Ethyl glucuronide and alcohol abstinence: A correlation study in hair and fingernails to establish a cut-off value in fingernails for teetotalers.

<bold>Introduction: </bold>Excessive use of alcohol increases the risk to be involved in a road traffic accident. According to many legislations, certain maximal blood-alcohol-concentrations (BAC) have to be respected to be allowed to drive on public roads. Acute alcohol intoxication is evaluated by blood analysis or analysis of the exhaled alveolar air. In many cases, evaluation of the alcohol consumption during the past months can be useful. In this light, ethyl glucuronide (EtG), a direct alcohol biomarker which can be found in keratinized matrices (hair, nails) is valuable and can be used for the long-term follow-up of alcohol consumption.<bold>Research Aim: </bold>To compare the EtG concentration in hair and fingernails from teetotalers, and to propose a cut-off value for EtG in fingernails for alcohol abstinence.<bold>Material and Methods: </bold>Paired samples of hair and nails were collected from participants, with a minimum age of 18 years. They all stated alcohol abstinence for at least 6 months. Participants were asked to complete a questionnaire about age, gender and the use of hair care products and nail polish. Analysis of EtG in the nail and hair samples were conducted following a validated analytical method.<bold>Results: </bold>From 126 participants a hair and nail sample were collected. Of this group, 15 participants were finally not included in the study because of insufficient amount of hair or nails collected. There were more female participants (65%) and the average age of participants was 39 years. The EtG concentration in hair was below the limit of detection of 2.1 pg/mg in all but 4 samples (2.1, 2.1, 2.9, and 3.5 pg/mg). The EtG concentration in nails was below the limit of detection in 97 of the 111 samples. The concentrations in nails ranged between 2.3 and 23 pg/mg.<bold>Discussion and Conclusion: </bold>In a population of 111 teetotalers, the 97.5% percentile of EtG concentrations in fingernails is 7.6 pg/mg. The highest EtG concentration observed was 23 pg/mg. These results suggest that the cut-off value for alcohol abstinence may be lower than the previous suggested 59 pg/mg and 37 pg/mg. [ABSTRACT FROM AUTHOR]