Test Catalog

Test Name

Marijuana Δ9-Tetrahydrocannabinol (THC)


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.


  • 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)

Approximate Detection Times

Marijuana/Cannabis (THC-COOH) LOQ (ng/mL) Detection Time* up to
     Single Use
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.