A cannabis drug test cut off level for work is the concentration of THC metabolites that a lab uses to decide if a sample is positive or negative. For federal urine testing, the screening cutoff is 50 ng/mL and the confirmation cutoff is 15 ng/mL. Many employers follow these numbers, but some use different cutoffs or test other specimens like oral fluid or hair.
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What a cutoff level means in practice
A cutoff level is not a measure of impairment. It is a lab threshold. If a sample has less THC metabolite than the cutoff, the result is negative. If it meets or exceeds the cutoff, the lab calls it positive. The cutoff protects against false positives from trace amounts or cross-reactivity.
Standard urine cutoff levels for cannabis
Federal guidelines from the Substance Abuse and Mental Health Services Administration (SAMHSA) set the baseline for many workplace urine tests. The two-step process uses:
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- Screening immunoassay: 50 ng/mL for THC metabolite
- Confirmatory gas chromatography or mass spectrometry: 15 ng/mL for THC metabolite
These numbers apply to federal employees and safety-sensitive transportation workers under Department of Transportation rules. Private employers may adopt them or set their own.
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Cutoff levels for other specimen types
Urine is the most common workplace sample, but cannabis testing can use other specimens. Each has its own cutoff scale.
- Oral fluid: Cutoffs are lower than urine because THC appears in saliva at smaller amounts. Federal oral fluid testing uses a 4 ng/mL screening cutoff and a 2 ng/mL confirmation cutoff.
- Hair: Cutoffs are measured in picograms per milligram. Hair tests look for parent THC, not just metabolites. Hair cutoffs are not comparable to urine cutoffs.
- Blood: Blood tests measure active THC and metabolites. Cutoffs vary by lab and are not standardized for workplace testing.
Why employers use different cutoff levels
Employers balance safety, legal risk, and cost. Some follow SAMHSA cutoffs. Others use lower cutoffs to catch more recent use. State laws can also shape what employers can do for medical cannabis patients. Safety-sensitive roles, such as truck drivers and pilots, must follow federal cutoffs.
What can push a result near the cutoff
Many factors change how much THC metabolite is in your sample at test time. These include:
- How often and how much you use cannabis
- Your metabolism and body fat
- How hydrated you are
- How long since your last use
- The sensitivity of the lab test
A heavy, frequent user may stay above the cutoff for weeks. A one-time user may drop below the cutoff in a few days. These are patterns, not guarantees.
What to do if you face a workplace cannabis test
If you use cannabis and face a test, know the cutoff level your employer uses. Ask for the testing policy in writing. If you use medical cannabis, check your state law and talk to an employment lawyer. Do not try to dilute your sample with excessive water, as labs can flag dilute specimens as invalid.