The comparative and correlation study of postmortem ethanol levels between axillosubclavian blood and femoral venous blood in forensic autopsy cases at Thammasat University Hospital, Thailand

Abstract

Background: Femoral venous blood (FVB) is accepted as a standard sample for postmortem ethanol analysis, but owing to the nature of unnatural death cases, FVB may not always be obtainable, and subclavian blood might be used for alternative specimens. This study investigated the correlation between postmortem ethanol concentrations in FVB and axillosubclavian blood (ASB) from autopsy cases in the tropical climate of Central Thailand. Two other factors potentially affecting the correlation, the time of death and ethanol absorption state, were also investigated. FVB, ASB, and vitreous humor were collected from 100 subjects between May 2021 and May 2022. Subjects with decomposition signs and large open wounds were excluded. ASB was drawn from the axillosubclavian vein at the thoracic outlet. Ethanol concentrations in all samples were measured by headspace GC-FID. Results: Ethanol concentrations in ASB were statistically identical to those in FVB (p = 0.6761) and their relationship was statistically correlated (r = 0.9818, p < 0.001). The correlation was not statistically influenced by time since death or absorptive statuses. The diagnostic study to assess the practical application of ASB instead of FVB at a cut-off concentration above 50 mg/dL yielded an area under the ROC curve of 0.96. Conclusions: Our study indicated that ASB can be used as an alternative specimen for postmortem ethanol analysis when FVB is unavailable in dead bodies that are in a tropical climate.