Marijuana is composed of more than sixty C21 compounds found in the leaves and flowering tops of the plant Cannabis sativa L. These compounds and their metabolites, collectively called cannabinoids, are excreted in the urine of marijuana users. This test is a confirm-only test for two cannabinoids in urine:
1. THCA (or 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid) is the primary metabolite of the psychoactive drug THC found in marijuana and comprises about one third to one half of the cannabinoids found in urine.
2. CBD (or cannabidiol) is a cannabinoid also found in marijuana, and has seen a recent surge in over-the-counter supplements that fall into the fringe of legality. Unlike THC, it has no known psychoactive properties. Currently, the only FDA-approved medical use for CBD is treatment of refractory epilepsy.
This LC-MS/MS confirmation-only test is intended for use only in patients where an initial drug screening test has already been performed at the time of specimen collection (i.e. point-of-care drug screening cup, dipstick, etc.). The specimen will not be screened by immunoassay in the laboratory; it will only be tested by LC-MS/MS. If an initial drug screen has not been performed at the specimen collection site, it is more appropriate to order the "Cannabinoids, Urine" (CAN) test code which includes an initial screen.
Current Cutoff Levels for Toxicology
The marijuana metabolite is retained in adipose tissue, and has a widely variable detection time. In general, single-use can be detected up to 3 days afterward; chronic heavy use can be detected 21-30 days after the last use.