THC and its metabolites can remain detectable in the body for days to weeks after marijuana use, depending on frequency of use, body composition, and the testing method. Blood tests typically detect active THC for 12 to 24 hours in occasional users, longer in frequent users. Urine tests can detect THC metabolites for 3 to 30 days. This long detection window is a critical defense angle in Rhode Island marijuana DUI cases because Rhode Island has no per se THC blood limit. A positive test does not prove current impairment; it only proves past use. The prosecution must connect the test result to actual impairment at the time of driving.
