Cannabis Intoxication Breath Test Imminent: Part I

The breath test intended to reveal levels of pot intoxication is considered by some to be arbitrary and inaccurate, unable to determine impairment.

The long-discussed and relatively feared prospect of a Cannabis breathalyzer may soon become a reality, although the idea is not a new one. While we are making progress in America with regards to marijuana legalization, the roadside weed breath test represents an unavoidable trap for many Cannabis users, and some activists worry about the potential damage that could result from false positives.

Unfortunately, however, the very progress that we are experiencing is leading to increasing numbers of drivers who are impaired - a full quarter of drivers in Washington state tested positive for THC in 2013, the first year that Initiative 502 was implemented, an increase from just below nineteen percent in 2012 [Source: Washington State Toxicology Laboratory]. Even worse, unimpaired vehicle operators who happen to be pot smokers would simply fail a THC test due to the long half-life of Cannabis (the amount of time that its metabolites are detectable within the body), which has been determined by at least one study to be up to sixty-seven days for regular users of the drug.

In the majority of American states, DUI(D) or driving under the influence (of drugs) laws have posed one of the largest threats to pot smokers, although even legal users in Colorado and Washington continue to fall prey to this roadside snare, combined with a zero tolerance, 'per se' approach, in spite of their ability to legally purchase and consume the drug - any driver testing at five nanograms or above per milliliter of blood is considered impaired. The three recent converts to legal weed - Alaska, Oregon and Washington, D.C. - must carefully consider this issue as well. Even worse, the half of the country with medical Cannabis laws on the books must also deal with the unfortunate reality of the possibility of failing a police THC test. While suspected drunk drivers can be breathalyzed with relative accuracy - assuming that proper protocols are followed - an accurate equivalent has yet to have been produced. However, the first wave of such products is definitely in the works and may be released sooner than previously thought.

Detractors of such technology insist that five nanograms is an arbitrary amount that does not correspond with any scientifically-backed levels of impairment or even intoxication. Also, different smokers experience varying levels of intoxication when consuming the same amount of cannabinoids. European driving laws assume

Washington State University chemistry professor Herbert Hill and Jessica Tufariello, a doctoral candidate, are developing what will be the first portable, breath-reliant THC testing device. Hill explained to The News Tribune that the proposed weed breathalyzer discerns the presence of THC in a breath sample via ion mobility spectrometry.

For those worried about a sudden deluge of roadside weed breath tests, there is no immediate threat - the proposed tester has not yet been fully developed or produced. Before the device can be field tested, professor Hill and his research team intend to conclude laboratory experimentation and testing with their pot breathalyzer prototype this year. Next year, the device will be trialled upon human subjects between January and June.

When a driver suspected of impaired vehicle operation is pulled over, the police officer must determine, via several means, whether or not the driver is impaired and, if so, exactly what substances are responsible. The options of blood, breath or urine tests suffices for drunk driving cases, but law enforcement has long been requiring a roadside weed test that does not rely upon a blood sample, due to the logistics of having to arrest the driver and escort them to the police station for testing - not to mention the need for immediate test results.

Existing weed tests, regardless of the chosen biological matrix (blood, breath or urine), only record the presence of the marijuana metabolites rather than identifying and quantifying Cannabis impairment. This is worrying, considering that arbitrary 'intoxication' levels, such as the legal limit of five nanograms of THC per milliliter of blood on the law books in both Washington state and Colorado, combined with zero tolerance edicts in place across the country, means that drivers who may have smoked a joint days or even weeks ago may face arrest, loss or suspension of their driver's license, steep fines, jail terms and potentially even loss of employment.

Unlike the results of an alcohol breath test, a pot breathalyzer conducted in a zero tolerance state would not only fail to determine exact levels of intoxication but would instead ensure that at least minimal charges would be filed.

A 2012 study in the Iranian Journal of Psychiatry states that, in addition to the concerning amount of unimpaired drivers who will test positive for THC, "false negative and false positive results occur from structurally related drugs that are recognized by the antibodies or occasionally artifacts such as adulterants affecting pH, detergents and other surfactants."

The study outlines another issue: "In Chronic cannabis users, it is particularly difficult to determine whether a positive result for Cannabis represents a new episode of drug use or continued excretion of residual drug. Algorithmic models have been devised to determine whether THC levels represent new use or the carry-over from previous use. However, these models are not very accurate in discriminating new use and carry-over in chronic users."

Before a fresh wave of paranoia overtakes legitimate medical and recreational users - as well as the unlucky millions who regularly use Cannabis illegally - it is important to remember that it will take a while for the technology to become accurate, reliable and cost-effective enough for most law enforcement departments to consider such a purchase. Additionally, according to the forthcoming weed breath tester's co-developer, Herbert Hill, the test will most likely only be able to determine the presence of THC in a subject's system, rather than having the ability to accurately quantify the amount of THC metabolites.

Hill told the Tribune that "We believe at least initially that it would lower the false positives that an officer would have...[.] They would have a higher level of confidence in making an arrest."

Stay tuned for Part II, in which we explore the pharmacokinetic actions of Cannabis and its metabolites in the human body.