During the investigation of fatal aviation accidents, postmortem samples from the pilot/copilot are submitted to the Federal Aviation Administration's (FAA's) Civil Aerospace Medical Institute for toxicological analysis. Blood specimens are received in approximately 70% of the fatal aviation accidents analyzed by the FAA's Toxicology and Accident Research Laboratory. The lack of blood available is usually due to the severe damage to a pilot's body during an aviation accident and/or to the length of time taken to recover the body following an accident. Therapeutic and toxic levels for most drugs are reported in the scientific literature for blood and plasma only. Therefore, it is imperative for an accident investigator and forensic toxicologist to be able to estimate drug concentrations in a fatal aviation accident victim's blood from the available concentrations in the tissue.