Ethyl glucuronide determination: head hair versus non-head hair

In previous studies, hair analysis of ethyl glucuronide (EtG), a non-volatile, water-soluble, direct metabolite of ethanol, was shown to be adequate for the detection of social and chronic excessive alcohol consumption. As in some cases scalp hair is not available, the analysis of hair from alternative anatomical sites becomes of interest.

In this study, hair samples from head, beard, chest, armpit, stomach, pubis, arms and legs from 32 subjects were analyzed when available, in order to compare the EtG concentrations and to study if the cut-offs used for head hair could be used for non-head hair.

EtG was determined by GC/MS in negative chemical ionization mode using EtG-d5 as internal standard, after extraction by solid phase extraction using Oasis MAX columns and pentafluoropropionic anhydride (PFPA) derivatization.

The results showed that in the cases of negative findings in head hair (EtG < 7 pg/mg), in 7 out of 12 cases negative results could also be found in non-head hair. The five others were positive, due to a positive EtG finding in pubic hair. In 20 cases of positive EtG results for head hair, in all cases positive results could also be found in non-head hair.

In conclusion, although preliminary results indicate a clear trend regarding the accordance between EtG results in head hair and non-head hair, interpretation of non-head hair results remains to be carefully done for pubic hair, for which often higher concentrations have been found.