DETROIT — The Michigan State Police crime lab has stopped screening blood samples for THC, the compound that gives marijuana users a high, after problems with testing, a spokeswoman said.
County prosecutors were informed this week, Shanon Banner told The Associated Press.
The suspension will be in place “as we work to learn more and/or until we can institute another validated method of testing to ensure accuracy,” Banner said in an email.
Since 2018, marijuana has been legal under state law for people who are at least 21. Medicinal use was approved 10 years earlier.
It's still illegal to drive under the influence of marijuana but Michigan, unlike some other states, has no established limit. In 2019, a commission recommended against creating a threshold because of a “poor correlation” between bodily content and driving impairment.
Nonetheless, prosecutors still can present evidence of THC in court, defense attorney Mike Nichols said.
“Somebody gets pulled over and there’s an accident where someone is hurt or killed,” he said. “It's been a bigger deal since we went medical in 2008. I get more and more cases.”
Banner said a “discrepancy” in the lab was discovered this week in which the presence of CBD may have led to a positive result for THC.
CBD, also found in marijuana, does not cause a high and is often sold as a dietary supplement or included in creams and other personal care products. CBD products are legal, with some restrictions, in almost all states.
“We are actively working to identify the scope, but likely won’t have additional information until next week,” Banner said.
Nichols believes the problem rests with inadequate technology in the lab.
"There is a more sensitive methodology, but those instruments cost a lot more,” he said.
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