A moderately decomposed unidentified male is brought for autopsy. Femoral vein blood ethanol is 190 mg%. Vitreous humour ethanol sent from the same sample batch is reported as zero. The BEST interpretation is:
- A Postmortem microbial production of alcohol in the blood, with the vitreous spared ✓
- B Ante-mortem heavy drinking with delayed vitreous equilibration
- C Laboratory error, both samples must be retested
- D Fatal alcoholic ketoacidosis masking vitreous ethanol
Correct answer: A. Postmortem microbial production of alcohol in the blood, with the vitreous spared
Explanation
Putrefying bacteria generate ethanol in blood and viscera after death, so a high femoral blood level alone cannot prove ante-mortem drinking. Vitreous humour sits in a sealed chamber and resists bacterial invasion and diffusion far longer than blood, so it mirrors central blood ethanol in life. Blood positive with vitreous negative therefore points to postmortem production. Delayed equilibration is not a recognised cause of a completely nil vitreous value, and ketoacidosis does not abolish measurable ethanol.
Reference: Knight's Forensic Pathology, 4th ed.
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Written and medically reviewed by the StethoPrep medical team.