Referred Tests
| Web: | mayocliniclabs.com |
|---|---|
| Email: | mcl@mayo.edu |
| Telephone: | 800-533-1710 |
| International: | +1 855-379-3115 |
| Values are valid only on day of printing. | |
Marijuana Δ9-Tetrahydrocannabinol (THC)
Interpretation
The parent drug, Δ9-tetrahydrocannabinol (THC), has a clearance half-life of less than 30 minutes and is not detectable in urine. Following a dose of THC, the metabolite typically appears in the urine within 60 minutes, but can take as long as 4 hours.
Note: The presence of the major THC-COOH > LOQ indicates exposure to THC within 3 days after a single use, to approximately 30 days in heavy chronic users.
Metabolites
- The major metabolite is tetrahydrocannabinol carboxylic acid (THC-COOH). THC-COOH is inactive and very lipid soluble.
Δ9-tetrahydrocannabinol (THC) → tetrahydrocannabinol carboxylic acid (THC-COOH)
Confirmation Tests
Approximate Detection Times
| Marijuana/Cannabis (THC-COOH) | LOQ (ng/mL) | Detection Time* up to |
|---|---|---|
| Single Use | 3 | 3 days |
| Moderate Use (4 times per week) | 5 days | |
| Heavy Use (daily) | 10 days | |
| Chronic Heavy Use | 30 days |
*These are approximate detection times for the drug or metabolites in urine. The actual detection time depends on dose, frequency of
use, and individual metabolism.