A new study funded by the US Department of Justice’s National Institute of Justice highlights the difficulties of developing a breathalyzer-like device for cannabis. The study, conducted by researchers at the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder, found that even when using carefully collected samples and laboratory analysis, THC levels were too inconsistent to determine whether someone had recently smoked marijuana. The authors of the study said, “a lot more research is needed to show that a cannabis breathalyzer can produce useful results,” and that detecting THC in breath as a single measurement could not reliably indicate recent cannabis use.
The study involved testing breath and blood samples from 18 participants in Colorado who smoked the same type of retail marijuana containing approximately 25% THC. Samples were collected before and after people smoked marijuana. Of the 14 participants who provided breath samples both before and after smoking marijuana, only eight showed an increase in THC after cannabis use, while THC was not detected in three post-use breath extracts. Blood measurements indicated that THC concentrations in plasma seemed to be a far more reliable indicator of recent cannabis use than breath measurements.
The research team acknowledged that due to the small scale of the study, the results do not carry statistical weight. However, they also said the findings highlight the need for further research. Lead author Kavita Jeerage told Marijuana Moment that researching different modes of consumption such as edibles and beverages is an important future direction for cannabis and breath detection work.
The development of a cannabis breathalyzer has been seen as an essential step in combating impaired driving related to drug usage. While many policymakers view field sobriety tests as crucial in battling impaired driving, data on highway safety concerning cannabis legalization is highly contentious due to difficulties in accurately measuring the amount of cannabis in a person’s system, as well as its impact on driving ability.
In conclusion, while there is potential for a cannabis breathalyzer to be developed, it can only happen after a lot of research. The findings of this study highlight the challenges in developing such a device and how much more work is required before it can be considered reliable.