Driving license regranting: Hair EtG, serum CDT, and the role of sociodemographic and medicolegal variables

Driving under the influence (DUI) of alcohol is a road safety problem. Driving license regranting is based on the evaluation of medicolegal and toxicological variables that may include serum carbohydrate-deficient transferrin (CDT) and hair ethyl glucuronide (hEtG). The aim of the study was to compare the diagnostic performance of CDT and hEtG in a population of DUI offenders. Other factors potentially associated with heavy alcohol use were explored. The population included DUI offenders examined during the period of January 1, 2019, through June 30, 2022. Sociodemographic, medicolegal, and toxicological variables were collected. CDT in serum and EtG in head hair were determined in all subjects. Excessive alcohol intake (hEtG ≥30 pg/mg) was considered cause for unfitness to drive. Cohen's kappa coefficient was calculated. Descriptive analyses were performed using chi-square and Mann-Whitney tests. Variables significantly different between the groups were included in a multivariate binary logistic regression model. The sample encompassed 838 subjects (case group: 179, comparison group: 689). CDT exhibited poor agreement (κ = 0.053) with hEtG as the reference test. Lower education, age at DUI, heavy smoking, and GGT levels associated with heavy alcohol consumption differentiated the two groups. For DUI offenders, the use of CDT to assess heavy alcohol consumption is limited, possibly due to the time-window assessed, the time required for normalization, and the different amount of ethanol needed to reach higher CDT levels, in comparison to hEtG; thus, hEtG assessment is strongly recommended for this population. Heavy smoking, GGT, education, and age could be related to heavy alcohol consumption and higher risk of DUI.

Towards Best Practice in Hair Metabolomic Studies: Systematic Investigation on the Impact of Hair Length and Color

Untargeted metabolomic studies are used for large-scale analysis of endogenous compounds. Due to exceptional long detection windows of incorporated substances in hair, analysis of hair samples for retrospective monitoring of metabolome changes has recently been introduced. However, information on the general behavior of metabolites in hair samples is scarce, hampering correct data interpretation so far. The presented study aimed to investigate endogenous metabolites depending on hair color and along the hair strand and to propose recommendations for best practice in hair metabolomic studies. A metabolite selection was analyzed using untargeted data acquisition in genuine hair samples from different hair colors and after segmentation in 3 cm segments. Significant differences in metabolites among hair colors and segments were found. In conclusion, consideration of hair color and hair segments is necessary for hair metabolomic studies and, subsequently, recommendations for best practice in hair metabolomic studies were proposed.

Ethyl glucuronide hair testing: A review

Ethyl glucuronide (EtG) is a minor, non-oxidative ethanol metabolite that can be detected in several matrices (e.g. blood, urine, hair, meconium) for variable periods of time. Quantification of EtG in hair (hEtG) has established itself, over recent years, as one of the most reliable biomarkers of long-term alcohol consumption habits, with the Society of Hair Testing (SoHT) offering cut-off values for assessment of both abstinence and heavy drinking (>60 g/day). Despite its high diagnostic performance, however, issues concerning inter- and intra-laboratory variability as well as data interpretation are still being investigated and represent the ultimate barrier to widespread acceptance of hEtG in the forensic context. The aim of this review is to summarize currently available analytical methods of hEtG testing, provide a framework to understand current hEtG cut-offs and their possible upcoming changes (in particular, a lower abstinence cut-off has been proposed for the 2019 revision of the SoHT consensus), and offer a schematic but exhaustive overview of the pitfalls in result reproducibility and interpretation that may limit applications of hEtG testing in the forensic context. Ultimately, the purpose of the authors is not to undermine the reliability of hEtG as an alcohol use marker, but rather to enhance it by promoting familiarization with all aspects related to it, from ethanol pharmacokinetics and EtG incorporation into hair, to sample preparation and analytical methods, to specific cases warranting close attention and additional tests for correct interpretation of hEtG results.