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                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

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

                                  SCHEDULE 13G

           INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO
              RULES 13d-1 (b), (c) AND (d) AND AMENDMENTS THERETO
                           FILED PURSUANT TO 13d-2 (b)
                               (Amendment No. 1)*

                                 TheraSense Inc.
--------------------------------------------------------------------------------
                                (Name of Issuer)

                                  Common Stock
--------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                   883381 10 5
--------------------------------------------------------------------------------
                                 (CUSIP Number)

                                   12-31-2002
--------------------------------------------------------------------------------
             (Date of Event Which Requires Filing of this Statement)

Check the  appropriate box to designate the rule pursuant to which this Schedule
is filed:

      |_|   Rule 13d-1(b)

      |_|   Rule 13d-1(c)

      |X|   Rule 13d-1(d)

*The  remainder of this cover page shall be filled out for a reporting  person's
initial filing on this form with respect to the subject class of securities, and
for any  subsequent  amendment  containing  information  which  would  alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the  Securities  Exchange  Act of
1934 ("Act") or otherwise  subject to the liabilities of that section of the Act
but  shall be  subject  to all other  provisions  of the Act  (however,  see the
Notes).


                               Page 1 of 25 pages


CUSIP No. 883381 10 5                                         Page 2 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      InterWest Partners V, LP
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      California
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        100,306
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            0
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               100,306
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        0
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      100,306
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      0.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      PN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!


CUSIP No. 883381 10 5                                         Page 3 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      InterWest Management Partners V, LP
      (the general partner of InterWest Partners V, LP)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      California
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        100,306
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            0
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               100,306
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        0
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      100,306
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      0.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      PN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!


CUSIP No. 883381 10 5                                         Page 4 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      InterWest Partners VI, LP
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      California
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        3,237,103
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            0
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               3,237,103
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        0
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      3,237,103
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      8.0%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      PN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!


CUSIP No. 883381 10 5                                         Page 5 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      InterWest Investors VI, LP
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      California
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        101,494
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            0
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               101,494
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        0
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      101,494
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      0.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      PN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!


CUSIP No. 883381 10 5                                         Page 6 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      InterWest Management Partners VI, LLC (the general partner of InterWest
      Partners VI, LP and InterWest Investors VI, LP)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      California
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        3,338,597
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            0
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               3,338,597
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        0
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      3,338,597
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      8.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      PN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!


CUSIP No. 883381 10 5                                         Page 7 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      InterWest Partners VII, LP
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      California
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        1,449,082
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            0
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               1,449,082
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        0
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      1,449,082
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      3.6%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      PN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!


CUSIP No. 883381 10 5                                         Page 8 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      InterWest Investors VII, LP
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      California
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        69,396
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            0
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               69,396
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        0
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      69,396
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      0.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      PN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!


CUSIP No. 883381 10 5                                         Page 9 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      InterWest Management Partners VII, LLC (the general partner of InterWest
      Partners VII, LP and InterWest Investors VII, LP)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      California
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        1,518,478
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            0
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               1,518,478
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        0
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      1,518,478
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      3.7%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      PN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!


CUSIP No. 883381 10 5                                        Page 10 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      Stephen C. Bowsher
      (a Venture Member of InterWest Management Partners VII, LLC)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        0
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            1,518,478
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               0
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        1,518,478
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      1,518,478
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      3.7%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

Neither the filing of this  statement  on Schedule  13G nor any of its  contents
shall be deemed to  constitute an admission by Stephen C. Bowsher that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.


CUSIP No. 883381 10 5                                        Page 11 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      Harvey B. Cash (a Managing Director of InterWest Management Partners VI,
      LLC and InterWest Management Partners VII, LLC )
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        31,764
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            4,857,075
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               31,764
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        4,857,075
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      4,888,839
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      12.0%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

Neither the filing of this  statement  on Schedule  13G nor any of its  contents
shall be  deemed to  constitute  an  admission  by Harvey B. Cash that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.


CUSIP No. 883381 10 5                                        Page 12 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      Alan W. Crites (a General Partner of InterWest  Management Partners V, LP,
      and a Managing  Director  of  InterWest  Management  Partners  VI, LLC and
      InterWest Management Partners VII, LLC)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        2,000
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            4,957,381
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               2,000
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        4,957,381
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      4,959,381
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      12.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

Neither the filing of this  statement  on Schedule  13G nor any of its  contents
shall be deemed to  constitute  an  admission  by Alan W.  Crites that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.


CUSIP No. 883381 10 5                                        Page 13 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      Philip T. Gianos (a General  Partner of InterWest  Management  Partners V,
      LP, and a Managing Director of InterWest  Management  Partners VI, LLC and
      InterWest Management Partners VII, LLC)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        0
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            4,957,381
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               0
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        4,957,381
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      4,957,381
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      12.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

Neither the filing of this  statement  on Schedule  13G nor any of its  contents
shall be deemed to  constitute  an  admission by Philip T. Gianos that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.


CUSIP No. 883381 10 5                                        Page 14 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      Wallace R. Hawley
      (a General Partner of InterWest Management Partners V, LP)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        0
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            100,306
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               0
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        100,306
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      100,306
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      0.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

Neither the filing of this  statement  on Schedule  13G nor any of its  contents
shall be deemed to  constitute  an admission by Wallace R. Hawley that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.


CUSIP No. 883381 10 5                                        Page 15 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      W. Scott Hedrick (a General  Partner of InterWest  Management  Partners V,
      LP, and a Managing Director of InterWest  Management  Partners VI, LLC and
      InterWest Management Partners VII, LLC)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        21,764
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            4,957,381
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               21,764
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        4,957,381
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      4,979,145
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      12.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

Neither the filing of this  statement  on Schedule  13G nor any of its  contents
shall be deemed to  constitute  an admission by W. Scott  Hedrick that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.


CUSIP No. 883381 10 5                                        Page 16 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      W. Stephen Holmes (a General Partner of InterWest  Management  Partners V,
      LP, and a Managing Director of InterWest  Management  Partners VI, LLC and
      InterWest Management Partners VII, LLC)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        0
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            4,957,381
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               0
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        4,957,381
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      4,957,381
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      12.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

Neither the filing of this  statement  on Schedule  13G nor any of its  contents
shall be deemed to constitute  an admission by W. Stephen  Holmes that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.


CUSIP No. 883381 10 5                                        Page 17 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      Gilbert H. Kliman (a Venture Member of InterWest  Management  Partners VI,
      LLC and a Managing Director of InterWest Management Partners VII, LLC)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        10,000
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            4,857,075
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               10,000
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        4,857,075
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      4,867,075
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      12.0%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

Neither the filing of this  statement  on Schedule  13G nor any of its  contents
shall be deemed to  constitute  an admission by Gilbert H. Kliman that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.


CUSIP No. 883381 10 5                                        Page 18 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      Robert R. Momsen (a General  Partner of InterWest  Management  Partners V,
      LP, and a Managing Director of InterWest Management Partners VI, LLC)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        153,813
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            3,438,903
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               153,813
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        3,438,903
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      3,592,716
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      8.8%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

Neither the filing of this  statement  on Schedule  13G nor any of its  contents
shall be deemed to  constitute  an  admission by Robert R. Momsen that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.


CUSIP No. 883381 10 5                                        Page 19 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      Arnold L. Oronsky (a General Partner of InterWest  Management  Partners V,
      LP, and a Managing Director of InterWest  Management  Partners VI, LLC and
      InterWest Management Partners VII, LLC)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        0
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            4,957,381
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               0
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        4,957,381
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      4,957,381
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      12.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

Neither the filing of this  statement  on Schedule  13G nor any of its  contents
shall be deemed to  constitute  an admission by Arnold L. Oronsky that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.


CUSIP No. 883381 10 5                                        Page 20 of 25 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      Thomas L. Rosch
      (a Managing Director of InterWest Management Partners VII, LLC)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        0
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            1,518,478
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               0
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        1,518,478
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      1,518,478
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      3.7%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

Neither the filing of this  statement  on Schedule  13G nor any of its  contents
shall be deemed to  constitute  an  admission  by Thomas L. Rosch that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.


Item 1.

(a)   Name of Issuer: TheraSense, Inc. ("Issuer")

(b)   Address of Issuer's Principal Executive Offices:

      1360 South Loop Road
      Alameda, CA 94502

Item 2.

(a)   Name of Person(s) Filing:

      InterWest Partners V, LP ("IWP V")
      InterWest Management Partners V, LP ("IMP V")
      InterWest Partners VI, LP ("IWP VI")
      InterWest Investors VI, LP ("II VI")
      InterWest Management Partners VI, LLC ("IMP VI")
      InterWest Partners VII, LP ("IWP VII")
      InterWest Investors VII, LP ("II VII")
      InterWest Management Partners VII, LLC ("IMP VII")
      Stephen C. Bowsher ("Bowsher")
      Harvey B. Cash ("Cash")
      Alan W. Crites ("Crites")
      Philip T. Gianos ("Gianos")
      Wallace R Hawley ("Hawley")
      W. Scott Hedrick ("Hedrick")
      W. Stephen Holmes ("Holmes")
      Gilbert H. Kliman ("Kliman")
      Robert R. Momsen ("Momsen")
      Arnold L. Oronsky ("Oronsky")
      Thomas L. Rosch ("Rosch")

(b)   Address of Principal Business Office or, if none, Residence:

      2710 Sand Hill Road
      Second Floor
      Menlo Park, CA 94025


                              Page 21 of 25 pages


(c)   Citizenship/Place of Organization:

      IWP V:            California
      IMP V:            California
      IWP VI:           California
      II VI:            California
      IMP VI:           California
      IWP VII:          California
      II VII:           California
      IMP VII:          California
      Bowsher:          United States
      Cash:             United States
      Crites:           United States
      Gianos:           United States
      Hawley            United States
      Hedrick:          United States
      Holmes:           United States
      Kliman:           United States
      Momsen:           United States
      Oronsky:          United States
      Rosch:            United States

(d)   Title of Class of Securities: Common Stock

(e)   CUSIP Number: 883381 10 5

Item 3. Not applicable.

Item 4. Ownership.



====================================================================================================================================
                          IWP V      IMP V       IWP VI        II VI         IMP VI         IWP VII           II VII       IMP VII
------------------------------------------------------------------------------------------------------------------------------------
                                                                                               
(a)   Beneficial
      Ownership          100,306    100,306    3,237,103       101,494      3,338,597      1,449,082          69,396      1,518,478
------------------------------------------------------------------------------------------------------------------------------------
(b)   Percentage of
      Class                 0.2%       0.2%         8.0%          0.2%           8.2%           3.6%            0.2%           3.7%
------------------------------------------------------------------------------------------------------------------------------------
(c)   Sole Voting
      Power              100,306    100,306    3,237,103       101,494      3,338,597      1,449,082          69,396      1,518,478
------------------------------------------------------------------------------------------------------------------------------------
      Shared
      Voting
      Power                    0          0            0             0              0              0               0              0
------------------------------------------------------------------------------------------------------------------------------------
      Sole
      Dispositive
      Power              100,306    100,306    3,237,103       101,494      3,338,597      1,449,082          69,396      1,518,478
------------------------------------------------------------------------------------------------------------------------------------
      Shared
      Dispositive
      Power                    0          0            0             0              0              0               0              0
====================================================================================================================================



                              Page 22 of 25 pages




====================================================================================================================================
                         Bowsher                                                                                          Other
                          Rosch        Cash         Crites        Hawley      Hedrick       Momsen         Kliman      Individuals *
------------------------------------------------------------------------------------------------------------------------------------
                                                                                             
(a)   Beneficial
      Ownership         1,518,478   4,888,839     4,959,381       100,306    4,979,145     3,592,716**    4,867,075     4,957,381
------------------------------------------------------------------------------------------------------------------------------------
(b)   Percentage
      of Class               3.7%       12.0%         12.2%          0.2%        12.2%            8.8%        12.0%         12.2%
------------------------------------------------------------------------------------------------------------------------------------
(c)   Sole
      Voting
      Power                     0      31,764         2,000             0       21,764       153,813**       10,000             0
------------------------------------------------------------------------------------------------------------------------------------
      Shared
      Voting
      Power             1,518,478   4,857,075     4,957,381       100,306    4,957,381       3,438,903    4,857,075     4,957,381
------------------------------------------------------------------------------------------------------------------------------------
      Sole
      Dispositive
      Power                     0      31,764         2,000             0       21,764       153,813**       10,000             0
------------------------------------------------------------------------------------------------------------------------------------
      Shared
      Dispositive
      Power             1,518,478   4,857,075     4,957,381       100,306    4,957,381       3,438,903    4,857,075     4,957,381
====================================================================================================================================


*Individuals included in this column are Gianos, Holmes, and Oronsky all of whom
are General Partners of IMP V and Managing Directors of IMP VI and IMP VII.

**Momsen includes options  exercisable through 3/1/03 representing 24,166 shares
of common stock.

Item 5. Ownership of Five Percent or Less of a Class

Not applicable.

Item 6. Ownership of More than Five Percent on Behalf of Another Person

Under certain circumstances set forth in the partnership agreement of IMP V, and
the limited  liability  operating  agreements of IMP VI and IMP VII, the general
partners and/or limited  partners of such  partnerships  and the members of such
limited  liability  companies have the right to receive  dividends  from, or the
proceeds from the sale of, the Common Stock of Issuer beneficially owned by such
partnerships and limited liability companies.

Item 7.  Identification  and Classification of the Subsidiary Which Acquired the
         Security Being Reported on By the Parent Holding Company.

Not applicable.

Item 8. Identification and Classification of Members of the Group

No   reporting   person  is  a  member  of  a  group  as   defined   in  section
240.13d-1(b)(1)(iii)(H) of the Act.

Item 9. Notice of Dissolution of Group

Not applicable.

Item 10. Certification

Not applicable

EXHIBITS

A. Joint Filing Statement


                              Page 23 of 25 pages


                                    SIGNATURE

After  reasonable  inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.

Date: February ____, 2003

INTERWEST PARTNERS V, LP

By: InterWest Management Partners V, LP          By: /s/ Stephen C. Bowsher
                                                     ---------------------------
                                                 Name: Stephen C. Bowsher
    By: /s/ W. Stephen Holmes
        --------------------------------         By: /s/ Harvey B. Cash
        General Partner                              ---------------------------
                                                 Name: Harvey B. Cash

INTERWEST MANAGEMENT PARTNERS V, LP              By: /s/ Alan W. Crites
                                                     ---------------------------
                                                 Name: Alan W. Crites
By: /s/ W. Stephen Holmes
    ------------------------------------         By: /s/ Philip T. Gianos
    General Partner                                  ---------------------------
                                                 Name: Philip T. Gianos

INTERWEST PARTNERS VI, LP                        By: /s/ Wallace R. Hawley
                                                     ---------------------------
By: InterWest Management Partners VI, LLC        Name: Wallace R. Hawley

                                                 By: /s/ W. Scott Hedrick
     By: /s/ W. Stephen Holmes                       ---------------------------
        --------------------------------         Name: W. Scott Hedrick
        Managing Director
                                                 By: /s/ W. Stephen Holmes
                                                     ---------------------------
INTERWEST INVESTORS VI, LP                       Name: W. Stephen Holmes

                                                 By: /s/ Gilbert H. Kliman
By: InterWest Management Partners VI, LLC            ---------------------------
                                                 Name: Gilbert H. Kliman
    By: /s/ W. Stephen Holmes
        --------------------------------         By: /s/ Robert R. Momsen
        Managing Director                            ---------------------------
                                                 Name: Robert R. Momsen
INTERWEST MANAGEMENT PARTNERS VI, LLC
                                                 By: /s/ Arnold L. Oronsky
                                                     ---------------------------
By: /s/ W. Stephen Holmes                        Name: Arnold L. Oronsky
    ------------------------------------
    Managing Director                            By: /s/ Thomas L. Rosch
                                                     ---------------------------
                                                 Name: Thomas L. Rosch
INTERWEST PARTNERS VII, LP

By: InterWest Management Partners VII, LLC

    By: /s/ W. Stephen Holmes
        --------------------------------
        Managing Director

INTERWEST INVESTORS VII, LP

By: InterWest Management Partners VII, LLC

    By: /s/ W. Stephen Holmes
        --------------------------------
        Managing Director

INTERWEST MANAGEMENT PARTNERS VII, LLC

By:  /s/ W. Stephen Holmes
     -----------------------------------
     Managing Director


                              Page 24 of 25 pages


                                    EXHIBIT A

                             JOINT FILING STATEMENT

We, the undersigned, hereby express our agreement that the attached Schedule 13G
is filed on behalf of each of us.

Date: February ____, 2003

INTERWEST PARTNERS V, LP

By: InterWest Management Partners V, LP          By: /s/ Stephen C. Bowsher
                                                     ---------------------------
                                                 Name: Stephen C. Bowsher
    By: /s/ W. Stephen Holmes
        --------------------------------         By: /s/ Harvey B. Cash
        General Partner                              ---------------------------
                                                 Name: Harvey B. Cash

INTERWEST MANAGEMENT PARTNERS V, LP              By: /s/ Alan W. Crites
                                                     ---------------------------
                                                 Name: Alan W. Crites
By: /s/ W. Stephen Holmes
    ------------------------------------         By: /s/ Philip T. Gianos
    General Partner                                  ---------------------------
                                                 Name: Philip T. Gianos

INTERWEST PARTNERS VI, LP                        By: /s/ Wallace R. Hawley
                                                     ---------------------------
By: InterWest Management Partners VI, LLC        Name: Wallace R. Hawley

                                                 By: /s/ W. Scott Hedrick
     By: /s/ W. Stephen Holmes                       ---------------------------
        --------------------------------         Name: W. Scott Hedrick
        Managing Director
                                                 By: /s/ W. Stephen Holmes
                                                     ---------------------------
INTERWEST INVESTORS VI, LP                       Name: W. Stephen Holmes

                                                 By: /s/ Gilbert H. Kliman
By: InterWest Management Partners VI, LLC            ---------------------------
                                                 Name: Gilbert H. Kliman
    By: /s/ W. Stephen Holmes
        --------------------------------         By: /s/ Robert R. Momsen
        Managing Director                            ---------------------------
                                                 Name: Robert R. Momsen
INTERWEST MANAGEMENT PARTNERS VI, LLC
                                                 By: /s/ Arnold L. Oronsky
                                                     ---------------------------
By: /s/ W. Stephen Holmes                        Name: Arnold L. Oronsky
    ------------------------------------
    Managing Director                            By: /s/ Thomas L. Rosch
                                                     ---------------------------
                                                 Name: Thomas L. Rosch
INTERWEST PARTNERS VII, LP

By: InterWest Management Partners VII, LLC

    By: /s/ W. Stephen Holmes
        --------------------------------
        Managing Director

INTERWEST INVESTORS VII, LP

By: InterWest Management Partners VII, LLC

    By: /s/ W. Stephen Holmes
        --------------------------------
        Managing Director

INTERWEST MANAGEMENT PARTNERS VII, LLC

By:  /s/ W. Stephen Holmes
     -----------------------------------
     Managing Director

                              Page 25 of 25 pages