Role of Red Cell Distribution Width (RDW) in the diagnosis of iron deficiency anemia

Background: Iron deficiency anemia (IDA) is the most common nutritional deficiency worldwide. Morphologically, IDA is hypochromic and microcytic as is anemia on chronic disease (ACD) thus 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 IDA Methods: a total of 93 patients with microcytic (MCV<80 ) anemia were classified into iron deficient (IDA) and anemia on chronic disease (ACD/non-IDA) based on serum ferritin and total iron binding capacity (TIBC). RDW values were attained on Sysmex XN series hematology autoanalyzer. ROC was built, and the utility of RDW in the iron deficiency diagnosis was studied. Results: RDW mean 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 17.35% cut-o value, as found from the ROC, the sensitivity and specificity of RDW in IDA diagnosis were 85.96% and 69.44% and a positive and negative predictive value of 81.66% and 75.75% consecutively. Conclusions: In IDA screening diagnosis, RDW has a good sensitivity in patient with hypochromic microcytic anemia.