West Virginia ED screens show fentanyl often missed by traditional opiate tests

BACKGROUND: Traditional opiate immunoassays do not reliably detect fentanyl, and patterns of presumptive drug co-positivity in psychiatric emergency care remain poorly characterized. OBJECTIVES: To describe class-specific urine drug screen positivity, quantify co-positivity among explicitly co-tested encounters, and assess the fentanyl testing gap among adult psychiatric emergency department encounters at two hospitals in West Virginia. METHODS: We retrospectively analyzed 1,091 adult psychiatric emergency department encounters at two West Virginia hospitals from October 2020 through December 2024. Testing was clinician-directed. Class-specific estimates used only encounters tested for each class. Six-core-class co-positivity was assessed among 281 complete-panel encounters; complete and incomplete panels were compared. Multivariable logistic regression evaluated fentanyl and amphetamine/methamphetamine co-positivity among 350 co-tested encounters. RESULTS: Among tested encounters, tetrahydrocannabinol was positive in 214 of 513 (41.7%), amphetamine/methamphetamine in 203 of 509 (39.9%), and fentanyl in 146 of 519 (28.1%). Among complete-panel encounters, 128 of 281 (45.6%) were positive for at least two core classes. Substance-related chief complaints were more common among complete-panel encounters than among incomplete-panel encounters (73.3% versus 56.8%; p < .001). Among fentanyl-positive encounters co-tested for amphetamine/methamphetamine, 81 of 108 (75.0%) were also positive for amphetamine/methamphetamine. Amphetamine/methamphetamine positivity was associated with fentanyl positivity (adjusted odds ratio, 8.5; 95% confidence interval, 4.8-14.9). Among 118 fentanyl-positive encounters co-tested using the traditional opiate assay, 91 (77.1%) were opiate-screen-negative. CONCLUSIONS: Fentanyl and amphetamine/methamphetamine screens frequently overlapped in clinically selected subsets, and traditional opiate screening missed most fentanyl-positive screens. Psychiatric emergency services in fentanyl-affected regions should evaluate fentanyl-specific testing. Because immunoassays were presumptive and testing was nonprotocolized, findings represent screening yield, not confirmed exposure or population prevalence.