Remarks: THC (tetrahydrocannabinol) is the major urine metabolite of cannabis. Its amount in urine is not related to source, time of exposure or amount of cannabis used. THC gives positive results for 8 to 10 days after a light or moderate cannabis use and as long as a month to 6 weeks after heavy use. After use a rapid storage of THC metabolites in fatty tissue occurs . This substance is then released from storage sites slowly over time.