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Background: DBS are an increasingly common clinical matrix., Methods & Results: Sensitive and specific methods for DBS and venous blood cocaine and metabolite detection by LC-HRMS and 2D GC-MS, respectively, were validated to examine correlation between concentrations following controlled intravenous cocaine administration. Linear ranges from 1 to 200 µg/l were achieved, with acceptable bias and imprecision. Authentic matched specimens' (392 DBS, 97 venous blood) cocaine and benzoylecgonine concentrations were qualitatively similar, but DBS had much greater variability (21.4-105.9 %CV) and were lower than in blood., Conclusion: DBS offer advantages for monitoring cocaine intake; however, differences between capillary and venous blood and DBS concentration variability must be addressed., Competing Interests: Financial & competing interests disclosure This work was supported by the Intramural Research Program (IRP), National Institute on Drug Abuse (NIDA), NIH. JL da Costa received a postdoctoral fellowship from Brazilian National Counsel of Technological and Scientific Development (CNPq) to conduct this research. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.

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.