In this article, Dr. Autopsies are systematic medical inspections that occur after death postmortem. Their purpose is to address questions about the cause of death of the individual.
The autopsy may also involve obtaining a postmortem sample for a toxicology screen. Most Commonly Autopsied Causes in the U. At times, lawyers may ask forensic toxicologists to review the postmortem toxicology report and provide an opinion regarding the postmortem drug or alcohol concentrations. The central question is often whether the concentrations indicate antemortem intoxication or impairment. In some cases, the toxicologist is asked to determine whether the postmortem levels of drugs, alcohol, or other chemicals reflect therapeutic, toxic, or lethal concentrations.
On the surface, these questions seem like they should have simple answers. In reality, interpreting postmortem drug and alcohol levels can be quite complex and requires careful examination and analysis by experts. The lack of a coordinated effort to foster communication among these groups results in a lost opportunity to collectively raise the level of awareness of the emergent public health crisis, obscures the extent and prevalence of the various types of drugs being used, and diminishes efforts to reduce the overall rate of drug overdose deaths.
Hospital-based pathologists, laboratory professionals, emergency department physicians, and hospital administrative personnel should work with local medicolegal death investigation offices to establish protocols for collecting and retaining appropriate blood samples for eventual toxicologic analysis in cases in which patients are admitted for a suspected drug overdose and eventually die. Despite a thorough investigation and the attention given to these components, questions about the cause of death may persist in some cases.
Postmortem and antemortem specimens. Biological specimens collected during an autopsy and submitted for toxicological analysis are typically considered the gold standard for providing information to assist in determining the cause of death in cases of suspected drug overdose. Without question, the reliability of toxicology results relies heavily on the fidelity of the specimen collection process.
Forensic pathologists are trained in multiple aspects of specimen collection protocol, including the selection of a suitable specimen container, collection of an appropriate volume of specimen, proper specimen labelling, and storage in a manner that best preserves endogenous and xenobiotic constituents until the specimen can be delivered to the testing location.
In certain cases, however, it may not be possible to establish the cause of death by analyzing postmortem specimens, and the availability of blood collected prior to death becomes critical. Patients who have overdosed may be hospitalized for hours, days, or even weeks prior to death.
This interval provides time for the body to significantly metabolize drugs and alcohol, leading to lower or undetectable drug levels in postmortem specimens. Additionally, resuscitative efforts such as high-volume fluid restoration may have a diluting effect on drug or alcohol concentrations in postmortem specimens.
In such cases, blood samples procured soon after hospital admission can be essential in ascertaining which drugs were present and to what degree they likely contributed to death. These antemortem blood samples generally reflect the substances circulating throughout the body prior to death, have the potential to provide information about the likelihood that a toxic effect was produced, and have the advantage of eliminating potential interpretive issues associated with changes in the concentration of drugs or other substances in the blood due to their movement from one area of the body to another after death postmortem redistribution.
Toxicology tests performed for autopsies are called forensic or post-mortem toxicology tests. Experts also measure the amount of drugs and look to see if the concentration is of a lethal dosage. During an autopsy, a pathologist collects samples of blood, various tissues and, if present, urine. Usually, pathologists collect blood from multiple areas of the body. Tissue samples might be taken from the liver, brain, spleen, kidney and the eyes.
Once the samples are collected, they are tested by medical examiner personnel in laboratories that are accredited by the CAP or other organizations to maintain quality standards. Pathologists, toxicologists and chemists work together during this process, which can involve several rounds of tests.
The first tests are basic screens for drugs in the blood and urine, typically using an immunoassay. Interpretation of these findings is often difficult when assisting in a death investigation, because the time that these toxins were deposited in the bones cannot be determined with reasonable certainty.
Hair and Nails - Hair specimens, usually taken from the back of the head, can be used to test for exposure to heavy metals and drugs over a period of weeks to months. Hair is predominantly used to test for drugs such as amphetamines, cocaine, marijuana THC and heroin, and more recently tests have been created to determine if the deceased was drinking heavily in the last few months before death.
Drug analysis can also be done on finger- and toenails in order to provide an even longer potential window of exposure than hair. However, relatively little is known about how the nails process toxins, so interpretation of results is more difficult.
Hair is subject to external contamination issues that can mitigate its value, so special sample preparations in the lab may be needed for a given case. In the typical autopsy, fluids and tissue samples are collected specifically for toxicology testing. The types of samples collected from the body, and the testing targets in these biological fluids and tissues, are determined by circumstances of the case and the condition of the body.
Once at the laboratory, a series of tests will be conducted, usually on blood, for a large range of over-the-counter, prescription and illicit drugs as well as alcohol and other toxicants; e. Routine testing, or testing without specific instructions to look for a particular substance, will generally include the drugs shown below in Table 2, but not all drugs.
The list of the most common drugs detected is included in a standard attachment to all toxicology reports. Tricyclics e. Amphetamine, methamphetamine, MDMA ecstasy , pseudoephedrine, fenfluramine, phentermine, caffeine. Additional or specific requests to the toxicology laboratory can be made, depending on the circumstances of a case.
The most common examples of specific drugs that analysts may be asked to look for are outlined in Table 3, below. These all require specialized tests and the laboratory is alerted to their possible usage or involvement in the death when requests for toxicology testing are submitted.
In Europe, individuals may become part of the European Register of Toxicologists through EuroTox , through a similar process. International discussion and participation in toxicology is widespread. Forensic toxicologists employ a large number of analytical techniques to determine the drugs or poisons relevant to a case investigation; the capacity of a laboratory to conduct routine toxicological analysis will vary dependent upon equipment, technical capability and analyst experience.
When needed, there are specialty toxicology labs that can test for virtually any potential toxin or metabolite in almost every kind of post-mortem sample. A laboratory should be accredited to perform the analytical work and must be subject to regular inspections by approved accreditation personnel.
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