National Institute on Drug Abuse (NIDA) scientists recently published a study on a breath test that can detect recent marijuana use. According to the study the test is able to detect whether a person used marijuana within the previous ½ hour to 2.5 hours, depending on the frequency of use. In an attempt to determine the time period and window of detection of cannabinoids in breath – THC, THCCOOH and cannabinol were measured after a controlled amount of marijuana was inhaled.
Exhaled breath was collected from chronic (greater than or equal to 4 times per week) and occasional (less than twice per week) smokers before and after smoking a cigarette that was 6.8% tetrahydrocannabinol (THC). The results showed that THC was the primary cannabinoid measurable in breath, only one sample contained cannabinol and none of the samples contained THCCOOH. Additionally, detectable amounts of THC were present in the breath of chronic smokers for a longer period of time.
“Among chronic smokers (n = 13), all breath samples were positive for THC at 0.89 h, 76.9% at 1.38 h, and 53.8% at 2.38 h, and only 1 sample was positive at 4.2 h after smoking. Among occasional smokers (n = 11), 90.9% of breath samples were THC-positive at 0.95 h and 63.6% at 1.49 h. One occasional smoker had no detectable THC.”
Although limited to a short detection window, breath analysis may offer an alternative detection method for marijuana use, and may prove to be a valuable tool for workplace or roadside marijuana testing in the future.