Oral fluid (OF) is an alternative biological matrix for monitoring cannabis intake in drug testing, and drugged driving (DUID) programs, but OF cannabinoid test interpretation is challenging. Controlled cannabinoid administration studies provide a scientific database for interpreting cannabinoid OF tests.
We compared differences in OF cannabinoid concentrations from 19h before to 30h after smoking a 6.8% THC cigarette in chronic frequent and occasional cannabis smokers. OF was collected with the Statsure Saliva Sampler™ OF device. 2D-GC-MS was used to quantify cannabinoids in 357 OF specimens; 65 had inadequate OF volume within 3h after smoking.
All OF specimens were THC-positive for up to 13.5h after smoking, without significant differences between frequent and occasional smokers over 30h. CBD and CBN had short median last detection times (2.5–4h for CBD and 6–8h for CBN) in both groups. THCCOOH was detected in 25 and 212 occasional and frequent smokers’ OF samples, respectively. THCCOOH provided longer detection windows than THC in all frequent smokers. As THCCOOH is not present in cannabis smoke, it’s presence in OF minimizes the potential for false positive results from passive environmental smoke exposure, and can identify oral THC ingestion, while OF THC cannot. THC≥1μg/L, in addition to CBD≥1μg/L or CBN≥1μg/L suggested recent cannabis intake (≤13.5h), important for DUID cases, whereas THC≥1μg/L or THC≥2μg/L cutoffs had longer detection windows (≥30h), important for workplace testing. THCCOOH windows of detection for chronic, frequent cannabis smokers extended beyond 30 h, while they were shorter (0–24h) for occasional cannabis smokers.
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