Evaluating cross-reactivity of new psychoactive substances (NPS) in human whole blood by enzyme-linked immunosorbent assay (ELISA).

This article evaluates the effectiveness of enzyme-linked immunosorbent assays (ELISA) for detecting five subclasses of novel psychoactive substances (NPS)—novel synthetic opioids, fentanyl analogs, stimulants, benzodiazepines, and hallucinogens—in whole blood by assessing their cross-reactivity on commercially available ELISA kits. Results showed no cross-reactivity for novel synthetic opioids on the morphine ELISA plate, while fentanyl analogs, novel benzodiazepines, and certain hallucinogens demonstrated significant cross-reactivity with their respective ELISA kits, indicating potential for reliable screening. Novel stimulants generally showed low cross-reactivity except for 4-fluoroamphetamine, which exhibited high cross-reactivity on the amphetamine ELISA plate. The study highlights the utility and limitations of ELISA-based screening for NPS detection, emphasizing the need for updated confirmatory methods to reduce false negatives and improve forensic toxicology practices.