Method validation of the biochip array technology for synthetic cannabinoids detection in urine

Background: Synthetic cannabinoids (SC) are widely-abused cannabimimetic drugs that do not screen positive in traditional cannabinoids immunoassays, making detection difficult. Methods and results: The first commercially-available immunoassay for urinary SC was validated. Limits of detection (5–20 µg/L), imprecision (<13.1% intra-, <37.7% inter-assay), and cross-reactivity profiles of 22 SC and 37 metabolites were obtained. A large negative bias (-80.8 to -28.0%) was observed. Sensitivity (98.3%), specificity (48.1%) and efficiency (53.9%) were determined from screening 20,017 urine specimens and confirming 1432 presumptive positive and 1069 selected negative specimens by LC–MS/MS. Cutoff optimization improved performance to 87.6% sensitivity, 85.2% specificity, and 85.4% efficiency. Conclusion: This high-throughput urine SC assay has good sensitivity and improved specificity and efficiency at modified cutoff concentrations.