Cannabinoid (THC), Screen and Confirmation, Urine

Urine

20 mL

Use plastic urine drug bottle and evidence tape or tamper-evident container for forensic specimen. Collection kits are available by request from the laboratory.

Detect and confirm the presence of cannabinoids

Initial testing by immunoassay (IA); confirmation of positives by mass spectrometry (MS).

A positive test for cannabinoids indicates the presence of cannabinoid metabolites; 11-nor-9-carboxy-δ-9-THC is the major metabolite (carboxy THC) in urine but is not related to source, time of exposure, amount, or impairment. Unless the test is confirmed by MS, a positive result is presumptive and an unconfirmed test should not be used in workplace drug testing programs. Urine may contain carboxy THC for a week or 10 days after light or moderate use and as long as a month to six weeks after heavy use. Rapid storage of THC metabolites in body fat occurs after use. These substances are then released from storage sites slowly over time.

A marijuana cigarette is made from the dried leaves of the plant, Cannabis sativa. The immediate effects of smoking marijuana include a faster heartbeat and pulse rate, bloodshot eyes, and a dry mouth and throat. The drug can impair or reduce short-term memory, alter sense of time, and reduce the ability to do things that require concentration, swift reactions and coördination, such as driving and operating machinery.

Driving experiments show that marijuana affects a wide range of skills needed for safe driving. Thinking and reflexes are slowed, making it hard for drivers to respond to sudden unexpected events. Furthermore, a driver's ability to “track” through curves, brake quickly, and maintain speed and proper distance between vehicles is affected. Research shows that these skills are impaired for at least four to six hours after smoking a single marijuana cigarette. If a driver drinks alcohol along with using marijuana, the risks of an accident greatly increase.