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                                                                    Exhibit 8.2



            [LETTERHEAD OF SKADDEN, ARPS, SLATE, MEAGHER & FLOM LLP]



July 11, 2002



Unilab Corporation

18448 Oxnard Street

Tarzana, California  91356

Ladies and Gentlemen:


We have acted as counsel to Unilab Corporation ("Unilab") in connection with the
Offer and the proposed merger (the "Merger") of Unilab with and into Quest
Diagnostics Newco Incorporated ("Merger Sub"), a Delaware corporation and a
direct wholly owned subsidiary of Quest Diagnostics Incorporated, a Delaware
corporation ("Quest"), pursuant to the Agreement and Plan of Merger, dated as of
April 2, 2002 and amended as of May 13, 2002 and as of June 20, 2002, among
Quest, Merger Sub and Unilab (the "Merger Agreement"). This opinion is being
furnished in connection with the proxy statement/prospectus (the "Proxy
Statement/Prospectus") which is included in the Registration Statement on Form
S-4 of Quest (the "Registration Statement") filed on the date hereof with the
Securities and Exchange Commission (the "Commission") under the Securities Act
of 1933, as amended (the "Securities Act"), and in accordance with the
requirements of Item 601(b)(8) of Regulation S-K under the Securities Act.
Unless otherwise indicated, each capitalized term used herein has the meaning
ascribed to it in the Merger Agreement.



For purposes of our opinion, we have assumed that the conditions to the
consummation of the Offer set forth in Annex I of the Merger Agreement
(including the Minimum Condition, as defined in Section  2.01(b)(1) of the
Merger Agreement) will be satisfied, none of the conditions permitting a
Reverse Merger set forth in Section 3.01(b)(A) and Section 3.01(b)(B) of the
Merger Agreement will be satisfied and the Merger will be consummated at the
Effective Time as a forward merger of the Company with and into Merger Sub in
accordance with the terms of the Merger Agreement and the laws of the State of
Delaware.


In rendering our opinion set forth below, we have examined and, with the consent
of Unilab, Quest and Merger Sub, relied upon the accuracy and completeness
(which we have neither investigated nor verified) of the facts, information,
covenants, representations and warranties contained in originals or copies,
certified or otherwise identified to our satisfaction, of the Merger Agreement,
including the exhibits thereto, the Proxy Statement/Prospectus and such other
documents and corporate records as we have deemed necessary or appropriate as a
basis for our opinion set forth below. We have also relied upon statements and
representations made to us by officers and other representatives of Unilab and
Quest (which statements and representations we have assumed are true without
regard to any qualification as to knowledge and belief), including in their
respective letters dated the date hereof (the "Tax Certificates") and we have
assumed that such statements, representations and Tax Certificates are, and will
continue to


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be, complete and accurate, and will be re-executed by appropriate officers,
as of the Effective Time.



In rendering our opinion set forth below, we have assumed that (i) the Offer and
the Merger will be consummated in accordance with the terms of the Merger
Agreement and as described in the Proxy Statement/Prospectus and that none of
the terms and conditions contained therein will be or have been waived or
modified in any respect at or prior to the Effective Time and (ii) the Proxy
Statement/Prospectus, the Merger Agreement, the Tax Certificates and such other
documents and records as we have considered reflect all the material facts
relating to the Offer, the Merger, Unilab, Quest and Merger Sub. Our opinion is
conditioned upon, among other things, the initial and continuing accuracy and
completeness of the assumptions set forth above and the facts, information,
covenants, representations and warranties made by Unilab and Quest (including,
without limitation, those set forth in the Merger Agreement and the Tax
Certificates). Any change or inaccuracy in the foregoing or the facts referred
to, set forth or assumed herein, in the Proxy Statement/Prospectus, the Merger
Agreement or in the Tax Certificates (giving effect to all events occurring
subsequent to the Effective Time) may affect the conclusions stated herein.



We have also assumed the genuineness of all signatures, the legal capacity of
all natural persons, the authenticity of all documents submitted to us as
originals, the conformity to original documents of all documents submitted to us
as certified or photostatic copies and the authenticity of the originals of such
documents.


In addition, we have considered applicable provisions of the Internal Revenue
Code of 1986, as amended (the "Code"), Treasury Regulations promulgated
thereunder (the "Regulations"), pertinent judicial authorities, rulings of the
Internal Revenue Service (the "IRS") and such other authorities as we have
considered relevant, in each case, in effect on the date hereof. It should be
noted that the Code, the Regulations, judicial decisions, administrative
interpretations and such other authorities are subject to change at any time
and, in some circumstances, with retroactive effect. Additionally, our opinion
is not binding on the IRS or a court and, accordingly, the IRS may assert a
position contrary to our opinion and a court may agree with the IRS's position.
A change in any of the authorities upon which our opinion is based, or any
variation or difference in any fact from those set forth or assumed herein or in
the Proxy Statement/Prospectus, could affect our conclusions stated herein.


Based solely upon and subject to the foregoing and the other limitations,
qualifications, exceptions and assumptions set forth herein, (i) we are of the
opinion that, under current law, the Offer and the Merger will be treated as a
reorganization within the meaning of Section 368(a) of Code for United States
federal income tax purposes, and (ii) we confirm that the discussion in the
Proxy Statement/Prospectus under the heading "The Offer--Federal Income Tax
Consequences," to the extent it consists of statements of law and legal
conclusions, and subject to the limitations and qualifications set forth
therein, constitutes our opinion as to the material United States federal income
tax consequences of the Offer and the Merger to Unilab stockholders.



Except as expressly set forth above, we express no other opinion regarding the
tax consequences of the Offer and/or the Merger. This opinion is for your
benefit and is not to be used, circulated, quoted or otherwise referred to for
any purpose, except that in accordance with the requirements of Item 601(b)(23)
of Regulation S-K under the Securities Act, we hereby consent to the reference
to this opinion and the use of our name under the captions "The Offer--Federal
Income Tax Consequences" and "Legal Matters" in the Proxy Statement/Prospectus
and to the filing of this opinion as an Exhibit to the Registration Statement.
In giving this consent, we do not admit that we come within the category of
persons whose consent is required under Section 7 of the Securities Act or the
rules and regulations of the Commission thereunder.




The opinion expressed herein is as of the date hereof, and we disclaim any
undertaking to advise you of changes of facts stated or assumed herein or any
subsequent changes in applicable law.


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Very truly yours,



/s/ Skadden, Arps, Slate, Meagher & Flom LLP





