Cocaine and metabolite concentrations in DBS and venous blood after controlled intravenous cocaine administration

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 mu g/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.