Most urine drug screens look for THC-COOH, the main metabolite of THC, using an immunoassay with a 50 ng/mL cutoff. A result at or above that level is a presumptive positive and is normally confirmed by GC-MS or LC-MS/MS, where the cutoff drops to 15 ng/mL. How long THC stays detectable depends on how sensitive the test is and how heavily you use.
Key Features
- Standard immunoassay screening cutoff: 50 ng/mL; confirmatory cutoff: 15 ng/mL.
- One-time or occasional use: usually clears in about 1 to 3 days.
- Moderate use, a few times a week: typically 5 to 10 days.
- Heavy daily use: often 15 to 30 days, longer with high body fat.
- Some at-home strips use 20 ng/mL or 15 ng/mL, which stretches the detection window.
- Concentrates and edibles can raise metabolite levels more than flower.
- Hydration, metabolism, body fat and activity shift individual clearance times.
Materials and test specs
Urine kits use lateral-flow immunoassay strips coated with antibodies that bind THC-COOH. A control line confirms the strip worked, while a test line appears when the metabolite sits below the cutoff. Most devices need a midstream sample, read in about 5 minutes, and stay stable at room temperature until the printed expiration date. Laboratory testing follows SAMHSA guidelines, and any presumptive positive is sent for mass spectrometry confirmation before a result is reported.
cannabis urine test detection window
Shipping and returns
Discreet packaging is standard, and orders ship without any reference to the contents. Unopened, unused kits are generally returnable within 30 days, and defective strips or unclear results are usually replaced at no cost. Check the expiration date as soon as your order arrives.
How accurate are at-home THC urine tests?
Quality strips are roughly 95% accurate at their stated cutoff when read inside the recommended window. Reading too early or too late is the most common cause of a misleading result.
Does drinking water change test results?
Fluids dilute urine and can lower metabolite concentration, but they do not remove THC-COOH. Very dilute samples may be flagged as invalid, so creatinine levels are often checked too.
How long after last use can a urine test detect THC?
Plan on about 3 days for a single use and up to 30 days for chronic daily use, with concentrates and edibles at the longer end. A more sensitive 15 ng/mL test can add several days to any estimate.