Evaluation of the EMIT reagent system for measurement of caffeine with the EMIT Lab 5000 System and a centrifugal analyzer.

摘要

Using a Syva EMIT Lab 5000 System, we evaluated a newly developed EMIT assay for measurement of caffeine in serum of neonates. The method is rapid, and coefficients of variation for within-run and day-to-day precision were less than 5%. The accuracy of the method, as evaluated from analytical recovery and a calibrator-crossover study, is excellent. Comparison of the results analyzed by the EMIT caffeine assay (y) and the liquid-chromatographic comparison method (x) yielded the linear regression equation y = 1. 052x + 0.293 (n = 110, r = 0.987, and Sy . x = 0.625). The method was also adapted to a COBAS-BIO centrifugal analyzer (y) and optimized to minimize sample and reagent consumption. Linear regression analysis yielded the equation y = 1. 031x + 0.227 (n = 61, r = 0.992, and Sy . x = 0.488). As many as 400 assays per EMIT kit can be performed with the analyzer method, with excellent precision and accuracy. The kit assay and this centrifugal analyzer are well suited for rapid batch testing: 28 analyses (including six calibrators) in 10 min.