Current assets

Exhibit 4.1

CERTIFICATE OF DESIGNATIONS
OF
RIGHTS, PREFERENCES, PRIVILEGES AND RESTRICTIONS
OF
SERIES C JUNIOR PARTICIPATING PREFERRED STOCK
OF
QUIDEL CORPORATION

(Pursuant to Section 151(g) of the Delaware General Corporation Law)

     The undersigned, Robert J. Bujarski, Senior Vice President, General Counsel and Corporate Secretary of Quidel Corporation, a Delaware corporation (the “Corporation”), does hereby certify that pursuant to the authority conferred upon the Board of Directors of the Corporation (the “Board of Directors”) by the Certificate of Incorporation of the Corporation (the “Certificate of Incorporation”), on September 1, 2010, the following resolutions were duly adopted by the Board of Directors:

     “NOW, THEREFORE, BE IT RESOLVED, that pursuant to the authority vested in the Board of Directors by the Certificate of Incorporation, the Board of Directors does hereby provide for the issue of a series of Preferred Stock, par value $.001 per share, of the Corporation, to be designated “Series C Junior Participating Preferred Stock” (the “Series C Preferred Stock”), initially consisting of 50,000 shares, and to the extent that the rights, preferences, privileges and restrictions of the Series C Preferred Stock are not stated and expressed in the Certificate of Incorporation, does hereby fix and herein state and express such rights, preferences, privileges and restrictions thereof as follows (all terms used herein that are defined in the Certificate of Incorporation shall be deemed to have the meanings provided therein):

     1. Designation and Amount. The shares of such series shall be designated as “Series C Junior Participating Preferred Stock” and the number of shares constituting such series shall be 50,000. Such number of shares may be increased or decreased by resolution of the Board of Directors; provided, that no decrease shall reduce the number of shares of Series C Preferred Stock to a number less than the number of shares then outstanding plus the number of shares reserved for issuance upon the exercise of outstanding options, rights or warrants or upon the conversion of any outstanding securities issued by the Corporation convertible into Series C Preferred Stock.

     2. Dividends and Distributions.

     (a) Subject to the prior and superior rights of the holders of any shares of any series of Preferred Shares ranking prior and superior to the shares of Series C Preferred Stock with respect to dividends, the holders of shares of Series C Preferred Stock shall be entitled to receive, when, as and if declared by the Board of Directors out of funds legally available for the purpose, quarterly dividends payable in cash on the 15th day of January, April, July and October and in each year (each a “Quarterly Dividend Payment Date”), commencing on the first Quarterly Dividend Payment Date after the first issuance of a share or fraction of a share of Series C Preferred Stock, in an amount per share (rounded to the nearest cent) equal to, subject to the provision for adjustment hereinafter set forth, 1,000 times the aggregate per share amount of all cash dividends, and 1,000 times the aggregate per share amount (payable in kind) of all non-cash dividends or other distributions other than a dividend payable in Common Shares or a subdivision of the outstanding Common Shares (by reclassification or otherwise), declared on the Common Shares since the immediately preceding Quarterly Dividend Payment Date, or, with respect to the first Quarterly Dividend Payment Date, since the first issuance of any share or fraction of a share of Series C Preferred Stock. In the event the Corporation shall at any time: (i) declare any dividend on Common Shares payable in Common Shares, (ii) subdivide the outstanding Common Shares, or (iii) combine the outstanding Common Shares into a smaller number of shares, then in each such case the amount to which holders of shares of Series C Preferred Stock were entitled immediately prior to such event under the preceding sentence shall be adjusted by multiplying such amount by a fraction, the numerator of which is the number of Common Shares outstanding immediately after such event and the denominator of which is the number of Common Shares that were outstanding immediately prior to such event.

     (b) The Corporation shall declare a dividend or distribution on the Series C Preferred Stock as provided in paragraph (a) above concurrently with any declaration of a dividend or distribution on the Common Shares (other than a dividend payable in Common Shares).

     (c) Dividends shall begin to accrue and be cumulative on outstanding shares of Series C Preferred Stock from the Quarterly Dividend Payment Date next preceding the date of issue of such shares of Series C Preferred Stock, unless the date of issue of such shares is prior to the record date for the first Quarterly Dividend Payment Date, in which case dividends on such shares shall begin to accrue from the date of issue of such shares, or unless the date of issue is a Quarterly Dividend Payment Date or is a date after the record date for the determination of holders of shares of Series C Preferred Stock entitled to receive a quarterly dividend

and before such Quarterly Dividend Payment Date, in either of which events such dividends shall begin to accrue and be cumulative from such Quarterly Dividend Payment Date. Accrued but unpaid dividends shall not bear interest. Dividends paid on the shares of Series C Preferred Stock in an amount less than the total amount of such dividends at the time accrued and payable on such shares shall be allocated pro rata on a share-by-share basis among all such shares at the time outstanding. The Board of Directors may fix a record date for the determination of holders of shares of Series C Preferred Stock entitled to receive payment of a dividend or distribution declared thereon, which record date shall be no more than 30 days prior to the date fixed for the payment thereof.

     3. Voting Rights. The holders of shares of Series C Preferred Stock shall have the following voting rights:

     (a) Subject to the provision for adjustment hereinafter set forth, each share of Series C Preferred Stock shall entitle the holder thereof to 1,000 votes on all matters submitted to a vote of the stockholders of the Corporation. In the event the Corporation shall at any time (i) declare any dividend on Common Shares payable in Common Shares, (ii) subdivide the outstanding Common Shares, or (iii) combine the outstanding Common Shares into a smaller number of shares, then in each case the number of votes per share to which holders of shares of Series C Preferred Stock were entitled immediately prior to such event shall be adjusted by multiplying such number by a fraction the numerator of which is the number of Common Shares outstanding immediately after such event and the denominator of which is the number of Common Shares that were outstanding immediately prior to such event.

     (b) Except as otherwise provided herein or by law, the holders of shares of Series C Preferred Stock and the holders of Common Shares shall vote together as one class on all matters submitted to a vote of stockholders of the Corporation.

     (c) Except as set forth herein, holders of Series C Preferred Stock shall have no special voting rights and their consent shall not be required (except to the extent they are entitled to vote with holders of Common Shares as set forth herein) for taking any corporate action.

     4. Certain Restrictions.

     (a) The Corporation shall not declare any dividend on, make any distribution on, or redeem or purchase or otherwise acquire for consideration any Common Shares after the first issuance of a share or fraction of a share of Series C Preferred Stock unless concurrently therewith it shall declare a dividend on the Series C Preferred Stock as required by Section 2 hereof.

     (b) Whenever quarterly dividends or other dividends or distributions payable on the Series C Preferred Stock as provided in Section 2 have been declared but not paid, thereafter and until all accrued and unpaid dividends and distributions, whether or not declared, on shares of Series C Preferred Stock outstanding shall have been paid in full, the Corporation shall not

     (i) declare or pay dividends on, make any other distribution on, or redeem or purchase or otherwise acquire for consideration any shares of stock ranking junior (either as to dividends or upon liquidation, dissolution or winding up) to the Series C Preferred Stock;

     (ii) declare or pay dividends on or make any other distributions on any shares of stock ranking on a parity (either as to dividends or upon liquidation, dissolution or winding up) with the Series C Preferred Stock, except dividends paid ratably on the Series C Preferred Stock and all such parity stock on which dividends are payable or in arrears in proportion to the total amounts to which the holders of all such shares are then entitled;

     (iii) redeem or purchase or otherwise acquire for consideration shares of any stock ranking on a parity (either as to dividends or upon liquidation, dissolution or winding up) with the Series C Preferred Stock, provided that the Corporation may at any time redeem, purchase or otherwise acquire shares of any such parity stock in exchange for shares of any stock of the Corporation ranking junior (either as to dividends or upon dissolution, liquidation or winding up) to the Series C Preferred Stock;

     (iv) purchase or otherwise acquire for consideration any shares of Series C Preferred Stock, or any shares of stock ranking on a parity with the Series C Preferred Stock, except in accordance with a purchase offer made in writing or by publication (as determined by the Board of Directors) to all holders of such shares upon such terms as the Board of Directors, after consideration of the respective annual dividend rates and other relative rights and preferences of the respective series and classes, shall determine in good faith will result in fair and equitable treatment among the respective series or classes.

     (c) The Corporation shall not permit any subsidiary of the Corporation to purchase or otherwise acquire for consideration any shares of stock of the Corporation unless the Corporation could, under paragraph (a) of this Section 4, purchase or otherwise acquire such shares at such time and in such manner.

     5. Reacquired Shares. Any shares of Series C Preferred Stock purchased or otherwise acquired by the Corporation in any manner whatsoever shall be retired and canceled promptly after the acquisition thereof. All such shares shall upon their cancellation become authorized but unissued Preferred Shares and may be reissued as part of a new series of Preferred Shares to be created by resolution or resolutions of the Board of Directors, subject to the conditions and restrictions on issuance set forth herein.

     6. Liquidation, Dissolution or Winding Up.

     (a) Upon any liquidation (voluntary or otherwise), dissolution or winding up of the Corporation, no distribution shall be made to the holders of shares of stock ranking junior (either as to dividends or upon liquidation, dissolution or winding up) to the Series C Preferred Stock unless, prior thereto, the holders of shares of Series C Preferred Stock shall have received $1,000 per share, plus an amount equal to accrued and unpaid dividends and distributions thereon, whether or not declared, to the date of such payment (the “Series C Liquidation Preference”). Following the payment of the full amount of the Series C Liquidation Preference, no additional distributions shall be made to the holders of shares of Series C Preferred Stock unless, prior thereto, the holders of Common Shares shall have received an amount per share (the “Common Adjustment”) equal to the quotient obtained by dividing (i) the Series C Liquidation Preference by (ii) 1,000 (as appropriately adjusted as set forth in subparagraph (c) below to reflect such events as stock splits, stock dividends and recapitalizations with respect to the Common Shares) (such number in clause (ii), the “Adjustment Number”). Following the payment of the full amount of the Series C Liquidation Preference and the Common Adjustment in respect of all outstanding shares of Series C Preferred Stock and Common Shares, respectively, holders of Series C Preferred Stock and holders of Common Shares shall receive their ratable and proportionate share of remaining assets to be distributed in the ratio of the Adjustment Number to one (1) with respect to such Preferred Shares and Common Shares, on a per share basis, respectively.

     (b) In the event, however, that there are not sufficient assets available to permit payment in full of the Series C Liquidation Preference and the liquidation preferences of all other series of Preferred Shares, if any, which rank on a parity with the Series C Preferred Stock, then such remaining assets shall be distributed ratably to the holders of such parity shares in proportion to their respective liquidation preferences. In the event, however, that there are not sufficient assets available to permit payment in full of the Common Adjustment, then such remaining assets shall be distributed ratably to the holders of Common Shares.

     (c) In the event the Corporation shall at any time (i) declare any dividend on Common Shares payable in Common Shares, (ii) subdivide the outstanding Common Shares, or (iii) combine the outstanding Common Shares into a smaller number of shares, then in each such case the Adjustment Number in effect immediately prior to such event shall be adjusted by multiplying such Adjustment Number by a fraction the numerator of which is the number of Common Shares outstanding immediately after such event and the denominator of which is the number of Common Shares that were outstanding immediately prior to such event.

     7. Consolidation, Merger, etc. In case the Corporation shall enter into any consolidation, merger, combination or other transaction in which the Common Shares are exchanged for or changed into other stock or securities, cash and/or any other property, then in any such case the shares of Series C Preferred Stock shall at the same time be similarly exchanged or changed in an amount per share (subject to the provision for adjustment hereinafter set forth) equal to 1,000 times the aggregate amount of stock, securities, cash and/or any other property (payable in kind), as the case may be, into which or for which each Common Share is changed or exchanged. In the event the Corporation shall at any time (i) declare any dividend on Common Shares payable in Common Shares, (ii) subdivide the outstanding Common Shares, or (iii) combine the outstanding Common Shares into a smaller number of shares, then in each such case the amount set forth in the preceding sentence with respect to the exchange or change of shares of Series C Preferred Stock shall be adjusted by multiplying such amount by a fraction the numerator of which is the number of Common Shares outstanding immediately after such event and the denominator of which is the number of Common Shares that were outstanding immediately prior to such event.

     8. No Redemption. The shares of Series C Preferred Stock shall not be redeemable.

     9. Ranking. The Series C Preferred Stock shall rank junior to all other series of Preferred Shares, if any, as to the payment of dividends and the distribution of assets, unless the terms of any such series shall provide otherwise.

     10. Amendment. The Certificate of Incorporation shall not be further amended in any manner which would materially alter or change the powers, preferences or special rights of the Series C Preferred Stock so as to affect them adversely without the affirmative vote of the holders of a majority or more of the outstanding shares of Series C Preferred Stock, voting separately as a class.

     11. Fractional Shares. Series C Preferred Stock may be issued in fractions of a share, which shall entitle the holder, in proportion to such holder’s fractional shares, to exercise voting rights, receive dividends, participate in

distributions and to have the benefit of all other rights of holders of Series C Preferred Stock.

     RESOLVED, FURTHER, that the President or any Vice President and the Secretary or any Assistant Secretary of the Corporation be, and they hereby are, authorized and directed to prepare and file a Certificate of Designation of Rights, Preferences, Privileges and Restrictions in accordance with the foregoing resolution and the provisions of Delaware law and to take such actions as they may deem necessary or appropriate to carry out the intent of the foregoing resolution.”

     IN WITNESS WHEREOF, this Certificate of Designations is executed on October 5, 2010.