Abstract
OBJECTIVES: Clinical laboratories should use only validated procedures. Precision is an important factor in the validation and verification of a new measurement procedure. Our objective was to verify the precision and trueness of different analysers used for the biochemical and immunochemical characterization of analytes. METHODS: Advia 1800(®), Immulite(®)2000 and CentaurXP(®) analysers and the Atellica(®)Solution system were used. Five analytes were characterized biochemically, whereas another five analytes were characterized immunochemically. Imprecision was assessed using BioRad(®) and Siemens(®) control materials. Within-run and between-run imprecision were calculated by analysing three replicates of each control in a single run every day for five days. Bias was assessed using 40 samples of serum by the analysis of differences and linear regression. RESULTS: The within-run and between-run imprecision values obtained with the new measurement procedure were lower than the ones claimed by the manufacturer for all the analytes studied. In the bias study, a proportional but not constant systematic error was observed in some analytes. CONCLUSIONS: The coefficients of variation obtained with Atellica(®)Solution verified both, the imprecision specifications claimed by the manufacturer and by the laboratory. The conditions of calibration should be revised for some parameters and a wider range of samples should be used.