Salicylate determined with a microcentrifugal analyzer, and compared with Du Pont aca, Trinder, and liquid-chromatographic methods

We describe a new automated method for measuring serum salicylate in the Multistat III microcentrifugal analyzer. Ferric nitrate reagent and serum blanking are used. We compare this new method, the automated Du Pont aca method, and the manual Trinder method with a 'high-performance' liquid-chromatographic method. The unblanked Trinder method had the poorest correlation (r = 0.980, S(y.x) = 19.1) with the chromatographic method. The serum-blanked aca and Multistat III methods showed better correlation (r = 0.995, S(y.x) = 9.5 mg/L, and r = 0.991, S(y.x) = 13.0 mg/L, respectively) with the chromatographic method. However, we conclude that all three colorimetric methods gave clinically useful results and that the increased time, expense, and expertise required for chromatographic salicylate analysis are difficult to justify in a routine clinical laboratory.