Toxicology is used to determine the presence or absence of toxins or poisons in the body. Death investigators will often send a specimen to a lab for testing to determine what was in someone’s body when he or she died. Toxicology results can take weeks to come back with results, but the report can be extremely valuable to an investigation, so the wait is worth it.
- Blood, Urine, Liver
Blood is the most common specimen sent away for testing in a forensic lab. Blood testing is especially important after a hospital death, because if poisoning is suspected, blood samples taken right after admission and immediately after death are testing to see the differences in the samples. Taking blood samples to be sent away can be complicated especially when the body is in decomposition. Urine is helpful when determining what drugs had previously been in the body but have had time to process through the body. The liver is sometimes sent for testing because “it is where the body metabolizes most drugs and toxicants” (“A Simplified Guide”). This means that even if the presence of drugs is not detected in the blood, it can be in the liver because drugs become concentrated in the liver.
- Vitreous Humor
Vitreous humor is the substance that is located in the eye. It is most commonly tested for blood alcohol concentration because alcohol concentrations are a little higher in the vitreous humor than in other parts of the body.
- Stomach Contents
Because toxins are sometimes ingested by mouth, they’ll end up in the stomach at some point. If someone dies soon enough after taking the drugs, they might still be somewhat intact in the stomach during an autopsy. Identifying the drugs present is easier when they are undissolved or still partially intact.
- Bone, Hair, and Nails
Bones can contain toxins, but they are not usually used because it is often not possible to determine when the toxins were deposited. Hair is often sent to be tested for the presence of drugs or alcohol, and the same goes for finger or toenails.
The substances that are usually tested for in post-mortem toxicology include alcohol, analgesics, antidepressants, antihistamines, antipsychotics, benzodiazepines, cardiovascular drugs, marijuana, cocaine, and stimulants. The analysis is performed by forensic toxicologists, who are trained specifically for this job. There are four conclusions the toxicologists can come to when testing a substance:
- true-positive: the presence of a drug is correctly identified
- false-positive: a drug is identified when it is not present
- true-negative: the absence of a drug is correctly identified
- false-negative: a drug is not identified when it is present
Toxicology can be extremely important in a death investigation. A toxicology report can show cause of death or detect that foul play was involved in a death. Toxicologists have invaluable jobs and it is important that drug analysis is done correctly.
Source: “A Simplified Guide to Toxicology.” Forensic Science Simplified. 2013. Web. 12 Feb. 2016.