A Drug Breathalyzer? We're Still Not There

Breathalyzers have long been used to measure blood alcohol levels in suspected drunk drivers, but with marijuana now legalized in several states and the rising epidemic of heroin and prescription opioid abuse in the U.S., there's a growing demand for a similar test to detect drug-impaired driving.

Marijuana is the second most commonly detected drug (after alcohol) in the blood of individuals involved in accidents. A 2010 study revealed that 47 percent of drivers in fatal crashes tested positive for prescription drugs, most often painkillers.

At present, marijuana is detected using blood or urine tests, but there is growing interest from law enforcement and others in adopting a breath test — similar to the one used to assess alcohol impairment — since it is simpler to perform and provides immediate results.

Creating an effective drug breathalyzer is not as straightforward as modifying the existing models used for alcohol detection. This is due to the different ways substances are metabolized. To determine blood levels from breath, one must understand the vapor pressure of the substance — which refers to how a compound behaves when it transitions from liquid to gas, such as when a molecule moves from the blood to the breath. Substances with high vapor pressures, like ethyl alcohol, are constantly escaping, which is why alcohol is easy to detect, whether it's in a person's breath or in an open bottle of rum.

THC, the active ingredient in marijuana responsible for the 'high,' has an extremely low vapor pressure. This is so low that the traditional method of measuring alcohol — sealing the substance in a container and waiting for the pressure to equalize — does not work for THC. This process would take too long. Recently, researchers discovered that using a technology called PLOT-cryo allows them to detect the small amounts of THC that enter the vapor phase, potentially leading to the development of a marijuana breathalyzer.

A 2013 study published in the Journal of Breath Research explored whether breath could be used to identify drug intoxication. Swedish researchers tested for substances like marijuana, cocaine, methamphetamine, methadone, and morphine, using liquid chromatography-mass spectrometry for both breath and blood plasma analysis. 'In general, data from breath, plasma, urine, and self-reporting were in good agreement, but in 23 percent of cases, substances were detected that had not been self-reported,' the study notes. 'All substances tested were found in a number of breath samples. Considering that breath sampling was often done approximately 24 hours after intake, the detection rate was high for most substances.'

However, the researchers were unable to pinpoint the exact time when the individual last used the drug, which presents a challenge in determining whether someone is driving under the influence. 'Opioids stay in your system longer because they are not as soluble as alcohol,' explains Dr. Harold Jonas, CEO and founder of Sober.com, in an email. 'Some opioids can remain in your body for weeks, unlike alcohol.' This is also true for THC.

Clare Waismann, a certified addiction treatment counselor and the founder of the Waissman Method of rapid detox, highlights a particular challenge in opioid detection. 'How soon, or rather how late after taking an opioid, can the test detect opioid intoxication? For example, some opioids are extended release, and others are immediate release,' she says in an email. 'Considering this, how accurate would the test be for the overall situation, rather than the exact moment of intake?'

Despite these challenges, numerous companies are actively working to develop an accurate and reliable breath test for drugs. Dave Claflin, founder of Fastest Labs, mentions that Lifeloc Technologies is one company currently in the research phase for breathalyzer technology designed for quick drug testing. Even once a breathalyzer is ready, it must pass federal regulations set by the Department of Transportation, as well as individual state requirements, Claflin explains. '[States] have standards that this handheld machine must meet. It has to incorporate its own checks and balances within the machine itself.'