Determination of target values for use in Quality Control of hematology analysers

Abstract

The authors report a retrospective study realized with hematimetrics values (hemoglobin, hematocrit and erythrocyte), Red blood cell indexes (mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration) and leukocyte, obtained from 3 years (1988-1990), presented by 2 semi-automatic hematology analyzers, priorly calibrated with primary standards and control sample, in order to obtain target values (average on the daily means), that will be used in monitoring the accuracy of these equipments. Firstly the means, the medians, the modes and the frequencies from first 1000 determinations of 1988, were calculated, in order to assess the distributions of the studied population. Secondly, a retrospective statistical study made by a microcomputer, was performed, to analyse 613 routines with 392,000 determinations from 56,000 patients registered at the Health Centers of the ERSA 2, São Paulo Cíty; the arithmetical means, the standard deviations, and the variation coefficients were calculated, and the medians and the maximun and minimun arithmetical means of each year and of the 3 years in question were determined. From the relationship among the hematimetric values, empirical formulas were obtained, to be used in the control of the hematological analyzers. The obtained target values were: Hemoglobin 13.4 g/dL, Hematocrit 40.1%, Erythrocyte 4.63xl0⁶/mm3, mean corpuscular volume 86,7 µ³, mean corpuscular hemglobin 29.1 pg, mean mean corpuscular hemoglobin concentration 33,5% and Leukocyte 7.91 x 10 /mm³. The reference intervals of the target values are presented with 1 and 2 Standard deviations.