Ethyl glucuronide in hair: is it a reliable marker of chronic high levels of alcohol consumption?

Aims: This study aims to investigate the relationship between ethanol daily intake (EDI) and the levels of ethyl glucuronide in hair. Design: Ethyl glucuronide concentration was determined in hair samples from different classes of ethanol drinkers and results were compared with the reported information about drinking habits. Setting: Pavia, Italy. Participants: Twenty-two known alcoholics, 21 volunteers self-reporting an EDI from 2 to 60 g, and seven teetotallers were involved in this study. Measurements: Ethyl glucuronide determination in hair samples was performed by liquid chromatography-tandem mass spectrometry (limit of detection: 2 pg/mg, lower limit of quantification: 3 pg/mg). Findings: Current known alcoholics (n = 21) had ethyl glucuronide hair concentration in the range 4.0-434.7 pg/mg (average: 62.8, median 37.4 pg/mg); ethyl glucuronide was not detected in hair samples from teetotallers (n = 7); all volunteers reporting an EDI of at least 30 g ('non-moderate drinkers' according to the US Department of Health and Human Services) tested positive for ethyl glucuronide (cut-off: 4 pg/mg). All volunteers declaring an ethanol daily intake higher than 40 g ('heavy drinkers' according to the World Health Organization, Regional Committee for Europe) tested positive for this compound (cut-off: 5 pg/mg). The application of a cut-off of either 4 pg/mg or 5 pg/mg resulted in one false positive, coming from a volunteer asserting an ethanol daily intake of 30 g. No false negatives were found. Conclusions: The concentration of ethyl glucuronide in hair appears to correlate with EDI.