FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES 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(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * Brown Thomas D   2. Issuer Name and Ticker or Trading Symbol QUIDEL CORP /DE/ [QDEL] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 29890 TANYA TRAIL 3. Date of Earliest Transaction (Month/Day/Year) 05/14/2013 (Street) LIBERTYVILLE, IL 60048 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 05/14/2013   M   2,600 (1) A $ 0 19,028 (2) D

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Restricted Stock Units (Converted)

(3)

05/14/2013

A

2,116

(4)

(5)

Common Stock

2,116

$ 0

2,116

D

Restricted Stock Units (Premium)

(3)

05/14/2013

A

423

05/14/2014

(5)

Common Stock

423

$ 0

423

D

Non-Qualified Stock Option

$ 23.7

05/14/2013

A

8,081

05/14/2014

05/14/2023

Common Stock

8,081

$ 0

8,081

D

Restricted Stock Units (Equity Grant)

(3)

05/14/2013

A

371

05/14/2014

(6)

Common Stock

371

$ 0

371

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Brown Thomas D 29890 TANYA TRAIL LIBERTYVILLE, IL 60048	X

Signatures

Robert J. Bujarski, attorney-in-fact for Thomas D. Brown		05/16/2013
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Reflects vesting of prior restricted stock units, which were previously reported on a Form 4.
(2)	Does not reflect 2,469 restricted stock units, which were reported on Table I on a Form 4 filed on November 28, 2012 that were not required to be included.
(3)	Each restricted stock unit represents the right to receive one share of Quidel Corporation common stock.
(4)	The restricted stock units vest on the date of grant, May 14, 2013.
(5)	The restricted stock units were received in lieu of cash payments to the reporting person for certain retainer and Board of Director service-related fees under a deferred compensation program applicable to participating non-employee directors.
(6)	The restricted stock units vest upon the earlier of (a) immediately prior to the annual meeting of Quidel Corporation's stockholders in 2014 or (b) on the first anniversary of the grant date or May 14, 2014.

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