Press Release Details

LYNDHURST, N.J., Aug 09, 2007 /PRNewswire-FirstCall via COMTEX News Network/ -- An unprecedented decline in cocaine use by American workers drove use of the illicit drug to a new low during the first half of 2007, according to the "Quest Diagnostics Drug Testing Index: Cocaine Use Among America's Workers -- A Special 2007 Mid-Year Report." Released today by Quest Diagnostics Incorporated (NYSE: DGX), the nation's leading provider of diagnostic and employment-related drug testing services, the mid-year report describes positivity rates for cocaine only and does not assess positivity rates for other drugs among U.S. workers. The latest findings are based on results of more than 4.4 million workplace drug tests for cocaine performed by Quest Diagnostics across the U.S. between January and June 2007.

The 0.58 percent positivity rate for cocaine during the first six months of 2007 in the combined U.S. workforce represents a 15.9 percent decrease from the positivity rate for the full year 2006. Cocaine positivity in the first six months of 2007 among the combined U.S. workforce is at its lowest point since 1997, when the Quest Diagnostics Drug Testing Index first reported on the positivity rate for cocaine as a percentage of all employer-related drug tests performed to detect illicit drugs. The combined U.S. workforce refers to general workers and federally mandated, safety-sensitive workers.

The Quest Diagnostics Drug Testing Index showed that positivity for cocaine declined 20.7 percent among federally mandated, safety-sensitive workers, to 0.46 percent for the first six months of 2007, compared to 0.58 percent for all of 2006. Among the general workforce, positivity for cocaine declined 15.3 percent, falling to 0.61 percent for the period between January and June 2007 compared to 0.72 percent for 2006.

"Not only did the positivity rate fall to its lowest level since Quest Diagnostics began reporting on cocaine rates a decade ago, but also the decline was truly across the board, falling by double-digits in all but one of nine regions of the country," said Barry Sample, Ph.D., director of Science and Technology for the Employer Solutions division of Quest Diagnostics. "While it is too soon to point to a trend, the significant decline in positivity rates in different workforce categories and across regions may suggest that our nation's workers are choosing not to use cocaine or that they lack access to the drug."

Regional Declines

The Quest Diagnostics Drug Testing Index also tracked cocaine positivity rates for the combined U.S. workforce by nine geographic regional divisions of the U.S., as defined by the U.S. Census Bureau and reported in the National Survey of Drug Use and Health (NSDUH). The Northeast region's New England Division, consisting of Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island and Vermont, experienced a decline of 21.9 percent, the largest drop of all divisions, for the first six months of 2007 compared to 2006. The Midwest Region's West North Central Division, which consists of the Dakotas, Iowa, Kansas, Minnesota, Missouri and Nebraska, declined by 9.5%, the least significant decline of the divisions.

"The Quest Diagnostics Drug Testing Index: Cocaine Use Among America's Workers -- A Special 2007 Mid-Year Report" was developed partly at the prompting of the White House Office of National Drug Control Policy.

"These data are encouraging," said John Walters, director of National Drug Control Policy. "Cocaine has destroyed thousands of lives in the U.S. and brought lawlessness and misery to our neighbors. But in recent years, we have had unprecedented cooperation with leaders in Colombia and Mexico. Now is the time to build on this progress."

About the Quest Diagnostics Drug Testing Index

The Quest Diagnostics Drug Testing Index is published as a public service for government, media and industry, and has been considered a benchmark for national trends since its inception in 1988. It examines positivity rates, which represent the proportion of positive results for a drug to all such drug tests performed, among three major testing populations: federally mandated, safety-sensitive workers; the general workforce; and the combined U.S. workforce. Federally mandated, safety-sensitive workers include pilots, bus and truck drivers, and workers in nuclear power plants, for whom routine drug testing is mandated by the U.S. Department of Transportation and the Nuclear Regulatory Commission. The Drug Testing Index is released as a full-year and mid-year report. The Quest Diagnostics Drug Testing Index: Cocaine Use Among America's Workers -- A Special 2007 Mid-Year Report describes positivity rates for cocaine only and does not assess positivity rates for other drugs among U.S. workers.

About Quest Diagnostics

Quest Diagnostics is the leading provider of diagnostic testing, information and services that patients and doctors need to make better healthcare decisions. The company offers the broadest access to diagnostic testing services through its national network of laboratories and patient service centers, and provides interpretive consultation through its extensive medical and scientific staff. Quest Diagnostics is a pioneer in developing innovative new diagnostic tests and advanced healthcare information technology solutions that help improve patient care. Additional company information is available at: www.questdiagnostics.com.

The statements in this press release, which are not historical facts or information, may be forward-looking statements. These forward-looking statements involve risks and uncertainties that could cause actual results and outcomes to be materially different. Certain of these risks and uncertainties may include, but are not limited to, competitive environment, changes in government regulations, changing relationships with customers, payers, suppliers and strategic partners and other factors described in the Quest Diagnostics Incorporated 2006 Form 10-K and subsequent filings.

    Positivity Rates By Drug Category -- Cocaine Only
    (As a percentage of all such tests)
    (More than 4.4 million tests from January to June 2007)

    Testing Category           Jan-Jun
                                2007     2006     2005     2004     2003
    Federally Mandated,
     Safety-Sensitive
     Workforce                  0.46%    0.58%    0.60%    0.57%    0.59%
    General U.S.
     Workforce                  0.61%    0.72%    0.70%    0.72%    0.74%
    Combined U.S.
     Workforce                  0.58%    0.69%    0.69%    0.70%    0.71%



    Cocaine Positivity Rates By Regions of the U.S.
    (Sorted by rate of decline as a percentage)

    Region-Division (1)                Percent     Jan-Jun
                                       Decline       2007         2006
    Northeast Region -
     New England Division
     (Connecticut, Maine,
      Massachusetts,
      New Hampshire, Rhode Island,
      Vermont)                          21.9%        0.57%        0.73%

    South Region -
     West South Central Division
     (Arkansas, Louisiana,
      Oklahoma, Texas)                  20.5%        0.66%        0.83%

    Northeast Region -
     Middle Atlantic Division
     (New Jersey, New York,
      Pennsylvania)                     19.1%        0.55%        0.68%

    Midwest Region -
     East North Central Division
     (Illinois, Indiana,
      Michigan, Ohio, Wisconsin)        17.6%        0.56%        0.68%

    South Region -
     South Atlantic Division
     (Delaware, District of
      Columbia, Florida,
      Georgia, Maryland, North
      Carolina, South Carolina,
      Virginia, West Virginia)          16.7%        0.75%        0.90%

    West Region -
     Mountain Division
     (Arizona, Colorado, Idaho,
      Montana, Nevada, New Mexico,
      Utah, Wyoming)                    14.3%        0.36%        0.42%

    West Region -
     Pacific Division
     (Alaska, California,
      Hawaii, Oregon, Washington)       12.5%        0.28%        0.32%

    South Region -
     East South Central Division
     (Alabama, Kentucky,
      Mississippi, Tennessee)           11.3%        0.71%        0.80%

    Midwest Region -
     West North Central Division
     (Iowa, Kansas, Minnesota,
      Missouri, Nebraska, North
      Dakota, South Dakota)              9.5%        0.38%        0.42%


     (1) As defined by the U.S. Census Bureau and reported in the National
         Survey of Drug Use and Health (NSDUH).

    Quest Diagnostics Incorporated. All rights reserved.

SOURCE Quest Diagnostics Incorporated

Investors, Laure Park, +1-201-393-5030; or Media, Wendy H. Bost, +1-201-393-5700,
both for Quest Diagnostics Incorporated

http://www.questdiagnostics.com