Phencyclidine in Drivers and Decedents in Dallas County: A Five-Year Retrospective Review of Toxicological and Demographical Data

Presented are phencyclidine (PCP)-positive cases received by the Toxicology Laboratory at the Southwestern Institute of Forensic Sciences from local law enforcement agencies and the Office of the Medical Examiner (OME) between 1 January 2015 and 31 December 2020. Of the 43,940 requests for testing received during that time, 898 (2.04%) were positive for PCP. These cases were evaluated for PCP concentration, additional/concurrently reported drug concentrations and demographics. For ME cases, the cause and manner of death were also evaluated. Although the number of requests received by the Toxicology Laboratory increased each year, the percentage positive for PCP remained consistent. Subjects ranged from 18 to 71 years old (median 48 years) and were predominantly black (94.19%) and male (78.49%). PCP concentrations for all case types ranged from 0.02 to 2.33 mg/L (median 0.05 mg/L); driving while intoxicated (DWI) cases ranged from 0.02 to 0.14 mg/L (median 0.04 mg/L) and ME cases ranged from 0.02 to 2.33 mg/L (median 0.13 mg/L). In addition to PCP, one or more drug(s) or metabolite(s) was identified concurrently in 69.49% of cases. Cannabinoids were the most frequently detected (39.8%), followed by cocaine and its metabolites (22.0%) and ethanol (18.5%). Results were similar when comparing the additional drugs reported in ME and DWI cases. PCP concentrations in ME samples were generally higher, especially for stimulant drugs. Of the 264 ME cases positive for PCP, the manner of death was determined to be an accident for the majority of cases (62.54%), and the most common cause of death was drug toxicity (35.61%). The results from this study facilitate comparison of laboratory- or region-specific data sets, help determine whether laboratory scopes meet testing needs, contribute to reference ranges and provide the foundation for well-informed policy decisions.