The rate of positive test results for marijuana increased in nearly all workforce categories. In the general U.S. workforce, positive tests for marijuana increased nearly eight percent in urine testing (2.6 percent in 2017 versus 2.8 percent in 2018) and almost 17 percent since 2014 (2.4 percent). For the federally mandated, safety-sensitive workforce, which uses only urine testing, positive test results for marijuana grew nearly five percent between 2017 (0.84 percent) and 2018 (0.88 percent) and nearly 24 percent since 2014 (0.71 percent).

In the general U.S. workforce, positive test results for opiates in urine drug testing declined across all opiate categories. Among the general workforce screening for opiates (mostly codeine and morphine), positive test results declined nearly 21 percent between 2017 and 2018 (0.39 percent versus 0.31 percent), the largest drop in three years and a nearly 37 percent decrease since the peak in 2015 (0.49 percent). Among the more specific tests for other prescription opiates, the positivity for the semi-synthetic opiates (hydrocodone and/or hydromorphone) declined two percent between 2017 and 2018 (0.51 percent versus 0.50 percent) and 43 percent since the five-year high in 2014 (0.88 percent).

Similarly, positive test results for oxycodones (oxycodone and/or oxymorphone) declined more than 29 percent between 2017 and 2018 (0.61 percent vs. 0.43 percent) and more than 46 percent since the five-year high in 2014 (0.80%).

Quest also pointed out that urine drug test results for the general U.S. workforce for heroin, indicated by the presence of the 6-acetylmorphine (“6-AM”) metabolite, declined six percent (0.033 percent in 2017 versus 0.031 percent in 2018) and more than 16 percent since its peak in 2015 and 2016 (0.037 percent). Cocaine positivity declined nearly seven percent in urine and more than 19 percent in oral fluid testing, but increased slightly year-over-year (6.3 percent) in hair testing.

Both heroin and cocaine positivity in the federally mandated, safety-sensitive workforce showed large declines between 2017 and 2018. Heroin positivity declined nearly 32 percent between 2017 and 2018 (0.019 percent versus 0.013 percent), with a decrease of more than 43 percent since 2015 (0.023 percent). 2018 positivity for cocaine declined nearly 10 percent compared with 2017 (0.31 percent versus 0.28 percent), when the positive test results rate was the highest in more than five years.

Quest noted that changes to federal rules for drug testing the federally mandated, safety-sensitive workforce went into effect in January 2018. According to Quest, the addition of four semi-synthetic opiates contributed to the large increases in year-over-year positivity among those workers. In 2018, testing for semi-synthetic opiates (hydrocodone and/or hydromorphone) and for oxycodones (oxycodone and/or oxymorphone), the positive test rates were 0.45 percent and 0.34 percent, respectively. These positive test rates were both slightly less than general U.S. workforce testing.

In the federally mandated safety-sensitive workforce, Quest noted, positive test results for post-accident urine testing jumped more than 51 percent year-over-year (3.1 percent in 2017 versus 4.7 percent in 2018) and increased by nearly 81 percent between 2014 and 2018. The jump in 2018 was largely driven by the addition of prescription opiates to the panel where post-accident positive test results for the semi-synthetic opiates (hydrocodone and/or hydromorphone) and for oxycodones (oxycodone and/or oxymorphone) was 1.1 percent and 0.77 percent, respectively. Post-accident positive test results in the general U.S. workforce climbed nine percent year-over-year (7.7 percent in 2017 versus 8.4 percent in 2018), and 29 percent over five years. The post-accident positive test results 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, Ph.D., Quest's scientific director. “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.”

Quest said that its findings showed an increased percentage of urine specimens in both the federally mandated, safety-sensitive, and general U.S. workforces 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 mandated, safety-sensitive workforce jumped 80 percent (0.15 percent versus 0.27 percent), and 40 percent in the general U.S. workforce (0.15 percent versus 0.21 percent).

Learn more: www.QuestDiagnostics.com.