An improved method of determining ethanol use in a chronic pain population

Background: Determination of ethanol use in the pain patient population being treated with chronic opioid therapy is critically important to the treating physician. Urinary ethanol, ethyl glucuronide (EtG), and ethyl sulfate (EtS) have been used to identify alcohol use. Because urine samples are shipped to reference laboratories, the possibility of glucose fermentation during transit producing ethanol complicates interpretation. The purpose of this study was to establish whether ethanol-positive urine samples were due to ingestion or fermentation during shipping. Methods: The authors obtained 94 ethanol-positive urine samples from pain patients, which were further tested for EtG, EtS, and glucose. Results: Only 62 of the 94 samples contained EtS or EtS. Of the 94 samples, 63 samples had glucose values above 10 mg/dL. Four of the 32 EtG-negative patients had ethanol levels that were nonphysiologic. Limitations of the study include the lack of demographic data beyond treatment with opioids for chronic pain. Conclusions: Roughly one-third of the time, ethanol-positive urine samples that have been shipped were positive because of fermentation and not because of patient alcohol consumption. This method is a combination of urinary ethanol measurement and liquid chromatography tandem mass spectrometry quantitation of both EtG and EtS. In the absence of these metabolites, the presence of urinary ethanol is attributed to fermentation. The improvement is a better definition of the source of the ethanol. Confirmatory testing showing the presence of the ethanol metabolites EtG and EtS is needed to validate that the ethanol is due to consumption. The presence of glucose, while common in the ethanol-positive samples, is not an absolute indicator that the ethanol was due to fermentation.