Abstinence monitoring of suspected drinking drivers: ethyl glucuronide in hair versus CDT

Objective: Ethyl glucuronide (EtG) determinations in the hair of self-reported teetotallers were reviewed and compared with CDT blood tests (by immunochemistry and HPLC). Methods: A retrospective study was carried out on 154 people whose fitness to drive had to be assessed because of the suspicion of relevant alcohol problems. Results: EtG was detected in 55% of the hair samples, and abstinence thus disproved. In two thirds (67%) of these cases, alcohol consumption was even shown to be excessive (EtG values >30 pg/mg). Of the EtG-positive subjects 54% and 82% had CDT values within the reference range by immunochemistry and HPLC, respectively. 39% of the EtG-negative subjects had increased immunochemical CDT values; in contrast, 96% had HPLC CDT values within the normal range. Conclusions: EtG analysis in hair is a useful tool for assessing fitness to drive in suspected drinking drivers; compared to CDT values it provides a direct and unequivocal marker for reliable abstinence monitoring over a period of several months, depending on the length of the hair