Ethyl Glucuronide and Ethyl Sulphate in Urine: Caution in their use as markers of recent alcohol use

Aim: To clarify the role of the ethanol metabolites, ethyl glucuronide (EtG) and ethyl sulfate (EtS), in monitoring alcohol consumption. Method: We recruited 7 female and 17 male volunteers who were instructed to consume a quantity of beer (containing 48 gm ethanol) with food in one session. We examined urinary excretion of EtG and EtS over time and looked for correlations between the concentrations of the metabolites EtG and EtS. Results: EtG concentrations in urine varied between 0.026 and 430.372 μg/ml with average values between 11.85 μg/ml (SD 19.75), 30 min after alcohol intake, and 100.39 μg/ml (SD 101.34), 4.5 h after alcohol intake. EtS urinary concentration ranged from 0.006 to 101.432 μg/ml with average values between 4.77 μg/ml (SD 5.42), 30 min after alcohol intake, and 30.14 μg/ml (SD 27.20), 4.5 h after alcohol intake. Spearman's test showed that urinary EtG and EtS correlated significantly at several time points. Conclusion: The great interindividual variability in their excretion suggests caution in the use of urinary measurement of these metabolites in forensic investigations.