THC drug test meaning: what a result actually says
Published · Sources checked Oct 4, 2026
Short answer
A THC drug test reports whether a sample is above a set cutoff, not how much someone used or when. Federal urine rules screen at 50 ng/mL and confirm at 15 ng/mL of THC-COOH; oral fluid rules use 4 and 2 ng/mL of THC.
Screen, then confirm
Federal workplace testing has two steps. A quick immunoassay screen flags samples above a cutoff, and a second, more specific lab test confirms them at a lower cutoff.[1]
| Sample | What is measured | Screen | Confirmation |
|---|---|---|---|
| Urine | THC-COOH | 50 ng/mL[1] | 15 ng/mL[1] |
| Oral fluid | THC | 4 ng/mL[2] | 2 ng/mL[2] |
A sample below the screening cutoff is reported negative and goes no further.[1]
What “negative” and “positive” mean
A result says whether the sample was above the cutoff on the day it was taken. It does not say how much someone used, when, or whether they were impaired. In NIH abstinence studies, people who used the same way cleared THC and its metabolite at very different speeds.[4][7]
- Negative means below the cutoff, not zero. Research labs measured THC-COOH well below the federal urine cutoffs.[4]
- Positive means above the cutoff on a confirmed test. In federal programs a medical review officer then reviews the result before it reaches an employer.[1]
What can set off a THC screen
- Any THC. Smoked or eaten cannabis, smoked hemp THCA flower (heat turns THCA into THC), and hemp products that contain THC.
- Similar molecules. Urine screening kits reacted to delta-8 THC and its metabolites in a 2023 lab study.[10] See the delta-8 guide.
A naming trap
Federal urine rules abbreviate the metabolite THC-COOH as “THCA”.[1] The THCA sold as hemp flower is a different molecule, the acid form of THC in the raw plant. Smoking it produces THC, which the body then turns into THC-COOH.
Before you rely on a number
Private employers and clinics can use other cutoffs and other tests. Only the lab, or the medical review officer, who handled your test can tell you what your result means.
Questions
What is THC-COOH?
The inactive product the body makes from THC. Urine tests look for it because it stays in the body much longer than THC itself.
Is the THCA on a drug test report the same as THCA in flower?
No. Federal rules use THCA as shorthand for the urine metabolite THC-COOH. THCA in flower is the acid form of THC in the raw plant.
Does a positive screen mean a positive result?
Not on its own. Under federal rules a positive screen goes to a second, more specific lab test before it is reported.
Does a hemp label change how a result is read?
No. The test detects THC or its metabolite whatever product it came from.
Sources
Sources checked Oct 4, 2026. Numbers in the text link here.
- Substance Abuse and Mental Health Services Administration. Mandatory Guidelines for Federal Workplace Drug Testing Programs. Federal Register 82 FR 7920, January 23, 2017. www.federalregister.gov/d/2017-00979
- Substance Abuse and Mental Health Services Administration. Mandatory Guidelines for Federal Workplace Drug Testing Programs: Oral Fluid. Federal Register 84 FR 57554, October 25, 2019. www.federalregister.gov/d/2019-22684
- Lowe RH, Abraham TT, Darwin WD, Herning R, Cadet JL, Huestis MA. Extended urinary Delta9-tetrahydrocannabinol excretion in chronic cannabis users precludes use as a biomarker of new drug exposure. Drug Alcohol Depend. 2009;105(1-2):24-32. doi.org/10.1016/j.drugalcdep.2009.05.027
- Bergamaschi MM, Karschner EL, Goodwin RS, Scheidweiler KB, Hirvonen J, Queiroz RH, Huestis MA. Impact of prolonged cannabinoid excretion in chronic daily cannabis smokers' blood on per se drugged driving laws. Clin Chem. 2013;59(3):519-526. doi.org/10.1373/clinchem.2012.195503
- Wolf CE, Pokhai AA, Poklis JL, Williams GR. The cross-reactivity of cannabinoid analogs (delta-8-THC, delta-10-THC and CBD), their metabolites and chiral carboxy HHC metabolites in urine of six commercially available homogeneous immunoassays. J Anal Toxicol. 2023;47(8):732-736. doi.org/10.1093/jat/bkad059