[Red cell distribution width (RDW): its use in the characterization of microcytic and hypochromic anemias].

With the widespread use of cell counters we have now acquired new red cell indices complementary of the old ones, like the HDW and RDW (Red Cell Distribution Width) which detect the heterogeneity of red cell size and anisocytosis in the blood smear. We studied 90 patients with the following results. 1) in the control group of healthy volunteers (n = 50) RDW results were (mean +/- ES) 13.90 +/- 0.10% and MCV (mean +/- ES) 90 +/- 5 fl; 2) the iron deficiency patients (IDA) (n = 20) gave a MCV of (mean +/- ES) 68.60 +/- 1.77 fl., and RDW (mean +/- ES) 20.20 +/- 1.21%; 3) the beta-thalassemic patients (n = 20) had an MCV of (mean +/- ES) 66.45 +/- 1.95 fl, and RDW (mean +/- ES) 17.08 +/- 0.40%. We compared the results of MCV between IDA and thalassemics and against the control group with the following results: control vs IDA and control vs thalassemic with significant differences with p < 0.01, and no significant difference when we compared IDA vs thalassemics. Then we compared the results of RDW between IDA and thalassemics and against the control group with the following results: control vs IDA and control vs thalassemic with significant differences with p < 0.001 and with significant differences when we compared IDA vs thalassemics p < 0.001. The statistical results were obtained with the one-way analysis of variance (ANOVA). The results show that RDW is a more sensitive indicator than MCV to establish the possible origin of microcytic hypochromic anemias and that both should be used together in early diagnosis.