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Microbial ethanol production in postmortem urine sample
Davorka Sutlovic1, Marina Nestic, Zdravko Kovacic
1Department of Forensic Medicine, University Hospital and School of Medicine, Split, Croatia.
Medicine, Science, and the Law
|July 2, 2013
Summary
Postmortem urine ethanol levels can be misleading due to microbial fermentation in diabetic patients. Adding sodium fluoride to samples prevents inaccurate blood alcohol content (BAC) readings and misdiagnosis.
Area of Science:
- Forensic Toxicology
- Clinical Chemistry
- Microbiology
Background:
- Accurate postmortem ethanol quantification is crucial for determining cause of death.
- Diabetic patients may present unique challenges in postmortem toxicology due to altered metabolism.
Observation:
- A case study revealed significantly higher postmortem urine ethanol (6.0 g/kg) compared to blood (0.02 g/kg).
- Urine samples, lacking sodium fluoride, showed increasing ethanol levels with microbial (bacteria, yeasts) isolation from both blood and urine.
- The patient was identified as a diabetic with irregular insulin therapy.
Findings:
- Postmortem microbial fermentation in urine, particularly in diabetic individuals, can lead to falsely elevated ethanol concentrations.
- The absence of sodium fluoride in urine samples facilitated in-vitro ethanol production by microorganisms.
- External contamination was ruled out, supporting endogenous microbial activity.
Implications:
- Failure to add sodium fluoride to samples from diabetic patients can result in misinterpretation of ethanol levels.
- This can lead to incorrect conclusions regarding alcohol consumption and potentially misdiagnose the cause of death.
- Standardizing the addition of sodium fluoride to postmortem samples from diabetic patients is recommended to ensure toxicological accuracy.
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