Hair EtG Testing in Combination With Measurements of PEth and EtG in Blood to Improve the Assessment of Alcohol Consumption

Ethyl glucuronide detection in hair (H-EtG) effectively diagnoses long-term abstinence and differentiates between social and chronic excessive alcohol use. However, hair testing does not capture alcohol consumption within the week prior to sample collection. To address this limitation, blood tests like phosphatidylethanol (PEth) and blood ethyl glucuronide (B-EtG) are used alongside H-EtG, extending alcohol detection from minutes after drinking up to the period covered by hair. A total of 1205 cases were selected, where H-EtG was analysed in hair segments over 3 cm long, and concurrent fingertip blood samples in dried blood spots (DBSs) were analysed for PEth and B-EtG using UPLC/ESI-MS/MS with cut-offs: H-EtG = 5 pg/mg, PEth = 20 ng/mL and B-EtG = 10 ng/mL. A total of 468 (39%) cases showed H-EtG, PEth and B-EtG levels below cut-off, consistent with abstinence, while 198 (16%) were above cut-off, indicating continuous alcohol consumption. The remaining cases exhibited various patterns. B-EtG was negative in 282 cases (23%), with H-EtG and PEth detected, suggesting alcohol use but not recently. PEth was positive, but H-EtG and B-EtG were negative in 149 cases (12%), indicating alcohol use within a month, but not recently. H-EtG was positive in 78 cases (6%), with PEth and B-EtG negative, confirming recent abstinence. H-EtG was negative in 27 cases (2%), indicating no alcohol use for months, but recent consumption was confirmed by the detection of PEth and B-EtG. Only two cases (0.2%) had positive B-EtG with negative H-EtG and PEth, indicating recent alcohol use. The results confirm the value of combining H-EtG with concurrent blood testing of PEth and B-EtG, significantly enhancing drinking history assessment.