Importance of RDW value in differential diagnosis of hypochrome anemias

Red cell distribution width (RDW) was studied in adults carrying δ‐β thalassemia traits (δβ‐TT) who were 20–40 years of age (n = 29), β thalassemia traits (β‐TT) with an age range of 18–60 years (n = 49), iron deficiency anemia (IDA) in individuals aged 1–18 years (n = 27), and in controls with an age range of 20–40 years (n = 20). Although red blood cell count, MCV, and MCH values showed no statistically significant differences between δβ‐TT and β‐TT, the mean RDW value was significantly higher in δβ‐TT (20.14 ± 1.21) compared to β‐TT (14.88 ±1.77) (P < 0.001). No difference was observed between the means of RDW in δβ‐TT and IDA (18.00 ± 1.94) (P > 0.05). A significant rise in RDW in IDA 5–7 days after initiation of iron therapy (P = 0.00) which was continued to rise up to the 4th week of therapy was suggested as an important tool in differentiation of IDA from δβ‐TT. These observations could be kept in mind in the differential diagnosis of δβ‐TT from β‐TT and IDA by determining the red blood cell count, red cell indices, and RDW only. Am. J. Hematol. 69:31‐33, 2002. © 2002 Wiley‐Liss, Inc.