Ethyl glucuronide: A biomarker to identify alcohol use by health professionals recovering from substance use disorders

Aims: Physicians recovering from substance-related disorders are usually allowed to return to practice if they agree to remain abstinent from drugs, including alcohol, and to undergo random urine testing. Over 9000 physicians are currently involved in such monitoring programs in the US. To date, it has been difficult to adequately monitor abstinence from alcohol due to the short half-life of alcohol and no other highly specific marker. Ethyl glucuronide (EtG), a direct metabolite of alcohol, offers an extended window for assessment of drinking status (up to 5 days). Our aim was to assess the potential value of EtG testing in abstinence-based monitoring programs. Patients and methods: Urine samples were obtained from 100 participants in a physician monitoring program and additional samples were subsequently obtained 'for cause', 'to verify positive urine alcohol, when drinking was denied' and 'in high risk individuals'. All participants had signed contracts agreeing to remain abstinent from mood-altering drugs, including alcohol, and had agreed to random urine testing. EtG was determined using LC/MS-MS in addition to standard testing. The main outcome measure were urine specimens positive for EtG versus those positive based on standard testing for alcohol and other drugs. Results: Among the initial 100 random samples collected, no sample was positive for alcohol using standard testing; however, seven were positive for EtG (0.5-196 mg/l), suggesting recent alcohol use. Subsequent EtG testing was performed clinically during the course of monitoring. Of the 18 tests performed to date, eight of eight tests performed 'for cause' were positive for EtG but negative for all other drugs including urine alcohol. All eight were confirmed positive by self reported drinking by the patient when confronted regarding the positive test result. Of six tests performed to 'confirm a positive urine alcohol' two were positive for EtG and confirmed positive by self reported drinking. For the other four samples, especially as two are from a diabetic, in vitro fermentation of ethanol is discussed. Conclusions: These data suggest that physicians in monitoring programs have a higher rate of unrecognized alcohol use than previously reported. Incorporation of EtG testing into alcohol abstinence monitoring can strengthen these programs.