Positive Workplace Drug Test Rate Highest Since 2004

Medical / First Aid, Safety News

The rate of positive workforce drug test results hit a fourteen-year high in 2018, according to a new analysis released this month by Quest Diagnostics. Analysis of more than ten million workplace drug test results shows increases in marijuana positivity across nearly all employee testing categories. Increases in positive post-accident tests in the general U.S. workforce outpace those for all other testing reasons, including pre-employment screening.

“Our in-depth analysis shows that marijuana is not only present in our workforce, but use continues to increase,” said Barry Sample, PhD, senior director, science and technology, Quest Diagnostics. “As marijuana policy changes and employers consider strategies to protect their employees, customers and general public, employers should weigh the risks that drug use, including marijuana, poses to their business.”


Marijuana dominates in general workforce. Positive opiate tests decline

  • Marijuana again tops the list as the most commonly detected illicit substance across all workforce categories (general U.S. workforce; federally mandated, safety-sensitive workforce; and combined U.S. workforce, which includes both groups).
  • Marijuana positivity increased nearly 8 percent to 2.8 percent in the general U.S. workforce, which represents nearly a 17 percent increase since 2014.
  • Among federally mandated, safety-sensitive workers, positive tests grew nearly five percent between 2017 and 2018 to 0.88 percent – nearly a 24 percent increase since 2014.
  • Positive opiate tests in the general workforce declined nearly 21 percent between 2017 and 2018 to 0.31 percent, the largest drop in three years and nearly 37 percent decrease since the peak of 0.49 percent in 2015.
  • Positivity rates for both heroin and cocaine declined in general and federally mandated, safety-sensitive U.S. workforce testing

New rules for opioid testing drive increase among Federal workers

Revised Federal rules for drug testing of federally mandated, safety-sensitive workers took effect in January 2018. The addition of four semi-synthetic opiates contributed to the large increases in year-over-year positivity among those workers. In 2018, positive testing for semi-synthetic opiates and oxycodones was 0.45 percent and 0.34 percent, respectively. These positivity rates are both slightly less than general U.S. workforce testing.

Post-accident positives increase in all groups

In the federally mandated, safety-sensitive workforce, positive post-accident urine testing jumped more than 51 percent year-over-year to 4.7 percent in 2018. The jump was largely driven by the addition of prescription opiates to the test protocol. Post-accident positivity in the general U.S. workforce climbed nine percent year-over-year to 8.4 percent in 2018. The post-accident positivity rate has risen annually since 2011 in the general U.S. workforce and since 2010 in the federally mandated, safety-sensitive workforce.

“Increases in post-accident positivity among safety-sensitive workers should serve as a warning to employers that employee drug use may increase the risk of workforce accidents or injuries” said Kimberly Samano, PhD, scientific director, Quest Diagnostics. “Our analysis suggests that employers committed to creating a safe, drug-free work environment should incorporate strategies that monitor drug use above and beyond pre-employment drug screening.”

More workers are trying to cheat drug tests

Findings show an increased percentage of urine specimens in both groups reported as invalid due to inconsistency with normal human urine, suggesting attempts at specimen adulteration or substitution. Between 2017 and 2018, the percentage of invalid results in the federally group jumped 80 percent (0.15% versus 0.27%), and 40 percent in the general U.S. workforce (0.15% versus 0.21%).

Quest Diagnostics released the results of the Quest Diagnostics Drug Testing Index™ April 11 at the Drug and Alcohol Testing Industry Association annual conference in Chicago.


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