MADISON, N.J., March 7, 2013 /PRNewswire/ -- Job candidates subject to pre-employment drug screening tested positive for illicit drugs at a greater rate in the first six months of 2012 than in all of 2011, according to Drug Testing Index™ (DTI) data released today by Quest Diagnostics (NYSE: DGX), the world's leading provider of diagnostic information services.

The positivity rate from pre-employment urine drug screening in the U.S. general workforce increased by 5.7% in the first half of 2012 compared to 2011, while the positivity rate from random urine drug testing in the U.S. general workforce was down 5.8%. The positivity rate in pre-employment urine drug screening for the federally mandated, safety-sensitive workforce remained unchanged from 2011 through the first half of 2012, but the positivity rate from random testing among these workers was down 6.7% in the first six months of 2012 compared to 2011.

"The uptick in U.S. general workforce pre-employment data suggests that employers should be mindful of illicit drug use among prospective employees," said Dr. Barry Sample, Director of Science and Technology for Quest Diagnostics Employer Solutions. "These findings align with recent news reports citing some employers facing increasing drug positives when recruiting new workers."

Gap Between Oral Fluid and Urine Positivity Rates Grows

DTI data also 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. Sample. "Simply put, it is extremely difficult to cheat an oral fluid collection when someone is observing."

While both urine and oral fluid testing are highly effective in detecting recent drug use, urine specimen collection is unobserved, affording donors seeking to evade detection with the means to adulterate the specimen. In contrast, oral fluid specimens are collected when the donor places a swab in his or her mouth under direct observation of the drug test administrator.

Marijuana Continues to Be the Most Commonly Abused Drug

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.

Pre-employment oral fluid drug testing data showed a sharp increase (15.7%) in the positivity rate from 2011 to the first-half of 2012 (4.4% vs. 5.1%). This increase is likely related to the increase in marijuana positivity rates, which was driven by changes in testing technology. The positivity rate in random oral fluid drug testing is up 12.1% from 2011 to the first-half of 2012 (3.3% vs. 3.7%). This increase reversed the 8.3% decline seen between 2010 and 2011.

Substance misuse negatively affects the workplace through lost productivity, workplace accidents and injuries, employee absenteeism, low morale and increased illness and can have a serious impact on business operations.

According to the National Institute on Drug Abuse, "marijuana intoxication can cause distorted perceptions, impaired coordination, difficulty with thinking and problem solving, and problems with learning and memory. Research has shown that, in chronic users, marijuana's adverse impact on learning and memory can last for days or weeks after the acute effects of the drug wear off. As a result, someone who smokes marijuana every day may be functioning at a suboptimal intellectual level all of the time."

Cocaine Use Is Decreasing

According to the January to June 2012 DTI oral fluid data, the cocaine positivity rate was down 14.6% compared to 2011, continuing a downward trend from previous years; cocaine oral fluid positives in 2011 were down 10.9% compared to 2010. According to SAMHSA, in 2011, there were an estimated 1.4 million current cocaine users aged 12 or older, comprising 0.5% of the population.

Amphetamines Use Continues Five-Year Upward Trend

The 2012 DTI urine data further reports that amphetamines positives continue a five-year upward trend. In urine drug testing in the U.S. general workforce, the amphetamines positivity rate increased 11.7%, from 0.77% in 2011 to 0.86% from January to June 2012. In the federally mandated, safety-sensitive workforce, amphetamines positives increased 6.8%, from 0.44% in 2011 to 0.47% in the first half of 2012.

The new DTI report is based on an analysis of more than 3.4 million urine and 340 thousand oral fluid drug tests performed at Quest Diagnostics laboratories between January and June 2012.

About the Quest Diagnostics Drug Testing Index

The Quest Diagnostics Drug Testing Index is published as a public service for government, media and industry and has been considered a benchmark for national trends since its inception in 1988. It examines positivity rates - the proportion of positive results for each drug to all such drug tests performed - among three major testing populations: federally mandated, safety-sensitive workers; the general workforce; and the combined U.S. workforce.

For more information about the Quest Diagnostics Drug Testing Index, visit www.QuestDiagnostics.com/DTI.

About Quest Diagnostics

Quest Diagnostics is the world's leading provider of diagnostic information services that patients and doctors need to make better healthcare decisions. The company offers the broadest access to diagnostic information services through its network of laboratories and patient service centers, and provides interpretive consultation through its extensive medical and scientific staff. Quest Diagnostics is a pioneer in developing innovative diagnostic tests and advanced healthcare information technology solutions that help improve patient care. Additional company information is available at QuestDiagnostics.com. Follow us at Facebook.com/QuestDiagnostics and Twitter.com/QuestDX.

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SOURCE Quest Diagnostics