A cannabis drug test detects THC and its breakdown products, primarily the metabolite 11-nor-9-carboxy-THC (THC-COOH). It does not test for CBD. Standard screens run an immunoassay on urine, blood, saliva, or hair, and any positive result is confirmed with GC-MS or LC-MS/MS.
what does a cannabis drug test detect
How do cannabis drug tests actually work?
Most employers and testing labs use a two-step process. First, an immunoassay screen flags samples above a cutoff, usually 50 ng/mL for urine THC-COOH. Second, a mass spectrometry method confirms the exact molecule at a lower cutoff, typically 15 ng/mL.
How Long Before a Drug Test Should You Stop Cannabis?
This two-tier design exists because immunoassays can cross-react with similar compounds. A screen result alone is never considered a confirmed positive.
how long before a drug test should you stop cannabis
What does each test type detect?
Urine test
Urine is the most common cannabis test and detects THC-COOH, the inactive metabolite stored in body fat. It shows past use rather than current impairment. Detection windows range from about 3 days after a single use to 30 days or more in chronic heavy users.
Blood test
Blood tests detect both active delta-9 THC and THC-COOH. They are used in traffic-safety investigations because they can capture very recent use. Detectable levels usually clear within 1 to 2 days, though daily users may test positive for up to a week.
Saliva (oral fluid) test
Oral fluid swabs mainly detect the parent THC molecule, not metabolites. They are popular for roadside and workplace screening because collection is observed and non-invasive. Detection is short, generally 24 to 48 hours after use.
Hair test
Hair follicle analysis detects THC embedded in the keratin shaft as it grows. It offers the longest window, roughly 90 days, and cannot be beaten by short-term abstention. It is less common because of cost and slower turnaround.
What is on a standard 5-panel drug test?
- THC (cannabinoids)
- Cocaine metabolite
- Amphetamines and methamphetamine
- Opiates
- Phencyclidine (PCP)
CBD, CBG, CBN, and most other minor cannabinoids are not part of any standard panel. Labs would need a specialized cannabinoid profile to measure them.
Will CBD products trigger a positive cannabis test?
Pure CBD isolate should not cause a positive THC result, because the test targets THC-COOH specifically. The risk comes from full-spectrum or crude CBD oils that carry trace THC, which can accumulate with daily high-dose use.
Very high CBD doses have also been reported to interfere with some immunoassay screens, producing an initial flag that confirmation clears. Choosing broad-spectrum or isolate products with third-party COAs lowers that risk.
What is the difference between a screen and a confirmation?
A screening immunoassay is fast and cheap but not chemically specific. Confirmation uses chromatography paired with mass spectrometry to identify THC-COOH by molecular weight and retention time. Only a confirmed result should be treated as evidence of cannabis use.
How long does THC stay detectable?
- Urine: 3 days (single use) to 30+ days (heavy chronic use)
- Blood: 1 to 2 days, up to 7 days in daily users
- Saliva: 24 to 48 hours
- Hair: up to 90 days
Body fat percentage, dose, frequency, and hydration all shift these windows. No drink, supplement, or detox kit is proven to reliably mask THC-COOH.