Industry Buzz: Marijuana Driving More Positive Screening Tests

Possessing marijuana has morphed from being a felony to being legal in some states for medical and recreational use and as a result is flying high into the radars of laboratories that test for drug usage. Quest Diagnostics’ annual Drug Testing Index concluded that the rate of positive tests for pre-employment urine drug screening in the United States rose 5.7 percent during the first half of 2012 compared to the first half of 2011. “These findings align with recent news reports citing some employers facing increasing drug positives when recruiting,” said Barry Sample, M.D., director of science and technology for Quest Diagnostics’ employer solutions division. The report is based on an analysis of more than 3.4 million urine and 340,000 oral fluid drug tests performed at Quest Diagnostics laboratories between January and June 2012. But how comparatively illicit are the drugs leading to positive tests nowadays? According to Quest, marijuana is the drug that most commonly leads to a positive test—a 2 percent overall positive rate, more than twice as much as the second-leading drug, methamphetamine. The oral fluid testing positive rate during the first half of 2012 is up 15.7 percent compared to the 4.4 percent positive rate. This uptick in positive drug tests has been confirmed by another lab that performs drug screenings. According to Philip Radford, chief executive officer of AvuTox in Rocky Mount, N.C., the number of inconsistent results—indicating the presence or absence of a drug in a patient’s system—has risen to 43 percent from about 36 percent over the past six months. Marijuana is the number-one driver, according to Radford. Marijuana is now legal for recreational use in two states and legal for medicinal use in 13 others and the District of Columbia. “Many of our doctors don’t know what to do with it,” Radford said of a positive marijuana test. “They don’t know whether they should even be testing for it, or even be concerned about . . . it.” Quest spokesperson Wendy Bost noted that it remains illegal under federal law, and the company performs most of its drug testing for the “safety-sensitive workforce.”