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Scientists Edge Closer to a Marijuana Breathalyzer

Sirius J



Recently published research has developed the concentration-effect relationship for THC in breath. While devices for on-the-spot measuring of THC in breath already exist, nobody knew exactly how much THC they needed to measure in order to determine if a person was stoned.

Regulators in Colorado set the arbitrary limit of five nanograms of THC per liter of blood as the amount that means you’re too stoned to drive. Both the medical and cannabis communities have denounced this number because it horribly misrepresents whether somebody is stoned or not. A frequent dabber could do dabs all morning and be perfectly sober after eating lunch, yet his or her blood levels of THC in one liter could be enough to tranquilize a small mammal.

Despite the fact they have rejected the idea of the arbitrary regulation of five nanograms per liter of blood, marijuana activists know deep down that law enforcement needs a breathalyzer-type device to detect stoned drivers, for their own sake. Without such a device police would undoubtedly have rely on their “keen instincts” to tell if someone is stoned, meaning any driver with pacifist bumper sticker or a Bob Marley shirt will be accused of stoned driving due to stoner profiling.

The latest research out of Ghent, Belgium developed a sampling method that can pick up aerosolized breath particles to measure THC. It only has a detection window for THC of three hours after smoking, meaning you pretty much have to be high to give a positive reading, but THC detection times can be up to 3 months, so it’s hardly objective. In addition, the device does not pick up THC’s metabolite, so somebody that smoking a lot before three hours about taking the test does not show positive, even if their body is teeming with THC metabolites.

More importantly, the researchers developed a concentration-effect relationship to determine how much THC in breath it took to determine if somebody was high by measuring pulse rate and pupil diameter. The idea is this concentration-effect relationship should hold true for novice and experienced smokers alike because it only looks at how much THC is circulating in the blood at any given time, not how much metabolite is stored in their fat cells.

Breathalyzers such as the one developed by Cannabix from Vancouver or the University of British Columbia may one day use this concentration-effect relationship to take more accurate readings of stoned drivers.

Other on-the-spot drug testing technologies use immunoassay tests that deliver pass/fail readings based on a predetermined limit of THC in bodily fluids. Smartox, the American marketer and distributor for the British company Intelligent Fingerprinting, uses a fingerprinting device to measure THC, or other substances, present in human sweat. Oxtox from England uses a saliva swap to measure THC in a handheld device, but they seemed to have sacrificed accuracy for simplicity and ease of use. Police in Europe use a similar device called DrugWipe to test for a variety of substances such as MDMA, methamphetamine, THC, LSD, benzodiazapines, cocaine in one go, but some reports say DrugWipe is only two-thirds effective.

So far none of these devices have received approval from the Food and Drug Administration, and will not see use by any authorities until they do. However, your employer doesn’t need FDA approval to put a device such as Intelligent Fingerprinting at the front door of your office, and unsuspecting workers may see themselves subject to inaccurate drug tests that violate their civil liberties and falsely accuse them of being high when they’re not.

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