Press Release Details

Positive Results in Workplace Drug Testing Index Extend Dramatic Decline of Past Decade



TETERBORO, N.J., October 19, 1999 -- Workplace drug use decreased in the first six months of 1999, extending a dramatic 65% decline in positive results over the past decade, according to the semi-annual Drug Testing Index©, released today by Quest Diagnostics Incorporated, the leading provider of drug testing services in the United States.

The positive test results for drugs in the workplace continued a long-term downward trend. During the first six months of 1999, 4.7% of the approximately 2.8-million workplace drug tests performed during the period were reported positive, down from 4.8% for all of 1998. In 1988, when the Drug Testing Index was established, 13.6% of all drug tests were reported as positive.

Rates of use for several drugs, including cocaine and opiates, showed declines as a percentage of all positive test results. Cocaine use made up 16% of all positive results in the first half of 1999, down from 18% for 1998. The percentage of opiate tests that were reported positive declined by almost half in the current Drug Testing Index, from 10% of all positive results for all of 1998. At the same time, marijuana use increased nearly 4% as a percentage of all positive results to 63%.

The decline in reported opiate use coincides with a change in the cut-off level for all federally mandated opiate testing, from 300 to 2000 nanograms per milliliter, that became effective in December, 1998. Subsequently, most non-mandated opiate cut-offs were also changed to the same level. This change reduced the number of positive test results unrelated to opiate abuse but due to the use of certain prescription and over-the-counter medications or certain foods, including those containing poppy seeds.

Test cheaters made up a significant group of positive results on the Drug Testing Index. Cheaters, who test positive for substances used to adulterate or replace their specimens, accounted for nearly 2% of positive results for the first half of 1999. More people tested positive for adulterants and substituted specimens than for either opiates or amphetamines.

Approximately 2,400 job applicants were reported as positive for the use of oxidizing adulterants. More than 1,200 other samples were identified as having been "substituted" for valid test specimens. Oxidizing adulterants, which include nitrites, are used as masking agents in an attempt to defeat the process of detecting drug use. In addition, test results are reported as "substituted" when samples do not contain certain chemical components characteristic of normal human urine.

The Drug Testing Index summarizes the results of workplace drug tests performed between January and June, 1999, by SmithKline Beecham Clinical Laboratories (SBCL), which was acquired by Quest Diagnostics in August. The Drug Testing Index looks at positivity rates among three major testing populations: federally mandated, safety-sensitive workers; the general workforce; and the combined U.S. workforce. SBCL initiated adulterant and substituted-specimen testing in April, 1998 as a complement to workplace drug testing. In April, 1999, SBCL expanded its adulterant testing to include the additional oxidizing adulterants, bleach and pyridinium chlorochromate.

Color graphics of the Drug Testing Index©, including regional maps which show positivity rates by type of drug, are available on-line at to provide more localized workplace drug test data. The Drug Testing Index is released every six months as a service for government, media and industry, and is considered a benchmark for national trends.

For more details, please see The Drug Testing Index©.

Quest Diagnostics, which acquired SmithKline Beecham Clinical Laboratories on August 16, 1999, is the nation's leading provider of diagnostic testing, information and services to physicians, hospitals, managed care organizations, employers and government agencies with annualized revenues of more than $3 billion. The wide variety of tests performed on human tissue and fluids help doctors and hospitals diagnose, treat and monitor disease. Its Nichols Institute unit conducts research, specializes in esoteric testing using genetic screening and other advanced technologies, and manufactures and distributes diagnostic test kits and instruments. Quest Diagnostics is one of the leading providers of testing to support clinical trials of new pharmaceuticals worldwide. Quest Informatics collects and analyzes laboratory, pharmaceutical and other data to help large health care customers better manage the health of their patients. QuestNet is an innovative new product offering that provides network management services to large buyers of health care services. Additional company information can be found on the Internet at:

The Drug Testing Index © 1999 Quest Diagnostics Incorporated. All rights reserved.


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