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Oral fluid finding more positives; Marijuana remains most commonly detected

March 12, 2013
by Shannon Brys, Associate Editor
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Drug Testing Index (DTI) data released by Quest Diagnostics, provider of diagnostic information services, reveal a jump in positivity rates for marijuana in oral fluid vs. urine in the U.S. general workforce. While marijuana positivity rates in oral fluid and urine changed little between 2008 and 2011, the gap between oral fluid and urine positivity rates for marijuana increased during this time from a 29% higher positivity rate in oral fluid in 2008 to a 42% higher positivity rate in 2011. Due in part to advances in oral fluid testing technology implemented in late 2011, the oral fluid marijuana positivity rate was 70% higher than that of urine (3.4% vs. 2.0%) in the first half of 2012 as compared with 2011.

"The higher oral fluid detection rate for marijuana strongly suggests that observed oral fluid collection curbs evasive donor behavior," said Dr. Barry Sample, director of science and technology for Quest Diagnostics Employer Solutions. "Simply put, it is extremely difficult to cheat an oral fluid collection when someone is observing."

Data from DTI for January to June 2012 show that marijuana continues to be the most commonly detected drug. Data from urine drug tests show that marijuana positives in the U.S. general workforce (2.0%) are nearly twice that of amphetamines (0.86%), which ranked as the second most commonly detected drug. This finding is corroborated by data from the U.S. Substance Abuse and Mental Health Services Administration (SAMHSA), which estimated that in 2011, 7% percent of Americans (18.1 million people) were current users of marijuana -- up from 5.8% (14.5 million people) in 2007.

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