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

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.