FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM-13/24

Title and Subtitle: Distribution of Δ⁹-Tetrahydrocannabinol and 11-Nor-9-Carboxy-Δ⁹-Tetrahydrocannabinol in Postmortem Biological Fluids and Tissues From Pilots Fatally Injured in Aviation Accidents

Report Date: December 2013

Authors: Kemp PM, Cardona PS, Chaturvedi AK, Soper JW

Abstract: Despite a long history of research on the pharmacology of Δ⁹-tetrahydrocannabinol (THC), the primary active cannabinoid in marijuana, little is known of its distribution in postmortem fluids and tissues. This study presents postmortem fluid and tissue data for THC and its major metabolite, 11-nor-9-carboxy-Δ⁹-tetrahydrocannabinol (THCCOOH), from 55 pilots involved in fatal aviation accidents from 2005 - 2012.

Utilizing immunoassay screening followed by confirmation using gas chromatography/mass spectrometry, blood, urine, liver, brain, lung, heart, kidney, and muscle were analyzed, as needed, for each of the 55 cases.

Particular attention was paid to lung as this tissue is exposed to cannabinoid-rich marijuana smoke. Mean THC concentrations in blood, liver, lung, and kidney were 12.5 ng/mL, 52.8 ng/g, 766.0 ng/g, and 27.1 ng/g, respectively. Mean THCCOOH concentrations in those same specimens were 34.1 ng/mL, 322.4 ng/g, 38.0 ng/g, and 138.5 ng/g, respectively. Limited data were available for heart tissue (2 cases), muscle (2), and brain (1). Heart THC concentrations were 184.4 and 759.3 ng/g. The corresponding heart THCCOOH measured 11.0 and 95.9 ng/g, respectively. Muscle concentrations for THC were 16.6 and 2.5 ng/g; corresponding THCCOOH, "positive" and 1.4 ng/g. The only brain tested in this study showed 0.0 ng/g THC and 2.9 ng/g THCCOOH, low concentrations that correlated with low values in other specimens from this case.

This research emphasizes the need for cannabinoid testing in postmortem forensic toxicology laboratories. In addition, it demonstrates the usefulness of a number of tissues, most notably lung, for these analyses.

Key Words: Forensic Science, Toxicology, Marijuana, Cannabinoids, Δ⁹-Tetrahydrocannabinol (THC), 11-nor-9-carboxy-Δ⁹-Tetrahydrocannabinol (THCCOOH), Postmortem, Distribution, Pilot Fatalities, Aircraft Accident Investigation

No. of Pages: 13