Which type of sample is most commonly used for toxicology testing in postmortem investigations?

Blood samples are the most commonly used for toxicology testing in postmortem investigations because they provide a comprehensive overview of the drugs and toxins present in an individual's system at the time of death. Blood can accurately reflect the concentration of substances in the body and can help determine the cause of death.

In postmortem toxicology, blood is often preferred over other samples due to its ability to demonstrate the systemic effects of drugs, as it circulates throughout the body and interacts with various organs. Additionally, blood samples can be obtained reliably from the heart or major blood vessels, making it easier to analyze for a wide range of substances.

While urine samples can be useful and may provide insight into substances that have been excreted, they may fail to reflect the exact concentration of drugs present in the body at the time of death. Hair samples, although they can show a history of drug use over a longer period, are not typically used for determining acute toxicity or the circumstances surrounding death because they do not indicate current levels of toxicity effectively. The variability of cases does not negate the predominance of blood samples in postmortem toxicology testing.