Urinary ethyl glucuronide (EtG) and ethyl sulphate (EtS) assessment: valuable tools to improve verification of abstention in alcohol-dependent patients during in-patient treatment and at follow-ups

ABSTRACT Aims The aims of this study were (i) to assess the effect of additional urinary ethyl glucuronide (EtG) and ethyl sulphate (EtS) assessment on diagnosed relapse rates in detoxified alcohol‐dependent patients; and (ii) to compare dropout rates between EtG‐ and EtS‐negative and ‐positive patients. Design Two studies on detoxified alcohol‐dependent patients. If patients had no indication of relapse they were asked for a urinary sample at discharge from in‐patient treatment 3, 6 and 12 weeks after discharge (study 1) and 1, 3 and 6 weeks after discharge (study 2), respectively. Setting Department of Psychiatry, University of Luebeck, Germany. Participants A total of 107 and 32 detoxified alcohol‐dependent patients having participated in a 3‐week in‐patient motivation enhancement programme. Measurement Personal interviews, breathalyzer tests, assessment of urinary EtG and EtS with liquid chromatography‐tandem mass spectrometry (LC‐MS/MS analysis). Finding Urinary EtG and EtS were always positive at the same time. In the first study 13.5% of the patients were already positive before being discharged from hospital. At the follow‐ups 3, 6 and 12 weeks after discharge 12.2, 19.4 and 28.0%, respectively, of the patients coming to the follow‐up and denying relapse were positive on urinary EtG and EtS. In the second study, of those patients showing up for follow‐up after 1 week and denying relapse, EtG and EtS were positive in four cases (17.4%). Only one EtG‐ and EtS‐positive relapser (3.1%) came to the next follow‐ups. In both studies the rates of detected relapses were significantly higher for early follow‐ups if urinary EtG and EtS results were considered additionally. Dropout rates until the next follow‐up were significantly higher among positive than EtG‐ and EtS‐negative patients. Conclusion Urinary EtG and EtS improve verification of abstinence in studies of alcohol‐dependent patients.