Red Distribution Width (RDW): its usefulness for 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 Distr ibution Width) which detect the heterogeneity of red cell size and anisocyt osis 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 (( X) over bar +/- ES) 13.90 +/- 0.10% and MCV ((X) over bar +/- ES) 90 +/- 5 fl; 2) the iron deficiency patients (IDA) (n = 20) gave a MCV of ((X) over bar +/- ES) 68.60 +/- 1.77 fl., and RDW ((X) over bar +/- ES) 20.20 +/- 1.2 1%; 3) the beta-thalassemic patients (n = 20) had an MCV of (X +/- ES) 66.4 5 +/- 1.95 ft, and RDW ((X) over bar +/- ES) 17.08 +/- 0.40%. We compared t he results of AnCV between IDA and thalassemics and against the control gro up with the following results: control vs IDA and control vs thalassemic wi th significant differences with p < 0.01, and no significant difference whe n we compared IDA vs thalassemics. Then we compared the results of RDW betw een IDA and thalassemics and against the control group with the following r esults: control vs IDA and control vs thalassemic with significant differen ces with p < 0.001 and with significant differences when we compared IDA vs thatassemics p < 0.001. The statistical results were obtained with the one -way analysis of variance (ANOVA). The results show that RDW is a more sens itive indicator than MCV to establish the possible origin of microcytic hyp ochromic anemias and that both should be used together in early diagnosis.