Marijuana use drives up drug test positivity rates in Michigan
Failed workplace drug tests continue to rise in Michigan, largely due to marijuana legalization and normalization.
Among all drug categories — marijuana, amphetamines, cocaine and opiates — 6.8% of drug tests taken as a condition of employment in Michigan were positive last year, according to data from the country's largest drug testing diagnostics lab, Quest Diagnostics. Michigan's positivity rate far exceeds the national average of 4.6%.
Michigan's drug test positivity rate is largely buoyed by a spike in marijuana use. Employer-required drug test positives in Michigan for marijuana use have increased from 1.9% in 2008 when voters legalized medical use, to 3.3% in 2018 when a similar bill to legalize recreational adult-use marijuana was passed, to 5.8% in 2023. Quest did not disclose the number of drug tests given in Michigan last year or included in the sample size.
The national average for marijuana drug testing positivity is 4.7%, according to Quest data based on 9.8 million workplace-required drug tests collected last year.
Though marijuana positivity is increasing, fewer and fewer employers are considering the result as a barrier to employment, especially now that marijuana is legal in the state. The state of Michigan ended drug testing for most state government positions, about 54,000 full-time positions, on Oct. 1 last year, for instance.
However, Michigan remains a manufacturing state where safety-critical jobs require testing. Companies with federal contracts are also required to test for many jobs.
Nationally, the marijuana positivity rate in safety-sensitive jobs decreased to 0.95% last year from 0.98% in 2022. But when a workplace accident does happen, marijuana positivity has continued to climb — increasing 114.3% nationally since 2015. Although a positive test for marijuana post-accident does not indicate the person involved in the accident was actively using marijuana, as the drug can stay in a user’s systems for weeks and months.
But it’s office jobs that dominate marijuana positivity nationally, with increases in 13 of 15 industries. Finance and insurance workers led the way with marijuana positivity — up 35.7% from 2022. Public administration saw a year-over-year increase of 23.5% and real estate and leasing saw an increase of 22.2%.
"It isn't clear why we're seeing an increase in overall and marijuana drug positivity in office workers, but it isn't a stretch that a combination of unprecedented stress and isolation during the pandemic with work-from-home policies during and post-pandemic may be contributing to greater drug use in employees in traditionally white-collar fields," Sam Sphar, vice president and general manager of workforce health solutions for Quest, said in a press release. "The results underscore the growing need for mental health support and drug education programs to ensure employees are safe and productive, whether working at home or in the office."
Yet while marijuana positivity increased nationally and in Michigan, the positivity rate for other drugs has largely decreased over the past five years.
Natural opiate positivity decreased to 0.15% in Michigan last year from 0.26% in 2019. This class of drug includes heroin, morphine and codeine. The positivity rate of semi-synthetic opiates, such as hydrocodone and oxycodone, decreased to 0.38% from 0.5% in 2019.
Cocaine positivity also decreased to 0.19% in 2023 from 0.25% before the pandemic.
Amphetamine positivity, however, has largely remained consistent with a positivity rate of 1.4%.
