effective, the Company shall provide
     notice of such redemption to the Rights Agent and the holders of the then
     outstanding Rights in accordance with Section 26

                                       37
<PAGE>

     (provided that the failure to provide, or any defect in, such notice shall
     not affect the validity of such redemption). Any notice that is provided in
     the manner herein provided shall be deemed given, whether or not the record
     holder receives the notice. Each such notice of redemption will state the
     method by which the payment of the Redemption Price will be made.

     Section 24.  Exchange.
                  --------

            (a)   Exchange. The Board of Directors may, at its option, at any
                  --------
     time after any Person becomes an Acquiring Person, exchange all or part of
     the then outstanding and exercisable Rights (which shall not include Rights
     that have become null and void pursuant to the provisions of Section 7(e)
     hereof) for shares of Common Stock at an exchange ratio of one share of
     Common Stock per Right, appropriately adjusted to reflect any stock split,
     stock dividend or similar transaction occurring after the date hereof (such
     exchange ratio being hereinafter referred to as the "Exchange Ratio"),
                                                          --------------
     provided that the shares of Common Stock so exchanged shall be of the same
     class or series which the holders of such Rights would have been entitled
     to receive upon the exercise thereof.  Notwithstanding the foregoing, the
     Board of Directors shall not be empowered to effect such exchange at any
     time after any Person (other than an Exempted Person), together with all
     Affiliates and Associates of such Person, becomes the Beneficial Owner of
     Voting Securities of the Company then outstanding representing 50% or more
     of the Voting Power of the Company.

            (b)   Termination of Exercise Right. Immediately upon the action of
                  -----------------------------
     the Board of Directors ordering the exchange of any Rights pursuant to
     Section 24(a) hereof and without any further action and without any notice,
     the right to exercise such Rights shall terminate and the only right
     thereafter of the holders of Rights shall be to receive that number of
     shares of Common Stock equal to the number of such Rights held by such
     holders multiplied by the Exchange Ratio, provided that the shares of
     Common Stock so exchanged shall be of the same class or series which the
     holders of such Rights would have been entitled to receive upon the
     exercise thereof. The Company shall promptly make a public announcement of
     any such exchange; provided, however, that the failure to make, or any
                        --------  -------
     defect in, such public announcement shall not affect the validity of such
     exchange. Promptly after the action of the Board of Directors ordering the
     exchange of the Rights becoming effective, the Company shall provide notice
     of such exchange to the Rights Agent and all of the holders of the then
     outstanding Rights in accordance with Section 26 hereof (provided that the
     failure to give, or any defect in, such notice shall not affect the
     validity of such exchange). Any notice that is mailed in the manner
     provided in Section 26 hereof shall be deemed given, whether or not the
     holder receives the notice. Each such notice of exchange will state the
     method by which the exchange of the shares of Common Stock for Rights will
     be effected and, in the event of any partial exchange, the number of Rights
     that will be exchanged. Any partial exchange shall be effected based on the
     number of Rights (other than Rights that have become null and void pursuant
     to the provisions of Section 7(e) hereof) held by each holder of Rights.

            (c)   Substitution of Preferred Stock. In the event that there shall
                  -------------------------------
     not be authorized and unissued shares of the applicable class or series of
     Common Stock and/or

                                       38
<PAGE>

     authorized and issued shares of the applicable class or series of Common
     Stock held in its treasury sufficient to permit any exchange of Rights as
     contemplated in accordance with this Section 24, the Company shall take all
     such action as may be necessary to authorize additional shares of the
     applicable class or series of Common Stock for issuance upon exchange of
     the Rights. In the event the Company shall, after good faith effort, be
     unable to take all such action as may be necessary to authorize such
     additional shares of the applicable class or series of Common Stock, the
     Company shall substitute, for each share of such class or series of Common
     Stock that would otherwise be issuable upon exchange of a Right, a number
     of shares of the applicable series of Preferred Stock or fraction thereof
     (subject to Section 14(b) hereof) such that the Current Market Price per
     share of the applicable series of Preferred Stock multiplied by such number
     or fraction is equal to the Current Market Price per share of such class or
     series of Common Stock as of the date of issuance of such shares of such
     series of Preferred Stock or fraction thereof.

            (d)   Fractional Shares of Common Stock. The Company shall not issue
                  ---------------------------------
     fractions of shares of Common Stock or distribute certificates that
     evidence fractional shares of Common Stock upon an exchange of Rights for
     Common Stock pursuant to this Section 24.  In lieu of such fractional
     shares of Common Stock, the Company shall pay to the registered holders of
     the Rights Certificates with regard to which fractional shares of Common
     Stock would otherwise be issuable an amount in cash equal to the same
     fraction of the Current Market Price per share of the applicable class or
     series of Common Stock as of the Trading Day immediately prior to the
     record date of exchange pursuant to this Section 24.

     Section 25.  Notice of Certain Events.
                  ------------------------

             (a)  Notice of Dividend Payment, Distribution of Rights or
                  -----------------------------------------------------
     Warrants, Reclassification, Consolidation, Merger, Sale, Liquidation, Etc.
     -------------------------------------------------------------------------
     In case the Company shall propose, at any time after the Distribution Date,
     (i) to pay any dividend payable in stock of any class to the holders of
     Preferred Stock or to make any other distribution to the holders of
     Preferred Stock (other than a regular quarterly cash dividend out of
     earnings or retained earnings of the Company), or (ii) to offer to the
     holders of Preferred Stock rights or warrants to subscribe for or to
     purchase any additional shares of Preferred Stock or shares of stock of any
     class or any other securities, rights or options, or (iii) to effect any
     reclassification of its Preferred Stock (other than a reclassification
     involving only the subdivision of outstanding shares of Preferred Stock),
     or (iv) to effect any consolidation or merger into or with any other Person
     (other than a Subsidiary of the Company in a transaction that complies with
     Section 11(o) hereof), or to effect any sale or other transfer (or to
     permit one or more of its Subsidiaries to effect any sale or other
     transfer), in one transaction or a series of related transactions, of more
     than 50% of the assets or earning power of the Company and its Subsidiaries
     (taken as a whole) to any other Person or Persons (other than the Company
     and/or any of its Subsidiaries in one or more transactions each of which
     complies with Section 11(o) hereof), or (v) to effect the liquidation,
     dissolution or winding up of the Company, then, in each such case, the
     Company shall give to each holder of a Rights Certificate and to the Rights
     Agent, to the extent feasible and in accordance with Section 26 hereof, a
     notice of such proposed action, which shall specify the record date for the
     purposes of such stock dividend,

                                       39
<PAGE>

     distribution of rights or warrants, or the date on which such
     reclassification, consolidation, merger, sale, transfer, liquidation,
     dissolution, or winding up is to take place and the date of participation
     therein by the holders of the shares of Preferred Stock, if any such date
     is to be fixed, and such notice shall be so given in the case of any action
     covered by clause (i) or (ii) above at least twenty (20) days prior to the
     record date for determining holders of the shares of Preferred Stock for
     purposes of such action, and in the case of any such other action, at least
     twenty (20) days prior to the date of the taking of such proposed action or
     the date of participation therein by the holders of the shares of Preferred
     Stock, whichever shall be the earlier.

            (b)  Notice of Section 11(a)(ii) Event.  In the event that a Section
                 ---------------------------------
     11(a)(ii) Event shall occur, then in any such case (i) the Company shall as
     soon as practicable thereafter give to each holder of a Rights Certificate
     and to the Rights Agent, to the extent feasible and in accordance with
     Section 26 hereof, a notice of the occurrence of such event, which shall
     specify the event and the consequences of the event to holders of Rights
     under Section 11(a)(ii) hereof, and (ii) all references in Section 25(a) to
     Preferred Stock shall be deemed thereafter to refer to Common Stock and/or,
     if appropriate, other securities of the Company.

     Section 26. Notices.  Notices or demands authorized by this Agreement to
                 -------
be given or made by the Rights Agent or by the holder of any Rights Certificate
to or on the Company shall be sufficiently given or made if sent by first-class
mail, postage prepaid, addressed (until another address is filed in writing with
the Rights Agent), or by facsimile transmission, as follows:

                 OraSure Technologies, Inc.
                 8505 S.W. Creekside Place
                 Beaverton, Oregon 97008
                 Attention: Chief Executive Officer
                 Facsimile No.: (503) 520-6196

Subject to the provisions of Section 21, any notice or demand authorized by this
Agreement to be given or made by the Company or by the holder of any Rights
Certificate to or on the Rights Agent shall be sufficiently given or made upon
receipt by the Rights Agent, if sent by registered or certified mail, postage
prepaid, addressed (until another address is filed in writing with the Company),
or by facsimile transmission, as follows:

                 ChaseMellon Shareholder Services, L.L.C., as Rights Agent
                 400 South Hope Street, 4/th/ Floor
                 Los Angeles, CA 90071
                 Attention: Relationship Manager
                 Facsimile No.: (213) 553-9735

Notices or demands authorized by this Agreement to be given or made by the
Company or the Rights Agent to the holder of any Rights Certificate (or, if
prior to the Distribution Date, to the holder of certificates representing
shares of Common Stock) shall be sufficiently given or made if sent by first-
class mail, postage prepaid, addressed to such holder at the address of such
holder

                                       40
<PAGE>

as shown on the registry books of the Rights Agent (or, if prior to the
Distribution Date, on the registry books of the transfer agent for the Common
Stock of the Company).

     Section 27.  Supplements and Amendments.  Except as provided in the
                  --------------------------
penultimate sentence of this Section 27, for so long as the Rights are then
redeemable, the Company may in its sole and absolute discretion, and the Rights
Agent shall if the Company so directs, supplement or amend any provision of this
Agreement without the approval of any holders of the Rights.  At any time when
the Rights are no longer redeemable, except as provided in the penultimate
sentence of this Section 27, the Company may, and the Rights Agent shall if the
Company so directs, supplement or amend this Agreement without the approval of
any holders of Rights Certificates in order to (i) cure any ambiguity, (ii)
correct or supplement any provision contained herein that may be defective or
inconsistent with any other provisions herein, (iii) shorten or lengthen any
time period hereunder, or (iv) change or supplement the provisions hereunder in
any manner that the Company may deem necessary or desirable; provided that no
such supplement or amendment adversely affects the interests of the holders of
Rights as such (other than an Acquiring Person or an Affiliate or Associate of
an Acquiring Person) and no such amendment may cause the Rights again to become
redeemable or cause the Agreement again to become amendable other than in
accordance with this sentence.  Notwithstanding anything contained in this
Agreement to the contrary, no supplement or amendment shall be made which
changes the Redemption Price.  Upon the delivery of a certificate from an
appropriate officer of the Company that states that the proposed supplement or
amendment is in compliance with the terms of this Section 27, the Rights Agent
shall execute such supplement or amendment; provided, however, that the Rights
                                            --------  -------
Agent may, but shall not be obligated to, enter into any such supplement or
amendment that adversely affects or changes the Rights Agent's own rights,
duties or immunities under this Agreement.  Prior to the Distribution Date, the
interests of the holders of Rights shall be deemed coincident with the interests
of the holders of Common Stock.

     Section 28.  Successors.  All the covenants and provisions of this
                  ----------
Agreement by or for the benefit of the Company or the Rights Agent shall bind
and inure to the benefit of their respective successors and assigns hereunder.

     Section 29.  Determinations and Actions by the Board of Directors.  For
                  ----------------------------------------------------
all purposes of this Agreement, any calculation of the number of shares of
Common Stock outstanding at any particular time, including for purposes of
determining the particular percentage of such outstanding shares of Common Stock
of which any Person is the Beneficial Owner, shall be made in accordance with
the last sentence of Rule 13d-3(d)(1)(i) of the General Rules and Regulations
under the Exchange Act, as amended and in effect on the date hereof.  The Board
of Directors, except as otherwise specifically provided for herein, shall have
the exclusive power and authority to administer this Agreement and to exercise
all rights and powers specifically granted to the Board of Directors or to the
Company, or as may be necessary or advisable in the administration of this
Agreement, including, without limitation, the right and power to (i) interpret
the provisions of this Agreement, and (ii) make all determinations deemed
necessary or advisable for the administration of this Agreement (including a
determination to redeem or not redeem the Rights or to amend the Agreement).
All such actions, valuations, calculations, interpretations and determinations
(including, for purposes of clause (y) below, all omissions with respect to the
foregoing) which are done or made by the Board of Directors in good faith shall
(x) be final, conclusive and binding on the Company, the Rights Agent, the

                                       41
<PAGE>

holders of the Rights Certificates (and, prior to the Distribution Date, record
holders of the Common Stock) and all other Persons, and (y) not subject the
Board of Directors to any liability to the holders of the Rights.  With respect
to the immediately preceding sentence, the Rights Agent shall always be entitled
to assume that the Board of Directors acted in good faith and shall be fully
protected and shall incur no liability in reliance thereon.

     Section 30.  Benefits of this Agreement.  Nothing in this Agreement shall
                  --------------------------
be construed to give to any Person other than the Company, the Rights Agent and
the record holders of the Rights Certificates (and, prior to the Distribution
Date, record holders of the Common Stock) any legal or equitable right, remedy
or claim under this Agreement; but this Agreement shall be for the sole and
exclusive benefit of the Company, the Rights Agent and the record holders of the
Rights Certificates (and, prior to the Distribution Date, record holders of the
Common Stock).

     Section 31.  Severability.  If any term, provision, covenant or
                  ------------
restriction of this Agreement is held by a court of competent jurisdiction or
other authority to be invalid, void or unenforceable, the remainder of the
terms, provisions, covenants and restrictions of this Agreement shall remain in
full force and effect and shall in no way be affected, impaired or invalidated;
provided, however, that notwithstanding anything in this Agreement to the
contrary, if any such term, provision, covenant or restriction is held by such
court or authority to be invalid, void or unenforceable and the Board of
Directors of the Company determines in its good faith judgment that severing the
invalid language from this Agreement would adversely affect the purpose or
effect of this Agreement, the right of redemption set forth in Section 23 hereof
shall be reinstated and shall not expire until the Close of Business on the
tenth Business Day (or such longer period of time as permitted pursuant to
Section 27 of this Agreement) following the date of such determination by the
Board of Directors.  Without limiting the foregoing, if any provision requiring
that a determination be made by less than the entire Board of Directors (or at a
time or with the concurrence of a group of directors consisting of less than the
entire Board of Directors) is held by a court of competent jurisdiction or other
authority to be invalid, void or unenforceable, such determination shall then be
made by the Board of Directors in accordance with applicable law and the
Company's Certificate of Incorporation and Bylaws.  The Company shall promptly
provide the Rights Agent with written notice of such determination.

     Section 32.  Governing Law.  This Agreement, each Right and each Rights
                    -------------
Certificate issued hereunder shall be deemed to be a contract made under the
laws of the State of Delaware and for all purposes shall be governed by and
construed in accordance with the laws of such State applicable to contracts made
and to be performed entirely within such State; provided, however, that all
provisions regarding the rights, duties and obligations of the Rights Agent
shall be governed by and construed in accordance with the laws of the State of
Delaware applicable to contracts made and to be performed entirely within such
State.

     Section 33.  Counterparts.  This Agreement may be executed in any number
                  ------------
of counterparts, each of such counterparts shall for all purposes be deemed to
be an original, and all such counterparts shall together constitute but one and
the same instrument.

                                       42
<PAGE>

     Section 34.  Descriptive Headings.  Descriptive headings of the Sections
                  --------------------
of this Agreement are inserted for convenience of reference only and shall not
control or affect the meaning or construction of any of the provisions hereof.

     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed and their respective corporate seals to be hereunto affixed and
attested, all as of the day and year first above written.


                              ORASURE TECHNOLOGIES, INC.

     [SEAL]

                              By: __________________________________
                                  Name:  Robert D. Thompson
                                  Title: Chief Executive Officer

ATTEST:


By: ____________________
    Name:
    Title:

                                  CHASEMELLON SHAREHOLDER
                                  SERVICES, L.L.C., as Rights Agent


                                  By: ______________________________
                                         Name:
                                         Title:

ATTEST:


By:____________________
    Name:
    Title:

                                       43
<PAGE>

                                                                       EXHIBIT A
                                                                       ---------

                      FORM OF CERTIFICATE OF DESIGNATION

                          OF SERIES A PREFERRED STOCK
                                      OF
                          ORASURE TECHNOLOGIES, INC.
                          --------------------------

                        Pursuant to Section 151 of the
               General Corporation Law of the State of Delaware

          We, Robert D. Thompson, Chief Executive Officer, and Charles E.
Bergeron, Secretary of OraSure Technologies, Inc., a corporation organized and
existing under the General Corporation Law of the State of Delaware (the
"Corporation"), in accordance with the provisions of Sections 103 and 151(g)
thereof, DO HEREBY CERTIFY:

          That pursuant to the authority conferred upon the Board of Directors
by the Certificate of Incorporation of the Corporation, the Board of Directors
on May 6, 2000, adopted the following resolution creating a series of One
Hundred Twenty Thousand (120,000) shares of Preferred Stock designated as Series
A Preferred Stock, $0.000001 par value:

          RESOLVED, that pursuant to the authority vested in the Board
     of Directors of this Corporation in accordance with the
     provisions of its Certificate of Incorporation (the "Certificate
     of Incorporation"), a series of Preferred Stock, $0.000001 par
     value, of the Corporation be and it hereby is created, and that
     the designation and amount thereof and the voting powers,
     preferences and relative, participating, optional and other
     special rights of the shares of such series, and the
     qualifications, limitations and restrictions thereof are as
     follows:

          Section 1.  Designation and Amount. The shares of such
                      ----------------------
     series shall be designated as "Series A Preferred Stock" and the
     number of shares constituting such series shall be One Hundred
     Twenty Thousand (120,000). Such number of shares may be increased
     or decreased by resolution of the Board of Directors, provided
     that no decrease shall reduce the number of shares of Series A
     Preferred Stock to a number less than the number of shares
     outstanding plus the number of shares reserved for issuance upon
     the exercise of outstanding rights to purchase or convert into
     shares of Series A Preferred Stock.

          Section 2.  Dividends and Distributions.
                      ---------------------------

               (A) Subject to the prior and superior rights of the
          holders of any shares of any series of Preferred Stock
          ranking prior and superior to the shares of Series A
          Preferred Stock with respect to dividends, the holders of
          shares of Series A Preferred Stock, in preference to the
          holders of Common Stock, par value $0.000001 per share (the
          "Common Stock"), of the Corporation and of any other class
          of stock ranking junior (either as to dividends or upon
          liquidation, dissolution or winding up) to the shares of
          Series A Preferred Stock (together with the Common Stock,
          the "Junior
<PAGE>

          Stock"), shall be entitled to receive, when, as and if declared by the
          Board of Directors out of funds legally available for the purpose,
          dividends payable in cash in an amount per share (rounded to the
          nearest cent), equal to the product of the Series A Multiple (as
          defined below) then in effect times the aggregate per share amount of
          all cash dividends declared (but not withdrawn) on the Common Stock,
          plus the product of the Series A Multiple then in effect times the
          aggregate per share amount (payable in cash, based upon the fair
          market value at the time the non-cash dividend or other distribution
          is declared as determined in good faith by the Board of Directors) of
          all non-cash dividends or other distributions (other than a dividend
          payable in shares of Common Stock, or a subdivision of the outstanding
          shares of Common Stock (by reclassification or otherwise)), declared
          (but not withdrawn) on the Common Stock.

               (B) As used herein, the Series A Multiple shall initially be
          1,000. In the event the Corporation shall (i) declare any dividend on
          Common Stock payable in shares of Common Stock, (ii) subdivide the
          outstanding Common Stock, or (iii) combine the outstanding Common
          Stock into a smaller number of shares, then in each such case the
          Series A Multiple shall be adjusted by multiplying such amount by a
          fraction the numerator of which is the number of shares of Common
          Stock outstanding immediately after such event and the denominator of
          which is the number of shares of Common Stock that were outstanding
          immediately prior to such event.

               (C) The Board of Directors of the Corporation shall not declare a
          dividend or distribution on the Common Stock (other than a dividend
          payable in shares of Common Stock) unless it shall concurrently
          therewith declare a dividend or distribution on the Series A Preferred
          Stock. Payment of a dividend or distribution determined on the Series
          A Preferred Stock shall be in preference to payment of any dividend or
          distribution on any Junior Stock.

               (D) The Board of Directors may fix a record date for the
          determination of holders of shares of Series A Preferred Stock
          entitled to receive payment of a dividend or distribution declared
          thereon, which record date shall be no more than thirty (30) days
          prior to the date fixed for the payment thereof.

          Section 3.  Voting Rights.  Except as otherwise provided herein or by
                      -------------
     law and in addition to any rights provided in the Certificate of
     Incorporation, the holders of shares of Series A Preferred Stock shall have
     the following voting rights:

               (A)    Each share of Series A Preferred Stock shall entitle the
          holder thereof to a number of votes on all matters submitted to the
          stockholders of the Corporation equal to the product of the Series A

                                       2
<PAGE>

          Multiple then in effect times the number of votes that each share of
          Common Stock entitles its holder to vote at a meeting of the
          stockholders of the Corporation.

               (B) The holders of shares of Series A Preferred Stock and the
          holders of shares of Common Stock and any other capital stock of the
          Corporation having general voting rights shall vote together as one
          class on all matters submitted to a vote of the stockholders of the
          Corporation.

               (C) The holders of Series A Preferred Stock shall have no special
          voting rights and their consent shall not be required (except to the
          extent they are entitled to vote with holders of Common Stock as set
          forth herein) for taking any corporate action.

          Section 4.  Certain Restrictions.
                      --------------------

               (A)    Whenever dividends or distributions payable on the Series
          A Preferred Stock as provided in Section 2 are in arrears, thereafter
          and until all accrued and unpaid dividends and distributions on shares
          of Series A Preferred Stock outstanding shall have been paid in full,
          the Corporation shall not:

                      (i)    declare or pay dividends (other than a dividend
               payable in shares of Common Stock) on, make any other
               distributions on, or redeem or purchase or otherwise acquire for
               consideration any shares of Junior Stock;

                      (ii)   declare or pay dividends on or make any other
               distributions on any shares of stock ranking on a parity (either
               as to dividends or upon liquidation, dissolution or winding up)
               with the Series A Preferred Stock ("Parity Stock"), except
               dividends paid ratably on the Series A Preferred Stock and all
               such Parity Stock on which dividends are payable or in arrears in
               proportion to the total amounts to which the holders of all such
               shares are then entitled;

                      (iii)  redeem or purchase or otherwise acquire for
               consideration shares of any Parity Stock, provided that the
               Corporation may at any time redeem, purchase or otherwise acquire
               shares of any such Parity Stock in exchange for shares of any
               Junior Stock; or

                      (iv)   purchase or otherwise acquire for consideration any
               shares of Series A Preferred Stock, or any shares of Parity
               Stock, except in accordance with a purchase offer made in writing
               or by publication (as determined by the Board of Directors) to
               all holders of such shares upon such terms as the Board of
               Directors, after consideration of the respective annual dividend
               rates and other

                                       3
<PAGE>

               relative rights and preferences of the respective series and
               classes, shall determine in good faith will result in fair and
               equitable treatment among the respective series or classes.

               (B)    The Corporation shall not permit any subsidiary of the
          Corporation to purchase or otherwise acquire for consideration any
          shares of stock of the Corporation unless the Corporation could, under
          paragraph (A) of this Section 4, purchase or otherwise acquire such
          shares at such time and in such manner.

          Section 5.  Reacquired Shares.  Any shares of Series A Preferred Stock
                      -----------------
     purchased or otherwise acquired by the Corporation in any manner whatsoever
     shall be retired and canceled promptly after the acquisition thereof. All
     such shares shall upon their cancellation become authorized but unissued
     shares of Preferred Stock and may be reissued as part of a new series of
     Preferred Stock to be created by resolution or resolutions of the Board of
     Directors, subject to the conditions and restrictions on issuance set forth
     herein, in the Certificate of Incorporation, in any other Certificate of
     Designation establishing a series of Preferred Stock or any similar stock
     or as otherwise required by law.

          Section 6.  Liquidation, Dissolution or Winding Up.
                      --------------------------------------

               (A)    In the event of any voluntary or involuntary liquidation,
          dissolution or winding up of the Corporation, the holders of the
          shares of Series A Preferred Stock shall be entitled to receive, in
          preference to the holders of any Junior Stock, the greater of (a)
          $1,000.00 per share, plus accrued dividends to the date of
          distribution, whether or not earned or declared, or (b) an amount per
          share equal to the product of the Series A Multiple then in effect
          times the aggregate amount to be distributed per share to holders of
          Common Stock.

               (B)    In the event of any voluntary or involuntary liquidation,
          dissolution or winding up of the Corporation, the holders of Parity
          Stock shall not receive any distributions except for distributions
          made ratably on the Series A Preferred Stock and all other such Parity
          Stock in proportion to the total amounts to which the holders of all
          such shares are entitled upon such liquidation, dissolution or winding
          up.

          Section 7.  Consolidation, Merger, Etc.  In case the Corporation shall
                      ---------------------------
     enter into any consolidation, merger, combination or other transaction in
     which the shares of Common Stock are exchanged for or changed into other
     stock or securities, cash and/or any other property, then in any such case
     the shares of the Series A Preferred Stock shall at the same time be
     similarly exchanged or changed in an amount per share equal to the product
     of the Series A Multiple then in effect times the aggregate amount of
     stock, securities, cash and/or any other property (payable in kind), as the
     case may be, into which or for which each share of Common Stock is changed
     or exchanged.

                                       4
<PAGE>

          Section 8.   No Redemption.  The shares of Series A Preferred Stock
                       -------------
     shall not be redeemable.

          Section 9.   Ranking.  The Series A Preferred Stock shall rank junior
                       -------
     to all other series of the Corporation's Preferred Stock, or any similar
     stock that specifically provides that it shall rank prior to the shares of
     Series A Preferred Stock, as to the payment of dividends and the
     distribution of assets, unless the terms of any such series shall provide
     otherwise. Nothing herein shall preclude the Board of Directors from
     creating any series of Preferred Stock or any similar stock ranking on a
     parity with or prior to the shares of Series A Preferred Stock as to the
     payment of dividends or the distribution of assets.

          Section 10.  Fractional Shares.  Series A Preferred Stock may be
                       -----------------
     issued in fractions of a share which shall entitle the holder, in
     proportion to such holder's fractional shares, to exercise voting rights,
     receive dividends, participate in distributions and to have the benefit of
     all other rights of holders of Series A Preferred Stock.

          Section 11.  Amendment.  The Certificate of Incorporation, including
                       ---------
     this Certificate of Designation establishing the shares of the Series A
     Preferred Stock, shall not be amended in any manner that would materially
     alter or change the powers, preferences or special rights of the Series A
     Preferred Stock so as to affect them adversely without the affirmative vote
     of the holders of two-thirds or more of the outstanding shares of Series A
     Preferred Stock voting separately as a class.

                                       5
<PAGE>

     IN WITNESS WHEREOF, this Certificate is executed on behalf of the
Corporation by its president and attested by it Secretary this 21/st/ day of
July, 2000.



                                    ____________________________________
                                    Robert D. Thompson
                                    Chief Executive Officer
ATTEST:


______________________________
Charles E. Bergeron
Secretary



STATE OF OREGON               )
                              ) ss.
COUNTY OF WASHINGTON          )

     BE IT REMEMBERED, that before me, a notary public in and for the aforesaid
county and state, personally appeared Robert D. Thompson, Chief Executive
Officer, and Charles E. Bergeron, Secretary, of OraSure Technologies, Inc., a
Delaware corporation, who are known to me to be the same persons who executed
the foregoing instrument, and duly acknowledged the execution of the same this
21/st/ day of July, 2000.


                                         ___________________________
                                         Notary Public

My commission expires:



____________________________


                                       6
<PAGE>

                                                                       EXHIBIT B
                                                                       ---------
                          FORM OF RIGHTS CERTIFICATE

Certificate No. R-                                                        Rights

NOT EXERCISABLE AFTER MAY 6, 2010 OR EARLIER IF REDEEMED BY THE COMPANY.  THE
RIGHTS ARE SUBJECT TO REDEMPTION, AT THE OPTION OF THE COMPANY, AT  $.01 PER
RIGHT ON THE TERMS SET FORTH IN THE RIGHTS AGREEMENT.  UNDER CERTAIN
CIRCUMSTANCES, RIGHTS BENEFICIALLY OWNED BY AN ACQUIRING PERSON (AS SUCH TERM IS
DEFINED IN THE RIGHTS AGREEMENT) AND ANY SUBSEQUENT HOLDER OF SUCH RIGHTS MAY
BECOME NULL AND VOID. [THE RIGHTS REPRESENTED BY THIS RIGHTS CERTIFICATE ARE OR
WERE BENEFICIALLY OWNED BY A PERSON WHO IS OR WAS AN ACQUIRING PERSON OR AN
AFFILIATE OR ASSOCIATE OF AN ACQUIRING PERSON (AS SUCH TERMS ARE DEFINED IN THE
RIGHTS AGREEMENT).  ACCORDINGLY, THIS RIGHTS CERTIFICATE AND THE RIGHTS
REPRESENTED HEREBY MAY BECOME NULL AND VOID IN THE CIRCUMSTANCES SPECIFIED IN
SECTION 7(e) OF THE RIGHTS AGREEMENT.]*


                              RIGHTS CERTIFICATE

                          ORASURE TECHNOLOGIES, INC.

          This certifies that _____________________________________________, or
registered assigns, is the registered owner of the number of Rights set forth
above, each of which entitles the owner thereof, subject to the terms,
provisions and conditions of the Rights Agreement, dated as of ___________,
2000, as may be amended from time to time (the "Rights Agreement"), between
OraSure Technologies, Inc., a Delaware corporation (the "Company"), and
ChaseMellon Shareholder Services, L.L.C., a New Jersey limited liability company
(the "Rights Agent"), to purchase from the Company at any time after the
Distribution Date (as such term is defined in the Rights Agreement) and at any
time prior to 5:00 p.m. (New York City time) on May 6, 2010 at the office or
offices of the Rights Agent designated for such purpose, or its successors as
Rights Agent, one one-thousandth of a fully paid, nonassessable share of Series
A Preferred Stock (the "Preferred Stock") of the Company, at a purchase price of
$85.00 per one one-thousandth of a share (the "Purchase Price"), upon
presentation and surrender of this Rights Certificate with the Form of Election
to Purchase and related Certification duly executed. The number of Rights
evidenced by this Rights Certificate (and the number of one one-thousandths of a
share of Preferred Stock that may be purchased upon exercise thereof) set forth
above, and the Purchase Price per share set forth above, are the number and
Purchase Price as of _________, 2000, based on the Preferred Stock as
constituted at such date. As provided in the Rights Agreement, the Purchase
Price and the number and kind of shares of Preferred Stock or other securities
of the Company or any other Person (as such term is defined in the Rights
Agreement) that may be purchased upon the exercise of the Rights evidenced by
this Rights Certificate are

---------------
*    The portion of the legend in brackets will be inserted only if applicable
     and shall replace the preceding sentence.
<PAGE>

subject to modification and adjustment upon the happening of certain events
including a Triggering Event (as such term is defined in the Rights Agreement).

          Upon the occurrence of a Section 11(a)(ii) Event (as such term is
defined in the Rights Agreement), if the Rights evidenced by this Rights
Certificate are beneficially owned by (i) an Acquiring Person or an Affiliate or
Associate of any such Acquiring Person (as such terms are defined in the Rights
Agreement), (ii) a transferee of any such Acquiring Person, Affiliate or
Associate, or (iii) under certain circumstances specified in the Rights
Agreement, a transferee of a person who, after such transfer, became an
Acquiring Person or an Affiliate or Associate of an Acquiring Person, such
Rights shall become null and void and no holder hereof shall have any right with
respect to such Rights from and after the occurrence of such Section 11(a)(ii)
Event.

          This Rights Certificate is subject to all of the terms, provisions and
conditions of the Rights Agreement, which terms, provisions and conditions are
hereby incorporated herein by reference and made a part hereof and to which
reference is hereby made for a full description of the rights, limitations of
rights, obligations, duties and immunities hereunder of the Rights Agent, the
Company and the holders of the Rights Certificates, which limitations of rights
include the temporary suspension of the exercisability of such Rights under the
specific circumstances set forth in the Rights Agreement.  Copies of the Rights
Agreement are on file at the above-mentioned office of the Rights Agent and are
also available upon written request to the Rights Agent.

          This Rights Certificate, with or without other Rights Certificates,
upon surrender at the office or offices of the Rights Agent designated for such
purpose, may be exchanged for another Rights Certificate or Certificates of like
tenor and date evidencing Rights entitling the holder to purchase a like
aggregate number of one one-thousandths of a share of Preferred Stock as the
Rights evidenced by the Rights Certificate or Certificates surrendered shall
have entitled such holder to purchase.  If this Rights Certificate shall be
exercised in part, the holder shall be entitled to receive upon surrender hereof
another Rights Certificate or Certificates for the number of whole Rights not
exercised.

          Subject to the provisions of the Rights Agreement, the Rights
evidenced by this Certificate may be redeemed by the Company at its option at a
redemption price of $.01 per Right at any time prior to the earlier of the close
of business on (i) the tenth Business Day following the Stock Acquisition Date
(as such term is defined in the Rights Agreement, and as such time period may be
extended pursuant to the Rights Agreement), or (ii) the Final Expiration Date
(as such term is defined in the Rights Agreement).  In addition, subject to the
provisions of the Rights Agreement, each Right evidenced by this Certificate may
be exchanged by the Company at its option for one share of Common Stock of the
Company (subject to adjustment for any stock split, stock dividend or similar
transaction) following the Stock Acquisition Date and prior to the time an
Acquiring Person owns 50% or more of the shares of Common Stock of the Company
then outstanding.

          No fractional shares of Preferred Stock or other securities will be
issued upon the exercise of any Right or Rights evidenced hereby (other than
fractions which are integral multiples of one one-thousandth of a share of
Preferred Stock, which may, at the election of the

                                       2
<PAGE>

Company, be evidenced by depositary receipts), but in lieu thereof a cash
payment will be made, as provided in the Rights Agreement.

          No holder of this Rights Certificate shall be entitled to vote or
receive dividends or be deemed for any purpose the holder of shares of Preferred
Stock or of any other securities of the Company that may at any time be issuable
on the exercise hereof, nor shall anything contained in the Rights Agreement or
herein be construed to confer upon the holder hereof, as such, any of the rights
of a stockholder of the Company or any right to vote for the election of
directors or upon any matter submitted to stockholders at any meeting thereof,
or to give or withhold consent to any corporate action, or to receive notice of
meetings or other actions affecting stockholders (except as provided in the
Rights Agreement), or to receive dividends or subscription rights, or otherwise,
until the Right or Rights evidenced by this Rights Certificate shall have been
exercised as provided in the Rights Agreement.

          This Rights Certificate shall not be valid or obligatory for any
purpose until it shall have been countersigned by the Rights Agent.

          WITNESS the facsimile signature of the proper officers of the Company
and its corporate seal.


Dated as of _______________, ____.

                                    ORASURE TECHNOLOGIES, INC.


                                    By:______________________________
                                       Name:
                                       Title:

ATTEST:


_________________________________
Name:
Title:

Countersigned:

ChaseMellon Shareholder Services, L.L.C.
as Rights Agent


By:______________________________
   Name:
   Title:

                                       3
<PAGE>

                 [Form of Reverse Side of Rights Certificate]

                              FORM OF ASSIGNMENT

                 (To be executed by the record holder if such
              holder desires to transfer the Rights Certificate.)

FOR VALUE RECEIVED the undersigned hereby sells, assigns and transfers unto_____

______________________________________________________________________________

______________________________________________________________________________
 (Please print name, address and social security or other identifying number of
                                  transferee)

______________ (______) of the Rights represented by this Rights Certificate,
together with all right, title and interest therein, and does hereby irrevocably
constitute and appoint ____________________________________________________ its
attorney, to transfer the within Rights Certificate on the books of the within-
named Company, with full power of substitution.


Dated: __________________, ___.


                                        ________________________
                                                Signature


Signature Guaranteed:

     Signatures must be guaranteed by an Eligible Guarantor Institution as
defined by SEC Rule 17Ad-15 (12 C.F.R. 240.17Ad-15) or any similar rule which
the Rights Agent deems applicable.

                                       4
<PAGE>

           [Form of Reverse Side of Rights Certificate (continued)]

                                 Certification
                                 -------------


     The undersigned hereby certifies by checking the appropriate boxes that:

     (1) this Rights Certificate is not being sold, assigned and transferred by
or on behalf of a Person who is or was an Acquiring Person or an Affiliate or
Associate of any such Acquiring Person (as such terms are defined in the Rights
Agreement);

     (2) after due inquiry and to the best knowledge of the undersigned, the
undersigned did not acquire the Rights evidenced by this Rights Certificate from
any Person who is, was or subsequently became an Acquiring Person or an
Affiliate or Associate of an Acquiring Person.


Dated: __________________, ___.


                                             _________________
                                                 Signature


Signature Guaranteed:

     Signatures must be guaranteed by an Eligible Guarantor Institution as
defined by SEC Rule 17Ad-15 (12 C.F.R. 240.17Ad-15) or any similar rule which
the Rights Agent deems applicable.

                                    NOTICE
                                    ------

     The signature to the foregoing Assignment and Certification must correspond
to the name as written upon the face of this Rights Certificate in every
particular, without alteration or enlargement or any change whatsoever.

     In the event the certification set forth above is not or cannot be
completed, the Company and the Rights Agent will deem the beneficial owner of
the Rights evidenced by this Rights Certificate to be an Acquiring Person or an
Affiliate or Associate thereof (as defined in the Rights Agreement) and such
Assignment will not be honored.

                                       5
<PAGE>

           [Form of Reverse Side of Rights Certificate (continued)]

                         FORM OF ELECTION TO PURCHASE

              (To be executed if holder desires to exercise Rights
                     represented by the Rights Certificate)

To:  OraSure Technologies, Inc.:

     The undersigned hereby irrevocably elects to exercise ___________________
(____) Rights represented by this Rights Certificate to purchase the shares of
Preferred Stock issuable upon the exercise of the Rights (or such other
securities of the Company or of any other Person (as such term is defined in the
Rights Agreement) that may be issuable upon the exercise of the Rights) and
requests that certificates for such shares be issued in the name of:


_______________________________________________________________________________

_______________________________________________________________________________
  (Please print name, address and social security number or other identifying
                                    number)

     If such number of Rights shall not be all the Rights evidenced by this
Rights Certificate, a new Rights Certificate for the balance of such Rights
shall be registered in the name of and delivered to:


_______________________________________________________________________________

_______________________________________________________________________________
  (Please print name, address and social security number or other identifying
                                    number)

Dated: __________________, ___.


                                             ________________
                                                 Signature


Signature Guaranteed:

     Signatures must be guaranteed by an Eligible Guarantor Institution as
defined by SEC Rule 17Ad-15 (12 C.F.R. 240.17Ad-15) or any similar rule which
the Rights Agent deems applicable.

                                       6
<PAGE>

            [Form of Reverse Side of Rights Certificate (continued)]

                                 Certification
                                 -------------

     The undersigned hereby certifies by checking the appropriate boxes that:

     (1) the Rights evidenced by this Rights Certificate are not being exercised
by or on behalf of a Person who is or was an Acquiring Person or an Affiliate or
Associate of any such Acquiring Person (as such terms are defined in the Rights
Agreement);

     (2) after due inquiry and to the best knowledge of the undersigned, the
undersigned did not acquire the Rights evidenced by this Rights Certificate from
any Person who is, was or became an Acquiring Person or an Affiliate or
Associate of an Acquiring Person.

Dated: __________________, ___.


                                             _______________
                                                Signature


Signature Guaranteed:

     Signatures must be guaranteed by an Eligible Guarantor Institution as
defined by SEC Rule 17Ad-15 (12 C.F.R. 240.17Ad-15) or any similar rule which
the Rights Agent deems applicable.

                                     NOTICE
                                     ------


     The signature to the foregoing Election to Purchase and Certification must
correspond to the name as written upon the face of this Rights Certificate in
every particular, without alteration or enlargement or any change whatsoever.

     In the event the certification set forth above is not or cannot be
completed, the Company and the Rights Agent will deem the beneficial owner of
the Rights evidenced by this Rights Certificate to be an Acquiring Person or an
Affiliate or Associate thereof (as defined in the Rights Agreement) and such
Election to Purchase will not be honored.

                                       7
<PAGE>

                                                                       EXHIBIT C
                                                                       ---------

                                    FORM OF

                         SUMMARY OF RIGHTS TO PURCHASE
                                PREFERRED STOCK

          On May 6, 2000, the Board of Directors of OraSure Technologies, Inc.
("OraSure"), adopted a Stockholder Rights Plan providing for the distribution of
one Right to purchase its Series A Preferred Stock for each outstanding share of
its Common Stock. The Rights will be distributed together with the Common Stock
issued upon the consummation of the mergers of STC Technologies, Inc. ("STC")
with and into OraSure and Epitope, Inc. ("Epitope") with and into OraSure,
pursuant to that certain Merger Agreement, dated as of May 6, 2000 among
Epitope, STC and OraSure.  No income will be recognized by stockholders for tax
purposes on payment of the dividend.  The Rights are not now exercisable, and it
is not known at this time whether they ever will be exercisable.  No action can
be taken by holders of Rights at this time.  Until a Right is exercised, the
Right does not create any rights as a stockholder of OraSure, including the
right to vote or receive dividends.

          The Rights will trade with the Common Stock of OraSure.  In general,
the Rights detach from the Common Stock of OraSure and become exercisable on the
tenth business day after the earlier of either of the following two events
occurs:

          .    a person or entity, together with its Affiliates or Associates,
               becomes the beneficial owner of 15% or more of the outstanding
               shares of Common Stock of OraSure, or

          .    a person or entity, together with its Affiliates or Associates,
               announces or commences a tender offer that, if consummated, would
               result in them becoming the beneficial owner of 15% or more of
               the outstanding shares of Common Stock of OraSure.

An "Affiliate" of a person or entity is a person or entity that directly, or
indirectly through one or more intermediaries, controls, or is controlled by, or
is under common control with, the person or entity specified.  An "Associate" of
a person or entity is (a) any corporation or organization (other than OraSure or
any majority-owned subsidiary of OraSure) of which such person or entity is an
officer or partner or is, directly or indirectly, the beneficial owner of 10% or
more of any class of equity securities, (b) any trust or other estate in which
such person or entity has a substantial beneficial interest or as to which such
person or entity serves as trustee or in a similar fiduciary capacity, and (c)
any relative or spouse of such person or entity, or any relative of such spouse,
who has the same home as such person or entity or who is a director or officer
of such person or entity or any of its parents or subsidiaries.

          If the Rights detach and become exercisable as a result of the
commencement of a tender offer, each Right entitles its holder to purchase one
one-thousandth of a share of Series A Preferred Stock for an exercise price of
$85.00 unless the Rights are redeemed by OraSure. This exercise price and the
number of shares, or fraction of a share, of Series A Preferred Stock that can
be purchased are both subject to adjustment to prevent dilution in the event of
a stock
<PAGE>

dividend on the Series A Preferred Stock or a subdivision, combination or
reclassification of the Series A Preferred Stock or if OraSure distributes
certain rights, options, warrants, evidences of indebtedness or assets to the
holders of the Series A Preferred Stock.

     Because of the nature of the Series A Preferred Stock's dividend,
liquidation and voting rights, the value of one one-thousandth of a share of
Series A Preferred Stock that may be purchased upon the exercise of each Right
should approximate the value of one share of Common Stock.  In the event of the
liquidation of OraSure, the holders of shares of Series A Preferred Stock will
be entitled to the greater of

     .    a minimum preferential liquidation payment of $1,000 per share, plus
          accrued dividends, or

     .    1,000 times the aggregate amount to be distributed per share of Common
          Stock.

Each share of Series A Preferred Stock will have 1000 votes and will vote
together with the Common Stock as a single class.  Finally, in the event of any
merger, consolidation or other transaction involving OraSure (other than the
Merger) in which shares of Common Stock are exchanged for or changed into other
stock, securities, cash and/or other property, each share of Series A Preferred
Stock will be entitled to receive 1,000 times the amount received per share of
Common Stock. The dividend, liquidation, voting and other rights of the Series A
Preferred Stock will be proportionately adjusted to reflect any stock split,
stock dividend or similar transaction involving the Common Stock.

     After a person or entity (referred to as an Acquiring Person), together
with its Affiliates and Associates, becomes the beneficial owner of 15% or more
of the outstanding shares of Common Stock of OraSure in one or more transactions
that do not constitute a Qualifying Offer, each Right entitles its holder to
purchase, for the Right's exercise price, a number of shares of Common Stock (or
in certain circumstances, cash, property or other securities of OraSure) having
a value equal to two times the then current exercise price of the Right. All
Rights that are, or under certain circumstances were, beneficially owned by any
Acquiring Person, or Affiliates or Associates of that person or entity, will be
null and void.  A "Qualifying Offer" is an offer for outstanding shares of
Common Stock that a majority of the directors of OraSure who are not Affiliates
or Associates of an Acquiring Person determine, after receiving advice from one
or more investment banking firms, to be fair to the stockholders and otherwise
in the best interests of OraSure and its stockholders.

     If OraSure is involved in a merger or other business combination
transaction after the Rights become exercisable, each Right entitles its holder
to purchase, for the Right's exercise price, a number of the acquiring or
surviving company's shares of common stock having a market value equal to twice
the exercise price of the Right.  Similarly, if OraSure sells or transfers 50%
or more of its assets or earning power after the Rights become exercisable, each
Right entitles its holder to purchase, for the Right's exercise price, a number
of the acquiring company's shares of common stock having a market value equal to
twice the exercise price of the Right.

                                       2

<PAGE>

     At any time after any person or entity becomes an Acquiring Person and
before the acquisition by such person or entity, together with that person's
Affiliates or Associates,  of 50% or more of the Common Stock of OraSure, the
OraSure Board may exchange Common Stock for all or any part of the Rights other
than any Rights that have become null and void. The exchange rate is one share
of Common Stock for each Right. This exchange rate is subject to adjustment to
reflect any stock split, stock dividend or similar transaction involving the
Common Stock.

     OraSure is entitled to redeem the Rights at $.01 per Right at any time
until ten business days following a public announcement that a person, together
with that person's Affiliates or Associates, has become the beneficial owner of
15% or more of the outstanding shares of Common Stock of OraSure.  The terms of
the Rights expire on May 6, 2010, unless OraSure redeems the Rights before then
or unless the OraSure Board extends the Rights by amending the Rights Agreement.

     Until the Rights are no longer redeemable, the OraSure Board of Directors
may amend the Rights Agreement and Rights in any respect.  After the Rights are
no longer redeemable, the OraSure Board of Directors may amend the Rights
Agreement and the Rights to make changes that do not adversely affect the
interests of the holders of the Rights (excluding the interests of the Acquiring
Person or its Affiliates and Associates) or to shorten or lengthen any time
period under the Rights Agreement (except for the time period governing
redemption of the Rights).  No amendment of the Rights Agreement or Rights by
the OraSure Board of Directors is permitted to change the redemption price of
the Rights, regardless of whether the amendment occurs before or after the time
the Rights cease to be redeemable.

     The terms of the Rights are set forth in the Rights Agreement, which has
been filed with the Securities and Exchange Commission as an Exhibit to this
Registration Statement on Form S-4. A copy of the Rights Agreement is available
free of charge from the Company. This summary description of the Rights does not
purport to be complete and is qualified in its entirety by reference to the
Rights Agreement, which is incorporated herein by reference.

                                       3