Use of Red Cell Distribution Width Index for Screening and Differentiation of Iron Deficiency Anemia and Beta Thalassemia Trait During Pregnancy

Open Access

Abstract

Background: Microcytic anemia is commonly caused by iron deficiency anemia (IDA) and beta thalassemia trait (BTT). Differentiating these conditions is crucial for appropriate management, but conventional hematologic parameters often overlap. The Red Cell Distribution Width Index (RDWI) has been proposed as a reliable discriminative tool. Aim of the study: To evaluate the diagnostic accuracy of RDWI in distinguishing IDA from BTT and to compare its performance with established discrimination indices. Methods & Materials: A cross-sectional study was conducted on 240 newly diagnosed anemic individuals (IDA, n = 150; BTT, n = 90) at the Department of fetomaternal, Bangladesh Medical University, Bangladesh], Bangladesh. Complete blood counts and serum ferritin levels were measured, and RDWI, Mentzer, Green & King, and Shine & Lal indices were calculated. ROC curve analysis was performed to determine optimal cut-offs, and multivariable logistic regression identified independent predictors of IDA. Result: Participants with IDA exhibited lower hemoglobin, RBC count, MCH, MCHC, and serum ferritin, but higher RDW and RDWI compared to BTT (all p < 0.001). RDWI demonstrated superior diagnostic performance (AUC = 0.92; sensitivity 89.3%; specificity 86.7%) compared with Mentzer (AUC = 0.85), Green & King (AUC = 0.87), and Shine & Lal (AUC = 0.78) indices. Multivariable analysis identified RDWI >220 (adjusted OR = 7.42; 95% CI: 3.48–15.81), elevated RDW, and female sex as independent predictors of IDA. Conclusion: RDWI is a simple, reliable, and highly accurate index for differentiating IDA from BTT, outperforming conventional hematologic indices. Its implementation in routine laboratory practice could facilitate timely and precise diagnosis of microcytic anemia.