B-289 Definitive Urine Drug Testing in Emergency Medicine: Recreational and Psychiatric Drug Findings

Background Clinical management of drug-related emergency department (ED) visits relies on available history, toxidrome findings and drug screening. In this study prevalence of drug and polydrug use in an emergency setting is assessed by definitive drug testing and performance of widely-used drug screening by immunoassays is compared with direct-to-definitive testing. Methods Definitive testing for 116 illicit and therapeutic drugs and metabolites was performed retrospectively on urine from ED patients. De-identified specimens from 400 adult patients presenting to the Albany Medical Center Emergency Department between June and September 2024 were tested under an institutional review board approved protocol. Clinically ordered drug screening by commercial immunoassays for amphetamines, barbiturate, benzodiazepines, cannabinoids, cocaine, methadone, opiates and phencyclidine were compared with the definitive drug test findings. Results Definitive testing resulted in 1,350 drug-use findings based on 1,950 positive drug and metabolites test results. Testing revealed a high percentage of patients using nicotine (63%), cocaine (34%), ?9 tetrahydrocannabinol (34%), fentanyl (17%), morphine or heroin (11%) and methamphetamine (6%). Forty percent of patients were also positive for antidepressants and 24% positive for antipsychotics. Notable lower-frequency use of other recreational drugs included xylazine, ?8 tetrahydrocannabinol, bromazolam, MDMA, mitragynine and psilocybin. Associated drug findings indicated significant co-use patterns for the high frequency recreational drugs across multiple toxidrome categories. Significant patterns of co-drug use were found for cocaine, fentanyl, morphine and nicotine, including exclusive use of xylazine and bromazolam by fentanyl users. Additional serotonergic drug use was frequent among the 112 patients positive for serotonin-targeted antidepressants, suggesting a risk for serotonin syndrome. Immunoassay performance showed high false negative rates for detection of benzodiazepines (40%), amphetamines (38%), barbiturates (33%), opiates (25%), methadone (20%) and cocaine (16%), along with inaccuracy in phencyclidine detection. Immunoassay missed 890 of the 1,350 drug findings by definitive testing, due to either high cutoff thresholds or limited testing scope. Discussion A high prevalence and diversity of abused drugs and of psychiatric medications in emergency department patients is evidenced by the study. The frequent co-use of illicit and therapeutic drugs and the potential for unrecognized serotonergic interactions with psychiatric medications demonstrate the clinical value of definitive drug testing in the ED setting. This study also shows the limitations of immunoassay drug testing in both scope and sensitivity, with a high rate of undetected drug use. Conclusion The study provides evidence-based support for recommended implementation of definitive drug testing in emergency medicine as a guide to clinical management in drug-related ED visits.