• Everything You Need to Know About Post Mortem Toxicology Testing

    Post mortem toxicology or forensic toxicology is a discipline of forensic science that is used to aid in medical or legal investigations of death, poisoning, and drug use. It focuses on the study of alcohol, drugs (licit and illicit) and poisons, including their chemical composition, preparations and identification. A toxical analysis can be performed to various specimens, such as blood, urine, stomach contents, bile, liver, hair, and vitreous humor. The types of blood samples that are typically used in post mortem analysis include the ante mortem blood, the postmortem blood, and the anatomical site blood.

    A blood sample of approximately 10 mL is usually enough to detect and confirm most common toxic substances. Ante mortem blood is noted as the best possible blood and is typically collected prior the expiration of the patient. This type of blood sample is available in cases where the deceased was rushed to hospital and where blood was collected in the hospital emergency room.

    Urine is another specimen collected in post mortem analysis. Urine is produced by the kidneys as a result of blood filtration.  Along with other wastes, drugs and their metabolites are filtered by the kidneys and are contained in urine.  Urine is stored in the bladder until voided. However, since urine is stored for a period of time before it is expelled, the presence of a drug in the urine does not necessarily mean the drug was present in the blood at the time of death.  It simply means that some time prior to death the drug or poison was present in the blood.

    Currently, postmortem toxicology analyses rely predominantly on immunoassays, gas chromatography/nitrogen phosphorous detection (GC-NPD) and color-reaction tests for screening samples to determine if drugs or toxins are present. Initial results are then confirmed for identity and concentration using gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS). Below is a list of post mortem toxicology tests that experts can use to aid in their forensic investigations.

    Post Mortem Toxicology Test

    • Forensic Drug Screen Analysis (2 to 3 non-tissue specimen types allowed)

    Reasons for Performing Post Mortem Toxicology

    In a document from the Center of Forensic Sciences, the cases below are the types that typically fall into the realm of postmortem forensic toxicology.

    1. Unexplained deaths, with no apparent cause (often suspected to be drug intoxication cases) as well as those that are strongly suspected of being drug intoxication cases.
    2. Fire deaths – measurement of toxic gases such as carbon monoxide and cyanide which may be inhaled during a fire.  Furthermore, drugs may be implicated as having incapacitated a victim, thereby preventing their escape from a fire.
    3. Homicides – homicidal poisonings themselves, are rare – but many homicide cases are related to drug use and drug abuse.
    4. Driver and pilot fatalities – where drug impairment may help determine the cause of a crash. Other traumatic causes of death will also require postmortem toxicology analysis (such as drowning, falls)
    5. Therapeutic drug monitoring – for example, determining whether an individual with a seizure disorder has been compliant in their medication use.
    6. SIDS – by definition, SIDS is a diagnosis of exclusion. Therefore, toxicology must be comprehensive in these cases to rule out any other cause of death.

    Pros and Cons of Post Mortem Toxicology Test

    Post mortem toxicology testing is part of the autopsy report in several specific cases, such as unexplained death, homicides, driver fatalities, and therapeutic drug management. It involves comprehensive lab procedures to identify and quantify potential toxins, which include prescription medications and drugs of abuse. When done properly, it will help establish the role of alcohol, drugs and poisons in the death of an individual.

    The most obvious drawback of post mortem toxicology test is the turnaround time needed before a complete report is generated. Post mortem analysis is very time consuming as there are many specimens that need to be tested. The standard turnaround time is between several weeks to months. The slowness in processing delays the signing of death certificates, which delays investigations, criminal prosecutions, and payment of death benefits to survivors.

    When it comes to sample handling and storage, specimens must be in secure, well-sealed, and sterile container. Furthermore, specimens should be delivered to the lab without delay and should be analyzed as soon as possible.

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    One thought on “Everything You Need to Know About Post Mortem Toxicology Testing

    • Robertha Jones says:

      I am a student studying BA in science and have a few questions I hope you can enlighten me with. Should the individual pass away in hospital how soon must blood samples be taken and tested? Would un- preserved blood diminish the true results?

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