Q: While I was at a party a few weeks ago I was around a lot of people who were smoking pot. I have a urine drug test coming up and I’m wondering if I might test positive.
A: The urine marijuana test detects a chemical called tetrahydrocannabinol (THC), which is the active drug in marijuana. THC is stored in body fat and excreted in the urine. For someone who smokes a single marijuana cigarette, THC metabolites are detectable for several days. For chronic marijuana smokers, the level of THC builds up in the body fat over time and is excreted for weeks after the last time they used the drug. Urine drug tests are set with a high threshold to eliminate false positives (people that test positive but do not use the drug).
Traces of marijuana may be detectable in the urine for a day or two in someone who was around marijuana smoke, but if you didn’t personally smoke it, you likely have nothing to worry about. Smelling marijuana smoke at an outside event is very unlikely to result in a positive test, but it’s probably a good idea to avoid enclosed areas where people are smoking, like cars and closed rooms.
BTW, if you are getting drug tested, it is wise to bring along all prescription and non-prescription medicines you are currently taking. Prescription drugs are increasing becoming popular drugs of abuse, and so, are being tested for in many drug screens. If a drug is found in your pee, it avoids a lot of problems if you can prove that it should be there.
John Vaughn, MD and Roger Miller, MD (OSU Student Health Services)