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.