ASSESSMENT AND DETECTION Detection Times for Urinary Ethyl Glucuronide and Ethyl Sulfate in Heavy Drinkers during Alcohol Detoxification

Aims: Ethyl glucuronide (EtG) and ethyl sulfate (EtS) are conjugated ethanol metabolites formed in low amounts after alcohol consumption. Compared with ethanol, EtG and EtS are excreted in urine for a prolonged time, making them useful as sensitive alcohol biomarkers. This study determined the detection times for EtG and EtS in alcoholic patients undergoing alcohol detoxification. Methods: Alcohol-dependent patients (n = 32) with an initial alcohol concentration ≥1 g/L based on breath testing were followed during detoxification. Urine samples for determination of EtG, EtS, ethanol and creatinine were collected on admission to the hospital and thereafter once daily for several days. EtG and EtS measurements were performed by liquid chromatographymass spectrometry (LC-MS) and EtG also using an immunochemical assay (DRI-EtG EIA, ThermoFisher/Microgenics). Results: The detection time for urinary EtG was weakly correlated (r = 0.434, P = 0.013) with the initial alcohol concentration (range 1.0–3.4 g/L). For EtG, the individual time range until return to below the applied cut-off limit (<0.5 mg/L) was ∼40–130 h (median 78) with a similar time course observed for EtS. After correction for urine dilution, the time until an EtG/creatinine ratio <0.5 mg/g was ∼40– 90 h (median 65). The detection times after an estimated zero ethanol concentration were ∼30–110 h (median 66) for EtG and ∼30– 70 h (median 56) for EtG/creatinine. The EtG results by LC-MS and the immunoassay were in good agreement. Conclusions: During alcohol detoxification, EtG and EtS remained detectable in urine for several days. The detection times showed wide inter-individual variations, also after adjusting values for urine dilution and to the estimated times for a completed ethanol elimination.