DRUG TESTING INDEX SHOWS 48% DECLINE IN
CHEATING ON WORKPLACE DRUG TESTS

TETERBORO, NJ, December 1, 2000 — Cheating on workplace drug tests by using chemical additives called masking agents or oxidizing adulterants declined sharply during the first half of 2000 compared to 1999, according to the semi-annual Drug Testing Index released today by Quest Diagnostics Incorporated (NYSE: DGX), the leading provider of drug testing services in the United States.

The Drug Testing Index summarizes the results of workplace drug tests performed between January and June, 2000 by Quest Diagnostics. 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.

The proportion of individuals who used masking agents to thwart the drug testing process declined by 48% during the first half of 2000 compared to the prior year period, according to the Drug Testing Index. Masking agents are chemicals that are added to drug testing specimens in an attempt to defeat the process of detecting drug use. These agents include oxidizing adulterants, which include nitrites, as well as bleach and pyridinium chlorochromate. Quest Diagnostics initiated adulterant testing in April, 1998 as a complement to workplace drug testing, and expanded its adulterant testing to include additional oxidizing adulterants as well as "substituted" specimens in early 1999.

During the first half of 2000, 0.12% of the individuals evaluated tested positive for the presence of oxidizing adulterants, compared to 0.23% in 1999. In addition, 0.03% of the total specimens were identified as having been "substituted" for valid test specimens, compared to 0.04% in 1999. Test results are reported as "substituted" when samples do not contain certain chemical components characteristic of normal human urine.

"The significant decline in the incidence of cheating on drug tests appears to be closely linked to the heightened surveillance by our clients using specimen validity testing to detect tampering," said R.H. Barry Sample, Ph.D., Director of Science and Technology for Quest Diagnostics' Corporate Health and Wellness division. "As more and more employers have begun to test for the presence of adulterants and substituted specimens, cheaters no longer can rely on techniques they may have successfully used in the past."

Overall, workplace drug use, as measured by the rate of positive samples among all samples, remained unchanged from 1999 at 4.7% of the approximately 3 million workplace drug tests performed during the period. Rates of use for several drugs, including cocaine and opiates, showed declines in incidence. Cocaine use was indicated in 0.71% of all drug tests performed in the first half of 2000, down from 0.80% in 1999 and 0.91% in 1998. However, marijuana use increased to its highest level since 1997 at 3.33%, up from 3.17% in both 1998 and 1999.

 Color graphics of the Drug Testing Index, including regional maps which show positivity rates by type of drug. 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.

Quest Diagnostics is the nation's leading provider of diagnostic testing, information and services with annualized revenues of more than $3 billion. The testing performed on human specimens helps doctors diagnose, treat and monitor disease; enables employers to detect workplace drug abuse; and supports pharmaceutical and biotechnology companies in clinical trials of new therapeutics worldwide. Quest Informatics analyzes laboratory and other medical data to help health care providers improve the care of patients. 

The Drug Testing Index Ó 2000 Quest Diagnostics Incorporated. All rights reserved.

 Tables to Follow

Annual Positivity Rates

Positivity Rates by Testing Category

Positivity Rates by Testing Reason
(For Federally Mandated, Safety Sensitive Workforce)
(More than 400,000 tests from January to June 2000)