Recommendations for Toxicological Investigation of Drug-Impaired Driving and Motor Vehicle Fatalities—2025 Update

This document describes updates to previously published recommendations for drug testing in drug-impaired driving cases. A survey of drug testing practices in driving under the influence of drug (DUID) and motor vehicle fatality cases was sent to toxicology laboratories across the United States and Canada. Following compilation of survey data, a virtual consensus meeting was held where forensic science practitioners and the authors reviewed the survey results and conducted a comprehensive review of the 2021 recommendations using a modified Delphi method. Tier I and Tier II screening and confirmation scope and cutoffs were re-evaluated to update the recommendations. Carisoprodol and meprobamate were moved to the Tier II scope from Tier I; gabapentin was promoted to the Tier I scope from Tier II; screening cutoffs were differentiated for immunoassay versus non-immunoassay (e.g. chromatographic) screening for blood and oral fluid; cross-reactivity screening requirements were removed and clarified with specific cutoff values; several cutoffs for screening and confirmation were increased or removed for blood and oral fluid; urine was removed as a recommended matrix for testing in cases involving suspected drug impairment.