The term anisocytosis indicates the degree of variation in the size of red cells observed on the microscope. The above expression is observed in the automated hemogram through two parameters: RDW-CV Red Blood Cell Distribution Width measured by Variation Coeficient) and RDW-SD the same measured by Standard Deviation), which are calculated from the mean corpuscular volume (MCV), which represents the average size of erythrocytes. Together, the two parameters RDW and MCV may help in the differential diagnosis of various diseases, particularly certain types of anemia. The objective of this study was to determine the reference values of the parameters RDW, and verify the existence of any relation between these and the MCV through the hemograms of 306 patients in the clinic of Central Laboratory of the Hospital Universitário Oswaldo Cruz. In addition it was also determined the reference values in relation to sex and age. Moreover, to verify the possible relation between the RDW parameters and MCV it was performed the statistical test of Pearson correlation. The reference values for the general population were similar to those found in the literature, whereas the comparison of results did not show significant differences between sexes. The study by age group showed the need to reassess the division of age groups in future studies with these parameters, because some of these groups showed no significant difference between them. The statistical results showed a correlation for the relationship between microcytic MCV and RDW-CV and between the macrocytic MCV and RDW-SD. For the VCM normocytic significant correlation was observed only with the RDW-SD.
Blood; reference values; erytrocytes; erythrocytes index
