What Are Cannabis Breathalyzers – And What Do They Check For?

Marijuana is now legal for medicinal purposes in a majority of American states. It is also fully legal in Canada. As a result, law enforcement has a new problem: an increased number of stoned motorists. Whether we like to admit it or not, driving while high is not a good idea. As a result, companies are doing their best to create a cannabis breathalyzer.

In theory, it can detect THC, the most prevalent psychoactive compound, in a person’s blood. In this scenario, a police officer could stop someone suspected of driving while high. They could administer a test similar to what is available to test potentially drunk drivers. It is a technological advance that proved elusive. Until now, that is.

Are We About to See the World’s First Marijuana Breathalyzer?

The California Highway Patrol (CHP) already uses a marijuana test of sorts. It has a plastic swab stick stuck into a computerized unit that looks like a portable credit card reader. Alere Toxicology developed it. A representative for the company claims the device has a 95% accuracy rate. It tests for weed, opiates, methamphetamines, and cocaine.

The device tests a person’s saliva and can detect whether you have used weed within a couple of hours. It does so by testing the saliva for THC-COOH, also known as THC metabolites. Although we find it odd that California doesn’t have a cannabis intoxication threshold, it is a necessary step. There is one in Washington of 5 nanograms per ml of blood, and it is even stricter in Nevada at 2ng/ml.

A New Form of Marijuana Testing

Hound Labs, a diagnostics company, based in Oakland, is about to go one step further. It aims to introduce a functional marijuana breathalyzer to the market. It will propel the company to fame and help law enforcement catch and arrest stoned drivers if it works. Hound Labs first began working on the device back in 2015. At the time of writing, it is not yet available commercially.

The company first began conducting clinical trials in 2016. The following year at TechCrunch, Hound Labs’ founder, Mike Lynn, was asked, “Why are you such a narc?” onstage! In recent times, Lynn said, “we’re not Theranos,” a thinly veiled swipe at the company infamous for inferior blood testing technology.

Unusual Testing

Hound Labs claims to have conducted a vast array of testing, although some of these tests have rightly been criticized. One of the daftest videos was uploaded to YouTube, which shows high drivers crashing into things.

Hound invited the volunteers to get as high as they wanted then drive at 65 miles an hour around a 1.5-mile track. In this situation, there was a 99% chance of the motorists hitting objects. However, Hound laughably claimed it was the equivalent of hitting cyclists on the road.

The device consists of a small plastic cartridge that slides into a device that resembles a cellphone from the late 1980s. A small plastic tube sticks out at one end, and you are supposed to blow into it for 30 seconds. On the screen, you can see indicator bars that detect THC in your breath.

According to the company, the device will detect whether you have consumed weed within the last two hours. It makes sense to minimize the time frame. This practice can prevent individuals from being arrested because they had a joint the night before. There is also a base station which is around the same size as a standard laptop. Its primary role is to protect the cartridge, which is damaged by extreme cold or hot temperatures.

Interestingly, the Hound Labs device also acts as a standard alcohol breathalyzer. It gives law enforcement officials a handy two-in-one testing kit.

The Problem with Marijuana Testing

At present, police officers can’t scientifically test for marijuana use roadside. Instead, they can assume consumption based on a driver’s appearance or behavior. They can also smell weed from the car. When it comes to alcohol consumption, there are per se drunk driving laws. Drivers are automatically guilty of DUI if their Blood Alcohol Concentration (BAC) level is at 0.08 or greater.

The problem with marijuana per se laws is the lack of good science involved. Several American states also say that you are guilty of DUI if the THC level in your blood is 5ng/ml or over. These limits are completely arbitrary. They are a result of treating weed and alcohol as the same kind of drug.

Alcohol is water-soluble, which means it diffuses through the body quickly. Its peak effects and impairment tend to occur up to an hour after ingestion. Then, it slowly reduces over time. Therefore, alcohol breathalyzers can provide police officers with a reliable measurement of driver impairment.

Marijuana behaves differently in the body. THC is not particularly soluble in blood, so it ends up in our fat stores. Our maximum THC level occurs within 10 minutes of smoking. In some tests, blood levels fell below 5 ug/L after 84 minutes, and below 2.0 after 198 minutes. However, some people stayed above 2 ug/L for up to 8 hours.

As THC builds up in our fat cells, it gets released over a long time. As a result, you could have it in your blood from previous exposure. It is possible to ‘fail’ an impairment test even though you haven’t used weed that day. Furthermore, it is virtually impossible to link a blood THC measurement to impairment levels. This is because it can easily cause impairment in an individual with a reading of 2ng/ml.

To What Degree Does Marijuana Impair Driving Performance?

That is the million-dollar question. Until we get an answer, there is no evidence that Hound Labs’ device will prove effective. The existing tests on the market test for saliva, urine, or blood. It can take days for the test results to arrive. These tests also can’t tell if a person used weed a week ago or an hour ago.

Hound Labs claims it can accurately measure THC in a person’s breath molecules in parts per trillion; that’s a bold claim. Yet any marijuana breathalyzer must be this accurate. Impairment from alcohol is measured in parts per thousand. In contrast, THC has a concentration of up to one billion times less.

According to Lynn, this technical issue is the main reason why Hound Labs has taken years to perfect the device. The machine can detect THC in your breath. However, it can’t calculate how much THC you have consumed. Several police departments should test the breathalyzer as we speak. Perhaps it can provide them with the objective roadside data that has previously eluded them.

However, is this device likely to be effective given the lack of evidence to link THC with traffic accidents caused by impaired driving? A study by Keyes, Brady, and Li, published in Injury Epidemiology in 2015, showed that approximately half of young drivers (aged 16-25) involved in a fatal traffic accident were under the influence of weed, alcohol, or both.

Researchers acknowledge that they don’t know the extent to which cannabis affects a driver’s judgment, skill, or response. However, it seems as if marijuana impacts drivers differently than alcohol. According to one Harvard researcher, drunk drivers run red lights while stoned drivers stop at green lights! Of course, this kind of driving can also cause accidents.

A Dubious Breakthrough

In late February 2019, Hound Labs proudly announced the results of its second clinical trial involving the Hound Breathalyzer. It was conducted at the University of California San Francisco (UCSF) and featured 20 volunteers. The device measured their breath over three hours and took nine samples from each person. According to Dr. Kara Lynch of the UCSF, it was the most extensive study of its kind to date.

The trial found that THC moves quickly from the blood to the breath. It appears in very low concentrations for up to three hours. They also said it was proof that the technology is ultra-sensitive and capable of measuring THC in a person’s breath in parts for trillion, also known as picograms.

However, no one outside of the UCSF researchers and 20 volunteers have tested the device. Also, the volunteers brought the cannabis and consumed it.

Lynn also made a somewhat troubling statement. He admitted that the breathalyzer would show THC in your breath if you used any in the previous two hours. You will ‘fail’ the test whether you have half a dozen bong hits or a small puff of a joint. You could theoretically get arrested and lose your job for taking a small bite of an edible at lunchtime. It doesn’t matter if you live in a state where it is perfectly legal to do so.

Remember, we are just about coming to terms with the fact that cannabis microdosing could have health benefits. One would hope that the Hound device does fulfill its promise to ensure your ng/ml reading is accurate. Otherwise, we will see a spike in the number of DUI arrests. This is excellent news for any officers seeking to fulfill their monthly quota. It is not so good for legal marijuana users who microdose.

A More Scientific Breakthrough?

According to research published in Organic Letters in 2020, UCLA chemists have made the key chemical discovery to create a small electronic breathalyzer. Evan Darzi and Neil Garg are responsible for creating this chemistry. However, they have not yet created a device to combat Hound Labs.

The scientists developed a basic oxidation process similar to what you’ll find in an alcohol breathalyzer. These devices convert ethanol into an organic chemical compound. During the oxidation process, hydrogen is lost.

According to Garg, the chemistry they are doing with THC is the same thing as what happens with an alcohol breathalyzer. They remove a hydrogen molecule from THC. It results in a change in the color of the molecule, and this is detectable.

The next step involves achieving the same result with a breath sample from someone who recently used cannabis. Garg ultimately hopes that a cannabis breathalyzer is cheap enough for consumers to buy. Though it is an exciting finding, it seems as if a commercially available device is some time away.

Final Thoughts on the Marijuana Breathalyzer

At present, we don’t know the extent to which marijuana consumption impacts a person’s driving skills. Logically, it stands to reason that it impairs you, but we don’t know the degree.

Studies to date show that drivers under the influence of cannabis are less likely to drive recklessly. However, traveling too slowly or failing to indicate when turning can cause an accident, just like overtaking in the wrong place or driving too fast can.

A marijuana breathalyzer works well in theory. This is especially the case if Hound Labs’ device is genuinely capable of determining THC’s level in the blood. The main problem is that no state or nation knows what the ‘correct’ impairment level is. The existing limits are utterly useless because they wrongly treat cannabis and alcohol as similar drugs.

There is no question that law enforcement needs assistance on this issue. Increased legalization means more people are using pot and driving than ever before. We can’t allow drivers to get stoned before hitting the highway. However, there are a few flaws in the mooted marijuana breathalyzer. After years of testing, we still don’t know if and when Hound Labs will officially launch its device. However, we’re all holding our breath.