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Suburban police hope saliva holds the solution to the marijuana impairment puzzle

Daily Herald

Monday, September 9, 2019  |  Article  |  Elena Ferrarin

Drugs (32)

With no standardized roadside testing in place for marijuana impairment before recreational pot legalization begins Jan. 1, the focus is on saliva.


Carol Stream police are leading the way in Illinois with their second saliva pilot program. But law enforcement and medical experts caution there is no real consensus about determining impairment via chemical testing and observation of drivers' behavior remains crucial.


Carol Stream's current pilot program involves drivers charged with driving under the influence of drugs who voluntarily agree to be tested at the police station with a device manufactured by a Texas company, Sgt. Brian Cluever said. Officers get two swabs of saliva: one is tested immediately with the device, the other is saved for retesting. The device has a cutoff detection of 40 nanograms of THC, the active component in marijuana, per milliliter of saliva.


Testing has been limited, so there's not enough data yet to opine on the device's accuracy, Cluever said. The department will report results to the Illinois Department of Transportation, from which it obtained a grant, he said.


Part of the goal is to determine the viability of roadside testing, including the amount of time it takes, Cluever said.


"Ten minutes on the side of the road with vehicles going by 60 miles an hour can be a long time," he said.


Saliva testing pilot programs also have been done by law enforcement in other parts of the country. Illinois State Police are considering establishing a saliva testing pilot program, but there's been no decision about when that might happen, how long it might last or which testing equipment will be used, state police Sgt. Jacqueline Cepeda said.

Illinois law says drivers are impaired when they have 10 nanograms of THC per milliliter of saliva or other bodily fluid, or 5 nanograms per milliliter of blood. Carol Stream conducted its first pilot program last year with a different saliva testing device that had a cutoff of 50 nanograms of THC.


"We're hoping to get to the point where they can increase the technology so that (detection) goes down to 10 nanograms," Cluever said.


However, an overarching problem is the limits set by law are debatable, because people can be impaired with much less in their system, Cluever said.


Lake in the Hills police Sgt. Adam Carson, a drug recognition expert, agreed. There can be differences in how people react to marijuana, depending on factors such as its strength, whether people are novices or habitual users, and whether they also drank alcohol or took prescription drugs, he said.


"I personally had people that have been over 50 nanograms that aren't showing signs of impairment, and I've had people that have been at 5 (nanograms) and can't stand up," he said.


The nanogram levels set by Illinois law, mirroring those under Colorado's recreational pot law, are debated in academic circles, said Dr. Jenna Nikolaides, a medical toxicologist at Rush University Medical Center in Chicago. Unlike alcohol, which has a predictable effect, assessing the correlation between marijuana levels in the body and an actual "high" is much more difficult, she said.


"Is that (level) impairing? Is it not impairing? Is it too much to be driving? Is it fine to be driving?" she said. "No one knows."


The connection between THC levels in a person's saliva, blood and brain also hasn't been accurately established, Nikolaides said. THC is fat-soluble, meaning it is stored in fatty tissue and can slowly enter the bloodstream over time. But even when THC blood levels are low, brain levels might be high, she said. Urine levels are unreliable, because habitual users can urinate THC for weeks, she said.


Saliva testing can "probably" detect the presence of THC, but its connection to impairment is unclear, she said. Saliva also might detect if people recently ate marijuana edibles, but if they haven't digested them yet, there might be no impairment, she said.


Another problem is drivers might be under the legal threshold for alcohol and marijuana, but the combined effect might make them impaired, Nikolaides and the officers said.