Exhibit 10.14
                                                                 
                          AMENDMENT dated as of November 21, 1997, to the Credit
                  Agreement dated as of December 5, 1996, among QUEST
                  DIAGNOSTICS INCORPORATED (formerly known as Corning Clinical
                  Laboratories Inc.), the BANKS listed on the signature pages
                  thereof, NATIONSBANK, N.A., as Issuing Bank, WACHOVIA BANK OF
                  GEORGIA, N.A., as Swingline Bank, MORGAN GUARANTY TRUST
                  COMPANY OF NEW YORK, as Administrative Agent, and MORGAN
                  GUARANTY TRUST COMPANY OF NEW YORK, NATIONSBANK, N.A. and
                  WACHOVIA BANK OF GEORGIA, N.A., as Arranging Agents.


        WHEREAS, the Borrower has requested that the Banks agree to amend the
Credit Agreement as set forth herein;

        Accordingly, in consideration of the mutual agreements herein contained
and other good and valuable consideration, the sufficiency and receipt of which
are hereby acknowledged, the parties hereto agree as follows:

        SECTION 1. Definitions; References. Unless otherwise specifically
defined herein, each capitalized term used herein which is defined in the Credit
Agreement shall have the meaning assigned to such term in the Credit Agreement.
Each reference to "hereof", "hereunder", "herein" and "hereby" and each other
similar reference and each reference to "this Agreement" and each other similar
reference contained in the Credit Agreement shall from and after the Amendment
Effective Date (as defined below) refer to the Credit Agreement as amended
hereby.

        SECTION 2.  Amendment to Section 1.01 of the Credit Agreement.

(a) The definition of the term "Consolidated EBITDA" is hereby amended by adding
at the end thereof "and any Excluded Charges for such period.

(b) The definition of the term "Debt Coverage Ratio" is hereby amended by adding
at the end thereof the following proviso: "; provided that, solely for the
purposes of determining compliance with Section 5.19 (and not for purposes of
determining Pricing Periods), the amount of Consolidated Total Debt determined
pursuant



to clause (i) above at any time shall be reduced by the aggregate amount of cash
and cash equivalents held by the Borrower and its Consolidated Subsidiaries at
such time (but the amount of such reduction pursuant to this proviso shall not
at any time exceed $100,000,000)."

(c) Section 1.01 is hereby further amended by the addition of the following
definition in the appropriate alphabetical order:

        "Excluded Charges" means nonrecurring charges of the Borrower and its
Consolidated Subsidiaries taken during the fiscal year ending December 31, 1997
and the fiscal year ending December 31, 1998, not exceeding, in the aggregate
for all such periods, $68,000,000.

        SECTION 3. Amendment to Section 4.04(d) of the Credit Agreement. Section
4.04(d) of the Credit Agreement is hereby amended by inserting, immediately
after the words "it is understood that" at the beginning of the proviso thereto,
the words "the Excluded Charges and".

        SECTION 4. Amendment to Section 5.18 of the Credit Agreement. Section
5.18 of the Credit Agreement is hereby amended by replacing the table therein
with the following table:

Period                                                           Ratio

Effective Date through December 31, 1998                         0.55 to 1.00

January 1, 1999 through December 31, 1999                        0.50 to 1.00

January 1, 2000 and thereafter                                   0.45 to 1.00

        SECTION 5. Amendment to Section 5.20 of the Credit Agreement. Section
5.20 of the Credit Agreement is hereby amended by replacing the table therein
with the following table:

        Calculation Period Ending During the Period              Ratio

        Effective Date through June 30, 1997                     1.80 to 1.00

        July 1, 1997 through December 31, 1998                   2.00 to 1.00

        January 1, 1999 through December 31, 1999                2.25 to 1.00




        January 1, 2000 through December 31, 2000                2.75 to 1.00

        January 1, 2001 and thereafter                           3.00 to 1.00

        SECTION 6.  [Omitted]

        SECTION 7. Representations and Warranties. The Borrower represents and
warrants to each of the Banks that:

        (a) The representations and warranties set forth in the Loan Documents
after giving effect to this Amendment are true and correct in all material
respects with the same effect as if made on the date hereof, except to the
extent such representations and warranties expressly relate to an earlier date.

        (b) After giving effect to this Amendment, the Borrower is in compliance
in all material respects with all the terms and provisions contained in the
Credit Agreement and in the other Loan Documents required to be observed or
performed.

        (c) After giving effect to this Amendment, no Default has occurred and
is continuing.

        SECTION 8. Amendment Fee. The Borrower agrees to pay to the Agent, for
the account of each Bank that executes and delivers to the Agent (or its
counsel) a counterpart of this Amendment, an amendment fee equal to the
Applicable Amendment Percentage, as defined below, multiplied by the sum of such
Bank's outstanding Term Loans and Working Capital Commitment determined as of
the Amendment Effective Date; provided that the Borrower shall not be required
to pay such amendment fee to any Bank unless and until this Amendment becomes
effective. Such amendment fees shall be due and payable (a) at the time that
this Amendment becomes effective, with respect to each Bank that is entitled to
receive an amendment fee at such time, or (b) within two Domestic Business Days
after such Bank executes and delivers a counterpart of this Amendment entitling
it to receive such amendment fee, in the case of each other Bank. The Borrower
may in its discretion, but shall not have any obligation to, pay any amendment
fee to any Bank that does not execute and deliver a counterpart of this
Amendment on or before November 21, 1997, provided that the Applicable Amendment
Percentage used in calculating the amendment fee for any such bank shall be no
greater than .05%.



        "Applicable Amendment Percentage" means for any Bank which executes and
delivers to the Agent (or its counsel) a counterpart of this Amendment (i) on or
before November 14, 1997, .08% or (ii) after November 14, 1997 and on or before
November 21, 1997, .05%.

        SECTION 9. Effectiveness. This Amendment shall become effective on the
date (the "Amendment Effective Date") that each of the following conditions is
satisfied:
        (a) receipt by the Agent of counterparts of this Amendment that, when
taken together, bear the signatures of the Borrower and the Required Banks;
provided, however, that amendments set forth in Section 2 shall, to the extent
such amendments affect the determination of Pricing Periods, only become
effective (i) with respect to Pricing Periods for Tranche A Term Loans, upon the
receipt by the Agent of counterparts of this Amendment that, when taken
together, bear the signatures of all the Tranche A Banks and (ii) with respect
to Pricing Periods for Working Capital Loans and Working Capital Commitments,
upon the receipt by the Agent of counterparts of this Amendment that, when taken
together, bear the signatures of all the Working Capital Banks and, in each
case, upon the satisfaction of all other conditions under this Section 9.

        (b) receipt by the Agent, for its account and the account of each
Arranging Agent entitled thereto, of all fees and other compensation payable to
the Agent and the Arranging Agents on or prior to the Amendment Effective Date
pursuant to their agreements with the Borrower; and

        (c) receipt by the Agent for the account of each Bank then entitled
thereto of all amendment fees payable under Section 8 of this Amendment.

        The Agent shall promptly notify the Borrower and the Banks of the
Amendment Effective Date, and such notice shall be conclusive and binding on all
parties hereto.

        SECTION 10. Miscellaneous. (a) Except as expressly set forth herein, the
Credit Agreement shall continue in full force and effect in accordance with the
terms and provisions thereof on the date hereof.

        (b) Section headings used herein are for convenience of reference only
and are not to affect the construction of, or to be




taken into consideration in interpreting, this Amendment.

        (c) THIS AMENDMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH
THE LAWS OF THE STATE OF NEW YORK.

        (d) This Amendment may be executed in any number of counterparts, each
of which shall be an original but all of which, when taken together, shall
constitute but one instrument.

           IN WITNESS WHEREOF, the parties hereto have caused this Amendment to
   be duly executed by their respective authorized officers as of the date first
   above written.



                               QUEST DIAGNOSTICS INC.,

                                     by
                                       ----------------------------
                                          Name:
                                          Title:


                               MORGAN GUARANTY TRUST COMPANY OF NEW YORK,

                                     by
                                       ----------------------------
                                          Name:
                                          Title:


                               NATIONSBANK, N.A.,

                                     by
                                       -----------------------------
                                          Name:
                                          Title:




                         WACHOVIA BANK OF GEORGIA, N.A.,

                                     by
                                       -----------------------------
                                          Name:
                                          Title:


                         BANK OF AMERICA ILLINOIS,

                                     by
                                       -----------------------------
                                          Name:
                                          Title:


                         BANK OF MONTREAL,


                                     by
                                       -----------------------------
                                          Name:
                                          Title:


                         THE BANK OF NEW YORK,

                                    by
                                      ------------------------------
                                          Name:
                                          Title:


                         BANQUE PARIBAS,

                                   by
                                     -------------------------------
                                          Name:
                                          Title:


                                    by
                                     -------------------------------
                                          Name:
                                          Title:



                         CITY NATIONAL BANK,

                                   by
                                     -------------------------------
                                          Name:
                                          Title:


                         CONTINENTAL ASSURANCE COMPANY,

                             by PROTECTIVE ASSET MANAGEMENT
                                COMPANY, as Attorney-in-Fact,

                                  by
                                    --------------------------------
                                          Name:
                                          Title:


                         CREDIT LYONNAIS NEW YORK BRANCH, 


                                  by
                                    --------------------------------
                                          Name:
                                          Title:


                         CYPRESS TREE INVESTMENT PARTNERS I LTD.,

                             by CYPRESS INVESTMENT
                                  MANAGEMENT CO. INC., as
                                     Portfolio Manager,

                                  by
                                    --------------------------------
                                          Name:
                                          Title:



                         THE FUJI BANK, LIMITED, NEW YORK
                              BRANCH,

                                  by
                                    --------------------------------
                                         Name:

                         MERRILL LYNCH SENIOR FLOATING RATE
                              FUND, INC.,

                                  by
                                    --------------------------------
                                        Name:
                                        Title:


                        ML CBO IV CAYMAN LTD.,

                             by PROTECTIVE ASSET MANAGEMENT
                                 COMPANY, as Collateral Manager,

                                  by
                                    ---------------------------------
                                       Name:
                                       Title:


                        PAMCO CAYMAN LTD.,


                             by PROTECTIVE ASSET MANAGEMENT
                                 COMPANY, as Collateral Manager,

                                  by
                                    ----------------------------------
                                      Name:
                                      Title:



                        THE SANWA BANK, LIMITED, NEW YORK
                             BRANCH,

                               by
                                 -----------------------------------
                                      Name:
                                      Title:


                        UNION BANK OF CALIFORNIA, N.A.,

                              by
                                ------------------------------------
                                      Name:
                                      Title:


                        VAN KAMPEN AMERICAN CAPITAL PRIME RATE
                             INCOME TRUST,

                              by
                                ------------------------------------
                                     Name:
                                     Title:


                        OCTAGON CREDIT INVESTORS LOAN PORTFOLIO
                             (A UNIT OF THE CHASE MANHATTAN BANK),

                             by
                               -------------------------------------
                                     Name:
                                     Title: