X0304 4 2012-03-19 0 0000353569 QUIDEL CORP /DE/ QDEL 0001406652 BRYANT DOUGLAS C 10165 MCKELLAR COURT SAN DIEGO CA 92121 1 1 0 0 President & CEO Common Stock 2012-01-18 4 F 0 5028 15.14 D 193261 D Common Stock 2012-02-02 4 F 0 9163 14.51 D 184098 D Common Stock 2012-03-19 4 P 0 10000 16.5462 A 194098 D The disposition of shares as set forth above was in connection with the Issuer's withholding of common shares to satisfy tax withholding obligations related to the issuance of common shares upon vesting of restricted stock units. The amount of securities beneficially owned following the reported transaction includes 3,893 shares acquired under the Issuer's Employee Stock Purchase Plan. The weighted average purchase price for these transactions was $16.54616 per share, with a range of $16.30 to $16.58 per share. Upon request, the Reporting Person hereby undertakes to provide to staff of the U.S. Securities and Exchange Commission, the Issuer, or a security holder, the full information regarding the number of shares purchased at each separate price. Robert J. Bujarski, attorney-in-fact for Douglas C. Bryant 2012-03-21