Red blood cell distribution width index in some hematologic diseases.

The red blood cell distribution width index (RDW) was determined in a group of anemic male patients and normal male blood donors. Elevated mean RDW values were found in the anemic patients, with the highest value seen in sickle cell anemia, sickle cell-beta thalassemia, sickle cell trait, beta-thalassemia trait, and iron deficiency in decreasing order of magnitude. The mean RDW of the normal male subjects was 11.3. It was found that the RDW was proportional to the reticulocyte count, with the highest values in the patients with the highest reticulocyte count (sickle cell anemia). One clinical value of the RDW therefore may lie in its capacity for reflecting active erythropoiesis. For example, patients with normal or near-normal hemoglobin and with high RDWs may be suspected of having an elevated reticulocyte count that may indicate a hemoglobinopathy, such as sickle cell trait or thalassemia trait.