4 1 p17025_4.txt STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP ------------------------------ OMB APPROVAL ------------------------------ ------ OMB Number: 3235-0287 FORM 4 Expires: January 31, 2005 ------ Estimated average burden hours per response ....... 0.5 ------------------------------ UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(f) of the Investment Company Act of 1940 [ ] Check this box if no longer subject of Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b). ================================================================================ 1. Name and Address of Reporting Person* InterWest Partners VI, LP -------------------------------------------------------------------------------- (Last) (First) (Middle) 2710 Sand Hill Road; Second Floor -------------------------------------------------------------------------------- (Street) Menlo Park, CA 94025 -------------------------------------------------------------------------------- (City) (State) (Zip) ================================================================================ 2. Issuer Name and Ticker or Trading Symbol TheraSense, Inc. (THER) ================================================================================ 3. I.R.S. Identification Number of Reporting Person, if an entity (Voluntary) ================================================================================ 4. Statement for Month/Date/Year April 29, 2003 ================================================================================ 5. If Amendment, Date of Original (Month/Year) ================================================================================ 6. Relationship of Reporting Person(s) to Issuer (Check all applicable) [ ] Director [X] 10% Owner [ ] Officer (give title below) [ ] Other (specify below) ------------------------------------ ================================================================================ 7. Individual or Joint/Group Filing (Check applicable line) [ ] Form filed by One Reporting Person [X] Form filed by More Than one Reporting Person ================================================================================ Page 1 of 3 Form 4 (continued) Table I -- Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. * If the Form is filed by more than one Reporting Person, see Instruction 4(b)(v). PERSONS WHO RESPOND TO THE COLLECTION OF INFORMATION CONTAINED IN THIS FORM ARE NOT REQUIRED TO RESPOND UNLESS THE FORM DISPLAYS A CURRENTLY VALID OMB CONTROL NUMBER. Page 2 of 3 Form 4 (continued) Table II -- Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)

Explanation of Responses: (1) See attached joint filer information. (2) The shares are held in the name of The Momsen Living Trust U/A/D 1-5-95 of which Robert Momsen is the Trustee. (3) The shares are held in the name of Alan W. Crites and Carol B. Crites, Trustees of the Crites Family Trust-2000 u/i dated 2/18/00. *See attached signature pages* ------------------------------- ------------ **Signature of Reporting Person Date ** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a). Note: File three copies of this Form, one of which must be manually signed. If space provided is insufficient, see Instruction 6 for procedures. Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number. Page 3 of 3 FORM 4 Joint Filer Information Name: InterWest Partners VI, L.P. ("Partners VI") InterWest Investors VI, L.P. ("Investors VI") InterWest Partners VII, L.P. ("Partners VII") InterWest Investors VII, L.P. ("Investors VII") InterWest Management Partners VI, LLC InterWest Management Partners VII, LLC Harvey B. Cash Alan W. Crites Philip T. Gianos W. Scott Hedrick W. Stephen Holmes Gilbert H. Kliman Thomas L. Rosch Arnold L. Oronsky Robert R. Momsen Address: 2710 Sand Hill Road Second Floor Menlo Park, CA 94025 Designated Filer: InterWest Partners VI, L.P. Issuer and Ticker Symbol: TheraSense, Inc.-("THER") Statement for Month/Date/Year: April 29, 2003 The individual Reporting Persons listed above (excluding Harvey B. Cash, Gilbert H. Kliman and Thomas L. Rosch) are general partners of InterWest Management Partners V, LP. InterWest Management Partners V, LP has sole voting and investment control over shares owned by Interwest Partners V, LP ("Partners V"). The individual Reporting Persons listed above (excluding Thomas L. Rosch) are managing directors of InterWest Management Partners VI, LLC. InterWest Management Partners VI, LLC has sole voting and investment control over shares owned by Partners VI and Investors VI. Certain of the individual Reporting Persons listed above (excluding Robert R. Momsen) are also managing directors of InterWest Management Partners VII, LLC. InterWest Management Partners VII, LLC has sole voting and investment control over shares owned by Partners VII and Investors VII. All Reporting Persons disclaim beneficial ownership of shares of TheraSense, Inc. stock held by Partners V, Partners VI, Investors VI, Partners VII and Investors VII, except to the extent of their respective pecuniary interest therein. The filing of this statement shall not be deemed an admission that, for purposes of Section 16 of the Securities Exchange Act of 1934, or otherwise, any of the Reporting Persons are the beneficial owner of all of the equity securities covered by this statement. Each of the Reporting Persons listed above hereby designates Partners VI as its designated filer of Forms 3, 4 and 5 in accordance with Section 16(a) of the Securities Exchange Act of 1934 and the rules thereunder. 1 of 3 SIGNATURE PAGES TO FORM 4: TheraSense, Inc. InterWest Partners VI, L.P. /s/ W. Stephen Holmes 4/30/03 ------------------------------------------------------ --------------- By: InterWest Management Partners VI, LLC Date Its General Partner by W. Stephen Holmes, Managing Director InterWest Investors VI, L.P. /s/ W. Stephen Holmes 4/30/03 ------------------------------------------------------ --------------- By: InterWest Management Partners VI, LLC Date Its General Partner by W. Stephen Holmes, Managing Director InterWest Partners VII, L.P. /s/ W. Stephen Holmes 4/30/03 ------------------------------------------------------ --------------- By: InterWest Management Partners VII, LLC Date Its General Partner by W. Stephen Holmes, Managing Director InterWest Investors VII, L.P. /s/ W. Stephen Holmes 4/30/03 ------------------------------------------------------ --------------- By: InterWest Management Partners VII, LLC Date Its General Partner by W. Stephen Holmes, Managing Director InterWest Management Partners VI, LLC /s/ W. Stephen Holmes 4/30/03 ------------------------------------------------------ --------------- By: W. Stephen Holmes, Managing Director Date InterWest Management Partners VII, LLC /s/ W. Stephen Holmes 4/30/03 ------------------------------------------------------ --------------- By: W. Stephen Holmes, Managing Director Date SIGNATURE PAGES TO FORM 4: TheraSense, Inc. /s/ Harvey B. Cash 4/30/03 ------------------------------------------------------ --------------- By: Harvey B. Cash Date /s/ Alan W. Crites 4/30/03 ------------------------------------------------------ --------------- By: Alan W. Crites Date /s/ Philip T. Gianos 4/30/03 ------------------------------------------------------ --------------- By: Philip T. Gianos Date /s/ W. Scott Hedrick 4/30/03 ------------------------------------------------------ --------------- By: W. Scott Hedrick Date /s/ W. Stephen Holmes 4/30/03 ------------------------------------------------------ --------------- By: W. Stephen Holmes Date /s/ Gilbert H. Kliman 4/30/03 ------------------------------------------------------ --------------- By: Gilbert H. Kliman Date /s/ Thomas L. Rosch 4/30/03 ------------------------------------------------------ --------------- By: Thomas L. Rosch Date /s/ Arnold L. Oronsky 4/30/03 ------------------------------------------------------ --------------- By: Arnold L. Oronsky Date /s/ Robert R. Momsen 4/30/03 ------------------------------------------------------ --------------- By: Robert R. Momsen Date

INTERWEST PARTNERS VI L P 4