Comparison of hemoglobin and red blood cell distribution width in the differential diagnosis of microcytic anemia.

In a total group of 415 subjects (100 normal controls, 115 with iron deficiency anemia, 100 with the alpha-thalassemia trait, and 100 with the beta-thalassemia trait), the following indexes were analyzed: hemoglobin distribution width, red blood cell distribution width (RDW)-coefficient of variation, and RDW-SD. The hemoglobin distribution width and RDW-coefficient of variation were examined with a laser light scattering system (Technicon H1), whereas the RDW-SD was determined with an impedance autoanalyzer (Sysmex M-2000). All of these parameters helped, to some extent, in the differential diagnosis of microcytic anemia. However, our data suggested a low RDW-SD might provide significantly more value in differentiating thalassemia traits from iron deficiency anemia, as well as from normal controls, while the hemoglobin distribution width gave no help in the differential diagnosis between iron deficiency anemia and the beta-thalassemia trait.