Marijuana passive smoking false positives

In rare circumstances, Marijuana passive smoking can cause false positives in urine tests, up to 4 days after exposure, although those who passively smoke have noticeably less concentrations in their urine.

There is some controversy over whether the cut-off levels used to detect Marijuana's THC in blood and urine tests is too low, leading to a high degree of false positives. If you feel your drug test is false due to passive Marijuana smoking, then you could demand that the threshold of your test is 65ng/ml, not the 15ng/ml of many laboratories. The higher level is thought to distinguish between active and passive Marijuana smoking.