Every instant drug test has a cutoff level: the concentration a substance must reach in urine before the test reads positive. Understanding cutoffs explains why two tests can give different results, and helps you choose the right test.
What is a cutoff level?
Cutoff levels are measured in nanograms per milliliter (ng/mL). If the amount of a substance in the sample is at or above the cutoff, the test reads preliminary positive. If it is below the cutoff, the test reads negative, even if a small amount is present.
That is why a negative result does not always mean "none at all." It means "not above the cutoff."
Reading codes like THC50 and OPI300
Test labels often combine the substance code with the cutoff. THC50 means marijuana at a 50 ng/mL cutoff. OPI300 means the OPI panel at 300 ng/mL. BUP10 means buprenorphine at 10 ng/mL.
Lower cutoff vs. higher cutoff
| Lower cutoff | Higher cutoff | |
|---|---|---|
| Sensitivity | Detects smaller amounts | Needs a larger amount to read positive |
| Detection window | Can detect use for longer | Shorter window |
| Incidental positives | More likely (for example EtG from hand sanitizer) | Less likely |
Cutoff levels on our tests
| Test | Cutoff (ng/mL) |
|---|---|
| THC (marijuana) | 50 |
| COC (cocaine) | 300 on most cups and strips, 150 on the 12 panel CLIA with PCP |
| AMP / MET | 1000 on most tests, 500 on the 12 panel CLIA with PCP |
| BZO (benzodiazepines) | 300 |
| BAR (barbiturates) | 300 |
| BUP (buprenorphine) | 10 |
| MTD (methadone) | 300 |
| OXY (oxycodone) | 100 |
| MDMA | 500 |
| PCP | 25 |
| EtG (alcohol) | 500 on strips, 300 on the 20 panel cup |
| KRA (kratom) | 500 on strips and the 20 panel cup |
| GAB (gabapentin) | 2000 on strips, 1000 on the 20 panel cup |
Each product page lists its exact cutoffs. Federal workplace programs have updated some cutoffs over the years (for example, lowering amphetamines to 500 and cocaine to 150), and both the older and newer levels are common on instant tests.
Why cutoffs matter when comparing results
If an instant test and a lab test disagree, different cutoffs are often the reason. Lab confirmation tests (such as GC/MS) use their own, usually lower, cutoffs and identify the exact substance. That is why any preliminary positive should be confirmed by a lab before action is taken.
See also: how long drugs stay in urine and how to read a drug test cup.
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Request a Bulk QuoteFrequently asked questions
What does ng/mL mean on a drug test?
Nanograms per milliliter, the concentration of a substance in urine. The test reads positive when the concentration is at or above the cutoff.
Does a negative test mean no drugs were used?
Not necessarily. It means any amount present was below the test's cutoff level.
What is the standard THC cutoff?
50 ng/mL is the most common THC cutoff for urine screening, and it is the cutoff our THC tests use.
Why do some tests have different cutoffs for the same drug?
Manufacturers and programs choose different sensitivity levels. Lower cutoffs detect smaller amounts; higher cutoffs reduce incidental positives.
Instant urine tests give preliminary results. Confirm any preliminary positive with a laboratory test (such as GC/MS) before taking action. Always follow the package insert.