Exhibit 10.1 FIRST AMENDMENT TO CREDIT AGREEMENT This FIRST AMENDMENT TO CREDIT AGREEMENT (this "Amendment") is entered into as of September 20, 2002 among QUEST DIAGNOSTICS INCORPORATED, a Delaware corporation (the "Borrower"), certain Subsidiaries of the Borrower as Guarantors, the Lenders party hereto and BANK OF AMERICA, N.A., as Administrative Agent for the Lenders (the "Administrative Agent"). Capitalized terms used herein and not otherwise defined shall have the meanings set forth in the Credit Agreement (as defined below). RECITALS WHEREAS, the Borrower, the Guarantors, the Lenders and the Administrative Agent entered into that certain Credit Agreement dated as of June 21, 2002 (as amended hereby and as the same may hereafter be further amended, modified or supplemented, the "Credit Agreement"); WHEREAS, the Credit Parties are requesting that the Lenders amend certain terms of the Credit Agreement in order to extend the Maturity Date; and WHEREAS, the Lenders have agreed to amend certain terms of the Credit Agreement in order to extend the Maturity Date, subject to the conditions set forth below. NOW THEREFORE, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto agree as follows: AGREEMENT 1. Amendment to Credit Agreement. (a) Section 1.1. The definition of "Maturity Date" set forth in Section 1.1 of the Credit Agreement is hereby amended and restated in its entirety to read as follows: "Maturity Date" means (i) December 31, 2002 if the Unilab Acquisition is not consummated on or prior to such date or (ii) June 21, 2007 if the Unilab Acquisition is consummated on or prior to December 31, 2002. (b) Section 3.4. Section 3.4 of the Credit Agreement is hereby amended by adding the following two sentences at the end of such Section to read as follows: The Borrower agrees to pay to the Administrative Agent, for the account of the Lenders on a pro rata basis based on their Term Loan Commitment Percentage, a ticking fee equal to 0.25% per annum (the "Ticking Fee") calculated on the then applicable Term Loan Committed Amount (giving effect to any reduction thereof pursuant to Section 2.1(d)). The Ticking Fee shall accrue daily from October 1, 2002 to the earlier of the Funding Date or the Maturity Date and shall be payable monthly in arrears on the last Business Day of each month and on the Funding Date or the Maturity Date, as applicable. 2. Effectiveness; Conditions Precedent. This Amendment shall be deemed to have become effective as of the date above written upon receipt by the Administrative Agent of copies of this Amendment duly executed by the Credit Parties and the Lenders. 3. Ratification of Credit Agreement. The term "Credit Agreement" as used in each of the Credit Documents shall hereafter mean the Credit Agreement as amended and modified by this Amendment. Except as herein specifically agreed, the Credit Agreement, as amended by this Amendment, is hereby ratified and confirmed and shall remain in full force and effect according to its terms. The Credit Parties acknowledge and consent to the modifications set forth herein and agree that this Amendment does not impair, reduce or limit any of their obligations under the Credit Documents (including, without limitation, the indemnity obligations set forth therein) and that this Amendment shall constitute a Credit Document. Notwithstanding anything herein to the contrary and without limiting the foregoing, each of the Guarantors reaffirms its guaranty obligations set forth in the Credit Agreement. 4. Authority/Enforceability. Each of the Credit Parties represents and warrants as follows: (a) It has taken all necessary action to authorize the execution, delivery and performance of this Amendment. (b) This Amendment has been duly executed and delivered by such Person and constitutes such Person's legal, valid and binding obligations, enforceable in accordance with its terms, except as such enforceability may be subject to (i) bankruptcy, insolvency, reorganization, fraudulent conveyance or transfer, moratorium or similar laws affecting creditors' rights generally and (ii) general principles of equity (regardless of whether such enforceability is considered in a proceeding at law or in equity). (c) No consent, approval, authorization or order of, or filing, registration or qualification with, any court or governmental authority or third party is required in connection with the execution, delivery or performance by such Person of this Amendment. (d) The execution and delivery of this Amendment does not violate, contravene or conflict with any Requirement of Law applicable to it or any of its Subsidiaries. 5. No Default. The Credit Parties represent and warrant to the Lenders that after giving effect to this Amendment (a) the representations and warranties of the Credit Parties set forth in Section 6 of the Credit Agreement are true and correct as of the date hereof and (b) no event has occurred and is continuing which constitutes a Default or an Event of Default. 2 6. Release. In consideration of entering into this Amendment, each of the Credit Parties releases the Agents, the Lenders, and each Agent's and each Lender's respective Affiliates, Subsidiaries, officers, employees, representatives, agents, counsel and directors from any and all actions, causes of action, claims, demands, damages and liabilities of whatever kind or nature, in law or in equity, now known or unknown, suspected or unsuspected to the extent that any of the foregoing arises from any action or failure to act with respect to the Credit Agreement or the other Credit Documents on or prior to the date hereof. 7. Counterparts/Telecopy. This Amendment may be executed in any number of counterparts, each of which when so executed and delivered shall be an original, but all of which shall constitute one and the same instrument. Delivery of executed counterparts of this Amendment by telecopy shall be effective as an original and shall constitute a representation that an original shall be delivered promptly upon request. 8. Entirety. This Amendment and the other Credit Documents embody the entire agreement between the parties hereto and supersede all prior agreements and understandings, oral or written, if any, relating to the subject matter hereof. 9. GOVERNING LAW. THIS AMENDMENT AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES HEREUNDER SHALL BE GOVERNED BY AND CONSTRUED AND INTERPRETED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK. 10. Venue; Jurisdiction; Waivers. The venue, jurisdiction, waiver of jury trial and waiver of consequential damages provisions set forth in Sections 11.11 and 11.12 of the Credit Agreement are hereby incorporated by reference, mutatis mutandis. [remainder of page intentionally left blank] 3 Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement IN WITNESS WHEREOF, each of the parties hereto has caused a counterpart of this Amendment to be duly executed and delivered and this Amendment shall be effective as of the date first above written. BORROWER: QUEST DIAGNOSTICS INCORPORATED, A Delaware corporation By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- GUARANTORS: QUEST DIAGNOSTICS HOLDINGS INCORPORATED, a Delaware corporation QUEST DIAGNOSTICS CLINICAL LABORATORIES, INC., a Delaware corporation QUEST DIAGNOSTICS INCORPORATED, a California corporation QUEST DIAGNOSTICS INCORPORATED, a Maryland corporation QUEST DIAGNOSTICS INCORPORATED, a Michigan corporation QUEST DIAGNOSTICS OF PENNSYLVANIA, INC., a Delaware corporation METWEST, INC., a Delaware corporation NICHOLS INSTITUTE DIAGNOSTICS, a California corporation DPD HOLDINGS, INC., a Delaware corporation DIAGNOSTICS REFERENCE SERVICES INC., a Maryland corporation Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement AMERICAN MEDICAL LABORATORIES, INCORPORATED, a Delaware corporation AML INC., a Delaware corporation QUEST DIAGNOSTICS INCORPORATED (NV), a Nevada corporation MEDICAL LABORATORIES CORPORATION d/b/a American Medical Laboratories, a Virginia corporation QUEST DIAGNOSTICS LLC, an Illinois limited liability company QUEST DIAGNOSTICS LLC, a Connecticut limited liability company QUEST DIAGNOSTICS LLC, a Massachusetts limited liability company APL PROPERTIES, LLC, a Nevada limited liability company By: ------------------------------------ Name: Joseph P. Manory Title: Vice President and Treasurer PATHOLOGY BUILDING PARTNERSHIP, a Delaware general partnership By: Quest Diagnostics Incorporated, a Maryland corporation, its general partner By: -------------------------------- Name: Joseph P. Manory Title: Vice President and Treasurer Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement LENDERS: BANK OF AMERICA, N.A., individually in its capacity as a Lender and in its capacity as Administrative Agent By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement ALLFIRST BANK By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement BANK HAPOALIM B.M. By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement THE GOVERNOR & COMPANY OF THE BANK OF IRELAND By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement BANK LEUMI USA By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement THE BANK OF NEW YORK By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement BANK ONE, NA (MAIN OFFICE CHICAGO) By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement BAYERISCHE HYPO- UND VEREINSBANK AG, NEW YORK BRANCH By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement BNP PARIBAS By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement CHANG HWA COMMERCIAL BANK, LTD., NEW YORK BRANCH By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement CHINATRUST COMMERCIAL BANK, LTD., NEW YORK BRANCH By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement CREDIT LYONNAIS NEW YORK BRANCH By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement DEUTSCHE BANK AG, NEW YORK BRANCH By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement E. SUN COMMERCIAL BANK, LTD., LOS ANGELES BRANCH By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement FLEET NATIONAL BANK By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement GENERAL ELECTRIC CAPITAL CORPORATION By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement KEY CORPORATE CAPITAL INC. By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement LASALLE BANK NATIONAL ASSOCIATION By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement MERRILL LYNCH CAPITAL CORPORATION By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement MIZUHO CORPORATE BANK, LTD. By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement NATIONAL CITY BANK By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement THE NORINCHUKIN BANK, NEW YORK BRANCH By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement PB CAPITAL CORPORATION By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement PNC BANK, NATIONAL ASSOCIATION By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement SUMITOMO MITSUI BANKING CORPORATION By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement SUNTRUST BANK By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement UNION BANK OF CALIFORNIA, N.A. By: ------------------------------------ Name: ---------------------------------- Title: --------------------------------- Signature Page to First Amendment to Quest Diagnostics Incorporated Credit Agreement WACHOVIA BANK, NATIONAL ASSOCIATION By: ------------------------------------ Name: ---------------------------------- Title: ---------------------------------