<SUBMISSION>
<ACCESSION-NUMBER>0000950117-06-004130
<TYPE>8-K
<PUBLIC-DOCUMENT-COUNT>2
<PERIOD>20060930
<ITEMS>1.01
<ITEMS>9.01
<FILING-DATE>20061004
<DATE-OF-FILING-DATE-CHANGE>20061003
<FILER>
<COMPANY-DATA>
<CONFORMED-NAME>QUEST DIAGNOSTICS INC
<CIK>0001022079
<ASSIGNED-SIC>8071
<IRS-NUMBER>161387862
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<FILING-VALUES>
<FORM-TYPE>8-K
<ACT>34
<FILE-NUMBER>001-12215
<FILM-NUMBER>061125988
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>ONE MALCOLM AVE
<CITY>TETERBORO
<STATE>NJ
<ZIP>07608
<PHONE>2013935000
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>ONE MALCOLM AVE
<CITY>TETERBORO
<STATE>NJ
<ZIP>07601
</MAIL-ADDRESS>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>CORNING CLINICAL LABORATORIES INC
<DATE-CHANGED>19960903
</FORMER-COMPANY>
</FILER>
<DOCUMENT>
<TYPE>8-K
<SEQUENCE>1
<FILENAME>a44490.htm
<DESCRIPTION>QUEST DIAGNOSTICS INC
<TEXT>
<HTML>

<HEAD><TITLE></TITLE></HEAD>
<BODY>

<BR>

<TABLE ALIGN=CENTER  BORDER=0 CELLSPACING=0 CELLPADDING=0 WIDTH="100%">
 <TR style="font-size:1px">
  <TD WIDTH="100%" VALIGN=TOP>
  <P>&nbsp;</P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P ALIGN=CENTER><FONT SIZE=4>SECURITIES AND EXCHANGE
  COMMISSION</FONT></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P ALIGN=CENTER><FONT SIZE=3>WASHINGTON, DC 20549</FONT></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P ALIGN=CENTER><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
 </TR>
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  <TD  VALIGN=TOP>
  <HR SIZE=1 WIDTH="100%" NOSHADE COLOR=GRAY ALIGN=CENTER>

  </TD>
 </TR>
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  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P ALIGN=CENTER><FONT SIZE=5>FORM 8-K</FONT></P>
  </TD>
 </TR>
</TABLE>

<P ALIGN=CENTER><FONT  SIZE=3><B>CURRENT
REPORT PURSUANT TO SECTION 13 OR 15(d) OF<BR>
THE SECURITIES EXCHANGE ACT OF 1934</B></FONT></P>

<P ALIGN=CENTER><FONT  SIZE=2>Date of Report
(Date of Earliest Event Reported): September 30, 2006</FONT></P>

<P ALIGN=CENTER><FONT  SIZE=2>Commission File
Number 001-12215</FONT></P>

<DIV ALIGN=CENTER><FONT  SIZE=6><B>Quest
Diagnostics Incorporated</B></FONT></DIV>

<DIV ALIGN=CENTER><FONT  SIZE=2>1290 Wall Street
West<BR>
Lyndhurst, NJ 07071<BR>
(201) 393-5000</FONT></DIV>

<P ALIGN=CENTER><FONT  SIZE=2><B>Delaware<BR>
</B>(State of Incorporation)</FONT></P>

<P ALIGN=CENTER><FONT  SIZE=2><B>16-1387862<BR>
</B>(I.R.S. Employer Identification Number)</FONT></P>

<TABLE ALIGN=CENTER  BORDER=0 CELLSPACING=0 CELLPADDING=0 WIDTH="100%">
 <TR style="font-size:1px">
  <TD WIDTH="100%" VALIGN=TOP>
  <P ALIGN=CENTER>&nbsp;</P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <HR SIZE=1 WIDTH="100%" NOSHADE COLOR=GRAY ALIGN=CENTER>

  </TD>
 </TR>
</TABLE>
<BR>
<HR COLOR=#000000 NOSHADE><P STYLE='PAGE-BREAK-BEFORE: ALWAYS'></P><PAGE>

<P><FONT SIZE=2><B>Item
1.01. Entry into a Material Definitive Agreement</B></FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Quest
Diagnostics Incorporated (the &#147;Company&#148;), Enterix Inc. and MedPlus, Inc. (the
&#147;Additional Subsidiary Guarantors&#148;), and The Bank of New York, as Trustee,
entered into the Ninth Supplemental Indenture effective as of September 30,
2006. The Ninth Supplemental Indenture supplements the indenture dated as of
June 27, 2001 among the Company, the Subsidiary Guarantors (as defined therein)
and the Trustee, as subsequently supplemented by a first supplemental
indenture, dated as of June 27, 2001, as further supplemented by a second
supplemental indenture, dated as of November 26, 2001, as further supplemented
by a third supplemental indenture, dated as of April 4, 2002, as further
supplemented by a fourth supplemental indenture, dated as of March 19, 2003, as
further supplemented by a fifth supplemental indenture, dated as of April 16,
2004, as further supplemented by a sixth supplemental indenture dated October
31, 2005, as further supplemented by a seventh supplemental indenture dated
November 21, 2005, and as further supplemented by an eighth supplemental
indenture dated July 31, 2006 (collectively, the &#147;Indenture&#148;). </FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The
Ninth Supplemental Indenture adds the Additional Subsidiary Guarantors as
guarantors to the Company&#146;s 7&#189;% Senior Notes due 2011, 5.125% Senior Notes due
2010 and 5.45% Senior Notes due 2015 issued pursuant to the Indenture. The
Ninth Supplemental Indenture is attached hereto as Exhibit 4.1.</FONT></P>

<P><FONT SIZE=2><B>Item
9.01. Financial Statements and Exhibits</B></FONT></P>

<TABLE ALIGN=CENTER  BORDER=0 CELLSPACING=0 CELLPADDING=0 WIDTH="100%">
 <TR style="font-size:1px">
  <TD WIDTH="5%" VALIGN=TOP>
  <P>&nbsp;</P>
  </TD>
  <TD WIDTH="5%" VALIGN=TOP>
  <P>&nbsp;</P>
  </TD>
  <TD WIDTH="90%" VALIGN=TOP>
  <P>&nbsp;</P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=2>c.</FONT></P>
  </TD>
  <TD  COLSPAN="2" VALIGN=TOP>
  <P><FONT SIZE="2"><U>Exhibits</U> </FONT></P>
  </TD>
 </TR>


<TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
</TR>

 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=2>4.1</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=2>Ninth Supplemental Indenture, dated as of September
  30, 2006, among the Company, the guarantors named therein and The Bank of New
  York, as Trustee. </FONT></P>
  </TD>
 </TR>
</TABLE>
<BR>
<HR COLOR=#000000 NOSHADE><P STYLE='PAGE-BREAK-BEFORE: ALWAYS'></P><PAGE>
<BR>
<HR SIZE=1 WIDTH="100%" NOSHADE COLOR=GRAY ALIGN=CENTER>

<P ALIGN=CENTER><FONT  SIZE=2><B>Signature</B></FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Pursuant
to the requirements of the Securities Exchange Act of 1934, the registrant has
duly caused this report to be signed on its behalf by the undersigned hereunto
duly authorized.</FONT></P>

<TABLE ALIGN=CENTER  BORDER=0 CELLSPACING=0 CELLPADDING=0 WIDTH="100%">
 <TR style="font-size:1px">
  <TD WIDTH="47%" VALIGN=TOP>
  <P>&nbsp;</P>
  </TD>
  <TD WIDTH="4%" VALIGN=TOP>
  <P>&nbsp;</P>
  </TD>
  <TD WIDTH="47%" VALIGN=TOP>
  <P>&nbsp;</P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  COLSPAN="2" VALIGN=TOP>
  <P><FONT SIZE=2>October 2, 2006</FONT><BR><BR></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  COLSPAN="2" VALIGN=TOP>
  <P><FONT SIZE=2>QUEST DIAGNOSTICS INCORPORATED </FONT><BR><BR></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=2>By:</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=2>/s/ Leo C. Farrenkopf, Jr. </FONT></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <HR SIZE=1 WIDTH="50%" NOSHADE COLOR=GRAY ALIGN=LEFT>

  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=2>Leo C. Farrenkopf, Jr. <BR>
  Vice President and Assistant Secretary</FONT></P>
  </TD>
 </TR>
</TABLE>
<BR>
<HR COLOR=#000000 NOSHADE>

</BODY>

</HTML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-4
<SEQUENCE>2
<FILENAME>ex4-1.htm
<DESCRIPTION>EXHIBIT 4.1
<TEXT>
<HTML>

<HEAD><TITLE></TITLE></HEAD>
<BODY>

<BR>

<DIV ALIGN=RIGHT><FONT SIZE=2><B>Exhibit 4.1</B></FONT></DIV>
<DIV ALIGN=CENTER><FONT  SIZE=2><B>NINTH
SUPPLEMENTAL INDENTURE</B></FONT></DIV>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;SUPPLEMENTAL
INDENTURE dated as of September 30, 2006 (this &#147;Ninth Supplemental Indenture&#148;),
among ENTERIX INC., a Delaware corporation, and MEDPLUS, INC., an Ohio
corporation (the &#147;Additional Subsidiary Guarantors&#148;), QUEST DIAGNOSTICS
INCORPORATED, a Delaware corporation (the &#147;Company&#148;), and THE BANK OF NEW YORK,
a New York banking corporation, as Trustee (the &#147;Trustee&#148;).</FONT></P>

<P ALIGN=CENTER><FONT  SIZE=2><B>RECITALS
OF THE COMPANY</B></FONT></P>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;WHEREAS,
the Company, the Trustee and the Initial Subsidiary Guarantors (as hereinafter
defined) executed and delivered an Indenture, dated as of June&nbsp;27, 2001
(the &#147;Base Indenture&#148;), as supplemented by the first supplemental indenture,
dated as of June 27, 2001, among the Company, the Initial Subsidiary Guarantors
(as defined therein) party thereto, and the Trustee, as further supplemented by
a second supplemental indenture, dated as of November 26, 2001, among the
Company, the Subsidiary Guarantors (as defined therein) party thereto and the
Trustee, as further supplemented by a third supplemental indenture, dated as of
April 4, 2002, among the Company, the additional Subsidiary Guarantors (as
defined therein) party thereto and the Trustee, as further supplemented by a
fourth supplemental indenture, dated as of March 19, 2003, among the Company,
the additional Subsidiary Guarantors (as defined therein) party thereto and the
Trustee, as further supplemented by a fifth supplemental indenture, dated as of
April 16, 2004, among the Company, the additional Subsidiary Guarantors (as
defined therein) party thereto and the Trustee, as further supplemented by a
sixth supplemental indenture dated October 31, 2005, among the Company, the
Subsidiary Guarantors (as defined therein) party thereto, as further
supplemented by a seventh supplemental indenture dated November 21, 2005, among
the Company, the additional Subsidiary Guarantors (as defined therein) parties
thereto and the Trustee, as further supplemented by an eighth supplemental
indenture dated July 31, 2006, among the Company, the additional Subsidiary
Guarantors (as defined therein) parties thereto and the Trustee, to be further
supplemented by this Ninth Supplemental Indenture (collectively, the
&#147;Indenture&#148;), to provide for the issuance by the Company from time to time of
Securities to be issued in one or mores series as provided in the Indenture;</FONT></P>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;WHEREAS,
the Additional Subsidiary Guarantors intend to guarantee the Securities under
the Indenture and the issuance of guarantees has been authorized by resolutions
adopted by the Boards of Directors of such Additional Subsidiary Guarantors; </FONT></P>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;WHEREAS,
Sections 901(1) and 901(11) of the Indenture provide that without the consent
of Holders of the Securities of any series issued under the Indenture, the
Company and the Subsidiary Guarantors, when authorized by a Board Resolution,
and the Trustee may enter into one or more indentures supplemental to the
Indenture to (a) evidence the successor of another Person to any Subsidiary
Guarantor and the assumption by such successor of the covenants of such
Subsidiary Guarantor in the Indenture and in the Securities and (b) add a
guarantor or guarantors for any series or all series of the Securities;</FONT></P>

<HR COLOR=#000000 NOSHADE><P STYLE='PAGE-BREAK-BEFORE: ALWAYS'></P><PAGE>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;WHEREAS,
pursuant to Sections 904, 1601, 1602 and 1604 of the Indenture, by delivery of
a Supplemental Indenture to the Trustee in accordance with the terms of the
Indenture, each Person that becomes a Subsidiary Guarantor after the date of
the Base Indenture will be deemed to have executed and delivered the Subsidiary
Guarantee for the benefit of the Holder of the Security upon which the
Subsidiary Guarantee is endorsed, with the same effect as if such Subsidiary
Guarantor had been named thereon and had executed and delivered the Subsidiary
Guarantee; and</FONT></P>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;WHEREAS,
all things necessary to make this Ninth Supplemental Indenture a valid
supplement to the Indenture according to its terms and the terms of the
Indenture have been done;</FONT></P>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;NOW,
THEREFORE, for and in consideration of the foregoing, the parties hereto hereby
enter into this Ninth Supplemental Indenture, for the equal and proportionate
benefit of all Holders of the Securities, as follows:</FONT></P>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;SECTION
1 <U>Certain Terms Defined in the Indenture</U>.</FONT></P>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;All
capitalized terms used but not defined herein shall have the meanings assigned
to them in the Indenture.</FONT></P>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;SECTION
2 <U>Agreement to Guarantee</U>.</FONT></P>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The
Additional Subsidiary Guarantors, by their signature below, agree to become
Additional Subsidiary Guarantors under the Indenture with the same force and
effect as if originally named therein as Subsidiary Guarantors. The Additional
Subsidiary Guarantors hereby agree to all the terms and provisions of the
Indenture applicable to them as Additional Subsidiary Guarantors thereunder and
each reference to a &#147;Subsidiary Guarantor&#148; in the Indenture shall be deemed to
include the Additional Subsidiary Guarantors.</FONT></P>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;SECTION
3 <U>Indenture remains in Full Force and Effect</U>.</FONT></P>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Except
as expressly supplemented by this Ninth Supplemental Indenture, the Indenture
shall remain in full force and effect in accordance with its terms.</FONT></P>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;SECTION
4 <U>New York Law to Govern</U>.</FONT></P>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;THIS
NINTH SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE
WITH THE LAWS OF THE STATE OF NEW YORK, WITHOUT REGARD TO PRINCIPLES OF
CONFLICT OF LAWS.</FONT></P>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;SECTION
5 <U>Separability</U>.</FONT></P>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;In
case any one or more of the provisions contained in this Ninth Supplemental
Indenture should be held invalid, illegal or unenforceable in any respect, the
validity, legality and enforceability of the remaining provisions contained
herein and in the Indenture shall not in any way be affected or impaired. The
parties hereto shall endeavor in good faith negotiations to replace any
invalid, illegal or enforceable provisions herein with valid provisions, the
economic </FONT></P>

<HR COLOR=#000000 NOSHADE><P STYLE='PAGE-BREAK-BEFORE: ALWAYS'></P><PAGE>

<P><FONT SIZE=2>effect of which comes as close as possible to that of
the invalid, illegal or unenforceable provisions.</FONT></P>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;SECTION
6 <U>May be Executed in Counterparts</U>.</FONT></P>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;This
Ninth Supplemental Indenture may be executed in counterparts, each of which
when taken together shall constitute one and the same instrument. This Ninth
Supplemental Indenture shall become effective when the Trustee shall have
received a counterpart thereof that bears the signatures of the Additional
Subsidiary Guarantors.</FONT></P>

<P><FONT
SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;SECTION
7 <U>Trustee</U>.</FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The Trustee makes no representations as to the
validity or sufficiency of this Ninth Supplemental Indenture. The recitals and
statements herein are deemed to be those of the Company and the Additional
Subsidiary Guarantors and not of the Trustee. </FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;IN WITNESS WHEREOF, the Company, the Additional
Subsidiary Guarantors, and the Trustee have duly executed this Ninth
Supplemental Indenture as of the day and year first above written.</FONT></P>

<TABLE ALIGN=CENTER  BORDER=0 CELLSPACING=0 CELLPADDING=0 WIDTH="100%">
 <TR style="font-size:1px">
  <TD WIDTH="50%" VALIGN=TOP>
  <P>&nbsp;</P>
  </TD>
  <TD WIDTH="6%" VALIGN=TOP>
  <P>&nbsp;</P>
  </TD>
  <TD WIDTH="44%" VALIGN=TOP>
  <P>&nbsp;</P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  COLSPAN="2" VALIGN=TOP>
  <P><FONT SIZE=2>QUEST DIAGNOSTICS INCORPORATED</FONT></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  COLSPAN="2" VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  COLSPAN="2" VALIGN=TOP>
  <P><FONT SIZE=2>By: /s/ Joseph P. Manory</FONT></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  COLSPAN="2" VALIGN=TOP>
  <HR SIZE=1 WIDTH="60%" NOSHADE COLOR=GRAY ALIGN=LEFT style="margin-left:25px">

  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=2>Name:</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=2>Joseph P. Manory</FONT></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=2>Title:</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=2>Vice President and Treasurer</FONT></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  COLSPAN="2" VALIGN=TOP>
  <P><FONT SIZE=2>ENTERIX INC. </FONT></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  COLSPAN="2" VALIGN=TOP>
  <P><FONT SIZE=2>MEDPLUS, INC., as Additional Subsidiary Guarantors</FONT></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  COLSPAN="2" VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  COLSPAN="2" VALIGN=TOP>
  <P><FONT SIZE=2>By: /s/ Joseph P. Manory</FONT></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  COLSPAN="2" VALIGN=TOP>
  <HR SIZE=1 WIDTH="60%" NOSHADE COLOR=GRAY ALIGN=LEFT style="margin-left:25px">

  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=2>Name:</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=2>Joseph P. Manory</FONT></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=2>Title:</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=2>Vice President and Treasurer</FONT></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
  </TD>
 </TR>
 <TR>
  <TD  VALIGN=TOP>
  <P><FONT SIZE=1>&nbsp;</FONT></P>
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  <P><FONT SIZE=2>THE BANK OF NEW YORK, as Trustee</FONT></P>
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  <P><FONT SIZE=1>&nbsp;</FONT></P>
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  <P><FONT SIZE=1>&nbsp;</FONT></P>
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  <P><FONT SIZE=2>By: /s/ Robert A. Massimillo</FONT></P>
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  <HR SIZE=1 WIDTH="60%" NOSHADE COLOR=GRAY ALIGN=LEFT style="margin-left:25px">

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  <P><FONT SIZE=1>&nbsp;</FONT></P>
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  <P><FONT SIZE=2>Name: </FONT></P>
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  <P><FONT SIZE=2>Robert A. Massimillo</FONT></P>
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  <P><FONT SIZE=2>Title: </FONT></P>
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  <P><FONT SIZE=2>Vice President</FONT></P>
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