Q: Why does XALIVA® THC use a 10 ng/mL THC cut-off in saliva?

A: XALIVA^® THC tests have a detection window that starts immediately after consumption and lasts for the entire impairment window, which can last up to 10 hours.

The illustration below is modeled on several peer-reviewed publications showing THC concentration in saliva over time. While concentrations of THC in saliva can vary from person to person, these studies show that oral fluid THC concentration follows this general trend over time.

The United States Substance Abuse and Mental Health Services Administration (SAMHSA) has set a 4 ng/mL saliva THC cut-off for the Department of Transportation (DOT) and federally regulated employees. Using a 4 ng/mL cut-off has a window of detection of about 20-24 hours; this longer window of detection may be suitable for DOT and federally regulated employees.

For non-federally regulated employees (non-DOT), a 4 ng/mL cut-off may be too strict in balancing safety and fairness. A 10 ng/mL cut-off is aligned with a window of detection of about 10 hours; this covers a typical working day and the window of impairment from consuming cannabis.

Thus, XALIVA^® THC rapid saliva-based testing enables an easy, cost-effective method for deterring cannabis use in the workplace.

Sources

McCartney, D, et al. Determining the magnitude and duration of acute Δ9-tetrahydrocannabinol (Δ9-THC) induced driving and cognitive impairment: A systematic and meta-analytic review, Neuroscience & Biobehavioral Reviews, Volume 126, 2021:175-193. Link

Lee, D. et al., Cannabinoid disposition in oral fluid after controlled smoked cannabis. Clin. Chem. 58, 748–56 (2012). Link

Lee, D. et al. Oral Fluid Cannabinoids in Chronic, Daily Cannabis Smokers during Sustained, Monitored Abstinence: Chem. 57, 1127–1136 (2011). Link

Milman, G., Schwope, D. M., Gorelick, D. A. & Huestis, M. A. Cannabinoids and metabolites in expectorated oral fluid following controlled smoked cannabis. Chim. Acta413, 765–770 (2012). Link

Vandrey, R. et al., Pharmacokinetic Profile of Oral Cannabis in Humans: Blood and Oral Fluid Disposition and Relation to Pharmacodynamic Outcomes. Anal. Toxicol. 41, 83–99 (2017). Link

Anizan, S. et al., Oral fluid cannabinoid concentrations following controlled smoked cannabis in chronic frequent and occasional smokers. Bioanal. Chem.405, 8451–8461 (2013). Link

Hoffman, M. A. et al., Blood and Oral Fluid Cannabinoid Profiles of Frequent and Occasional Cannabis Smokers. Anal. Toxicol.45, 851–862 (2021). Link

Swortwood, M. J. et al., Cannabinoid disposition in oral fluid after controlled smoked, vaporized, and oral cannabis administration. Drug Test. Anal. 9, 905–915 (2017). Link