Testing venous carbohydrate-deficient transferrin or capillary phosphatidylethanol with concurrent ethyl glucuronide and ethyl palmitate hair tests to assess historical and recent alcohol use.

Abstract

Hair biomarkers, ethyl glucuronide (EtG) and ethyl palmitate (EtPa), together with blood biomarker tests, carbohydrate-deficient transferrin (CDT) or phosphatidylethanol (PEth), are commonly used in identifying patterns of alcohol consumption as they possess different windows of detection. The detection of EtG in hair samples is mainly used in combination with EtPa when hair cosmetic treatments such as hair colouring and bleaching affect EtG levels. The main purpose of our study was to investigate the differences in frequency distribution of positive CDT and PEth results indicating alcohol had been used, when EtG and EtPa were not detected, where evidence of abstinence is paramount. Of the total 602 cases, for 179 (29.7%), neither EtG nor EtPa markers were detected. Of these, 0.5% of the cases produced positive CDT. However, 18.6% produced positive PEth, a significantly higher proportion. A similar pattern emerges when results are evaluated according to whether hair had been either cosmetically treated or untreated. When hair was untreated, one case produced positive CDT, and 19.3% were positive for PEth (median of 51 ng/ml). No cases of positive CDT results, but 20.8% of PEth were positive (median of 106.5 ng/ml) when hair samples had been cosmetically treated. Whether EtG or EtPa markers were detected or not, significantly higher proportions of PEth than CDT were seen. The results of this study substantiate the case for using hair EtG in conjunction with a PEth test, rather than CDT test, for efficient monitoring of recent and historical alcohol consumption.