Urinary ethyl glucuronide and ethyl sulfate testing for recent drinking in alcohol-dependent outpatients treated with...

Ethyl glucuronide (EtG) and ethyl sulfate (EtS) are sensitive and specific biomarkers for recent alcohol ingestion. This study compared urinary EtG and EtS measurement with self-reports for detection of prior drinking in alcohol-dependent outpatients treated with the anti-craving medication acamprosate or placebo.

Alcohol-dependent outpatients (26 women, 30 men) were randomized to 21 days of oral acamprosate (2 g/day) or placebo treatment in a double-blind design. They were instructed to refrain from drinking during the study. Return visits to the ward for blood and urine sampling and filling out questionnaires were made on Day 7, 14 (urine sample optional) and 22 (urine sample mandatory). EtG and EtS were determined by liquid chromatography-mass spectrometry.

On the first day (Day 0), 72% of all patients (acamprosate 65%, placebo 78%) tested positive for recent drinking according to urinary EtG (reporting limit ≥ 0.5 mg/l) and EtS (≥ 0.1 mg/l). On the final day (Day 22), the frequency of positive tests was significantly reduced to 30% in the acamprosate group (P = 0.0374) and 33% for placebo (P = 0.0050). However, there was no difference between the treatment groups. When both groups were combined, the EtG (P = 0.025) and EtS (P = 0.015) concentrations were lower on the final day. Altogether, EtG and EtS were detected in 76 of 156 (49%) urine samples. When drinking in the day before sampling was admitted, 93% of urines tested positive; when drinking was denied, still 28% of the samples were positive.

These results confirmed the value of urinary EtG and EtS as reliable indicators of recent drinking during outpatient treatment of persons with alcohol-related problems, and as objective outcome measures when evaluating new alcohol treatment strategies and pharmacotherapies.