Objective post-mortem diagnosis of chronic alcohol abuse – A review of studies on new markers

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.

Brief history of the alcohol biomarkers CDT, EtG, EtS, 5-HTOL, and PEth

This article traces the historical development of various biomarkers of acute and/or chronic alcohol consumption. Much of the research in this domain of clinical and laboratory medicine arose from clinics and laboratories in Sweden, as exemplified by carbohydrate deficient transferrin (CDT) and phosphatidylethanol (PEth). Extensive studies of other alcohol biomarkers, such as ethyl glucuronide (EtG), ethyl sulfate (EtS), and 5-hydroxytryptophol (5-HTOL), also derive from Sweden. The most obvious test of recent drinking is identification of ethanol in a sample of the person's blood, breath, or urine. However, because of continuous metabolism in the liver, ethanol is eliminated from the blood at a rate of 0.15 g/L/h (range 0.1-0.3 g/L/h), so obtaining positive results is not always possible. The widow of detection is increased by analysis of ethanol's non-oxidative metabolites (EtG and EtS), which are more slowly eliminated from the bloodstream. Likewise, an elevated ratio of serotonin metabolites in urine (5-HTOL/5-HIAA) can help to disclose recent drinking after ethanol is no longer measurable in body fluids. A highly specific biomarker of hazardous drinking is CDT, a serum glycoprotein (transferrin), with a deficiency in its N-linked glycosylation. Another widely acclaimed biomarker is PEth, an abnormal phospholipid synthesized in cell membranes when people drink excessively, having a long elimination half-life (median ~6 days) during abstinence. Research on the subject of alcohol biomarkers has increased appreciably and is now an important area of drug testing and analysis.

New evidence of high association between carbohydrate deficient transferrin (CDT) and alcohol-related road traffic accidents. A retrospective study on 929 injured drivers

BACKGROUND

It is well known that traffic injuries still represent one of the main causes of death and that high blood alcohol concentrations while driving significantly increase the occurrence of accidents. However, only limited literature on the correlation between chronic alcohol abuse and accident risk is available. The aim of the present study was to investigate the hypothesis of an association between elevated concentrations of carbohydrate deficient transferrin (CDT) and the occurrence of alcohol-related traffic accidents.

METHODS

The analytical determinations of BAC and CDT were performed following certified methods in HS-GC-FID and HPLC, respectively. For BAC, 0.50 g/L was used as cut-off, whereas 2.0% was used for CDT, according to the standardisation proposed by IFCC. A total of 929 drivers, tested for BAC at the time of hospital admission after a traffic accident, were classified into two groups: InjDr 1 (BAC ≤ 0.50 g/L) and InjDr 2 (BAC>0.50 g/L); all drivers were also tested for CDT.

RESULTS

InjDr 1 included 674 individuals, only 2.5% showing a CDT above the cutoff, whereas InjDr 2 group consisted of 255 subjects, 28.6% testing positive for CDT (Odds Ratio 15.5). When subdividing the InjDr group into increasing classes of CDT, a steady increase in the percentage of BAC-positive drivers was appreciated. Moreover, average BAC was found to parallel each class of CDT.

CONCLUSIONS

The reported data strongly support the use of CDT as a biomarker of increased risk of alcohol-related traffic accidents in the procedures of re-granting of the driving license upon confiscation for "drink driving".

Effects of postmortem interval, putrefaction, diabetes, and location of death on the analysis of ethyl glucuronide and ethyl sulfate as ethanol biomarkers of antemortem alcohol consumption

This study evaluated the forensic value of ethanol biomarkers ethyl glucuronide (EtG) and ethyl sulfate (EtS) under different conditions, including diabetes mellitus, drug abuse, and advanced decomposition. In addition, we explored whether ethanol, EtG, or EtS formation occurred in patients who died as a result of diabetes mellitus. Fifty-two routine postmortem cases were divided into three groups. Group 1 included only the post-mortem cases in which at least blood samples were available (n=47). Group 2 included all cases with positive BAC (n=28). Group 3 included the cases with negative BAC while information surrounding the cases suspected antemortem alcohol consumption and cases that tested negative for ethanol but positive for EtG and EtS. We analyzed multiple bodily fluid specimens, including the vitreous humor, for ethanol biomarker analysis and accurately identified antemortem ethanol consumption or postmortem ethanol synthesis. We also determined the utility of urine samples for analyzing ethanol and its metabolites in putrefaction cases. If no urine sample was available at autopsy due to urination before death or diabetes-associated glucosuria, vitreous humor samples were an appropriate alternative for ethanol biomarker testing. We observed postmortem ethanol synthesis in diabetic individuals even with a short postmortem interval (PMI), however, glucose did not increase postmortem ethanol production in individuals with diabetes under appropriate preservation. The shorter the PMI, the better the ethanol source can be determined. Postmortem ethanol production occurred in all body fluid specimens analyzed herein, including the vitreous humor. EtG and EtS levels were stable and provided accurate insight into ethanol sources, even in cases of postmortem ethanol production. While the present study focused on the use of vitreous humor for the analysis, it is expected such samples may not be available in cases of advanced decay. In cases where no other bodily fluid specimens are available, solid tissue specimens are highly preferred.

Significant postmortem diffusion of ethanol: A case report

In the realm of forensic pathology, ethanol is one of the most frequently encountered xenobiotics. The determination of ethanol concentration in blood after death is of great interest in forensic settings. It is important to be able to determine the level of intoxication of the deceased at the time of death, which is directly correlated to the ability to act prior to death, especially when a suicide is suspected. This estimation is not always easy to establish owing to various artifacts that are important to know for a proper ethanol blood level interpretation, among them postmortem (PM) diffusion. We describe here a case of unusual ethanol distribution in body compartments and discuss the importance of PM diffusion and redistribution while performing complementary toxicological analysis, especially when the blood and urine samples seemed to be inconsistent after the first results.

Evaluation of the Compatibility of Ethyl Glucuronide and Ethyl Sulphate Levels to Assess Alcohol Consumption in Decomposed and Diabetic Postmortem Cases

The aim of the study is to evaluate the contribution of ethanol metabolite detection in postmortem cases by showing the connection between the presence of ethanol metabolites, which are indicators of alcohol consumption, and the detection of potential postmortem ethanol formation in decomposed and diabetic cases. Determination of ethanol consumption before death is often one of the most important questions in death investigations. Postmortem ethanol formation or degradation products in the blood make it difficult to distinguish antemortem consumption or postmortem formation of ethanol and eventually may lead to misinterpretation. Decomposed bodies and diabetic cases are vulnerable to postmortem ethanol formation due to putrefaction, fermentation or other degradations. Ethyl glucuronide (EtG) and ethyl sulphate (EtS) are two metabolites of ethanol produced only in the antemortem time interval. In this study, EtG and EtS levels in urine and vitreous humor samples of 27 postmortem cases, including diabetic and degraded bodies were compared to ethanol results of their blood, urine, and vitreous humor samples. EtG and EtS in urine and vitreous humor were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS-MS) and ethanol was assayed by routine headspace gas chromatography-flame ionization detector (GC-FID). These cases were devoid of other influences from forensically relevant drugs, so ethanol and/or glucose were among the only positive findings in these cases. The results of this pilot study indicate the postmortem ethanol concentrations do not correlate with the measured EtG and EtS values but are beneficial in rulings of accidental or natural deaths. This preliminary study gives additional data to help distinguish between antemortem ethanol intake and postmortem formation. EtG and EtS were well correlated positively with antemortem ethanol use instead of forming spontaneously in samples from decedents who are decomposing or have a history of diabetic hyperglycemia.

Analytical and diagnostic aspects of carbohydrate deficient transferrin (CDT): A critical review over years 2007-2017

The need for investigating alcohol abuse by means of objective tools is worldwide accepted. Among the currently available biomarkers of chronic alcohol abuse, carbohydrate-deficient transferrin (CDT) is one of the most used indicator, mainly because of its high specificity. However, some CDT analytical and interpretation aspects are still under discussion, as witnessed by numerous research papers and reviews. The present article presents a critical review of the literature on CDT appeared in the period from 2007 to 2017 (included). The article is organized in the following sections: (1) introduction, (2) pre-analytical aspects (3) analytical aspects (4) diagnostic aspects (5) concluding remarks. As many as 139 papers appeared in the international literature and retrieved by the search engines PubMed, Web of Science and Scopus are quoted.

Sudden Death and Chronic Alcoholism

Alcohol is a common factor in many deaths. Chronic alcoholics may die suddenly from trauma, intoxication, and from preexisting disease. In many cases, there is no obvious cause of death in chronic alcoholics following initial postmortem examination. Determining the cause of death in chronic alcoholics can be challenging. Such deaths in chronic alcoholics may be due to a number of mechanisms, including alcoholic ketoacidosis and disorders of cardiac rhythm. Alcoholic ketoacidosis has been recognized as a cause of death since the 1990s. It can be diagnosed by postmortem analysis of ketone bodies, including acetone and β-hydroxybutyrate. It has been recognized clinically that patients with alcoholic liver disease have prolongation of the QT interval and a risk of sudden death. This paper reviews sudden natural deaths in chronic alcoholics, discussing pathological processes and mechanisms of death, especially where the cause of death is not obvious on initial autopsy.

Comparison of ethyl glucuronide and carbohydrate-deficient transferrin in different body fluids for post-mortem identification of alcohol use

AIMS

Alcohol abuse is a major risk factor for premature death. Confirming the role of alcohol consumption in cause-of-death investigations has, however, remained difficult, due to lack of reliable biomarkers.

METHODS

We compared ethyl glucuronide (EtG) and carbohydrate-deficient transferrin (CDT) assays from serum, urine, cerebrospinal fluid and vitreous humor in a forensic autopsy population with either a positive (n = 38) or negative (n = 22) history of alcohol abuse based on detailed medical and police records and forensic toxicological investigations.

RESULTS

A positive blood alcohol concentration (median 1.15‰, range 0-3.3‰) was found in 26/38 (68%) of the cases with a documented history of alcohol abuse. EtG concentrations (mean ± SD) in urine (339 ± 389 mg/l, P < 0.001), vitreous humor (4.2 ± 4.8 mg/l, P < 0.001), serum (6.9 ± 8.9 mg/l, P < 0.01) and cerebrospinal fluid (1.7 ± 2.7 mg/l, P < 0.01) were significantly higher among the cases with a positive history of alcohol use than those in the alcohol-history negative group, whereas in corresponding comparisons CDT was significantly different only in cerebrospinal fluid (4.3 ± 2.1 vs. 2.3 ± 0.6%, P < 0.05). The highest sensitivities (92%) in detecting ante-mortem alcohol use were obtained for urine and vitreous humor EtG assays.

CONCLUSION

Our data indicate that measurements of EtG in urine or vitreous humor show the highest diagnostic accuracies in post-mortem investigations of excessive alcohol consumption and can be recommended for routine applications.