QUEST DIAGNOSTICS SUPPLEMENTAL DEFERRED COMPENSATION PLAN

Exhibit 10.25

QUEST DIAGNOSTICS

SUPPLEMENTAL DEFERRED COMPENSATION PLAN

(PRE – 2005)

AMENDED DECEMBER 30, 2008

PREAMBLE

Effective as of January 1, 1999, Quest Diagnostics adopted this Quest Diagnostics Supplemental Deferred Compensation Plan for the benefit of certain of its Employees. As a result of the enactment in 2004 of Section 409A of the Internal Revenue Code of 1986, as amended from time to time (the “ Code ”), Quest Diagnostics adopted the Quest Diagnostics Supplemental Deferred Compensation Plan (Post-2004) document to reflect the terms that will govern amounts that were deferred (within the meaning of Treas. Reg. §1.409A-6(a)(1)) under the Plan in taxable years beginning on and after January 1, 2005. Quest Diagnostics hereby desires to amend the Plan document to evidence the intention that, with limited exceptions, amounts that were deferred (within the meaning of Treas. Reg. §1.409A-6(a)(1)) under the Plan in taxable years beginning before January 1, 2005 will be governed by the terms of the Plan as in effect as of October 3, 2004 and that Section 409A will not be applicable to such amounts (including any earnings thereon) and adopts this document, the Quest Diagnostics Supplemental Deferred Compensation Plan (Pre – 2005) for that purpose. Unless otherwise expressly determined by Quest Diagnostics, it is the intent that no amendment to this document be considered a “material modification” within the meaning of Treas. Reg. 1.409A-6(a)(4).

For these purposes, an amount is considered deferred before January 1, 2005, if before such date, the employee had a legally binding right to be paid the amount (within the meaning of Treas. Reg. §1.409A-1(b)(1)), and the right to the amount was earned and vested (within the meaning of Treas. Reg. §1.409A-6(a)).

The purpose of the Plan is to provide supplemental retirement income and to permit eligible Employees the option to defer receipt of Compensation, pursuant to the terms of the Plan. The Plan is intended to be an unfunded deferred compensation plan maintained for the benefit of a select group of management or highly compensated employees under sections 201(2), 301(a)(3) and 401(a)(1) of ERISA and therefore to be exempt from Parts 2, 3 and 4 of Subtitle B of Title I of ERISA to the maximum extent permissible under the provisions thereof.

TABLE OF CONTENTS

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1.1 Definitions . Pronouns used in the Plan are in the masculine gender but include the feminine gender unless the context clearly indicates otherwise. Wherever used herein, the following terms have the meanings set forth below, unless a different meaning is clearly required by the context:

(a) “Account” means an account established on the books of a Participant’s Employer for the purpose of recording Deferral Contributions and Employer Contributions credited on behalf of a Participant in respect of compensation for services to such Employer and any notional income, expenses, gains or losses related thereto. For each Participant who was a participant in the MetPath Inc. Deferred Compensation Plan, a MetPath Plan Subaccount was established as part of the Participant’s Account. For purposes of this Plan document, “Account” shall include only amounts that are deferred within the meaning of Treas. Reg. §1.409A-6(a)(1)) during taxable years before January 1, 2005. An amount is considered deferred before January 1, 2005, if before such date, the Participant had a legally binding right to be paid the amount (within the meaning of Treas. Reg. §1.409A-1(b)(1)), and the right to the amount was earned and vested (within the meaning of Treas. Reg. §1.409A-6(a)).

(b) “Administrator” means Quest Diagnostics acting through its officers and employees.

(c) “Appeals Committee” means the Quest Diagnostics Appeals Committee, which is designated from time to time by the Administrator to administer the claims and review procedures specified in Section 11.2.

(d) “Beneficiary” means the person or persons entitled under Section 6.2 to receive benefits under the Plan upon the death of a Participant.

(e) “Bonus” means the cash bonus that is payable each March (if not deferred pursuant to Section 3.1) under the Senior Management Incentive Plan or the Quest Diagnostics Incorporated Management Incentive Plan.

(f) “Code” means the Internal Revenue Code of 1986, as amended from time to time.

(g) “Compensation” shall have the meaning ascribed to the term “Deferral Compensation” by the Profit Sharing Plan; provided that any exclusion attributable to (i) deferred compensation deferred pursuant to this Plan or (ii) limits imposed by Code Section 401(a)(17) shall not apply.

(h) “Deferral Contributions” means those amounts credited to a Participant’s Account pursuant to Section 3.1.

(i) “Eligible Employee” means an Employee of an Employer who is determined by the Administrator to be among a select group of management or highly compensated Employees and who is designated by the Administrator as an Eligible Employee for purposes of the Plan.

(j) “Employee” means any employee of an Employer.

(k) “Employer” means Quest Diagnostics and any successors and assigns unless otherwise provided herein, and shall include any Related Employer or other affiliated employer adopting this Plan.

(l) “Employer Contributions” means amounts credited to a Participant’s Account pursuant to Section 3.2.

(m) “Employer Stock” means any class of common stock of Quest Diagnostics or the preferred stock of Quest Diagnostics that is convertible into common stock.

(n) “ERISA” means the Employee Retirement Income Security Act of 1974, as from time to time amended.

(o) “MetPath Plan Subaccount” means the subaccount established and maintained by the Administrator pursuant to Section 4.1 on behalf of each Participant who was a participant in the MetPath Inc. Deferred Compensation Plan.

(p) “Participant” means any Eligible Employee who has filed in accordance with Article 2 an election to defer Compensation pursuant to Section 3.1.

(q) “Plan” means this Quest Diagnostics Supplemental Deferred Compensation Plan as in effect from time to time.

(r) “Plan Year” means the calendar year.

(s) “Profit Sharing Plan” means the Profit Sharing Plan of Quest Diagnostics Incorporated, as amended from time to time.

(t) “Quest Diagnostics” means Quest Diagnostics Incorporated.

(u) “Related Employer” means any employer other than Quest Diagnostics, if Quest Diagnostics and such other employer are members of a controlled group of corporations (as defined in Section 414(b) of the Code) or an affiliated service group (as defined in Code Section 414(m)), or are trades or businesses (whether or not incorporated) which are under common control (as defined in Section 414(c)), or such other employer is required to be aggregated with Quest Diagnostics pursuant to regulations issued under Code Section 414(o).

(v) “Section 16 Executive” means an Eligible Employee who is designated as such by the Administrator.

(w) “Section 401(a)(17) Limit” means the maximum amount of annual compensation that can be taken into account by the Profit Sharing Plan pursuant to Code Section 401(a)(17).

(x) “Senior Executive” means an Eligible Employee who is designated as such by the Administrator.

(y) “Senior Management Incentive Plan” means the Quest Diagnostics Incorporated Senior Management Incentive Plan, as in effect from time to time.

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(z) “SMIP Bonus Subaccount” means the portion of a Participant’s Account established and maintained by the Administrator on behalf of each Participant who elects to defer a portion of his Bonus payable under the Senior Management Incentive Plan and any other plan intended to pay performance-based compensation within the meaning of Code Section 162(m)(4)(c).

(aa) “Supplemental Contribution” means an additional discretionary Employer Contribution credited to a Participant’s Account pursuant to Section 3.2.

(bb) “Trust” means the trust fund established pursuant to the terms of the Plan.

(cc) “Trust Agreement” means the agreement by and among the Trustee and each Employer establishing the Trust.

(dd) “Trustee” means the corporation or individuals named in the agreement establishing the Trust and such successor and/or additional trustees as may be named in accordance with the Trust Agreement.

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2.1 Participation . Each Eligible Employee who has an Account is a Participant covered under this Plan document. No other Eligible Employee shall become a Participant covered under this Plan document after December 31, 2004. An election to defer Compensation will be timely if it is filed in accordance with procedures established by the Administrator which shall require elections to be filed no later than January 1 of the Plan Year to which the deferral election applies or, if an individual is designated by the Administrator as an Eligible Employee during the Plan Year, within 30 days following the date of such designation.

2.2 Resumption of Participation Following Reemployment . If a Participant ceases to be an Employee and thereafter returns to the employ of an Employer before December 31, 2004, he may again become a Participant following his reemployment, provided he is an Eligible Employee and has timely filed an election to defer Compensation pursuant to Section 3.1.

2.3 Change in Employment Status . If any Participant continues in the employ of an Employer but ceases to be an Eligible Employee, he shall continue to be a Participant until the entire amount of the value of his Account is paid.

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3.1 Deferral Contributions .

(a) Participant deferral elections . Each Participant who is not a Senior Executive may elect to defer up to fifty (50) percent (in whole percentages) of his future Compensation in excess of the Section 401(a)(17) Limit.

(b) Senior Executive deferral elections . Each Participant who is a Senior Executive may elect to defer (1) up to fifty (50) percent (in whole percentages) of his future Compensation (excluding any Bonus deferred pursuant to Section 3.1(b)(2)) in excess of the Section 401(a)(17) Limit; and (2) up to ninety-five (95) percent (in whole percentages) of his future Compensation which constitutes Bonus.

(c) Effectiveness of deferral election . A deferral election shall become effective on the first day of the Plan Year (or for an individual who is designated as an Eligible Employee during the Plan Year and timely files a deferral election, the first day of the first payroll period that follows receipt by the Administrator of such election). The election will be effective to defer Compensation relating to all services performed in the Plan Year subsequent to the time such election becomes effective. Any subsequent election will be effective as of the first day of the following Plan Year and will apply only to Compensation payable with respect to services rendered after such date. Amounts credited to a Participant’s Account prior to the effective date of any subsequent election will not be affected by such subsequent election.

(d) Commencement of deferrals . (i) Deferrals made pursuant to Section 3.1(a) and 3.1(b)(1) . If a Participant’s Compensation for a Plan Year exceeds the Section 401(a)(17) Limit on account of payment of Compensation (excluding any Bonus), then deferrals pursuant to his election under Section 3.1(a) or 3.1(b)(1) shall commence as of the payroll period coincident with or next following the payroll period in which the Participant’s Compensation exceeds the Section 401(a)(17) Limit (but deferrals shall be made only on Compensation in excess of the Section 401(a)(17) Limit). If a Participant’s Compensation for a Plan Year exceeds the Section 401(a)(17) Limit on account of payment of Bonus, then deferrals pursuant to his election shall commence as of the payroll period in which the Participant’s Compensation exceeds the Section 401(a)(17) Limit (but deferrals shall be made only on Compensation in excess of the Section 401(a)(17) Limit). (ii) Deferrals made pursuant to Section 3.1(b)(2) . Deferrals of Bonus pursuant to Section 3.1(b)(2) shall be made in the payroll period in which the Bonus would otherwise be paid.

(e) Election irrevocable except as required pursuant to Profit Sharing Plan . An Employer shall credit to the Account maintained on behalf of a Participant the amount of Compensation deferred pursuant to such Participant’s election. Under no circumstances may an election to defer Compensation be adopted or effective retroactively. A Participant may not revoke or change an election to defer Compensation for a Plan Year during that year; provided, however, that a Participant who has made a hardship withdrawal under the Profit Sharing Plan may not defer Compensation under this Plan for a period of six months from the date of the withdrawal, unless otherwise determined by the Administrator.

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(f) SMIP Bonus Subaccount . A Participant’s Employer shall credit to the Participant’s SMIP Bonus Subaccount an amount corresponding to the amount of Bonus payable under the Senior Management Incentive Plan deferred pursuant to Section 3.1(b)(2).

(g) Vested Right . Subject to the claims of the Employer’s creditors in the event of the Employer’s insolvency, a Participant shall have a nonforfeitable right to the value of Deferral Contributions credited to his Account.

(h) No Deferral Contributions after 2004 . All Deferral Contributions made after 2004 and attributable to periods after 2004 shall be governed by the terms of the Quest Diagnostics Supplemental Deferred Compensation Plan (Post – 2004).

3.2 Participating Employer Contributions .

(a) Employer Contributions . (i) Matching Contribution . An Employer shall credit an Employer Contribution to the Account maintained on behalf of each Participant who had Deferral Contributions credited to his Account for a payroll period. Notwithstanding the preceding sentence, no Employer Contribution shall be credited to the Account of a Participant who is also a participant in the Quest Diagnostics Transferee Pension Plan for former Corning Incorporated employees. The amount of the Employer Contribution to be credited on behalf of a Participant shall be equal to the applicable percentage specified from time to time in Section 3.2 of the Profit Sharing Plan of the Deferral Contributions made on behalf of the Participant with respect to such payroll period. (ii) Vested Right . Subject to the claims of the Employer’s creditors in the event of the Employer’s insolvency, a Participant shall have a nonforfeitable right to the value of Employer Contributions credited to his Account.

(b) Supplemental Contributions . In addition, a Participant’s Employer may, from time to time in its sole discretion, credit a Supplemental Contribution to a Participant’s Account in an amount determined by such Employer in its sole discretion and without regard to any Deferral Contribution elected by such Participant. Unless otherwise specified by the Employer at the time the Supplemental Contribution is made, a Participant shall have a nonforfeitable right to the value of such Supplemental Contribution credited to his Account, subject to the claims of such Employer’s creditors in the