Autor(s): M. Buttarello, P. Bulian
Background: the determination of reference intervals is based on direct methods (with selection of reference subjects) or, alternatively, on indirect methods (based on analysis of data from wide database of subjects of selected groups, and underwent to appropriate statistical procedures). Because of the continuous development changes from birth to adulthood of pediatric subjects, we must estimate pediatric reference intervals after age related stratification. The aim of this work is to present pediatric reference intervals for quantitative cytohematology, obtained with the direct method through a multicentric study. Medhods: subjects (aged between 0 and 168 months) were selected with the a priori method and then classified in 6 age-related group. Each laboratory analized its specimens while the statistical analysis was performed centrally for the two main technologies (impedance and light scattering). Results: the results suggest that some parameters, as neutrophil or reticulocyte counts, are relatively uniform, while others as lymphocyte counts, hemoglobin concentration and mean corpuscolar volume show a decreasing (the first) or increasing (the seconds) trend. Conclusions: although our data set is still limited, certain features appear well defined as the progressive increase in hemoglobin concentration and the decrease of lymphocytes during age advance. It remain unclear wherefore the mean corpuscolar volume progressively raises reaching at the age of 14 years values comparable to adulthood.