Cannabis Metabolite in Blood: What Tests Detect and How Long It Lasts
The main cannabis metabolite in blood is THC-COOH, an inactive THC breakdown product. Learn detection windows, cutoffs, and what a positive result means.
Most people clear delta-9 THC from blood within 1 to 2 days after occasional cannabis use. Frequent, heavy use can extend detection to about 7 days, and the main metabolite (THC-COOH) may stay detectable a bit longer in some people. Blood tests have the shortest common detection window for cannabis, well behind urine and hair.
does cannabis stay in blood longer than urine
What a Blood Test Measures
A cannabis blood test usually looks for two things: delta-9 THC, the parent compound that causes the high, and 11-nor-9-carboxy-THC (THC-COOH), the main inactive metabolite. Labs report results in nanograms per milliliter (ng/mL) and apply a cutoff. A lower cutoff finds more positives and lengthens the apparent detection window. Whole blood and serum can give different numbers, so compare results only within the same test type.
How to Flush Cannabis From Blood: What Helps and What Doesn't
Typical Detection Windows
These ranges reflect common lab cutoffs and real-world use. Your result can fall outside them.
cannabis detection time in blood
- Occasional use (one session): delta-9 THC often detectable for 1 to 2 days.
- Frequent use (daily or near daily): delta-9 THC can remain detectable for about 3 to 7 days.
- Heavy chronic use (concentrates, edibles, multiple times per day): parent THC may reach 7 days or slightly longer in some cases. Metabolite detection can extend beyond that.
- Single very high dose: a large edible or concentrate dose can produce a longer tail than a small inhaled dose, but the effect varies by person.
What Changes the Window
- Frequency and dose: daily use and high-potency products build a larger body burden.
- Route: inhaled THC peaks fast and clears fast. Edibles produce a delayed peak and a longer exposure to the metabolite.
- Body fat and metabolism: THC is fat soluble. Higher body fat and slower metabolism can extend release into blood.
- Test cutoff: a 1 ng/mL cutoff will flag more samples and for longer than a 5 ng/mL or 15 ng/mL cutoff.
- Sample type: whole blood, serum, and plasma are not interchangeable. Lab methods differ.
- Other drugs and health factors: liver function and interactions can affect clearance, though the effect is hard to predict.
Estimate Your Own Detection Window
- Write down the date, time, route, and estimated dose of your last use.
- Mark whether your use is occasional (less than weekly), frequent (weekly to daily), or heavy (multiple times daily).
- Identify the test cutoff and sample type from the testing provider.
- Apply the matching range above and add a buffer of 1 to 3 days for heavy use.
- Treat the result as an estimate, not a clearance certificate.
Edibles and Concentrates
Edibles can take 1 to 3 hours to peak and may stay in the body longer than inhaled flower. Concentrates and vape oils carry high THC levels, so a single session can look like a larger dose to a lab. Neither route changes the basic biology, but both can push you toward the longer end of the range.
Cannabis Blood Test Cutoff Levels: What the Numbers Mean
Detection Is Not Impairment
A positive blood test shows exposure, not current impairment. THC concentrations do not map cleanly to driving or job performance, and regular users can test positive while sober. DUI laws and workplace policies vary by state, and some states use per se THC limits while others rely on evidence of impairment. Do not use a detection estimate to decide whether to drive.
Bottom Line
For occasional use, plan on 1 to 2 days in blood. For daily or heavy use, plan on up to 7 days for parent THC and possibly longer for metabolites. Test cutoff, route, body fat, and frequency move that number. If a blood test is scheduled, stop use early, confirm the cutoff with the testing lab, and get a private lab test if you need a data point before the real one.