This report describes the outcomes of a process undertaken to review and update the National Safety Council's Alcohol, Drugs and Impairment Division's recommendations for the toxicological investigation of suspected alcohol and drug-impaired driving cases and motor vehicle fatalities. The updates to the recommendations are made based on a survey of practices in laboratories in the USA and Canada performing testing in these cases, consideration of existing epidemiological crash and arrest data, current drug use patterns, and practical considerations of widely available technology platforms in laboratories performing this work. The final recommendations updates are derived from a consensus meeting of experts recruited from survey respondents and the membership of the National Safety Council's Alcohol, Drug and Impairment Division. The principal changes in this round of recommendations include removal of butalbital, phenobarbital, and phencyclidine from Tier I (mandatory) to Tier II (optional) due to changes in prevalence. In addition, buprenorphine, fentanyl, tramadol, and their metabolites were moved from Tier II to Tier I due to increased prevalence and concerns about their potential for causing impairment. In addition, screening and confirmatory cutoffs for the oral fluid scope were further refined. Other additions were made to the list of Tier II compounds including fentanyl analogs (e.g., acetylfentanyl, butyrylfentanyl, furanylfentanyl, etc), mitragynine, novel opioids (e.g., MT-45, U-47700), atypical antipsychotics, and novel benzodiazepines (e.g., clonazolam, flubromazolam, etc).

This report describes updates to the National Safety Council’s (NSC) Alcohol, Drugs, and Impairment Division’s (ADID) recommendations for drug testing in Driving Under the Influence of Drugs (DUID) cases and motor vehicle fatalities. The updates are based on a survey of drug testing practices in laboratories in the United States and Canada, a comprehensive review of the prior recommendations, and data and research on drugs most frequently detected in DUID cases. A consensus meeting was held with representative forensic science practitioners and the authors of this report to update recommendations. No changes were made to the Tier I scope; however, there were changes to cutoffs of some analytes for blood, urine and oral fluid. Due to increased prevalence in DUID cases, trazodone and difluoroethane were added to the Tier II scope. For clarification, Tier I cutoffs reflect free concentrations, and hydrolysis is recommended but not required. The consensus panel concluded that urine is an inferior matrix to blood and oral fluid as it may represent historical use or exposure unrelated to observed impairment; therefore, future iterations of these recommendations will not include urine as a recommended matrix. Laboratories currently testing urine should work with traffic safety partners to encourage the use of blood and oral fluid as more appropriate specimens and adjust their capabilities to provide that testing.