Health & Wellbeing

Is a breath test for marijuana nothing but a pipe dream?

Is a breath test for marijuana...
Cannabix claims its system will detect THC use within a two hour period and provide instant positive or negative results
Cannabix claims its system will detect THC use within a two hour period and provide instant positive or negative results
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Cannabix claims its system will detect THC use within a two hour period and provide instant positive or negative results
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Cannabix claims its system will detect THC use within a two hour period and provide instant positive or negative results
An alpha prototype of Cannabix marijuana breathalyzer
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An alpha prototype of Cannabix marijuana breathalyzer

Difficulties in testing for THC mean that curbing cannabis use amongst drivers hasn't been all that straightforward. Though marijuana use can be detected in the saliva for up to 24 hours after use, it can show up in blood and urine samples for anywhere up to a month. Existing methods like blood and urine samples therefore make it hard to determine whether a driver is actually impaired at the time that they jump behind the wheel. But companies like Canada's Cannabix are working on portable breathalyzers designed to test exclusively for recent use of the drug, a solution that could be of great assistance to law enforcement personnel in keeping impaired drivers off the road.

The spark may have been lit for a marijuana breath test in 2007, when a roadside survey carried out by the US National Highway Traffic Safety Administration found 8.7 percent of people driving at night time on the weekends were doing so under the influence of THC. In the time since, four US states have legalized recreational marijuana use, with others expected to follow suit.

But developing a more precise means of testing has been slow going. Cannabix's solution has been in the works for around two years, with the company only recently announcing an alpha prototype. It is not divulging a whole lot about how the patent-pending system will actually work, only to say it will detect THC use within a two hour period and provide instant positive or negative results. The company says it is now developing a beta version for third-party testing.

While Cannabix may be making the most noise about achieving a marketable product, there are a number of parties breathing down its neck. In April, a pair of University of Akron students announced they were developing The Cannibuster, a smartphone-sized device designed to test levels of THC in minutes using saliva. Meanwhile, researchers at Washington State University are developing a THC breath testing device that relies on ion mobility spectrometry.

A study undertaken by the National Institute on Drug Abuse (NIDA) last year suggested that breath testing for marijuana was feasible in principle using a SensAbues collection device. This Swedish-developed system captures metabolites in the breath with a polymetric filter and then screens for THC in the lab using mass spectrometry.

It tested the breath of 13 frequent users and 11 occasional users who had each smoked a single marijuana cigarette. The system returned positive results in all but one of the occasional users, with overall positive tests declining with the passing of time: 77 percent of breath samples taken at 1.4 hours tested positive, 54 percent at 2.4 hours and zero at three hours.

So there's no shortage of potential solutions on the horizon, but a haze still surrounds whether these efforts can actually translate to reliable, roadside breath testing systems. This largely stems from the fact that unlike alcohol, which remains in the bloodstream until you become sober, THC tends to linger long after its effects have worn off. So a real device that only returns a positive test if the subject is acutely affected by marijuana is yet to be comprehensively detailed.

This has unsurprisingly drawn criticism from users and non-users alike, with the prospect of people falling foul of the law despite using the drug days or even weeks before testing a potential consequence of marijuana breathalyzers. And that's not to mention the complexities in defining exactly what level of THC concentration constitutes an impairment for drivers.

Some states, such as Washington and Oregon, impose a five nanograms per milliliter limit, while others enforce a zero tolerance approach. Following their studies, researchers at the NIDA proposed experiments where subjects would take simulated driving tests while under the influence of marijuana to determine the actual THC concentrations that align with impairment.

So despite all the huffing and puffing, there appears to be some work to do before the science is truly settled and a patrol officer strolls up to your car with a marijuana breath test in tow.

13 comments
Charles Jones
People who smoke marijuana have been driving safely for decades without much of a problem as they are more relaxed. I would think that they cause less accidents than a person driving who is not under the influence of anything. Stress, distraction and the use of alcohol have been proven to cause more accidents than any other factor.
owlbeyou
The complexity of a marijuana breathalyzer test is well illustrated here.
If anything, you can sometimes spot a driver who has smoked a joint because he is driving s l o w e r than the other cars :)
RichDavis
"People who smoke marijuana have been driving safely..." hahaha. What are you smoking? There are plenty of accidents from people high on pot over the years.
Making up an excuse for this shows that you are in denial about something. The issue is that they haven't figured out what level is safe, so right now, as long as it's detectable, it's a potential DUI and it's up to the cop/judge to determine if it is.
I know someone that got a DUI from being high and he got retested 30 days later and it was STILL in his system and that was a probation violation. The other problem with pot is that depending on how much and how frequent you smoke/ingest, it can stay in your system and still be detectable for up to 90 days or so. So, it's a really bad drug to get in the habit of doing if you don't want to get a DUI, especially if they start carrying around breathalyzers for pot.
The reality is is that it's illegal to drive while under the influence, it can stay present in your system for as long as 90 days, and they are developing breathalyzers to carry around. That's the reality, so now it's up to you on whether or not you are going to take the risk and continue to use it or not. If you use pot, then the statistical probability that you will eventually get a DUI and there is no way they are going to make it legal to drive under the influence. About the ONLY thing they might do, eventually, is determine the minimum levels of being unsafe, but that hasn't been determined, so until it has, best advice is to take Uber, Lyft, taxi or have someone else drive you around if you don't want to get a DUI.
Tom Lee Mullins
With marijuana being legalized in so many states, a device to test for drivers under the influence. I think it could help make the roads safer.
Wolf0579
Science being used to criminalize otherwise benign behavior. Good job, Police State! Keep it up. We're already seeing people retaliate against the police with deadly force.
Dave Lawrence
There's a reason they call it dope - for the substance, for the user and for dickheads who justify it's unfettered use. Driving whilst under the influence of a controlled substance basically sends a two finger salute to everyone else in your life - family, friends, the law and especially the people who are on the sharp end of your arrant stupidity
When you have killed someone because you have been stupid enough to drive drunk, or stoned, perhaps your rose tinted view will change. Roads are more dangerous now, drivers less capable now, so many driving without proper instruction . . . . .
Personally i'd tattoo the heads of anyone convicted DUI - it might send out a message to the stupid people who think it won't matter
jerryd
There is the better non drug test, seeing if people can do certain tests tells whether they are impaired or not. If they can't, they shouldn't be behind the wheel no matter why. On the pot testing, THC is only one of many factors in pot. And unless you can put a number on it reliably, it is useless in court. Since pot effects everyone differently as does alcohol, the physical tests are more accurate on both in real life. Pot works because all these compounds work together in small amounts each. Until they can quantify that, drug testing isn't good enough for legal work. Like lie detecting which isn't that accurate, it has to work extremely well to be evidence. We have good testing, Let them touch their nose, walk a straight line, etc instead of these testers that can't be accurate because pot is too complex.
Jason Pase
Unlike alcohol - marijuana has NEVER been scientifically proven to cause any driver impairment at all.
HarryScrotum
This is undoubtedly the stupidest thing I've read lately. This is either a case of genuine ignorance by everyone concerned (which alone staggers the imagination) or knowledge suppressed for any of a number of reasons, all of them dishonest at best. Here's a news flash for those truly ignorant of the facts. If smoking marijuana really impaired driving, the population of the U.S. would be as much as 50% less than it is today. The reason being, by the late 70's until the late 80's, as much as 80% of the American workforce smoked pot.Those that didn't on the way to work (damn few) did so on the way home. For the blue collar part of the work force I know for a fact these numbers are accurate enough. Therefore,it would be only logical to extrapolate, if marijuana necessitated the restrictions that alcohol does, as those who ASSume the need for such testing ASSume, then people driving under the influence of marijuana should have eliminated the better part of at least a generation to a generation and a half of Americans in that time period. This of course is ridiculous and is the basis for my questioning the honesty of whatever panel that conceived the notion that any such device is mandated. Does everybody in the 50+ crowed suffer from amnesia? Or is it simply easier to follow the rest of the sheeple, like the inhabitants of the village in the old tale of the "Emperors New Clothes"?
curtiselmore
The only drug test we ever need is an outcome determinative test: Did someone hurt someone else? Was it intentional or grossly negligent? If so it doesn't matter what state of mind some fancy test says you're in or not in. But don't confuse the intent to use the drugs with the intent to commit harm. And don't condemn the former if no harm was committed. Your rights as an American expand until they come up against someone else's rights. If they never do, you should be free to go about your merry way.