Substance · cannabinoid
THC (cannabis / marijuana)
THC is the principal psychoactive cannabinoid in cannabis. In workplace and clinical screening, the marker is THC-COOH (an inactive metabolite) — not THC itself — and its presence in urine does not reliably indicate recent use or impairment.
Last updated:What is THC (cannabis / marijuana)?
Δ9-Tetrahydrocannabinol (THC) is the primary psychoactive cannabinoid in Cannabis sativa. Drug tests target a lipid-soluble metabolite, 11-nor-9-carboxy-THC (THC-COOH), which is stored in body fat and excreted slowly — explaining the unusually long urine detection window in chronic users.
Panels that include THC (cannabis / marijuana)
What drug tests detect
Drug tests for THC (cannabis / marijuana) typically target the following analytes / metabolites:
- THC-COOH (11-nor-9-carboxy-THC)
- 11-OH-THC
Confirmation testing uses GC-MS or LC-MS/MS.
Detection windows
| Specimen | Window | Pattern | Caveat |
|---|---|---|---|
| Urine | 1–3 days | occasional | Single use; cutoff and hydration affect detection. |
| 10–30 days | chronic | Daily, heavy use can extend to ~30 days or longer due to fat-soluble metabolite accumulation. | |
| Saliva | 1–24 hours | typical | Detects recent exposure (smoked/vaped); ingested edibles may shift the window. |
| Blood | 1–12 hours | occasional | THC redistributes quickly; not a reliable indicator beyond same-day use in non-chronic users. |
| 1–7 days | chronic | Residual THC and metabolites can persist longer in chronic, daily users. | |
| Hair | 7–90 days | typical | ~7–10 day incorporation delay; hair is not federally approved under SAMHSA/DOT and has documented bias concerns. |
Ranges are approximate and vary by individual physiology, hydration, dose, frequency of use, and lab cutoff. They are not predictive of whether someone will "pass" a test.
Cross-reactivity and MRO interpretation
The following can affect initial immunoassay screening and are normally resolved by mass-spectrometry confirmation and MRO review. None of these are a reason to draw conclusions from a single screening result.
- Some NSAIDs (rare, immunoassay-dependent)
- Hemp / CBD products containing trace THC
- Dronabinol (prescription)
Sources & references
drugtest.co content is sourced from primary regulatory and clinical references. We do not cite gray-market or "how to pass" sources.