UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549



                                  SCHEDULE 13G

                   Under the Securities Exchange Act of 1934*

                                 Amendment No. 3

                               Quidel Corporation
                               ------------------
                                (Name of Issuer)

                         Common Stock, $0.001 par value
                         ------------------------------
                         (Title of Class of Securities)

                                    74838J101
                                    ---------
                                 (CUSIP Number)

                                December 31, 2004
                                -----------------
             (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)
                                [X] Rule 13d-1(c)
                                [ ] 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 on 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).




-------------------                                            -----------------
CUSIP No. 74838J101                    13G                     Page 2 of 7 Pages
-------------------                                            -----------------

---------- ---------------------------------------------------------------------
1          NAME OF REPORTING PERSON
           S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

           Oracle Partners, L.P.
---------- ---------------------------------------------------------------------
2          CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                         (a) [ ]

                                                                         (b) [X]
---------- ---------------------------------------------------------------------
3          SEC USE ONLY
---------- ---------------------------------------------------------------------
4          CITIZENSHIP OR PLACE OF ORGANIZATION

           Delaware
-------------------- ------ ----------------------------------------------------
                     5      SOLE VOTING POWER

                            0
                     ------ ----------------------------------------------------
NUMBER OF            6      SHARED VOTING POWER
SHARES
BENEFICIALLY                1,792,445
OWNED BY             ------ ----------------------------------------------------
EACH                 7      SOLE DISPOSITIVE POWER
REPORTING
PERSON                      0
WITH                 ------ ----------------------------------------------------
                     8      SHARED DISPOSITIVE POWER

                            1,792,445
---------- ---------------------------------------------------------------------
9          AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

           1,792,445
---------- ---------------------------------------------------------------------
10         CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

           N/A
---------- ---------------------------------------------------------------------
11         PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

           5.7%
---------- ---------------------------------------------------------------------
12         TYPE OF REPORTING PERSON*

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




-------------------                                            -----------------
CUSIP No. 74838J101                    13G                     Page 3 of 7 Pages
-------------------                                            -----------------

---------- ---------------------------------------------------------------------
1          NAME OF REPORTING PERSON
           S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

           Oracle Associates, LLC
---------- ---------------------------------------------------------------------
2          CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                         (a) [ ]

                                                                         (b) [X]
---------- ---------------------------------------------------------------------
3          SEC USE ONLY
---------- ---------------------------------------------------------------------
4          CITIZENSHIP OR PLACE OF ORGANIZATION

           Delaware
-------------------- ------ ----------------------------------------------------
                     5      SOLE VOTING POWER

                            0
                     ------ ----------------------------------------------------
NUMBER OF            6      SHARED VOTING POWER
SHARES
BENEFICIALLY                2,294,845
OWNED BY            ------ ----------------------------------------------------
EACH                 7      SOLE DISPOSITIVE POWER
REPORTING
PERSON                      0
WITH                 ------ ----------------------------------------------------
                     8      SHARED DISPOSITIVE POWER

                            2,294,845
---------- ---------------------------------------------------------------------
9          AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

           2,294,845
---------- ---------------------------------------------------------------------
10         CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

           N/A
---------- ---------------------------------------------------------------------
11         PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

           7.2%
---------- ---------------------------------------------------------------------
12         TYPE OF REPORTING PERSON*

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




-------------------                                            -----------------
CUSIP No. 74838J101                    13G                     Page 4 of 7 Pages
-------------------                                            -----------------

---------- ---------------------------------------------------------------------
1          NAME OF REPORTING PERSON
           S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

           Larry N. Feinberg
---------- ---------------------------------------------------------------------
2          CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                         (a) [ ]

                                                                         (b) [X]
---------- ---------------------------------------------------------------------
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                2,579,110
OWNED BY             ------ ----------------------------------------------------
EACH                 7      SOLE DISPOSITIVE POWER
REPORTING
PERSON                      10,000
WITH                 ------ ----------------------------------------------------
                     8      SHARED DISPOSITIVE POWER

                            2,579,110
---------- ---------------------------------------------------------------------
9          AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

           2,589,110
---------- ---------------------------------------------------------------------
10         CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

           N/A
---------- ---------------------------------------------------------------------
11         PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

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

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




This Amendment No. 3 to Schedule 13G (this "Amendment No. 3") is being filed
with respect to the Common Stock of Quidel Corporation, a Delaware corporation,
to amend the Amendment No. 2 to Schedule 13G filed on February 12, 2003 (the
"Amendment No. 2"). Capitalized terms used but not defined herein have the
meaning ascribed thereto in the Amendment No. 2.

Item 4:             Ownership:
------              ---------

     Item 4 of the Amendment No. 2 is hereby amended by the deletion of the
entirety of the text thereof and its replacement with the following:

A.   Oracle Partners, L.P.
     ---------------------
     (a) Amount beneficially owned: 1,792,445
     (b) Percent of class: 5.7%. The percentages used herein and in the rest of
this Amendment No. 3 are calculated based upon the 31,687,083 shares issued and
outstanding as of October 20, 2004, as reflected in the Company's Quarterly
Report on Form 10-Q for the quarterly period ended September 30, 2004.
     (c) Number of shares as to which such person has:
          (i) Sole power to vote or direct the vote: -0-
          (ii) Shared power to vote or direct the vote: 1,792,445
          (iii) Sole power to dispose or direct the disposition: -0-
          (iv) Shared power to dispose or direct the disposition: 1,792,445

B.   Oracle Associates, LLC
     ----------------------
     (a) Amount beneficially owned: 2,294,845
     (b) Percent of class: 7.2%
     (c) Number of shares as to which such person has:
          (i) Sole power to vote or direct the vote: -0-
          (ii) Shared power to vote or direct the vote: 2,294,845
          (iii) Sole power to dispose or direct the disposition: -0-
          (iv) Shared power to dispose or direct the disposition: 2,294,845

C.   Larry N. Feinberg
     -----------------
     (a) Amount beneficially owned: 2,589,110
     (b) Percent of class: 8.2%
     (c) Number of shares as to which such person has:
          (i) Sole power to vote or direct the vote: 10,000
          (ii) Shared power to vote or direct the vote: 2,579,110
          (iii) Sole power to dispose or direct the disposition: 10,000
          (iv) Shared power to dispose or direct the disposition: 2,579,110


                                      -5-




Item 10:            Certification:
-------             -------------

     Each of the Reporting Persons hereby makes the following certification:

     By signing below I certify that, to the best of my knowledge and belief,
the securities referred to above were not acquired and are not held for the
purpose of or with the effect of changing or influencing the control of the
issuer of the securities and were not acquired and are not held in connection
with or as a participant in any transaction having that purpose or effect.


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                                      -6-




                                    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.

DATED: February 9, 2005


                                        /s/ Larry N. Feinberg
                                        ------------------------------
                                        Larry N. Feinberg


                                        ORACLE ASSOCIATES, LLC


                                        By: /s/ Larry N. Feinberg
                                            ------------------------------
                                            Name:  Larry N. Feinberg
                                            Title: Senior Managing Member


                                        ORACLE PARTNERS, L.P.

                                        By: Oracle Associates, LLC,
                                                its General Partner

                                        By: /s/ Larry N. Feinberg
                                            ------------------------------
                                            Name:  Larry N. Feinberg
                                            Title: Senior Managing Member










                               [SIGNATURE PAGE TO
                         AMENDMENT NO. 3 TO SCHEDULE 13G
                       WITH RESPECT TO QUIDEL CORPORATION]