Toxicology testing: checking body fluids for drugs (including alcohol) and other toxins (e.g. carbon monoxide).
Drugs and alcohol cause or contribute to a large percentage of the deaths we investigate. They are involved in accidental overdoses, suicides, vehicular related accidents (driver, passenger or pedestrian), or can kill in concert with other “pathology” (e.g. an overly sedated individual with sleep apnea can/will die). Drug-drug interactions can be even deadlier than the use of a single substance, e.g. the use of benzodiazepines (like Valium) is most often only deadly when combined with alcohol. We do toxicology testing on every decedent in whom drugs, alcohol and/or toxins could be a consideration. It is easier for us than some Coroner’s offices, because we have our own in-house toxicology lab.
We test various body fluids. Vitreous, the fluid inside the eyeball, gives an excellent reflection of what was bathing the brain at the time of death. Blood, the most considered body fluid for testing, gives important results, but does have some limitations. The finding of drugs and alcohol in blood most often are used as proof of impairment, depending on the level. A finding of cocaine in the blood reflects use within a couple hours of death, but because there are enzymes in blood cells that can continue to break down cocaine after death and even in the blood draw tube the level found in the blood may not reflect that at the time of death. Delta-9-THC in the blood reflects marijuana use within about an hour of death, while Carboxy THC can be found in the urine out to about a week depending on chronicity of use. The finding in urine does not reflect impairment. There is also a distribution problem with blood testing as the drug moves about the body and in and out of various body compartments. We also test bile in some individuals, but a finding here only tells us that the use has been with about the last 2-3 weeks.
This will serve as a bit of an introduction to tox testing that I will build on in the future.