Ep 15-A3 Precision-Based Verification of Original and Novel Commercial Kits of CRP on Beckman Coulter Au5800.

Abstract

Background: CRP is a hepatic acute-phase reactant protein, which is primarily induced by the interleukin-6 action due to an inflammatory/infectious process. Precision is closeness of agreement between indications or measured quantity values obtained by replicate measurements on the same or similar objects under specified conditions. Precision goals should be stated as the maximum allowable imprecision, SD, and/or CV expressed as a percentage (% CV) at each analyte´s concentration to be tested. The aim of this study was to verify the two different manufacturers' claims on C-reactive protein (CRP) based on the Clinical and Laboratory Standards Institute (CLSI) EP 15-A3 document.

Methods: To represent low, intermediate, and high level, 3 sera pools were prepared from remnant sera of patients. After the familiarization period of the operator, two runs per day (morning and afternoon) with ten replicates per run were performed for five days for each measurand concentrations. Original CRP kit of Beckman uses latex immunoturbidimetric assay (OSR 6299, Beckman) and novel kit practices enzymatic immunoturbidimetric assay (B21220, Bioanalytic) were utilized to measure CRP. For both kits, only one calibration was applied before the study in favor of daily internal control results within the eligible area.

Results: The original kit failed at all levels, even if the upper verification limit was applied. Novel kit passed for the intermediate- and high-level claim of the manufacturers. The highest CV% was 5.24%, and the EFLM recommendation for CRP is 8.5% at the optimum level.

Conclusions: Such experiments with expanded data should be performed with daily calibration to provide manufacturers' claim. Otherwise, it is hard to pass the precision verification. Studies are valuable in terms of demonstrating the reproducibility of the produced kits in end-user laboratories.