A large blood–vitreous ethanol discrepancy should prompt investigation of the specimens and circumstances before either result is converted into an earlier blood alcohol concentration. Brunet and Mura described one case with blood ethanol of 2.8 g/L and vitreous ethanol of 0.3 g/L. Only after obtaining more information did the laboratory learn that the death involved a firearm.
What was actually reported?
The laboratory initially received blood and vitreous humor without further case information. Headspace gas chromatography with flame-ionization detection produced the two ethanol measurements. The case account did not specify the blood collection vessel, the exact wound path, the death-to-collection interval, or the specimens’ complete preservation and storage history.
Those omissions limit reconstruction. The blood value cannot be relabeled femoral blood, and the case does not document a precisely timed change in ethanol concentration after death. Both results described the collected material at analysis.
Why the additional history mattered
The authors discussed gastric rupture and mixing of alcohol-rich gastric contents with blood as a possible explanation for discordant findings, particularly in deaths involving traumatic injury. Such contamination would be different from redistribution of absorbed ethanol between otherwise intact biological compartments.
However, the short case description did not report a demonstrated gastric rupture, measured gastric ethanol, cytological proof of contamination, or a quantified contamination fraction. The explanation should remain a case-context hypothesis rather than an experimentally established mechanism in this individual.
A separate blind-stick collection report with cytological evidence of gastric contamination illustrates the kind of additional evidence that can substantiate a specimen-source concern. That evidence cannot be imported into this gunshot case.
The paired series did not supply an individual correction
In the same paper, the authors reported 107 blood–vitreous pairs analyzed during 2009–2010. Seventy-five were negative in both matrices. Among the other 32, the mean vitreous/blood ratio was 1.15 with a standard deviation of 0.41.
That variability matters. The positive-pair average did not describe all 107 cases, and an average ratio was not a rule that every person’s vitreous must exceed blood. The gunshot example’s very different pattern cannot be corrected simply by applying that mean.
Nor should the average from this series be treated as a validated estimate of the concentration during life. The laboratory observations did not provide an independent prediction study establishing a guaranteed error interval for a new, potentially compromised specimen.
What the vitreous result added
The 0.3 g/L vitreous measurement supplied a second compartment that challenged an uncomplicated reading of 2.8 g/L blood. It was useful precisely because the discrepancy could reveal that the specimens required different interpretation.
It did not independently establish a particular earlier blood concentration, exclude every postmortem change, or determine impairment. A lower vitreous result is not a universal certificate that another specimen is contaminated.
What to retain in a case review
Preserve both measured values and their units, collection records, wound and autopsy findings, any gastric-content results, and the laboratory method. The report does not give numerical detection limits, quantitation limits or precision for this ethanol workflow; those must not be invented.
The lesson is to use a disagreement to investigate provenance. It does not justify selecting whichever number favors a conclusion or treating one concentration as a stand-alone cause-of-death finding.
Primary source
Brunet B, Mura P. L’humeur vitrée en toxicologie médico-légale : revue de la littérature et applications [Vitreous humor as an alternative matrix in forensic toxicology: literature review and applications]. Annales de Toxicologie Analytique. 2012;24(1):9–15. doi:10.1051/ata/2012004. The case findings discussed here are the authors’ own laboratory observations within this review-and-applications paper.
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