Researchers found that even when they used carefully collected samples in the lab and performed laboratory analyses, THC levels could not be determined.
Researchers at the National Institute of Standards and Technology and the University of Colorado Boulder found that the findings “does not support the notion that detecting THC as a simple measurement could reliably determine recent cannabis use,” the authors stated.
Kavita Jeerage is a materials research engineer at NIST and co-author of the study. She said that more research was needed to prove that a cannabis breathalyzer could produce useful results. The results of a breathalyzer can have a significant impact on someone’s life. People should be confident that they are accurate.
Researchers collected samples in a “comfortably appointed white van” that was parked outside participants’ homes 15 minutes before and an hour after they smoked marijuana. The study was published on Monday in the Journal of Breath Research. The samples were collected by a “comfortably appointed white van” that was parked outside the participants’ homes, according to a NIST release.
A cannabis breathalyzer could be developed to keep impaired drivers from the road. This future device will only be possible if there is a lot more research.
Here’s why: https://t.co/sEIQItZHh9 pic.twitter.com/XUYnoanGql
National Institute of Standards and Technology May 22, 2020
NIST stated that the analysis was performed in a laboratory, and not on the field. In an email sent to Marijuana Moment, a representative stressed that the agency was not “working on developing a roadside breathealyzer” but rather seeking to understand “the basic of how to accurately and measure THC in breath.”
Eight participants, a small majority, “showed an increase in THC following cannabis use” according to the authors. The results are noisy. Researchers wrote that “Three post-use breath samples were not positive for THC and the rest of the post-use samples were lower or similar to baseline extracts.”
The report states that “these observations suggest that reproducible aerosol breath collection remains a challenge.”
The study concluded that blood measurements–measured by THC levels in plasma—-were a more reliable indicator for recent cannabis use. The study found that THC levels in the breath 1 hour after use were not necessarily higher. This was true even when blood tests showed compliance with protocol and a minimum five-fold rise in THC immediately following use.
Tara Lovestead is a supervisory chemical engineering at NIST and one of the co-authors of the report. She said that the team was expecting to see higher concentrations THC in breath samples after participants had smoked marijuana. The measurements were similar before and after the use of marijuana.
Lovestead explained that in many cases the THC concentration on the breath of the smoker would have made it impossible to determine if the person had smoked within the past hour.
NIST admitted that because the study was small, the results “does not carry statistical significance.” However, the agency and report’s authors stated that the findings highlighted the need for additional study.
Lovestead stated that “we cannot answer the question of whether or not breath measurements can distinguish between someone who regularly uses cannabis but hasn’t consumed it in a while and someone who did so an hour ago.” A reproducible protocol will help us, and other researchers, answer this question.
As more states have legalized cannabis, scientists and entrepreneurs have scrambled to develop field sobriety tests for THC, with some pursuing Breathalyzer-inspired devices. In 2015 , Hound Labs, a California-based company based in Oakland, predicted that its device would be widely used by law enforcement agencies before the end of 2016. No cannabis field sobriety tests have been widely adopted.
NIST, a U.S. Department of Commerce agency, published a notice in 2013 seeking a contractor for a study on “how the content of cannabis compounds found on the breath of a user changes after marijuana use.”
The National Institute of Justice of the Department of Justice funded the current study. It has also awarded an additional $1.5M to the research team in order to expand and continue the study. NIST states that the next phase will include 40 or more participants, and more than 1,000 breath samples. This “should give the findings more statistical weight.”
Field sobriety testing is seen by many policymakers as an important tool in the fight against impaired driving. In a report from the House Appropriations Committee, members expressed concern about drivers under the influence in June last year. The report urged regulators “to continue efforts to ensure stakeholders are able to identify drug-impaired drivers and enforce the laws.”
In a letter dated a month ago, Rep. Earl Blumenauer (D-OR), called on the Department of Transportation to reform its cannabis test policies due to the difficulty of determining the most recent use. He noted agency data that showed tens and thousands of commercial drivers were penalized for cannabis use. It was not possible to determine whether the use occurred days or weeks before they were tested. The congressman said that Transportation Secretary Pete Buttigieg’s department should “reform requirements for testing drivers, returning them to work and develop an accurate impairment test.”
The data on highway safety is controversial, largely because it’s difficult to accurately measure the amount of marijuana in someone’s system and its effect on driving.
In a study published in 2019 it was concluded that people who drove at the legal THC level , which is usually between two and five nanograms per milliliter blood, did not have a statistically higher risk of being involved in an accident than those who had never used marijuana. Other studies indicate that there could be an increase in road fatalities following the legalization of adult-use marijuana.
Other research suggests that impaired driving is actually down after legalization. At least, this is what self-reported survey results suggest. RTI International, a research nonprofit, published a report last year that found people were more likely to not drive after consuming cannabis when they lived in states with legalized cannabis. Another study found that premiums for auto insurance decreased when medical marijuana was legalized in certain states.
Experts and advocates say that the evidence on the link between THC levels in blood and impairment is not clear.
The Congressional Research Service in 2019 determined that while “marijuana consumption can affect a person’s response times and motor performance…studies of the impact of marijuana consumption on a driver’s risk of being involved in a crash have produced conflicting results, with some studies finding little or no increased risk of a crash from marijuana usage.”
A second study concluded that CBD-rich marijuana did not have a “significant impact” on driving abilities despite the fact all participants had THC levels above the limit per se.
DEA is being sued by a former agent who was ‘wrongfully terminated’ over CBD use
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