Blood Feud: Advocacy Groups At Odds Over How To Test Impaired Drivers For Marijuana

Article by Kevin Maimann, Metro News

Two advocacy groups are at odds over whether blood testing should be done on motorists who are impaired by marijuana.

While MADD Canada supports the federal proposal to measure the amount of THC in a driver’s bloodstream, Smart Approaches to Marijuana (SAM) Canada has written to the federal government in opposition to the plan.

“A blood level is absolutely useless,” said Phillip Drum, a pharmacist who works with SAM as well as a U.S. group called Citizens Against Legalizing Marijuana. “It’s not the same molecule as alcohol. It’s residing in the brain, not the bloodstream.”

Drum said the body eliminates 80-90 per cent of marijuana from the bloodstream within an hour when smoked because it is fat-soluble, unlike alcohol.

Impairment doesn’t peak until it starts leaving the blood, so any reading of THC in the blood would be out of line with the driver’s actual level of impairment, he argued.

A 2015 U.S. study showed standard roadside field sobriety tests – the same tests used on suspected drunk drivers – conducted by police officers who are trained Drug Recognition Experts are the most reliable way to test for marijuana impairment.

“If the person fails two of the four (tests), with a 96.7 per cent accuracy rate they’re going to be able to determine whether they are under the influence of marijuana,” Drum said.

The next step, he said, would be an oral fluid test to confirm or deny the presence of marijuana or another drug.

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