Phosphatidylethanol (PEth) in blood samples from "driving under the influence" cases as indicator for prolonged excessive alcohol consumption.

ABSTRACT

Phosphatidylethanol (PEth) is considered as specific biomarker of alcohol consumption. Due to accumulation after repeated drinking, PEth is suitable to monitor long-term drinking behavior. To examine the applicability of PEth in "driving under the influence of alcohol" cases, 142 blood samples with blood alcohol concentrations (BAC) ranging from 0.0-3.12‰ were analyzed for the presence of PEth homologues 160/181 (889 ± 878 ng/mL; range LC-MS/MS. With receiver operating characteristic analysis, PEth thresholds were evaluated to differentiate moderate and excessive alcohol consumption with acceptable sensitivity and specificity in accordance with the 1.6‰ BAC limit. With a threshold of 700 ng/mL for PEth 160/181, prolonged excessive alcohol consumption was detected in 65.9% of drunk drivers with a BAC ≥ 1.6‰ and in 31.6% of the samples with a BAC < 1.6‰. Similar results were obtained for PEth 160/182 with a threshold of 300 ng/mL. Both criteria, PEth 160/181 and PEth 160/182, were conform in the evaluation of drinking habits in 88.7% of blood samples. These results show the possibility to detect prolonged excessive alcohol consumption, even if the BAC is below the legal threshold of 1.6‰ for driving aptitude assessment. As a consequence, concentrations of PEth 160/181 ≥ 700 ng/mL and of PEth 160/182 ≥ 300 ng/mL may be considered as indicators for the necessity of driving aptitude assessment in addition to BAC.