Four-year evaluation of drug-impaired driving drug concentrations.

This article focuses on analyzing trends in drug positivity among suspected impaired drivers in the USA from 2017 to 2020, using data primarily from NMS Labs in Pennsylvania and aligned with the National Safety Council's Alcohol, Drugs, and Impairment Division (NSC-ADID) Tier I drug testing recommendations. The study found that cannabinoids, especially delta-9 tetrahydrocannabinol (delta-9 THC), ethanol, amphetamine/methamphetamine, fentanyl, and alprazolam were the most commonly detected substances, with significant increases in positivity and concentrations for delta-9 THC, fentanyl, and methamphetamine, while CNS depressants, notably benzodiazepines like alprazolam, showed decreased positivity. Polydrug use was prevalent, particularly combinations involving cannabinoids and ethanol or stimulants, highlighting the complexity of impaired driving cases. The findings underscore the need for laboratories to maintain sensitive and comprehensive testing methods and for toxicologists to carefully interpret drug concentrations in the context of impaired driving.