As the RCMP and local police across Canada deal with rising drug-impaired driving rates and prepare for even more with the legalization of new cannabis products, edibles may not be detected in oral fluid testing.

James Wigmore, a forensic toxicologist who specializes on the effects of drinking and using cannabis, said the science behind it may also explain why edibles can cause more psychoactive effects in some users.

“When smoking, you don’t get the intermediate metabolite … the cannabis goes into your lungs and avoids the liver,” he said in a phone interview.

The intermediate metabolite he’s referring to is 11-hydroxy THC.

When a cannabis-infused food is eaten, it usually contains decarboxylated cannabis — marijuana without carboxylic acid. The edible travels through the digestive system before the liver processes it. Inside the liver, the main psychoactive component of cannabis, THC (also known as delta-9-Tetrahydrocannabinol), releases it’s main metabolite, 11-hydroxy-THC.

“It becomes an active metabolite, which some say is even more psychoactive (than THC),” Wigmore said.

“Not only (does the edible) last longer, it produces more of a psychoactive effect. That’s the reason people have the worst reaction (compared with smoking).”

And because most oral fluid tests only look for delta-9 THC, Wigmore said its psychoactive metabolite goes unnoticed.

“Theoretically, you could have low-THC level but high 11-hydroxy level,” he said. “Oral fluid testing is less effective for edibles … blood tests will indicate that.”

Graham Miner,  director of Prince Edward Island’s highway safety division with the Ministry of Transportation — and the only government official in Canada to agree to an interview for the series — doesn’t think that will be the biggest issue.

“I don’t know if the issue will be deception,” he said in a phone interview.

“The bigger concern will be — will the use of cannabis become larger now than the number of those who report smoking it?”

The concerns come amid calls for government-mandated drug testing for commercial drivers in Canada.

The RCMP declined multiple requests for an interview but, did respond in an e-mail that drug screening equipment must be approved by the Canadian Society for Forensic Science and the Attorney General before being used.

While the RCMP has classroom training for officers to learn how to use the technology, the national headquarters doesn’t supply the equipment for its detachments across the country. Instead, local police forces use money from Public Safety Canada to buy the technology.

Const. James C. Cadigan, from the Royal Newfoundland Constabulary, said his precinct, for one, will be without new technology as edibles and other cannabis products roll out.

“We feel it’s a whole community that comes together to battle and impact impaired driving.”

Windsor Police officers stop drivers during enforcement blitz and RIDE Program. Jason Kryk / The Windsor Star

Current drug technology  used by police include a urine test, oral fluid test and blood test. A recent report by the Conference Board of Canada showed each of the tests have flaws.

“The research just has to catch up with the fact that cannabis is legal,” Chris Gilpin, superintendent and director of Highway Safety for the Ontario Provincial Police said in a phone interview.

“Private industries are doing that type of research and work to create that product and equipment for better detection, and we’re just anxiously waiting for it to be presented and approved.”

Urinalysis is the “gold-standard” for drug testing but takes at least 24 hours to complete, which means it can’t detect a worker’s current level of impairment. Oral fluid testing can’t detect cannabis that is consumed in pill forms or oils rubbed on skin . SoToxa and the Draeger DrugTest 5000, the two oral-fluid tests approved for police use, detect the presence of delta-9 THC, but cannot test how impaired someone is at the time of the roadside test and may not detect 11-hydroxy-THC. Meanwhile, blood tests are accurate but results can take months to process.

Cst. Braydon Lawrence with the Edmonton Police Service performs a drug test using an oral swab, which is used in the Draeger DrugTest 5000 to detect the presence of cannabis or cocaine. Greg Southam - Postmedia

While the various tests indicate if drugs are in the body, the RCMP noted the technology is only used to show “that further investigation can be carried out.”

“The devices are not designed to give a quantitative value like alcohol ‘breathalyzers’ are,” read an email from Cpl. Megan Apostoleris from the RCMP’s national headquarters in Ottawa.

Drug screening equipment is “not required to enforce impaired driving legislation.”

“Impaired is impaired. The use of Standardized Field Sobriety Test training  (SFST) and Drug Recognition Experts (DRE) will continue to be the primary enforcement tools against drug-impaired drivers,” Apostoleris wrote.

Ontario Provincial Police Const. John Rozich, left, demonstrates part of the drug recognition test with an OPP auxiliary officer in Ottawa. Postmedia

Police only need an SFST to charge someone with impaired driving. Police can ask drivers to do the test if they think the person is impaired. Refusing to do the test counts as a failure and could lead to a charge.

Under the Highway Traffic Act, novice drivers under age 22 and commercial drivers must maintain a zero-blood-drug content, while requirements for all other drivers are consistent with alcohol.

During the SFST, drivers follow a moving object with their eyes, walk nine heel-to-toe steps in a straight line before turning on one foot and walk back, and stand on one leg while counting up from 1,000 for about half a minute.

Failing any of the tests could lead to a charge.

Although it isn’t required, officers recommend the driver meets with a DRE to undergo the 12-step test, which includes an interview, an examination in a darkroom and a sample of saliva, urine or blood. Refusing to do the test is against the law.

“Police officers rely on what they see and hear as well as what they smell, when investigating impaired driving offences,” Apostoleris wrote.

“How a person is driving or interacting with the police officer can also provide indicators of impairment. Regardless of how a drug is consumed there are signs of that consumption and police are trained to recognize them.”