MARIJUANA BY GC/MS URINE
- MARIJUANA BY GC/MS URINE
- Start Date
- Expiration Date
- Cannabinoids; Carboxy-THC Confirmation/Quantitation; THC
- CPT Codes
- Reference Test
- Transport Info
- Fasting Required?
- Patient Instructions
- Reference Range
Negative (less than assay limit of detection)
Gas Chromatography/Mass Spectrometry (GC/MS)
Confirm positive screen results by an alternate, specific method; detect use.
Marijuana and its sister drug, hashish, come from the hemp plant Cannabis sativa, which grows throughout the world. These drugs contain at least 61 cannabinoids, of which delta-9-tetrahydrocannabinol (THC) is the primary psychoactive compound. Principal routes of administration are inhalation (smoking) and oral ingestion. THC is highly fat soluble and therefore readily stored in fatty tissues, where it may remain in the body for several days or even weeks. It is rapidly transformed by liver enzymes to over 24 metabolites, the primary one being 11-nor-D9-tetrahydrocannabinol-9-carboxylic acid. Approximately 70% of a THC dose is excreted in feces and urine within 72 hours of administration. The concentrations of THC metabolites in urine are influenced by several factors; the amount of THC absorbed in the bloodstream; the frequency of prior use; the timing of urine specimen collection in relation to the last exposure to THC; and the rate of release of stored cannabinoids from fatty tissues. Heavy chronic THC users who stop taking the drug may show positive urine tests for a month or longer. Positive result indicates exposure to the drug and does not necessarily indicate impairment.