The concentration of tetrahydrocannabinol (THC) and its main metabolite 11-nor-D9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) as well as cannabinol (CBN), and cannabidiol (CBD) were measured in oral fluid following realistic exposure to marijuana in a Dutch coffee-shop.

THC-COOH was not detected in any specimens from passively exposed individuals. Therefore it is recommended that in order to avoid false positive oral fluid results assigned to marijuana use, by analyzing for only THC, the metabolite THC-COOH should also be monitored.

From Forensic Science International, by Christine Moore, Cynthia Coulter, Donald Uges, James Tuyay, Susanne van der Line, Arthur van Leeuwen, Margaux Garnier, Jonathan Orbita Jr.

Download article: Passive exposure to marijuana FSI 2011 (PDF).