Frequency of postmortem ethanol formation in blood, urine and vitreous humor - Improving diagnostic accuracy with the use of ethylsulphate and putrefactive alcohols

"Not everything that can be counted counts" in ethanol toxicological results: an antemortem and postmortem technical interpretation focusing on driving under the influence

Ethanol blood analysis is the most common request in forensic toxicology, and some studies point to positive results in approximately one-third of all unnatural deaths. However, distinguishing sober deaths from drunk deaths is not as simple as it may seem. This technical, clinical, and forensic interpretation is proposed to interpret the ethanol toxicological results, discussing several artefacts and pitfalls that must be considered, namely focusing on driving under the influence. This work is presented with a practical and objective approach, aiming to alleviate the complexities associated with clinical, physiological, pathophysiological, and toxicological aspects to enhance comprehension, practicality, and applicability of its content, especially to courts. Particularly the physical integrity of the body, the postmortem interval, putrefactive signs, anatomic place of blood collection, alternative samples such as vitreous humour and urine, the possibility of postmortem redistribution, the inclusion of preservatives in containers, and optimal temperature conditions of shipment are among some of the aspects to pay attention. Although several biomarkers related to postmortem microbial ethanol production have been proposed, their translation into forensic routine is slow to be implemented due to the uncertainties of their application and analytical difficulties. Specifically, in the interpretation of ethanol toxicological results, "not everything that can be counted counts and not everything that counts can be counted" (attributed to Albert Einstein).

Ethanol concentrations in various biological specimens: Living and postmortem forensic toxicology analysis and comprehensive literature review

Alcohol use upsurges the risk for many chronic ill-health consequences such as hepatitis, malignancies, and disastrous outcomes like road traffic accidents ending in fatal injuries. Biochemical and toxicological analysis of different body fluids is crucial for identifying the cause of death and postmortem interval in many forensic cases. Blood, urine, and vitreous fluid are the most valuable body fluids for detecting alcohol during any toxicological analysis. Alcohol is responsible for widespread morbidity and mortality worldwide. Blood alcohol concentration (BAC) is a necessary toxicological test to investigate various crime and accident scenes. This study comprehensively explores the demographic characteristics, BAC distribution, and correlations of alcohol concentrations in postmortem and living cases. Postmortem cases (N = 166) reveal intriguing demographic patterns, with notable variations in year distribution, nationality, sex, age groups, occupation, smoking habits, place of death, and psychiatric history. Living cases (N = 483) exhibit distinct demographic profiles, emphasizing differences in year distribution, nationality, sex, age groups, and smoking habits. Analysis of BAC distribution reveals diverse patterns in both postmortem and living cases, providing valuable insights into the prevalence of different BAC levels in each group. Correlation analyses unveil strong associations between alcohol concentrations in various biological samples in postmortem cases, highlighting the interdependence of blood, vitreous, and urine alcohol concentrations. Conversely, living cases display a moderate positive correlation between blood and urine alcohol concentrations. Comparative analyses showcase significant differences in mean alcohol concentrations between postmortem and living cases, suggesting variations in alcohol metabolism and distribution. These findings underscore the importance of considering temporal factors in interpreting alcohol concentrations in forensic and clinical contexts. In conclusion, this study enhances our understanding of alcohol-related incidents by delineating demographic profiles, BAC distributions, and correlations between different biological samples. Such insights are crucial for refining investigative and clinical approaches, contributing to the broader fields of forensic science and public health.

Preanalytical factors influencing the results of ethanol analysis in postmortem specimens

Excessive drinking and drunkenness are underlying factors in many fatal accidents, which make the quantitative determination of ethanol in postmortem (PM) specimens an essential part of all unnatural death investigations. The same analytical methods are used to determine ethanol in blood taken from living and deceased persons although the interpretation of the results is more complicated in medical examiner cases owing to various preanalytical factors. The biggest problem is that under anaerobic conditions ethanol can be produced naturally in decomposed bodies by microbial activity and fermentation of blood glucose. Ways are needed to differentiate antemortem ingestion of ethanol from PM synthesis. One approach involves the determination of ethanol in alternative specimens, such as bile, cerebrospinal fluid, vitreous humor and/or urine, and comparison of results with blood alcohol concentration (BAC). Another approach involves the analysis of various alcohol biomarkers, such as ethyl glucuronide, ethyl sulfate and/or phosphatidylethanol or the urinary metabolites of serotonin 5-hydroxytryptophol/5-hydroxyindoleacetic acid (5-HTOL/5-HIAA). If ethanol had been produced in the body by microbial activity, the blood samples should also contain other low-molecular volatiles, such as acetaldehyde, n-propanol and/or n-butanol. The inclusion of 1-2% w/v sodium or potassium fluoride, as an enzyme inhibitor, in all PM specimens is essential to diminish the risk of ethanol being generated after sampling, such as during shipment and storage prior to analysis. Furthermore, much might be gained if the analytical cut-off for reporting positive BAC was raised from 0.01 to 0.02 g% when PM blood is analyzed. During putrefaction low BACs are more often produced after death than high BACs. Therefore, when the cadaver is obviously decomposed, a pragmatic approach would be to subtract 0.05 g% from the mean analytical result. Any remaining BAC is expected to give a more reliable indication of whether alcohol had been consumed before death.