Statistical and graphical evaluation of erythrocyte volume distributions

rocyte volume distributions. Am. J. Physiol. 252 (Heart Circ. Physiol. 21): H857-H866, 1987-A protocol for the statistical and graphical evaluation of erythrocyte volume distributions has been developed using expectation-maximization methods for distribution parameter estimation. In a reference sample group of 50 healthy individuals, none of the red cell volume distributions determined by an aperture impedance method differed significantly from a log normal model. Measurements in 211 patients with anemia provided evidence that similar statistical methods could be used for the characterization of abnormal red cell volume distributions. Graphical displays ac-curately summarize the quantitative information derived from the analysis of volume distributions and show a reference distribution fitted to the observed distribution against the range of distributions found in healthy individuals. This protocol provides a specific, statistically valid implementation of the general principles for the analysis of cell volume distributions proposed by the International Committee for Standardization in Hematology. anemia; expectation-maximization algorithm; doubly truncated log normal distribution RECENT MODELS OF ELECTRONIC particle counters de-termine not only the mean red cell volume but also measure the volume of each red cell providing the red cell volume distribution. Several investigators (2-4, 13