Stability of ethyl glucuronide in urine, post-mortem tissue and blood samples

Abstract

The stability of ethyl glucuronide (EtG) under conditions of degradation was examined in urine samples of nine volunteers and in post-mortem tissue (liver, skeletal muscle) and blood taken from seven corpses at autopsies. Analysis was performed via LC-MS/MS. EtG concentrations in urine samples ranged from 2.5 to 296.5 mg/l. When stored at 4 degrees C in airtight test tubes, EtG concentrations remained relatively constant; when stored at room temperature (RT) for 5 weeks in ventilated vials, variations of EtG concentrations ranged from a 30% decrease to an 80% increase, with an average of 37.5% increase. Liver and skeletal muscle tissue of three corpses with positive blood alcohol concentrations (BAC; ranging from 0.106 to 0.183 g%) were stored for 4 weeks and analysed periodically. EtG concentrations decreased 27.7% on average in 4 weeks storage at RT but EtG was still detectable in all samples with initial EtG concentrations higher than 1 mug/g. Blood and liver samples of four corpses with negative BACs were stored at RT after addition of 0.1 g% ethanol, and no new formation of EtG was observed.

A study of ethyl glucuronide in post-mortem blood as a marker of ante-mortem ingestion of alcohol

“…Both our work (papers II and III) and other studies (115,138) showed that no EtG was formed, while another work (147) showed formation of EtG in clinical urine samples containing bacteria.…”

“…Both our study (paper II) and others have documented that EtG is unstable in the presence of bacteria, both in post mortem material (115,119) and in clinical urine samples (146,147 Weinmann, personal information). We found that refrigeration and the presence of preservatives made EtG stable (paper II), results that are also supported by other publications (146,148).…”

“…They also studied stability of EtG in liver and skeletal tissue (n=3) (115). Recently, more case reports where EtG was used post mortem and a stability study have been published (116-119).…”

Postmortem chemistry update part II

“…Schloegl et al [27] examined the stability of EtG in several substrates including urine from volunteers and postmortem specimens. The study was carried out on urine samples of nine volunteers who had consumed different amount of alcohol during the previous evening, stored up to 5 weeks at room temperature and at 4°C.…”

EtG and EtS in Autopsy Blood Samples With and Without Putrefaction Using UPLC–MS-MS

“…In the interpretation of a postmortem ethanol finding, criteria like specific case information and comparisons of ethanol levels in blood, urine and vitreous humor are often used, but are not always reliable (2,3). A supplementary method to distinguish antemortem ethanol consumption from postmortem ethanol formation is the analysis of the ethanol metabolites ethyl glucuronide (EtG) and ethyl sulfate (EtS) (4)(5)(6)(7). These metabolites are produced by enzymatic conjugation of ethanol in living individuals (8,9).…”