Role of Red Cell Distribution Width (RDW) in the Diagnosis of Iron Deficiency Anemia

Background: Iron deficiency anemia (IDA) is the most prevalent micronutrient deficiency in the world. Morphologically, IDA is microcytic and hypochromic as is anemia on chronic disease (ACD) thereby creating confusion on peripheral blood smear examination. Red cell distribution width (RDW) has been proposed to be a more sensitive indicator to establish the possible origin of microcytic hypochromic anemia. Various previous studies have debated the role of RDW in diagnosis of IDA, with no conclusive word on the utility of RDW in diagnosing iron deficiency anemia.Objective. To study the utility of RDW in the diagnosis of IDAMethods: 93 patients with microcytic (MCV<80 fl) anemia were classified into iron deficient (IDA) and anemia on chronic disease (ACD/non-IDA) on the basis of serum ferritin and total iron binding capacity (TIBC). RDW values were obtained on an automated hematology analyzer. Receiver operator curves (ROC) were constructed and the utility of RDW in diagnosis of iron deficiency was studied. Results: The mean RDW value was 20.07±7.67% in IDA group (57 patients) compared to 17.60±3.23 % in the ACD group (36 patients) (p<0.001; CI 95%: 4,14-33,42). At a cut-off value of 17,35%, as obtained from the ROC curve, the sensitivity and specificity of RDW in diagnosis of IDA were 85,96% and 69,44% and a positive and negative predictive value of 81,66% and 75,75% respectively. Conclusions: RDW has a good sensitivity for screening diagnosis of IDA among patient with microcytic hypochromic anemia.