Levels of Hair Ethyl Glucuronide in Patients with Decreased Kidney Function: Possibility of Misclassification of Social Drinkers

BACKGROUND: The use of hair ethyl glucuronide (EtG) levels as a biomarker for chronic high intake of ethanol (EtOH) is increasing, and misclassification of alcohol consumption may have large implications for the patient. The aim of this study was to compare levels of hair EtG in patients with reduced kidney function to levels seen in a comparable control group and to investigate whether the hair EtG levels among kidney failure patients who are social drinkers may lead to a false-positive diagnosis of heavy drinking. METHODS: A total of 41 patients with reduced kidney function and 42 healthy volunteers were included in the study. Both patients and the healthy volunteers reported moderate alcohol intake. The levels of EtG in hair (corrected for estimated daily intake of EtOH [EDI]) were compared between the 2 groups. RESULTS: There was no significant difference between the groups regarding EDI. Despite this, there were significant higher levels of hair EtG (corrected for EDI) in the patient group compared to the control group (p < 0.001). Eight subjects (20%) in the patient group showed EtG levels in hair above 30 pg/mg, in contrast to no subjects among healthy volunteers (p = 0.002). In the patient group, there was significant correlation between levels of EtG in hair and both estimated glomerulus filtration rate and serum creatinine levels. CONCLUSIONS: This study documents an increased risk of obtaining a false-positive diagnosis of heavy drinking among renal disease patients who are social drinkers. Interpretation of EtG levels in hair among patients with reduced kidney function must be performed with caution.