Workplace drug use has fallen to its lowest level in 11 years, but cheating incidents on drug tests are on the rise, according to a survey released Wednesday by the nation's largest independent processor of workplace drug tests.
New Jersey-based Quest Diagnostics Inc. compiles workplace drug testing data semiannually for clients, including government agencies, airlines, professional sports leagues, retailers and hospitals.
At the time of the first survey in 1988, 13.6% of all drug tests were reported as positive. But the percentage of positive tests has dropped steadily. And last year, only 4.6% of about 6 million tests performed by the company were positive.
In Orange County and elsewhere in Southern California, workers most commonly tested positive for amphetamines, according to the study.
Quest Diagnostics began checking for cheating in 1998. This year's study reported oxidizing adulterants such as bleach were found in 5,400 samples, used in an effort to mask a positive result, up slightly from results in 1998. An additional 2,400 samples had been substituted in an effort to pass the test, the company found.