Red blood cell distribution width in pediatric microcytic anemias.

The RBC distribution width has been reported to be of value in the discrimination of iron deficiency anemia from other microcytic anemias, but studies in pediatric populations are lacking. A population of 734 normal children was studied to establish age-appropriate normal values for RBC distribution width. The RBC distribution width of 47 patients with microcytic anemia was then evaluated. RBC distribution width was elevated in 19 of 22 patients with iron deficiency but was also increased in six of 14 patients with thalassemia trait and two of 11 patients with anemia secondary to inflammatory disease. The resulting discrimination was better than that obtained by using Mentzer's index or the discriminant function in the patients studied. The RBC distribution width, albeit a less then perfect tool, can be of value in evaluating pediatric patients with microcytic anemia.