Comparison of Δ9-tetrahydrocannabinol in venous and capillary blood following ad libitum cannabis smoking by occasional and daily users

Abstract Δ9-Tetrahydrocannabinol (Δ9-THC) is the most prominent and main psychoactive cannabinoid found in cannabis. In forensic matters involving cannabis, such as drugged driving or workplace accident investigations, blood Δ9-THC determination is typically required. Venipuncture by a phlebotomist at a medical facility is often the standard blood collection protocol, but this procedure is time consuming and requires specialized training. Capillary blood collection at the site of a transportation or workplace mishap may provide a collection method that is logistically easier and