Detectability of Dissociative Psychoactive Substances in Urine by Five Commercial Phencyclidine Immunoassays.
Journal of Analytical Toxicology July 24, 2019 Isabel Gomila, Maria Ángeles Leciñena, Miguel Ángel Elorza et al.
Methoxetamine (MXE) and two methoxy-substituted analogs of phencyclidine (3-MeO-PCP and 4-MeO-PCP) are sold as legal alternatives to banned dissociative drugs like ketamine and PCP. This study tested whether these new psychoactive substances cross-react with five commercial urine immunoassays designed to detect PCP. 3-MeO-PCP and 4-MeO-PCP showed cross-reactivity ranging from 1% to 143% across all assays, and urine samples from two overdose cases were positive for PCP. MXE showed very weak cross-reactivity (0.04% to 0.25%), and ketamine was not detected in any assay. The assays can rapidly screen for 3-MeO-PCP and 4-MeO-PCP but not for ketamine, and MXE's low reactivity limits its detection.