We compared oral fluid testing to urine testing in subjects who were administered single doses of marijuana by smoked and oral routes. Oral fluid specimens were collected with the Intercept™ DOA Oral Specimen Collection Device, screened for THC with the Cannabinoids Intercept MICRO-PLATE Enzyme Immunoassay (EIA) utilizing a 1.0-ng/mL cutoff concentration, and confirmed for THC by gas chromatography-tandem mass spectrometry (GC-MS-MS) with a 0.5-ng/mL cutoff concentration. Urine specimens were screened for 11-nor-carboxy-Δ9-tetrahydrocannabinol (THCCOOH) by immunoassay utilizing a 50-ng/mL cutoff concentration and confirmed for THCCOOH by GC-MS with a 15-ng/mL cutoff concentration. Oral fluid specimens tested positive following smoked marijuana (N = 10) consecutively for average periods (± SEM; range) of 15 (± 2; 1-24) and 13 h (± 3; 1-24) by EIA and GC-MS-MS, respectively. The average THC detection times of the last oral fluid positive specimen following smoked marijuana by EIA and GC-MS-MS were 31 (± 9; 1-72) and 34 h (± 11; 1-72), respectively. In comparison to oral fluid, urine specimens generally tested negative for THCCOOH immediately after marijuana use. The average times to detection of the first urine specimen positive for THCCOOH by EIA and GC-MS were 6 (± 2; 1-16) and 4 h (± 1; 2-8), respectively. Urine specimens tested positive consecutively for average periods of 26 (± 9; 2-72) and 33 h (± 10; 4-72) for EIA and GC-MS, respectively. The average THCCOOH detection times of the last specimen by EIA and GC-MS were 42 (± 10; 2-72) and 58 h (± 6; 16-72), respectively. Considering the non-invasive nature of oral fluid collection and improved detection of recent marijuana use compared to urine testing, it was concluded that oral fluid testing for THC offers specific advantages over other means of marijuana testing when used in safety-sensitive testing programs.
ASJC Scopus subject areas
- Analytical Chemistry
- Environmental Chemistry
- Health, Toxicology and Mutagenesis
- Chemical Health and Safety