U.S. researchers said cannabinoids -- psychoactive compounds of marijuana -- can be detected in the blood of daily pot smokers during a month of abstinence.
Dr. Marylin Huestis of the National Institutes of Health said the study involved 30 male daily marijuana smokers who temporarily lived in a secure research unit for up to 33 days. Their blood was collected daily. She said 27-of-30 participants were delta-9-tetrahydrocannabinol, or THC positive on admission. THC is the main psychoactive chemical in marijuana.
Pot can be detected in blood a month later
