Exhibit 10.1

September 12, 2011

Mr. Randall Steward

13380 Caminito Mar Villa

Del Mar, CA 92014

Dear Randy:

We are pleased to extend the following offer of employment to you:

In addition to the above, as a Quidel employee, you will be eligible to participate in our benefits programs, which will take effect on your first day of employment. A summary of these benefits is provided in the enclosed materials. Details of these benefit plans will be provided to you upon your employment.

As a condition of employment with Quidel Corporation, you will be required to: (1) read, sign and return one copy of the enclosed Invention and Confidential Information Agreement; (2) within

Mr. Randall Steward

Offer Letter

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the first three days of employment, you must provide documents from the enclosed List of Acceptable Documents (I-9) which prove your identity and right to work in the United States; and (3) read, sign and return one copy of page 5 of the enclosed Employee Code of Conduct.

This offer of employment is contingent upon successfully passing a pre-employment drug screen, background and reference check. Our vendor will be in contact with you to set up your drug screen appointment, which must be completed as soon as reasonably possible.

Quidel Corporation is an at-will employer. This means that you have the right to terminate your employment with Quidel at any time, for any reason, with or without notice. Similarly, Quidel has the right to terminate the employment relationship at any time, for any reason, with or without notice. Any contrary representations, which may have been made to you, are superseded by this offer. Any modifications to this “at-will” term of your employment must be in writing and signed by you and Quidel’s President.

This offer expires seven days from the date of this letter. Please indicate your acceptance of our offer by signing below and returning a copy of this letter to Human Resources as soon as possible.

Randy, on behalf of senior management and the Board of Directors, we are looking forward to having you join us as we work together to provide quality products to the medical community and to create value for the employees and shareholders of Quidel Corporation.

Sincerely,

Phyllis Huckabee

Vice President, Human Resources

cc:        Doug Bryant, CEO

             Human Resources

Enclosures

I have read, understand and accept these terms and conditions of employment. I further understand that while my salary, benefits, job title and job duties may change from time to time without a written modification of this agreement, the at-will term of my employment is a term of employment which cannot be altered or modified except in writing, signed by me and Quidel’s President.

Exhibit 10.2

AGREEMENT RE: CHANGE IN CONTROL

This AGREEMENT RE: CHANGE IN CONTROL (this “Agreement”) is dated as of September 19, 2011 and is entered into by and between Randall J. Steward (“Executive”) and Quidel Corporation, a Delaware corporation (the “Company”).

Background

The Company believes that because of its position in the industry, financial resources and historical operating results there is a possibility that the Company may become the subject of a Change in Control (as defined below), either now or at some time in the future.

The Company believes that it is in the best interest of the Company and its stockholders to foster Executive’s objectivity in making decisions with respect to any pending or threatened Change in Control of the Company and to assure that the Company will have the continued dedication and availability of Executive, notwithstanding the possibility, threat or occurrence of a Change in Control. The Company believes that these goals can best be accomplished by alleviating certain of the risks and uncertainties with regard to Executive’s financial and professional security that would be created by a pending or threatened Change in Control and that inevitably would distract Executive and could impair his ability to objectively perform his duties for and on behalf of the Company. Accordingly, the Company believes that it is appropriate and in the best interest of the Company and its stockholders to provide to Executive compensation arrangements upon a Change in Control that lessen Executive’s financial risks and uncertainties and that are reasonably competitive with those of other corporations.

With these and other considerations in mind, the Compensation Committee of the Company has authorized the Company to enter into this Agreement with the Executive to provide the protections set forth herein for Executive’s financial security following a Change in Control.

NOW, THEREFORE, in consideration of the foregoing, and for other good and valuable consideration the receipt of which is hereby acknowledged, it is hereby agreed as follows:

Agreement

1. Term of Agreement . This Agreement shall be effective as of the date of commencement of work and, subject to the provisions of Section 4, shall extend to (and thereupon automatically terminate) one (1) day after Executive’s termination of employment with the Company for any reason. No termination of this Agreement shall limit, alter or otherwise affect Executive’s rights hereunder with respect to a Change in Control which has occurred prior to such termination, including without limitation Executive’s right to receive the various benefits hereunder.

2. Purpose of Agreement . The purpose of this Agreement is to provide that, in the event of a “Change in Control,” Executive may become entitled to receive certain additional benefits, as described herein, in the event of his termination under specified circumstances.

3. Change in Control . As used in this Agreement, the phrase “Change in Control” shall mean:

(i) Except as provided by subparagraph (iii) hereof, the acquisition (other than from the Company) by any person, entity or “group”, within the meaning of Section 13(d)(3) or

14(d)(2) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) (excluding, for this purpose, the Company or its subsidiaries, or any executive benefit plan of the Company or its subsidiaries which acquires beneficial ownership of voting securities of the Company), of beneficial ownership (within the meaning of Rule 13d-3 promulgated under the Exchange Act) of forty percent (40%) or more of either the then outstanding shares of common stock or the combined voting power of the Company’s then outstanding voting securities entitled to vote generally in the election of directors; or

(ii) Individuals who, as of the date hereof, constitute the Board of Directors of the Company (as of the date hereof the “Incumbent Board”) cease for any reason to constitute at least a majority of the Board of Directors of the Company, provided that any person becoming a director subsequent to the date hereof whose election, or nomination for election by the Company’s stockholders, is or was approved by a vote of at least a majority of the directors then comprising the Incumbent Board (other than an election or nomination of an individual whose initial assumption of office is in connection with an actual or threatened election contest relating to the election of the Directors of the Company, as such terms are used in Rule 14a-l 1 of Regulation 14A promulgated under the Exchange Act) shall be, for purposes of this Agreement, considered as though such person were a member of the Incumbent Board; or

(iii) Approval by the stockholders of the Company of a reorganization, merger or consolidation with any other person, entity or corporation, other than

(1) a merger or consolidation which would result in the voting securities of the Company outstanding immediately prior thereto continuing to represent (either by remaining outstanding or by being converted into voting securities of another entity) more than fifty percent (50%) of the combined voting power of the voting securities of the Company or such other entity outstanding immediately after such merger or consolidation, or

(2) a merger or consolidation effected to implement a recapitalization of the Company (or similar transaction) in which no person acquires forty percent (40%) or more of the combined voting power of the Company’s then outstanding voting securities; or

(iv) Approval by the stockholders of the Company of a plan of complete liquidation of the Company or an agreement for the sale or other disposition by the Company of all or substantially all of the Company’s assets.

4. Effect of a Change in Control . In the event of a Change in Control, Sections 6 through 13 of this Agreement shall become applicable to Executive. These Sections shall continue to remain applicable until the third anniversary of the date upon which the Change in Control occurs. On such third anniversary date, and provided that the employment of Executive has not been terminated on account of a Qualifying Termination (as defined in Section 5 below), this Agreement shall terminate and be of no further force or effect.

5. Qualifying Termination . If following, or within thirty (30) days prior to, a Change in Control Executive’s employment with the Company and its affiliated companies is terminated, such termination shall be conclusively considered a “Qualifying Termination” unless:

(a) Executive voluntarily terminates his employment with the Company and its affiliated companies. Executive, however, shall not be considered to have

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voluntarily terminated his employment with the Company and its affiliated companies if, following, or within thirty (30) days prior to, the Change in Control, Executive’s base salary is reduced or adversely modified in any material respect, or Executive’s authority or duties are materially changed, and subsequent to such reduction, modification or change Executive elects to terminate his employment with the Company and its affiliated companies within sixty (60) days following such reduction, modification or change after having given the Company at least thirty (30) days notice of the same and a reasonable opportunity to cure during such 30-day notice period. For such purposes, Executive’s authority or duties shall conclusively be considered to have been “materially changed” if, without Executive’s express and voluntary written consent, there is any substantial diminution or adverse modification in Executive’s title, status, overall position, responsibilities, reporting relationship, general working environment (including without limitation secretarial and staff support, offices, and frequency and mode of travel), or if, without Executive’s express and voluntary written consent, Executive’s job location is transferred to a site more than twenty-five (25) miles away from his place of employment thirty (30) days prior to the Change in Control. In this regard as well, Executive’s authority and duties shall conclusively be considered to have been “materially changed” if, without Executive’s express and voluntary written consent, Executive no longer holds the same title or no longer has the same authority and responsibilities or no longer has the same reporting responsibilities, in each case with respect and as to a publicly held parent company which is not controlled by another entity or person.

(b) The termination is on account of Executive’s death or Disability. For such purposes, “Disability” shall mean a physical or mental incapacity as a result of which Executive becomes unable to continue the performance of his responsibilities for the Company and its affiliated companies and which, at least three (3) months after its commencement, is determined to be total and permanent by a physician agreed to by the Company and Executive, or in the event of Executive’s inability to designate a physician, Executive’s legal representative. In the absence of agreement between the Company and Executive, each party shall nominate a qualified physician and the two physicians so nominated shall select a third physician who shall make the determination as to Disability.

(c) Executive is involuntarily terminated for “Cause.” For this purpose, “Cause” shall be limited to only three types of events:

(1) the willful and deliberate refusal of Executive to comply with a lawful, written instruction of the Board of Directors, which refusal is not remedied by Executive within a reasonable period of time after his receipt of written notice from the Company identifying the refusal, so long as the instruction is consistent with the scope and responsibilities of Executive’s position prior to the Change in Control;

(2) an act or acts of personal dishonesty by Executive which were intended to result in substantial personal enrichment of Executive at the expense of the Company; or

(3) Executive’s conviction of any felony involving an act of moral turpitude.

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6. Severance Payment . If Executive’s employment is terminated as a result of a Qualifying Termination, the Company shall pay Executive within thirty (30) days after the Qualifying Termination a cash lump sum equal to two (2) times the Executive’s Compensation (the “Severance Payment”).

(a) For purposes of this Agreement, Executive’s “Compensation” shall equal the sum of (i) Executive’s highest annual salary rate with the Company within the three year period ending on the date of Executive’s Qualifying Termination, plus (ii) a “Bonus Increment.” The Bonus Increment shall equal the annualized average of all bonuses and incentive compensation payments paid to Executive during the two (2) year period immediately before the date of Executive’s Qualifying Termination under all of the Company’s bonus and incentive compensation plans or arrangement.

(b) [Intentionally Deleted.]

(c) The Severance Payment hereunder is in lieu of any severance payment that Executive might otherwise be entitled to from the Company in the event of a Change in Control under the Company’s applicable severance pay policies, if any, or under any other oral or written agreement; provided, however, that Executive shall continue to be entitled to receive the severance pay benefits under the Company’s applicable policies, if any, or under another written agreement if and to the extent Executive’s termination is not a Qualifying Termination after, or within thirty (30) days prior to, a Change in Control.

(d) Notwithstanding any provision of this Agreement to the contrary, if, at the time of Executive’s termination of employment with the Company, Executive is a “specified employee” as defined in Section 409A of the Code, and one or more of the payments or benefits received or to be received by Executive pursuant to this Agreement (or any portion thereof) would become subject to the additional tax under Section 409A(a)(l)(B) of the Code or any other taxes or penalties imposed under Section 409A of the Code (the “Section 409A Taxes”) if provided at the time otherwise required under this Agreement, no such payment or benefit will be provided under this Agreement until the earlier of (a) the date which is six (6) months after Executive’s “separation from service” or (b) the date of Executive’s death, or such shorter period that, as determined by the Company, is sufficient to avoid the imposition of Section 409A Taxes. The provisions of this Section 6(d) shall only apply to the minimum extent required to avoid Executive’s incurrence of any Section 409A Taxes. In addition, if any provision of this Agreement would cause Executive to incur any penalty tax or interest under Section 409A of the Code or any regulations or Treasury guidance promulgated thereunder, the Company may reform such provision to maintain to the maximum extent practicable the original intent of the applicable provision without violating the provisions of Section 409A of the Code.

7. Additional Benefits .

(a) In the event of a Qualifying Termination, any and all unvested stock options of Executive shall immediately become fully vested and exercisable and any and all restrictions on Executive’s restricted stock shall immediately and automatically lapse (except as otherwise expressly agreed to, in writing, by both parties, including whether prior to or after the execution of this Agreement).

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(b) In the event of a Qualifying Termination, Executive shall be entitled to continue to participate in the following executive benefit programs which had been made available to Executive (including his family) before the Qualifying Termination: group medical insurance, group dental insurance, and group vision insurance. These programs shall be continued at no cost to Executive, except to the extent that tax rules require the inclusion of the value of such benefits in Executive’s income. The programs shall be continued in the same way and at the same level as immediately prior to the Qualifying Termination. The programs shall continue for Executive’s benefit for two (2) years after the date of the Qualifying Termination; provided, however, that Executive’s participation in each of such programs shall be earlier terminated or reduced, as applicable, if and to the extent Executive receives benefits as a result of concurrent coverage through another program.

(c) In the event of a Qualifying Termination, Executive shall be entitled to receive from the Company, upon such Termination, the sum of $25,000 to help defray legal fees, tax and accounting fees, executive outplacement services, and other costs associated with transitional matters.

8. Limitation on Payments . Notwithstanding anything to the contrary herein, in the event that the sum aggregate present value of (i) the Severance Payment payable under Section 6 hereof, (ii) any and all additional amount or benefits which may be paid or conferred to or on behalf of Executive in accordance with Section 7 hereof, and (iii) any and all other amounts or benefits paid or conferred to or on behalf of Executive would constitute a “parachute payment” (“parachute payment” as used in this Agreement shall be defined in accordance with Section 280G(b)(2), or any successor thereto, of the Internal Revenue Code of 1986. as amended), the payments under this Agreement shall be reduced (by the minimum possible amounts) until no amount payable to Executive under this Agreement constitutes a parachute payment; provided, however, that no such reduction under this Section 8 shall be made if the net after-tax payment (after taking into account, Federal, state, local or other income and excise taxes) to which Executive would otherwise be entitled without such reduction would be greater than the net after-tax payment (after taking into account Federal, state, local or other income and excise taxes) to Executive resulting from the receipt of such payments with such reduction. If, as a result of subsequent events or conditions (including a subsequent payment or absence of a subsequent payment under this Agreement), it is determined that payments hereunder have been reduced by more than the minimum amount required under this Section 8, then an additional payment shall be promptly made to Executive in an amount equal to the excess reduction. All determinations required to be made under this Section 8, including whether a payment would result in a parachute payment and the assumptions to be utilized in arriving at such determination, shall be made and approved within fifteen (15) days after the Qualifying Termination by both (1) accountants selected by the Company and (2) Executive’s designated financial advisor.

9. Nonsolicitation Covenant . In consideration of the payments to be made to Executive hereunder, Executive hereby covenants, for a period of two (2) years following the Qualifying Termination, that he will not, directly or indirectly (whether as an officer, director, employee, individual proprietor, control shareholder, consultant, partner or otherwise) (i) solicit, recruit or hire-away any employee of the Company or successor of the Company or (ii) solicit, influence or attempt to influence any person or entity to terminate such person’s or entity’s contractual and/or business relationship with the Company or successor of the Company. With regard to this Section 9, Executive acknowledges that the provisions herein are reasonable in both scope and duration and necessary to protect the business of the Company or its successor.

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10. Rights and Obligations Prior to a Change in Control . Prior to the date which is thirty (30) days before a Change in Control, the rights and obligations of Executive with respect to his employment by the Company shall be determined in accordance with the policies and procedures adopted from time to time by the Company and the provisions of any written employment contract in effect between the Company and Executive from time to time. This Agreement deals only with certain rights and obligations of Executive subsequent, or within thirty (30) days prior to, a Change in Control, and the existence of this Agreement shall not be treated as raising any inference with respect to what rights and obligations exist prior to the date which is thirty (30) days before a Change in Control. Unless otherwise expressly set forth in a separate written employment agreement between Executive and the Company, the employment of Executive is expressly at-will, and Executive or the Company may terminate Executive’s employment with the Company at any time and for any reason, with or without cause, provided that if such termination occurs within thirty (30) days prior to or three (3) years after a Change in Control and constitutes a Qualifying Termination (as defined in Section 5 above) the provisions of this Agreement shall govern the payment of the Severance Payment and certain other benefits as provided herein.

11. Non-Exclusivity of Rights . Subject to Section 6(c) hereof, nothing in this Agreement shall prevent or limit Executive’s continuing or future participation in any benefit, bonus, incentive or other plan or program provided by the Company or any of its affiliated companies and for which Executive may qualify, nor shall anything herein limit or otherwise affect such rights as Executive may have under any stock option or other agreements with the Company or any of its affiliated companies. Except as otherwise provided in Section 6(c) hereof, amounts which are vested benefits or which Executive is otherwise entitled to receive under any plan or program of the Company or any of its affiliated companies at or subsequent to the date of any Qualified Termination shall be payable in accordance with such plan or program.

12. Full Settlement . The Company’s obligation to make the payments provided for in this Agreement and otherwise to perform its obligations hereunder shall not be affected by any set-off, counter-claim, recoupment, defense or other claim, right, or action which the Company may have against Executive or others. In no event shall Executive be obligated to seek other employment or to take any other action by way of mitigation of the amounts payable to Executive under any of the provisions of this Agreement. The Company agrees to pay, to the full extent permitted by law, all legal fees and expenses which Executive may reasonably incur as a result of Executive’s successful collection efforts to receive amounts payable hereunder, or as a result of any contest (regardless of the outcome thereof) by the Company or others of the validity or enforceability of, or liability under, any provision of this Agreement or any guarantee of performance thereof (including as a result of any contest by Executive about the amount of any payment pursuant to this Section).

13. Successors .

(a) This Agreement is personal to Executive, and without the prior written consent of the Company shall not be assignable by Executive other than by will or the laws of descent and distribution. This Agreement shall inure to the benefit of and be enforceable by Executive’s legal representatives.

(b) The rights and obligations of the Company under this Agreement shall inure to the benefit of and shall be binding upon the successors and assigns of the Company.

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14. Governing Law . This Agreement is made and entered into in the State of California, and the internal laws of California shall govern its validity and interpretation in the performance by the parties hereto of their respective duties and obligations hereunder.

15. Modifications . This Agreement may be amended or modified only by an instrument in writing executed by all of the parties hereto.

16. Dispute Resolution .

(a) Any controversy or dispute between the parties involving the construction, interpretation, application or performance of the terms, covenants, or conditions of this Agreement or in any way arising under this Agreement (a “Covered Dispute”) shall, on demand by either of the parties by written notice served on the other party in the manner prescribed in Section 17 hereof, be referenced pursuant to the procedures described in California Code of Civil Procedure (“CCP”) Sections 638, et seq ., as they may be amended from time to time (the “Reference Procedures”), to a retired Judge from the Superior Court for the County of San Diego or the County of Orange for a decision.

(b) The Reference Procedures shall be commenced by either party by the filing in the Superior Court of the State of California for the County of San Diego or the County of Orange of a petition pursuant to CCP Section 638(a) (a “Petition”). Said Petition shall designate as a referee a Judge from the list of retired San Diego County and Orange County Superior Court Judges who have made themselves available for trial or settlement of civil litigation under said Reference Procedures. If the parties hereto are unable to agree on the designation of a particular retired San Diego County or Orange County Superior Court Judge or the designated Judge is unavailable or unable to serve in such capacity, request shall be made in said Petition that the Presiding or Assistant Presiding Judge of the San Diego County Superior Court or the Orange County Superior Court, as relevant, appoint as referee a retired San Diego County or Orange County Superior Court Judge from the aforementioned list.

(c) Except as hereafter agreed by the parties, the referee shall apply the internal law of California in deciding the issues submitted hereunder. Unless formal pleadings are waived by agreement among the parties and the referee, the moving party shall file and serve its complaint within 15 days from the date a referee is designated as provided herein, and the other party shall have 15 days thereafter in which to plead to said complaint. Each of the parties reserves its respective rights to allege and assert in such pleadings all claims, causes of action, contentions and defenses which it may have arising out of or relating to the general subject matter of the Covered Dispute that is being determined pursuant to the Reference Procedures. Reasonable notice of any motions before the referee shall be given, and all matters shall be set at the convenience of the referee. Discovery shall be conducted as the parties agree or as allowed by the referee. Unless waived by each of the parties, a reporter shall be present at all proceedings before the referee.

(d) It is the parties’ intention by this Section 16 that all issues of fact and law and all matters of a legal and equitable nature related to any Covered Dispute will be submitted for determination by a referee designated as provided herein. Accordingly, the parties hereby stipulate that a referee designated as provided herein shall have all powers of a Judge of the Superior Court including, without limitation, the power to grant equitable and interlocutory and permanent injunctive relief.

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(e) Each of the parties specifically (i) consents to the exercise of jurisdiction over his person by a referee designated as provided herein with respect to any and all Covered Disputes; and (ii) consents to the personal jurisdiction of the California courts with respect to any appeal or review of the decision of any such referee.

(f) Each of the parties acknowledges that the decision by a referee designated as provided herein shall be a basis for a judgment as provided in CCP Section 644 and shall be subject to exception and review as provided in CCP Section 645.

17. Notices . Any notice or communications required or permitted to be given to the parties hereto shall be delivered personally or be sent by United States registered or certified mail, postage prepaid and return receipt requested, and addressed or delivered as follows, or at such other addresses the party addressed may have substituted by notice pursuant to this Section:

18. Captions . The captions of this Agreement are inserted for convenience and do not constitute a part hereof.

19. Severability . In case any one or more of the provisions contained in this Agreement shall for any reason be held to be invalid, illegal or unenforceable in any respect, such invalidity, illegality or unenforceability shall not affect any other provision of this Agreement, but this Agreement shall be construed as if such invalid, illegal or unenforceable provision had never been contained herein and there shall be deemed substituted for such invalid, illegal or unenforceable provision such other provision as will most nearly accomplish the intent of the parties to the extent permitted by the applicable law. In case this Agreement, or any one or more the provisions hereof, shall be held to be invalid, illegal or unenforceable within any governmental jurisdiction or subdivision thereof, this Agreement or any such provision thereof shall not as a consequence thereof be deemed to be invalid, illegal or unenforceable in any other governmental jurisdiction or subdivision thereof.

20. Counterparts . This Agreement may be executed in two or more counterparts, each of which shall be deemed an original, but all of which shall together constitute one in the same Agreement.

[Remainder of page left blank intentionally, signatures on following page]

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IN WITNESS HEREOF, the parties hereto have caused this Agreement to be duly executed and delivered as of the day and year first written above in San Diego, California.

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Exhibit 10.3

TRANSITION AGREEMENT

THIS TRANSITION AGREEMENT (this “ Agreement ”) is made and entered into as of the 18th day of October, 2011 by and between QUIDEL CORPORATION, a Delaware corporation (the “ Company ”), and JOHN RADAK, an individual (“ Radak ”).

BACKGROUND

A. Radak currently serves as the Company’s Chief Financial Officer. Pursuant to pre-existing and continuing employment and related understandings and agreements, Radak’s employment with the Company is “at will.”

B. The Company and Radak have agreed that Radak’s employment with the Company will terminate on the earlier of (i) Radak’s start date of employment with another company (i.e., Radak’s voluntary termination) or (ii) July 31, 2012 (the “ End Date ”).

C. The Company and Radak are entering into this Agreement to confirm their understandings as to Radak’s employment prior to the End Date and each party’s commitments and obligations on and after the End Date.

AGREEMENT

1. Employment . Upon and subject to the terms and conditions set forth herein, the Company shall continue to employ Radak on a full-time basis in his current position until October 31, 2011, and Radak accepts such continued employment. Radak acknowledges and agrees that, as of November 1, 2011, provided he has signed and not revoked the Release required by Section 4 hereof, his title will be changed to “Special Advisor to the Chief Executive Officer,” a position that will report to the Company’s Chief Executive Officer with such duties to include assisting with the financial review of the Company’s 2011 fiscal year, and assisting with other financial matters, as may be reasonably requested by the Chief Executive Officer from time to time. Unless earlier terminated pursuant to this Agreement, Radak will remain in this position through the End Date. In such role, Radak agrees to make himself available on an as-needed basis and generally up to eighty (80) hours per month for assignments and to dutifully complete such assignments to the best of his ability at such locations as reasonably designated by the Chief Executive Officer.

2. Term . The term of Radak’s employment shall continue until, and then automatically terminate, as of the End Date, unless terminated earlier pursuant to this Agreement.

3. Compensation and 2011 Bonus Eligibility .

a. Base Salary . Subject to the terms and conditions herein, Radak’s base salary shall continue at the same level as in effect as of the date of this Agreement through the End Date. Subject to the terms and conditions herein and in the event that the End Date is prior to April 30, 2012 due to Radak’s employment start date with another company before such date (i.e., Radak’s voluntary termination before such date), Company shall pay Radak the remainder of his base salary from the End Date through April 30, 2012 as a lump sum within ten (10) days of notice to Quidel that Radak has begun employment elsewhere.

b. Benefits and Bonus Eligibility . Radak’s employee benefits for medical, dental and vision and 401(k) plan shall continue through the End Date at the same levels as are in effect as of the date of this Agreement, provided that he has signed and not revoked the Release pursuant to Section 4 hereof. Radak acknowledges and agrees that he shall not receive any further grants of equity incentive awards nor shall he be eligible to participate in any bonus plans applicable to fiscal year 2012 or any year thereafter. Subject to the terms and conditions herein, Radak shall be eligible for his full annual bonus consistent with the terms of the Company’s 2011 program (40% annual target) for fiscal year 2011, if the Company’s Board of Directors or its Compensation Committee, determines in its sole discretion, that the Company has met its performance metrics for fiscal year 2011, provided that (i) such bonus payment shall be payable, if applicable, when all 2011 executive bonuses are paid, and (ii) he has signed and not revoked the Release pursuant to Section 4 hereof. In addition, Radak will continue to accrue vacation through the End Date, and payment for any accrued vacation as of such End Date shall be made as of the End Date.

c. Outplacement Services . Radak shall be eligible for executive outplacement services through Lee Hecht Harrison subject to a six (6) month limitation and a cap for such costs to be incurred by the Company for these services.

4. Release . On or before November 8, 2011, and as a material condition to Radak’s (a) continued employment hereunder pursuant to Sections 1 and 3 hereof, and (b) receipt of the benefits set forth in Sections 3 and 6 hereof, Radak shall execute and deliver to the Company (and thereafter not revoke) a Release in the form attached hereto as Exhibit A . For avoidance of doubt, the parties acknowledge and agree that Radak’s failure to deliver (and not thereafter revoke) the Release in the time period specified above shall result in termination of employment on or before November 8, 2011 and no further vesting of Radak’s equity awards thereafter.

5. Radak’s Acknowledgements and Obligations . As a material condition to Radak’s receipt of the benefits set forth in Sections 3 and 6 hereof, Radak acknowledges and reaffirms his continuing obligation to adhere to the Agreement Re Confidential Information, Inventions, Non-Solicitation and Conflicts of Interest (“Confidentiality Agreement”) he signed on December 14, 2006. In particular, Radak reaffirms his obligations under Section 4 of the Confidentiality Agreement, which precludes soliciting of or causing employees to leave their employment with Quidel for one year following the termination of his employment. In addition and as a material condition to Radak’s receipt of the benefits set forth in Sections 3 and 6 hereof, Radak agrees that while employed by the Company hereunder he will not, directly or indirectly, provide services, whether as an employee, consultant, director, independent contractor, agent, owner or partner, to any person or entity that competes or is planning to compete with the Company in the diagnostic test market; provided, however, that Radak’s passive investment of up to five percent (5%) of the outstanding voting securities or similar equity interest in a publicly held entity shall not be deemed a breach of this Agreement. Radak agrees that he will not make any statement that is disparaging of the Company or any of its affiliates, or any of their respective directors, employees or distributors (except to the extent necessary to respond truthfully to any inquiry from applicable regulatory authorities or to provide information pursuant to legal process). In the event that Radak is to start employment with another company prior to July 31, 2012, he shall promptly notify Company as to the start date of such new employment.

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6. Vesting of Equity Awards . The vesting of equity awards (restricted stock and options) held by Radak shall not be accelerated. Such equity awards shall, during Radak’s continuing employment, continue to vest through the End Date and be governed in accordance with the Company’s applicable equity incentive plans and specific equity award grant documentation. All equity awards held by Radak at the time of the termination of his employment shall also be handled in accordance with the Company’s applicable equity incentive plans and grant documentation.

7. Termination by the Company . In the event that Radak is terminated by the Company with “Cause” (as defined below), Radak shall not be entitled to the payments, benefits or vesting of equity described in Sections 3 or Section 6 hereof, but shall only be entitled to salary, accrued benefits and other amounts legally owing to Radak through the date of employment termination. The Company shall thereafter have no further obligations to Radak under this Agreement.

In the event that Radak is terminated by the Company without “Cause” (as defined below), provided that Radak executes and delivers to the Company within 21 calendar days after such termination (and thereafter does not revoke) a Release in the form attached hereto as Exhibit A , Radak shall be entitled to receive the following severance payments and benefits: (i) a lump-sum payment equal to the remaining amount of base salary that Radak would have received if the term of this Agreement had continued until July 31, 2012, less applicable taxes and withholdings, payable within thirty (30) days from the date of termination, (ii) the employee benefits described in the second and third paragraph of Section 3 hereof through July 31 2012, and (iii) the vesting of equity awards, as and to the extent described in and contemplated by Section 6 hereof, as though Radak’s employment continued through July 31, 2012.

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For purposes hereof, “Cause” shall be limited to the following: (1) fraud; (2) personal dishonesty involving money or property of the Company or that results in material harm to the Company; (3) Radak’s willful misconduct that is injurious to the Company; (4) a serious breach of a fiduciary duty to the Company involving personal profit; (5) Radak’s conviction for a felony (including via a guilty or nolo contendere plea), excluding traffic offenses; (6) Radak’s willful and continued neglect of duties (other than any such failure resulting from his incapacity because of physical or mental illness); or (7) Radak’s material breach of this Agreement; provided, however, that unsatisfactory job performance shall not be considered Cause for termination of Radak’s employment by the Company. Radak shall be afforded a reasonable opportunity of up to 30 days (as of and upon written notice from the Company) to cure any willful neglect of his duties and any other alleged material breach of this Agreement if such breach is reasonably susceptible of cure. If, in the reasonable good faith judgment of the Company, the alleged breach is not reasonably susceptible of cure, or such circumstances or material breach has not satisfactorily been cured within such thirty (30) day period, such neglect of duties or material breach shall thereupon constitute “Cause.”

8. Confidentiality of Business and Legal Information . Radak acknowledges that the Company holds as confidential and/or privileged certain information (including, but not limited to, non-public information obtained by Radak in his position as an officer of the Company), as well as certain trade secret information and knowledge concerning the intimate and confidential affairs of the Company and the various phases of its business, including, for example and without limitation, processes, formulae, data and know-how, improvements, inventions, techniques, marketing plans, strategies, forecasts, mailing lists, customer lists, pricing information, manufacturing processes, distribution systems, computer systems or programs and other types of similar information within Radak’s knowledge by virtue of his employment with the Company (collectively, the foregoing shall be referred to herein as “ Confidential Trade Secret, Proprietary and Legal Information ”). Radak agrees that all Confidential Trade Secret, Proprietary and Legal Information shall be the sole property of the Company and that the Company shall be and is the sole owner of all patents and other rights in connection therewith as well as any privileges. Radak further agrees to hold in strictest confidence and to refrain from using or disclosing to any other person or entity any Confidential Trade Secret, Proprietary and Legal Information, other than the Company, its employees, Directors and representatives. In that regard, Radak expressly acknowledges that he has not disclosed (other than to the Company, its employees, Directors and representatives) any Confidential Trade Secret, Proprietary and Legal Information. Radak specifically agrees that he will not disclose any Confidential Trade Secret, Proprietary and Legal Information at any time in the future (other than to the Company, its employees, Directors and representatives). Radak further represents and warrants that, on the last day of his employment, he will have returned to the Company all property and documents of the Company, whether kept electronically or in hard copy form and will have retained no copies thereof. This Section supplements the obligations of Radak contained in Section 5 hereof.

9. Entire Agreement

This Transition Agreement sets forth the entire agreement between the parties hereto and, except for the Confidentiality Agreement and the Indemnification Agreement between Radak and the Company, fully supersedes any and all prior agreements or understandings between the parties pertaining to the subject matter hereof. For the avoidance of doubt, the December 13,

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2006 Employment Offer Letter, as amended (the “Offer Letter”) and the Agreement Re: Change in Control between the Company and Radak entered into on December 18, 2006, as amended (the “CIC Agreement”), shall automatically expire as of the date of this Transition Agreement (after which the Offer Letter and CIC Agreement will be of no force or effect), and except as expressly provided in this Transition Agreement, Radak shall not be entitled to any payments or benefits of any kind in connection with a termination or resignation for any reason. The parties agree that no amendment or modification of this Transition Agreement shall be effective unless it is in writing signed by both parties.

10. Miscellaneous .

a. Notices . Any notice required or permitted to be given under this Agreement shall be sufficient if in writing and delivered in person or sent by registered or certified mail to Radak’s residence in the case of Radak or to its principal office in the case of the Company.

b. Arbitration . Any dispute arising out of this Agreement shall be resolved exclusively by final and binding arbitration, before a single arbitrator, in San Diego, California pursuant to the rules of JAMS. Judgment upon any such arbitration award may be entered by any state or federal court of competent jurisdiction. In the event any party to this Agreement initiates any arbitration action or proceeding in connection with enforcement of this Agreement, the prevailing party in such action or proceeding shall be entitled to recover its costs and attorney’s fees from the non-prevailing party.

c. Waiver . The waiver of any provision of this Agreement shall not operate or be construed as a waiver of any other provision of this Agreement. No waiver shall be valid unless in writing and executed by the party to be charged therewith.

d. Severability/Modification . In the event that any clause or provision of this Agreement shall be determined to be invalid, illegal or unenforceable, such clause or provision may be severed or modified to the extent necessary, and, as severed and/or modified, this Agreement shall remain in full force and effect.

e. Assignment . This Agreement may not be assigned by Radak. The rights and obligations of the Company under this Agreement shall inure to the benefit of and shall be binding upon the successors and assigns of the Company.

f. Governing Law and Jurisdiction . This Agreement shall be interpreted, construed, and enforced under the internal laws of the State of California. The courts and authorities of the State of California shall have sole jurisdiction and venue for purposes of enforcing the arbitration agreement above.

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g. Counterparts . This Agreement may be executed in two or more counterparts, each of which shall be deemed an original, but all of which together constitute one in the same Agreement.

IN WITNESS WHEREOF, the parties have executed and delivered this Agreement as of the date first written above.

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EXHIBIT A

GENERAL RELEASE

In consideration of the Transition Agreement by Quidel Corporation (the “Company”) and John Radak (“Radak”), Radak hereby gives the following General Release which will be effective 8 days after he signs and does not revoke it.

1. Release of Claims . Radak hereby irrevocably and unconditionally releases, acquits and forever discharges the Company, its affiliated companies and the Releasees (as defined below) from any and all charges, complaints, claims, liabilities, obligations, promises, agreements, controversies, damages, actions, causes of action, suits, rights, demands, remedies, costs, losses, debts, expenses and attorneys’ fees, including those arising out of or in connection with Radak’s employment with and/or consulting for the Company and/or the termination thereof. (All such charges, complaints, etc. are collectively referred to herein as “Claims.”) The Claims irrevocably and unconditionally released, acquitted and forever discharged include, for example and without limitation, Claims arising under the federal Age Discrimination in Employment Act of 1967, Title VII of the Civil Rights Act of 1964, the Civil Rights Act of 1866, the Americans With Disabilities Act, the California Fair Employment and Housing Act, the California Labor Code, claims under any state, federal and local statutes, claims for employment discrimination, tort claims and common law employment and wrongful discharge claims.

The Claims irrevocably and unconditionally released, acquitted and forever discharged by Radak extend to all such Claims by Radak against any and all of the current and former owners, stockholders, predecessors, successors, assigns, agents, directors, officers, employees, representatives, attorneys, divisions, parents, subsidiaries, affiliates (and the directors, officers, employees, representatives and attorneys of such divisions, parents, subsidiaries and affiliates) of the Company and all other persons acting by, through, under or in concert with any of them. All such persons and entities, as well as the Company, are collectively referred to herein as the “Releasees”. The Claims irrevocably and unconditionally released, acquitted and forever discharged herein by Radak also extend to all Claims which Radak now has, owns or holds, or contends to have, own or hold or which Radak at any time heretofore had, owned or held or contended to hold against any of the Releasees. Radak represents that he has not heretofore assigned or transferred or purported to have assigned or transferred to any person or entity any Claims released, acquitted and forever discharged herein. This General Release (a) shall not affect any Claims that Radak may have which arise solely after the effective date of this General Release, (b) shall not apply to any of the Company’s obligations under the Transition Agreement dated as of                      ,              (the “Agreement”), (c) shall not apply to any of Radak’s rights to vested benefits such as 401(k), and (d) shall not serve as a release of any claims that cannot be released as a matter of law, including, but not limited to, indemnification as required by law.

2. Release of Unknown and Unsuspected Claims . For the purpose of implementing a full and complete release and discharge of the Releasees, Radak expressly acknowledges that this General Release is intended to include in its effect, without limitation, all Claims (as defined above) which Radak does not know or suspect to exist in his favor at the time of execution

hereof, and this General Release contemplates the extinguishment of any and all such Claims. In this regard, Radak expressly waives the provisions of Section 1542 of the California Civil Code, which state:

A GENERAL RELEASE DOES NOT EXTEND TO CLAIMS WHICH THE CREDITOR DOES NOT KNOW OR SUSPECT TO EXIST IN HIS/HER FAVOR AT THE TIME OF EXECUTING THE RELEASE, WHICH IF KNOWN BY HIM/HER MUST HAVE MATERIALLY AFFECTED HIS/HER SETTLEMENT WITH THE DEBTOR.

Furthermore, Radak hereby expressly waives and relinquishes any rights and benefits he may have under other statutes or common law principles of similar effect. Radak understands that the facts under which he gives this full and complete release and discharge of the Releasees may hereafter prove to be different than now known or believed by him and Radak hereby accepts and assumes the risk thereof and agrees that his full and complete release and discharge of Releasees shall remain effective in all respects and not be subject to termination, rescission or modification by reason of any such difference in facts.

3. No Complaint, Charge or Lawsuit Pending . Radak represents that he has not filed with any governmental agency or court any complaint, charge or lawsuit against any of the Releasees involving any Claims released herein, and that, except as otherwise permitted by law, he will not do so at any time hereafter; provided, however, nothing in this General Release shall limit Radak from filing an action for the purpose of enforcing his rights under the Agreement or from filing a charge or complaint of discrimination with the EEOC.

4. Severability . The provisions of this General Release are severable, and if any part of this General Release is found unenforceable, invalid or illegal, the other parts of this General Release shall remain fully valid and enforceable.

5. Governing Law . This General Release and any dispute concerning the validity, interpretation or breach of any term or condition hereof shall be construed and interpreted under and in conformance with the laws of the State of California applicable to contracts negotiated and to be fully performed in the State of California.

6. Arbitration . Any dispute concerning the validity, interpretation or breach of this General Release or any term or condition hereof or any dispute concerning the Claims released herein shall be resolved exclusively by final and binding arbitration as provided in Section 11(b) of the Agreement. Judgment upon any such arbitration award may be entered by any state or federal court of competent jurisdiction. This General Release shall be admissible in any proceeding to enforce its terms.

7. Construction . Radak has had ample opportunity to make suggestions or changes to the terms and language of this General Release and agrees that principles of contract construction against the drafter shall have no application hereto. Radak agrees that this General Release should be construed fairly and not in favor of or against Radak or the Company as the drafter.

8. Waiting Period and Right of Revocation . Radak understands that this General Release releases any and all Claims for age discrimination, whether under state or federal law. Radak understands that pursuant to federal law, Radak has the right to review this General Release for 21 days before executing the same, and that Radak has the right to revoke this General Release in its entirety at any time within seven days after executing the same and that this General Release will not be effective until such seven day revocation period has expired. Radak acknowledges his right to consult with an attorney prior to signing this General Release, and that he has been advised to consult with an attorney prior to such signing.

9. Full Understanding of Terms . Radak represents and agrees that he fully understands his right to discuss all aspects of this General Release with his private attorney; that to the extent, if any, he desires, he has availed himself of this right; that he has carefully read and fully understands all of the provisions of this General Release; and that he is voluntarily entering into it.

Dated:                      ,