EXHIBIT 2.2


                                                                 EXECUTION COPY









                             STOCKHOLDER AGREEMENT



                                  by and among



                              ABBOTT LABORATORIES,



                           CORVETTE ACQUISITION CORP.



                                      and



                       THE STOCKHOLDERS SIGNATORY HERETO



                          Dated as of January 12, 2004














                             STOCKHOLDER AGREEMENT

     STOCKHOLDER AGREEMENT, dated as of January 12, 2004 (the "Agreement"),
among Abbott Laboratories, an Illinois corporation ("Parent"), Corvette
Acquisition Corp., a Delaware corporation and a wholly-owned subsidiary of
Parent ("Sub"), and the stockholders of TheraSense, Inc., a Delaware
corporation (the "Company"), listed on Schedule A hereto (collectively, the
"Stockholders" and, each individually, a "Stockholder"). Capitalized terms used
and not otherwise defined herein have the meanings given to them in the
Agreement and Plan of Merger, dated as of the date hereof, by and among Parent,
Sub and the Company (as the same may be amended or supplemented, the "Merger
Agreement").

     WHEREAS, Parent, Sub and the Company propose to enter into the Merger
Agreement providing for the merger of Sub with and into the Company (the
"Merger") upon the terms and subject to the conditions set forth in the Merger
Agreement;

     WHEREAS, each Stockholder owns (of record or beneficially), or is the
trustee of one or more trusts that are the record holder of, and whose
beneficiaries are the beneficial owners of, the number of shares of capital
stock of the Company set forth opposite their respective names on Schedule A
hereto (such shares of capital stock of the Company being referred to herein as
the Stockholder's "Original Shares" and the Original Shares, together with any
other shares of capital stock of the Company or other voting securities of the
Company acquired (of record or beneficially) by the respective Stockholder or
the trusts, if any, of which the respective Stockholder is a trustee, after the
date hereof and during the term of this Agreement (including through the
exercise of any warrants, stock options or similar instruments), being
collectively referred to herein as the Stockholder's "Subject Shares";
provided, however, that the Original Shares and the Subject Shares of a
Stockholder shall not be deemed to include any shares owned of record by an
Affiliate of such Stockholder to the extent such Stockholder has disclaimed
beneficial ownership thereof in Schedule A hereto);

     WHEREAS, the Company Board has unanimously adopted resolutions approving
and declaring advisable the Merger Agreement, this Agreement and the
transactions contemplated thereby and hereby (such approvals having been made
in accordance with the DGCL, including for purposes of Section 203 thereof) and
has amended the Rights Agreement; and

     WHEREAS, as a condition to the willingness of Parent and Sub to enter into
the Merger Agreement, and as inducement and in consideration therefor, each
Stockholder has agreed to enter into this Agreement.

     NOW, THEREFORE, in consideration of the foregoing and the representations,
warranties, covenants and agreements set forth herein and in the Merger
Agreement, the parties hereto agree as follows:


1



     SECTION 1. Representations and Warranties of the Stockholders. Each
Stockholder hereby represents and warrants as to himself, herself or itself to
Parent and Sub as follows:

     (a) Organization, Authority and Qualification of the Stockholders. If the
Stockholder is not an individual, such Stockholder is duly organized, validly
existing and in good standing under the laws of the jurisdiction of its
organization or formation and has all requisite power and authority to enter
into this Agreement, to carry out its obligations hereunder and to consummate
the transactions contemplated hereby. If the Stockholder is an individual, if
such Stockholder is married and the Subject Shares constitute community
property or if the Stockholder otherwise requires spousal or other approval for
this Agreement to be legal, valid and binding, this Agreement has been duly
executed and delivered by, and constitutes a legal, valid and binding
obligation of, such Stockholder's spouse, enforceable against such spouse in
accordance with its terms. If the Stockholder is a trustee under one or more
trusts, none of such trusts requires the consent of any beneficiary to the
execution and delivery of this Agreement or to the consummation of the
transactions contemplated hereby. The Stockholder has all necessary power and
authority to execute and deliver this Agreement and to consummate the
transactions contemplated by this Agreement. If applicable, the execution,
delivery and performance of this Agreement by the Stockholder and the
consummation by the Stockholder of the transactions contemplated by this
Agreement have been duly authorized by all necessary action on the part of the
Stockholder. This Agreement has been duly executed and delivered by the
Stockholder and constitutes (assuming due authorization, execution and delivery
by Parent and Sub) a valid and binding obligation of the Stockholder,
enforceable against the Stockholder in accordance with its terms.

     (b) No Conflict; Required Filings and Consents.

          (i) The execution and delivery of this Agreement do not, and the
     consummation of the transactions contemplated by this Agreement and
     compliance with the provisions of this Agreement shall not, (A) if the
     Stockholder is not an individual, conflict with, or result in any
     violation of, the certificate of incorporation or by-laws or the
     equivalent organizational documents of the Stockholder, (B) conflict with,
     or result in any violation of, any United States or foreign Law applicable
     to the Stockholder or by which any property or asset of the Stockholder is
     bound or affected or (C) result in any breach of, or constitute a default
     (with or without notice or lapse of time, or both) under, or give rise to
     a right of termination, amendment, cancellation or acceleration of any
     obligation or to a loss of a material benefit under, or result in the
     creation of any Liens in or upon any of the properties or assets of the
     Stockholder, pursuant to any loan or credit agreement, note, bond,
     mortgage, indenture,


                                       2



     lease, license, sublease, easement, covenant, condition, restriction,
     contract, instrument, permit, concession, franchise license or other
     instrument or obligation. For purposes of this Agreement, Law means any
     statute, law (including common law), ordinance, rule or regulation

          (ii) No consent, approval, Order or authorization of, or
     registration, declaration or filing with, or notification to, any
     Governmental Entity is required by or with respect to the Stockholder in
     connection with the execution and delivery of this Agreement by the
     Stockholder or the consummation by the Stockholder of the transactions
     contemplated by this Agreement, except the filing with the SEC of such
     reports under the Exchange Act as may be required in connection with this
     Agreement and the transactions contemplated hereby.

     (c) Absence of Litigation. As of the date of this Agreement, there is no
Proceeding pending or, to the knowledge of the Stockholder, threatened against
the Stockholder, or any property or asset of the Stockholder, before any
Governmental Entity that seeks to delay or prevent the consummation of the
transactions contemplated by this Agreement.

     (d) The Subject Shares. The Stockholder is the record and beneficial owner
(as defined in Rule 13d-3 under the Exchange Act, which meaning will apply for
all purposes of this Agreement) of, or is the trustee of one or more trusts
that are the record holder of, and whose beneficiaries are the beneficial
owners of, and has good and marketable title to, his, her or its Subject
Shares, free and clear of any and all Liens. Other than as set forth on
Schedule A hereto, the Stockholder does not own (of record or beneficially) any
shares of capital stock of the Company or any options, warrants, rights or
other similar instruments to acquire any capital stock or other voting
securities of the Company. The Stockholder has the sole right to vote and
Transfer (as defined in Section 3(c) of this Agreement) the Subject Shares, and
the Subject Shares are not subject to any proxies, voting trusts or other
agreements, understandings, arrangements or restrictions with respect to the
voting or the Transfer of the Subject Shares, except as set forth in Sections 3
and 4 of this Agreement.

     (e) No broker, finder or investment banker is entitled to any brokerage,
finder's or other fee or commission in connection with the transactions
contemplated by the Merger Agreement based upon arrangements made by or on
behalf of the Stockholder.

     SECTION 2. Representations and Warranties of Parent and Sub. Parent and
Sub represent and warrant to each Stockholder as follows:

     (a) Organization and Authority. Each of Parent and Sub is a corporation
duly organized, validly existing and in good standing under the laws of the
jurisdiction in which it is incorporated and has all requisite corporate power
and authority to own, lease, possess and operate its properties and assets and
to carry on its business as now being conducted. Parent and Sub each have all
necessary corporate power and


                                       3



authority to execute and deliver this Agreement and to consummate the
transactions contemplated by this Agreement. The execution, delivery and
performance of this Agreement by Parent and Sub and the consummation by Parent
and Sub of the transactions contemplated by this Agreement have been duly
authorized by all necessary corporate action on the part of each of Parent and
Sub. This Agreement has been duly executed and delivered by Parent and Sub and
constitutes (assuming due authorization, execution and delivery by the
Stockholders) a valid and binding obligation of each of Parent and Sub,
enforceable against each of Parent and Sub in accordance with its terms.

     (b) Authorization; Noncontravention.

          (i) The execution and delivery of this Agreement do not, and the
     consummation of the transactions contemplated by this Agreement and
     compliance with the provisions of this Agreement and shall not, (A)
     conflict with, or result in any violation of, the certificate of
     incorporation or by-laws of either of Parent or Sub or (B) conflict with,
     or result in any violation of, any United States or foreign Law applicable
     to Parent or Sub or by which any property or asset of Parent or Sub is
     bound or affected.

          (ii) No consent, approval, Order or authorization of, or
     registration, declaration or filing with, or notification to, any
     Governmental Entity is required by or with respect to Parent or Sub in
     connection with the execution and delivery of this Agreement by Parent or
     Sub or the consummation by Parent or Sub of the transactions contemplated
     by this Agreement, except (A) the filing of a pre-merger notification and
     report form by Parent and Sub under the HSR Act, and compliance with the
     pre-merger notification requirements in Austria, Germany, Ireland, Italy
     and the Czech Republic, (B) the filing with the SEC of such reports under
     the Exchange Act as may be required in connection with this Agreement and
     the transactions contemplated by hereby and (C) such other consents,
     approvals, Orders, authorizations, registrations, declarations, filings
     and notifications, the failure of which to be obtained or made would not,
     individually or in the aggregate, (x) impair in any material respect the
     ability of either Parent or Sub to perform its obligations under this
     Agreement or (y) prevent or materially delay the consummation of any of
     the transactions contemplated by this Agreement.

     SECTION 3. Covenants of the Stockholders. Each Stockholder covenants and
agrees as follows:

     (a) At any meeting of the stockholders of the Company called to vote upon
the Merger Agreement, the Merger, any of the other transactions contemplated by
the Merger Agreement or any other transaction pursuant to which Parent or Sub
proposes to acquire the Company, whether by merger or otherwise, in which
stockholders of the Company would receive consideration per share of Company
Common Stock in cash equal to or greater than the consideration to be received
by such stockholders in the


                                       4



Merger (an "Increased Acquisition Proposal"), or at any adjournment thereof, or
in any other circumstances upon which a vote or other approval with respect to
the Merger Agreement, the Merger, any of the other transactions contemplated by
the Merger Agreement or any Increased Acquisition Proposal is sought, the
Stockholder shall vote (or cause to be voted) all of the Subject Shares in
favor of the approval and adoption of the Merger Agreement, the Merger and the
terms thereof, each of the other transactions contemplated by the Merger
Agreement or any Increased Acquisition Proposal.

     (b) At any meeting of the stockholders of the Company or at any
adjournment thereof or in any other circumstances upon which a vote or other
approval is sought, the Stockholder shall vote (or cause to be voted) all of
the Subject Shares against any of the following: (i) any merger agreement or
merger (other than the Merger Agreement and the Merger), consolidation,
combination, sale of substantial assets, reorganization, recapitalization,
dissolution, liquidation or winding up of or by the Company, (ii) any
Alternative Acquisition Proposal or (iii) any amendment of the Company's
certificate of incorporation or by-laws or other proposal, action or
transaction involving the Company or any of the Company Subsidiaries or any of
its stockholders, which amendment or other proposal, action or transaction
would in any manner impede, frustrate, prevent or delay the consummation of the
Merger or the other transactions contemplated by the Merger Agreement or this
Agreement or change in any manner the voting rights of the holders of Company
Common Stock (collectively, "Frustrating Transactions"). The Stockholder shall
not commit to or agree to take any action inconsistent with the foregoing or
that would otherwise facilitate a Frustrating Transaction. Notwithstanding the
foregoing, nothing herein shall preclude a Stockholder from voting for or
otherwise approving an Increased Acquisition Proposal as set forth in Section
3(a) of this Agreement.

     (c) The Stockholder shall not (i) sell, transfer, pledge, assign or
otherwise dispose of (including by gift) (collectively, "Transfer"), or consent
to or permit any Transfer of, any Subject Shares or any interest therein, or
enter into any loan or credit agreement, bond, debenture, note, mortgage,
indenture, lease or other contract, commitment, agreement, option, instrument,
arrangement, understanding, obligation or undertaking, with respect to the
Transfer (including any profit sharing or other derivative arrangement) of any
Subject Shares or any interest therein, to any Person other than pursuant to
this Agreement or the Merger Agreement, (ii) enter into any voting arrangement,
whether by proxy, voting agreement or otherwise, with respect to any Subject
Shares and shall not commit or agree to take any of the foregoing actions,
other than pursuant to this Agreement or (iii) take any other action that would
in any way restrict, limit or interfere with the performance of the
Stockholder's obligations under this Agreement or the transactions contemplated
hereby. The Stockholder shall not, nor shall the Stockholder permit any entity
under the Stockholder's control to, deposit any Subject Shares in a voting
trust.

     (d) The Stockholder shall not, nor shall the Stockholder authorize or
permit any investment banker, attorney, accountant or other advisor or
representative of the Stockholder to, directly or indirectly, (i) solicit,
initiate, facilitate, encourage, engage in discussions or negotiate with any
Person or take any other action


                                       5



intended or designed to facilitate any inquiry or effort of any Person relating
to any Alternative Acquisition or other Frustrating Transaction, (ii) provide
information with respect to the Company or any Company Subsidiary to any Person
relating to a possible Alternative Acquisition or (iii) enter into any
agreement with respect to any proposal for an Alternative Acquisition or other
Frustrating Transaction. The Stockholder shall promptly advise Parent and Sub
orally and in writing of any Alternative Acquisition Proposal or inquiry made
to the Stockholder with respect to, or that could reasonably be expected to
lead to, any Alternative Acquisition Proposal or other Frustrating Transaction.
The Stockholder shall immediately cease participating in any discussions or
negotiations with any parties that may be ongoing with respect to any proposal
that constitutes, or reasonably may be expected to lead to, an Alternative
Acquisition Proposal.

     (e) The Stockholder hereby consents to and approves the actions taken by
the Company Board in approving the Merger Agreement and this Agreement, the
Merger and the other transactions contemplated by the Merger Agreement.

     SECTION 4. Grant of Irrevocable Proxy; Appointment of Proxy.

     (a) Each Stockholder hereby irrevocably grants to, and appoints, Parent,
Sub and any individual designated in writing by Parent, the Stockholder's proxy
and attorney-in-fact (with full power of substitution), for and in the name,
place and stead of the Stockholder, to vote all of his, her or its Subject
Shares, or grant any approval in respect of such Subject Shares, (i) in favor
of the adoption of the Merger Agreement and the approval of the terms thereof
and of the Merger and each of the other transactions contemplated by the Merger
Agreement or any Increased Acquisition Proposal, (ii) against any Alternative
Acquisition Proposal or other Frustrating Transaction and (iii) otherwise in
accordance with Section 3 of this Agreement. The Stockholder understands and
acknowledges that Parent and Sub are entering into the Merger Agreement in
reliance upon the Stockholder's execution and delivery of this Agreement.

     (b) Each Stockholder represents that any proxies heretofor given in
respect of his, her or its Subject Shares are not irrevocable and that all such
proxies are hereby revoked.

     (c) Each Stockholder hereby affirms that the irrevocable proxy set forth
in this Section 4 is given in connection with the execution of the Merger
Agreement and that such irrevocable proxy is given to secure the performance of
the duties of the Stockholder under this Agreement. The Stockholder hereby
further affirms that the irrevocable proxy is coupled with an interest and,
except as set forth in Section 9 hereof, is intended to be irrevocable in
accordance with the provisions of Section 212(e) of the DGCL. If for any reason
the proxy granted herein is not irrevocable, then the Stockholder agrees to
vote his, her or its Subject Shares as instructed by Parent in writing. The
Stockholder hereby ratifies and confirms all that such irrevocable proxy may
lawfully do or cause to be done by virtue hereof.


                                       6



     SECTION 5. Further Assurances. Each Stockholder shall use his, her or its
reasonable best efforts to take, or cause to be taken, all actions, and to do,
or cause to be done, and to assist and cooperate with the other parties in
doing, all things necessary, proper or advisable to consummate and make
effective, in the most expeditious manner practicable, the transactions
contemplated by this Agreement and the Merger Agreement. The Stockholder shall
not commit or agree to take any action inconsistent with the transactions
contemplated by this Agreement or the transactions contemplated by the Merger
Agreement. Without limiting the generality of the foregoing, the Stockholder
shall, from time to time, execute and deliver, or cause to be executed and
delivered, such additional or further consents, documents and other instruments
as Parent or Sub may request for the purpose of effectuating the matters
covered by this Agreement, including with respect to the grant of the proxy set
forth in Section 4.

     SECTION 6. Conditions to Obligations of Parent and Sub. Each Stockholder
acknowledges and agrees that the obligations of Parent and Sub to consummate
the Merger are subject to the satisfaction of each of the conditions set forth
in the Merger Agreement.

     SECTION 7. Certain Events. Each Stockholder agrees that this Agreement and
the obligations hereunder shall attach to his, her or its Subject Shares and
shall be binding upon any Person to which legal or beneficial ownership of the
Subject Shares shall pass, whether by operation of law or otherwise, including
the Stockholder's heirs, guardians, administrators or successors. If requested
by Parent, a Stockholder shall cause each certificate representing his, her or
its Subject Shares to be inscribed with a legend to such effect. In the event
of any stock split, stock dividend, reclassification, merger, reorganization,
recapitalization or other change in the capital structure of the Company
affecting the capital stock of the Company, the number of Original Shares and
the number of Subject Shares listed on Schedule A hereto shall be adjusted
appropriately. In addition, in the event that the Stockholder acquires any
additional shares of capital stock of the Company or other voting securities of
the Company (including through the exercise of any warrants, stock options or
similar instruments), the number of Subject Shares listed on Schedule A hereto
shall be adjusted appropriately. This Agreement and the representations,
warranties, covenants, agreements and obligations hereunder shall attach to any
additional shares of capital stock of the Company or other voting securities of
the Company issued to or acquired by the Stockholder (including through the
exercise of any warrants, stock options or similar instruments).

     SECTION 8. Assignment. Neither this Agreement nor any of the rights,
interests or obligations under this Agreement shall be assigned, in whole or in
part, by operation of law or otherwise, by either of the parties hereto without
the prior written consent of the other party hereto, except that each of Parent
and Sub may assign, in its sole discretion, any of or all its rights, interests
and obligations under this Agreement to any direct or indirect wholly-owned
subsidiary of Parent or Sub, as applicable. Any purported assignment in
violation of this Section 8 shall be null and void. Subject to the preceding
sentences of this Section 8, this Agreement shall be binding upon, inure to the
benefit of and be enforceable by the parties hereto and their respective
successors and assigns.


                                       7



     SECTION 9. Termination. This Agreement shall terminate upon the earlier to
occur of (a) the Effective Time or (b) the termination of the Merger Agreement
in accordance with its terms; provided, however, that termination of this
Agreement shall not prevent any party hereunder from seeking any remedies (at
law or in equity) against any other party hereto for such party's breach of any
of the terms of this Agreement prior to termination.

     SECTION 10. General Provisions.

     (a) Amendments. This Agreement may not be amended except by an instrument
in writing signed on behalf of each of the parties.

     (b) Notices. Except for notices that are specifically required by the
terms of this Agreement to be delivered orally, all notices and other
communications hereunder shall be in writing and shall be deemed given if
delivered personally, telecopied (with confirmation) or sent by nationally
recognized overnight or same-day courier (providing proof of delivery) to
Parent or Sub in accordance with Section 10.2 of the Merger Agreement and to
the applicable Stockholders at the addresses set forth opposite their
respective names on Schedule A hereto (or at such other address for a party as
shall be specified by like notice).

     (c) Interpretation. When a reference is made in this Agreement to a party
or to a Section or Schedule, such reference shall be to a party to, or a
Section of or a Schedule to, this Agreement unless otherwise indicated. The
table of contents and headings contained in this Agreement are for reference
purposes only and shall not affect in any way the meaning or interpretation of
this Agreement. Whenever the words "include," "includes" or "including" are
used in this Agreement, they shall be deemed to be followed by the words
"without limitation." The words "hereof," "herein," "hereunder" and words of
similar import, when used in this Agreement, shall refer to this Agreement as a
whole and not to any particular provision of this Agreement. The definitions
contained in this Agreement are applicable to the singular as well as the
plural forms of such terms.

     (d) Counterparts; Effectiveness. This Agreement may be executed in one or
more counterparts, all of which shall be considered one and the same agreement
and shall become effective when one or more counterparts have been signed by
each of the parties and delivered to the other party. The effectiveness of this
Agreement shall be conditioned upon the execution and delivery of the Merger
Agreement by each of the parties thereto.

     (e) Entire Agreement; No Third-Party Beneficiaries. This Agreement
(including the documents and instruments referred to herein) (i) constitutes
the entire agreement and supersedes all prior agreements and understandings,
both written and oral, among the parties with respect to the subject matter
hereof; and (ii) other than with respect to the persons specified as proxies in
Section 4, is not intended to confer upon any Person other than the parties any
rights or remedies hereunder.


                                       8



     (f) Governing Law. This Agreement shall be governed by and construed in
accordance with the laws of the State of Delaware, without regard to any
principles of conflicts of law of such state.

     (g) Severability. If any term or other provision of this Agreement is
invalid, illegal or incapable of being enforced by any rule or law or public
policy, all other conditions and provisions of this Agreement shall
nevertheless remain in full force and effect so long as the economic or legal
substance of the transactions contemplated hereby is not affected in any manner
materially adverse to any party. Upon such determination that any term or other
provision is invalid, illegal or incapable of being enforced, the parties shall
negotiate in good faith to modify this Agreement so as to effect the original
intent of the parties as closely as possible in an acceptable manner to the end
that transactions contemplated hereby are fulfilled to the extent possible.

     (h) Service of Process. Parent, Sub and each Stockholder irrevocably
consents to the service of process outside the territorial jurisdiction of the
courts referred to in Section 11 hereof in any such action or proceeding by
mailing copies thereof by registered United States mail, postage prepaid,
return receipt requested, to its address as specified in or pursuant to Section
10(b) hereof. However, the foregoing shall not limit the right of a party to
effect service of process on the other party by any other legally available
method.

     (i) Non-Waiver. The failure of any party hereto to exercise any right,
power or remedy provided under this Agreement or otherwise available in respect
hereof at law or in equity, or to insist upon compliance by any other party
hereto with its obligations hereunder, and any custom or practice of the
parties at variance with the terms hereof, shall not constitute a waiver by
such party of its right to exercise any such or other right, power or remedy or
to demand such compliance.

     SECTION 11. Enforcement. The parties agree that irreparable damage would
occur in the event that any of the provisions of this Agreement were not
performed in accordance with their specific terms or were otherwise breached.
It is accordingly agreed that the parties shall be entitled to an injunction or
injunctions to prevent breaches of this Agreement and to enforce specifically
the terms and provisions of this Agreement in any federal court located in the
State of Delaware or in any Delaware state court, this being in addition to any
other remedy to which they are entitled at law or in equity. In addition, each
of the parties (a) consents to submit itself to the personal jurisdiction of
any federal court located in the State of Delaware or any Delaware state court
in the event any dispute arises out of this Agreement or any of the
transactions contemplated by this Agreement, (b) agrees that it will not
attempt to deny or defeat such personal jurisdiction by motion or other request
for leave from any such court, (c) agrees that it will not bring any action
relating to this Agreement or the transactions contemplated by this Agreement
in any court other than a federal court located in the State of Delaware or a
Delaware state court and (d) waives any right to trial by jury with respect to
any action related to or arising out of this Agreement or any of the
transactions contemplated hereby.


                                       9



     SECTION 12. Stockholders Capacity. Each Stockholder does not make any
agreement or understanding herein in his or her capacity as a director or
officer of the Company. The Stockholder signs solely in his or her capacity as
the record holder and beneficial owner of, or the trustee of one or more trusts
that are the record holder of, and whose beneficiaries are the beneficial
owners of, the Subject Shares, and nothing herein shall limit or affect any
actions taken by the Stockholder in his or her capacity as an officer or
director of the Company to the extent specifically permitted by the Merger
Agreement.




                                     ******


                                      10



     IN WITNESS WHEREOF, each of Parent and Sub have caused this Agreement to
be signed by its officer thereunto duly authorized and each Stockholder has
signed this Agreement (if applicable, by its officer thereunto duly
authorized), all as of the date first written above.



                                  ABBOTT LABORATORIES


                                  By: /s/ Richard A. Gonzalez
                                      --------------------------------------
                                      Name:  Richard A. Gonzalez
                                      Title: President & Chief
                                             Operating Officer, Medical
                                             Products Group



                                  CORVETTE ACQUISITION CORP.


                                  By: /s/ Thomas C. Freyman
                                      --------------------------------------
                                      Name:  Thomas C. Freyman
                                      Title: President


                                  STOCKHOLDERS:

                                  InterWest Partners V, L.P.
                                  By:  Robert Monsen
                                       Its: General Partner


                                  By: /s/ Robert Monsen
                                      --------------------------------------
                                      Name:  Robert Monsen
                                      Title: General Partner


                                  InterWest Partners VI, L.P.
                                  By:  Robert Monsen
                                  Its:


                                  By: /s/ Robert Monsen
                                      --------------------------------------
                                      Name:  Robert Monsen
                                      Title: General Partner





                                  InterWest Partners VII, L.P.
                                  By:  Philip T. Gianos
                                  Its: General Partner


                                  By:  /s/ Philip T. Gianos
                                      --------------------------------------
                                      Name:  Philip T. Gianos
                                      Title: General Partner


                                  InterWest Investors, VI, L.P.
                                  By:  Robert Monsen
                                  Its: General Partner


                                  By: /s/ Robert Monsen
                                      --------------------------------------
                                      Name:  Robert Monsen
                                      Title: General Partner


                                  InterWest Investors, VII, L.P.
                                  By:  Philip T. Gianos
                                  Its: General Partner


                                  By:  /s/ Philip T. Gianos
                                      --------------------------------------
                                      Name:  Philip T. Gianos
                                      Title: General Partner


                                      /s/ W. Mark Lortz
                                      --------------------------------------
                                      Name:  W. Mark Lortz


                                  W. Mark Lortz and Patrice Rae Lortz
                                  Revocable Living Trust
                                  By:  W. Mark Lortz and Patrice Rae Lortz
                                  Its: Co-Trustees


                                  By: /s/ W. Mark Lortz and Patrice Rae Lortz
                                      ------------------------------------------
                                      Name:  W. Mark Lortz and Patrice Rae Lortz
                                      Title: Co-Trustees





                                      /s/ Charles T. Liamos
                                      --------------------------------------
                                      Name:  Charles T. Liamos


                                      /s/ Robert D. Brownell
                                      --------------------------------------
                                      Name:  Robert D. Brownell


                                      /s/ Eve A. Conner
                                      --------------------------------------
                                      Name:  Eve A. Conner


                                      /s/ Timothy T. Goodnow
                                      --------------------------------------
                                      Name:  Timothy T. Goodnow


                                      /s/ Lawrence W. Huffman
                                      --------------------------------------
                                      Name:  Lawrence W. Huffman


                                      /s/ Ross A. Jaffe
                                      --------------------------------------
                                      Name:  Ross A. Jaffe


                                  Brentwood Associates VIII, L.P.
                                  By:  Ross A. Jaffe
                                  Its: Managing Member


                                  By: /s/ Ross A. Jaffe
                                      --------------------------------------
                                      Name:  Ross A. Jaffe
                                      Title: Managing Member


                                      /s/ Robert R. Momsen
                                      --------------------------------------
                                      Name:  Robert R. Momsen


                                      /s/ Richard P. Thompson
                                      --------------------------------------
                                      Name:  Richard P. Thompson


                                      /s/ Rod F. Dammeyer
                                      --------------------------------------
                                      Name:  Rod F. Dammeyer





                                      DRD Family Partnership, L.P.
                                      By:
                                      Its:


                                      By: /s/ Rod Dammyer
                                          ----------------------------------
                                          Name:  Rod Dammyer
                                          Title:







                                                       SCHEDULE A


                                                                                            Number of      Number of   Number of
                                                                            Number of       Original       Subject     Subject
                                                                            Original        Shares         Shares      Shares
                                                                            Shares Owned    Owned          Owned       Owned
Stockholder                            Address                              of Record       Beneficially   of Record   Beneficially
- -----------------------------------    ---------------------------------    ------------    ------------   ---------   ------------
                                                                                                         
InterWest Partners V, L.P.             2710 Sand Hill Road, 2nd Floor
                                       Menlo Park, CA 94025                   100,306         100,306
InterWest Partners VI, L.P.            2710 Sand Hill Road, 2nd Floor
                                       Menlo Park, CA 94025                 3,237,103       3,327,103
InterWest Partners VII, L.P.           2710 Sand Hill Road, 2nd Floor
                                       Menlo Park, CA 94025                 1,449,082       1,449,082
InterWest Investors, VI, L.P.          2710 Sand Hill Road, 2nd Floor
                                       Menlo Park, CA 94025                   101,494         101,494
InterWest Investors, VII, L.P.         2710 Sand Hill Road, 2nd Floor
                                       Menlo Park, CA 94025                    69,396          69,396
W. Mark Lortz(1)                       TheraSense, Inc.
                                       1360 South Loop Road                     6,849         794,504
                                       Alameda, CA 94502
W. Mark Lortz and Patrice Rae Lortz    c/o TheraSense, Inc.                                                   To be determined
Revocable Living Trust                 1360 South Loop Road                   502,490               0       following execution
                                       Alameda, CA 94502                                                      of the Agreement
Charles T. Liamos                      TheraSense, Inc.
                                       1360 South Loop Road                    81,700         268,711
                                       Alameda, CA 94502
Robert D. Brownell                     TheraSense, Inc.
                                       1360 South Loop Road                    26,768          79,125
                                       Alameda, CA 94502
Eve A. Conner                          TheraSense, Inc.
                                       1360 South Loop Road                     5,853          61,523
                                       Alameda, CA 94502
Timothy T. Goodnow                     TheraSense, Inc.
                                       1360 South Loop Road                     6,745         162,644
                                       Alameda, CA 94502


1



Lawrence W. Huffman                    TheraSense, Inc.
                                       1360 South Loop Road                         1         135,375
                                       Alameda, CA 94502
Ross A. Jaffe(2)                       TheraSense, Inc.
                                       1360 South Loop Road                     4,379          39,379
                                       Alameda, CA 94502
Brentwood Associates VIII, L.P.        11150 Santa Monica Blvd.
                                       Suite 1200                             400,000               0
                                       Los Angeles, CA 90025
Robert R. Momsen(3)                    TheraSense, Inc.
                                       1360 South Loop Road                    27,647          62,647
                                       Alameda, CA 94502
Richard P. Thompson                    TheraSense, Inc.
                                       1360 South Loop Road                    31,200          66,200
                                       Alameda, CA 94502
Rod F. Dammeyer(4)                     TheraSense, Inc.
                                       1360 South Loop Road                   102,575         112,575
                                       Alameda, CA 94502
DRD Family Partnership, L.P.           c/o TheraSense, Inc.
                                       1360 South Loop Road                   102,575               0
                                       Alameda, CA 94502

(1) Excludes the 502,490 shares held by the W. Mark Lortz and Patrice Rae Lortz Revocable Living Trust, as to which Mr. Lortz
disclaims beneficial ownership for purposes of this Agreement.

(2) Excludes the 400,000 shares held by Brentwood Associates VIII, L.P., as to which Mr. Jaffe disclaims beneficial ownership for
purposes of this Agreement.

(3) Excludes the 4,957,381 shares held by InterWest Partners V, L.P., InterWest Partners VI, L.P. and InterWest Investors, VI, L.P.,
as to which Mr. Momsen disclaims beneficial ownership for purposes of this Agreement.

(4) Excludes the 102,575 shares held by DRD Family Partnership, L.P., as to which Mr. Dammeyer disclaims beneficial ownership for
purposes of this Agreement.