Elimination of EtG and EtS between two consecutive blood samples in apprehended drivers.

AIM: Ethyl glucuronide (EtG) and ethyl sulphate (EtS) are non-oxidative metabolites of ethanol, valuable as biomarkers of alcohol consumption in forensic and clinical contexts. This study aims to calculate the elimination half-lives (t₁/₂) of EtG and EtS in apprehended drivers based on two consecutive blood samples, enhancing the reliability of forensic alcohol consumption assessments.

METHODS

Data was extracted from a database including apprehended drivers in Norway from 2019 to 2024. The study included suspected drunk drivers in which ethanol, EtG and EtS were detected in two consecutive blood samples, drawn at least 20 min apart. In cases where the blood alcohol concentration (BAC) was at or below 0.20 g/kg, in at least one sample, the t₁/₂ was estimated using both empirical and Bayesian statistical methods.

RESULTS

In 670 cases, ethanol, EtG and EtS were detected in two consecutive samples. In 20 of these, the BAC was below 0.20 g/kg. In these 20 cases, the median time between blood samples was 0.46 h. The empirical calculations of t₁/₂ for cases with declining EtG and EtS concentrations yielded a median of 2.6 h for EtG and 2.4 h for EtS. A strong positive correlation was found between empirical t₁/₂ of EtG and EtS (rs=0.81, p < 0.001).

CONCLUSIONS

The t₁/₂ values for EtG and EtS in apprehended drivers are comparable to those reported in experimental studies. The findings contribute to forensic alcohol assessments and legal expert reports. Additional research is needed to investigate EtG and EtS elimination kinetics in real-life impaired driving scenarios.