Types of Drug Testing for THC: Urine, Blood, Hair & Saliva Explained
3 Ways to Test for Marijuana in Your System (Urine, Hair, Saliva)
Understand how urine drug tests, hair follicle tests, and saliva tests detect THC—and what affects detection windows.
If you’re preparing for screening, knowing the types of drug testing for THC can help set expectations. Tests detect either active THC or its metabolites; timelines vary by test method, frequency of use, body composition, hydration, sleep, and lab cutoffs.
1) Urine Drug Test (THC-COOH Metabolites)
The most common method. Urine screens don’t look for active THC; they measure THC-COOH (a non-psychoactive metabolite). Many labs use a 50 ng/mL cutoff for initial immunoassay.
- Occasional (≤3×/week): ~3 days
- Moderate (≈4×/week): ~5–7 days
- Daily: ~10–15 days
- Heavy daily / multiple times per day: 30+ days
Pros: widely available, fast, cost-effective. Cons: longer detection window for frequent users; dilution checks may flag extreme overhydration.
2) Hair Follicle Drug Test (Long Lookback)
Hair testing can detect patterns of use over a longer period (typically up to 90 days) by analyzing metabolites incorporated into the hair shaft. It’s less useful for pinpointing very recent use (past few days).
Pros: longest historical window. Cons: limited for recent use; cosmetic treatments may complicate analysis.
3) Saliva (Oral Fluid) Test (Recent Exposure)
Saliva tests can detect recent cannabis exposure, often within 24–72 hours depending on frequency, potency, and collection timing. They’re non-invasive and increasingly used for roadside or workplace screening.
Pros: easy collection, detects recent use. Cons: shorter window; food/drink/oral hygiene can affect collection if instructions aren’t followed.
Note on blood tests: Blood primarily detects active THC with a shorter window (often hours to ~1–2 days, longer for frequent users). It’s less common for routine workplace screening but used in certain legal/medical contexts.
What Influences Detection Times?
- Frequency & amount: more frequent use = longer windows
- Body composition: THC is fat-soluble; higher body fat can store more metabolites
- Metabolism & lifestyle: sleep, hydration, and nutrition affect elimination
- Lab thresholds: cutoffs (e.g., 50 ng/mL in urine) and confirmatory methods (e.g., GC/MS)
Support a Natural THC Cleanse
- Abstain early; time is the most reliable factor
- Hydrate steadily (avoid extreme overhydration)
- Favor fiber-rich, minimally processed foods
- Prioritize sleep and light-to-moderate activity
Want an in-depth explainer by test type? Read our internal guide to THC detection in urine, saliva, blood & hair.