Rate of positive drug tests is falling steadily
Some applicants caught trying to cheat
About 5% of job applicants tested positive on their pre-employment drug screens in the first half of 1998, and a significant number were caught trying to cheat the tests.
The results come from the Philadelphia-based SmithKline Beecham Drug Testing Index, an analysis of test results produced by the company as part of its service to employers and occupational health providers conducting pre-employment drug screens. Past years have seen a steady decrease in the rate of positive tests and the number of applicants trying to cheat the tests. (For rates in various drug-testing categories, see graphs, pp. 145-146.)
From the more than 2.7 million tests performed in the first six months of 1998, the overall positivity rate was 4.9%, compared to 5% for all of 1997. The positivity rate has fallen steadily since the company first started keeping tally in 1987, when the positivity rate was 18.1%.
Marijuana most frequently detected
The positivity rate fell to 13.6% in 1988, and then continued a steady decline to 5% in 1997. Though the first six months of 1998 yielded essentially the same rate at 4.9%, the full year data for 1998 is expected to continue the trend with a decrease.
Among confirmed positive samples, marijuana was detected most frequently at 60%. Cocaine was detected in 17% of all positive results, and opiates including heroin were found in less than 10% of all positive results.
Two categories used
SmithKline Beecham divides the tested workers into two categories: workers in safety-sensitive positions and all others, referred to as the general work force. Among the samples from workers in safety-sensitive positions, 3.4% of all pre-employment tests were positive for drugs, compared to 2.8% for tests conducted randomly.
In the general work force, 5.1% of all tests were positive for drugs, compared to 7.6% for tests done on a random basis. For samples submitted from the general work force for testing on a "for-cause basis," more than 25% were positive for drugs.
For the general work force, post-accident testing yielded a 6.5% rate in the first half of 1998, down slightly from 6.8% in 1997. Return-to-duty testing yielded a 7.2% rate in 1998, up from 6.1% in 1997.
Some regional differences
There were some regional differences in the test results, with workers in western and northwestern states showing above average detection rates of amphetamines and opiates. Southeastern and southwestern regions had above average rates for cocaine.
(For drug test results by state and region, see maps, inserted in this issue.)
SmithKline Beecham just recently started testing samples for adulterants and found 400 positive for nitrites in the first 10 weeks of testing. Nitrites are used as a masking agent to prevent the detection of illegal drug use.
Editor’s note: For more information, contact SmithKline Beecham at (800) 877-8570. World Wide Web: http://www.sb.com.
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