The postmortem blood alcohol concentration and the water content

Area of Science:

• Forensic Toxicology
• Postmortem Biochemistry

Background:

• Accurate blood alcohol concentration (BAC) determination is crucial in forensic investigations.
• Postmortem changes can affect BAC, necessitating an understanding of influencing factors.
• Blood water content is a potential variable affecting BAC measurements over time.

Purpose of the Study:

• To investigate the relationship between blood alcohol concentration and blood water content in postmortem specimens.
• To determine the influence of time postmortem and putrefaction on this relationship.
• To identify conditions requiring correction of BAC in forensic analysis.

Main Methods:

• Analysis of blood alcohol concentration and water content from 71 bodies.
• Collection of two blood specimens per body: short-time (0-9.6 hours) and long-time (8.0-229.9 hours) postmortem.
• Application of multiple regression analysis to establish correlations.

Main Results:

• In bodies without putrefaction, water content differences between early and late specimens significantly influenced BAC.
• Putrefaction diminished the influence of water content on BAC.
• A BAC correction is recommended for whole blood specimens sampled shortly after death from bleeding shock if water content exceeds 82%.

Conclusions:

• Blood water content is a significant factor in BAC accuracy, particularly in the early postmortem period and in the absence of putrefaction.
• Forensic toxicologists must consider postmortem interval, putrefaction, and blood water content for reliable BAC interpretation.
• Specific criteria, such as high water content in early specimens from bleeding shock cases, warrant BAC adjustments.