Patra index and Mentzer index - A retrospective comparative study to differentiate Beta-Thalassemia Trait from iron deficiency anemia.

Abstract

Beta-thalassemia trait (BTT) and iron deficiency anemia (IDA) are the two most common causes of microcytic hypochromic anemia. Differentiating these conditions is crucial, particularly in school-aged children, to reduce the societal burden of anemia. Red cell indices and formulas derived from red blood cell (RBC) parameters provide simple, rapid, and cost-effective diagnostic tools. While these indices are primarily used in pediatric populations, they can also aid in diagnosing microcytic anemia in adults. This cross-sectional observational study was conducted in the Department of Pathology, Rajendra Institute of Medical Sciences (RIMS), Ranchi, from May 1, 2016, to April 30, 2017. A total of 406 patients (190 males and 216 females), aged 3-50 years, with microcytic hypochromic anemia, were randomly selected. The diagnostic performance of the Mentzer index (mean corpuscular volume (MCV)/RBC count) and the Patra index (MCV/red cell distribution width (RDW)) was evaluated based on sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), efficiency, and Youden's index. The Patra index demonstrated superior diagnostic accuracy, with a sensitivity of 88.23%, specificity of 99.7%, and Youden's index of 87.93%. This index proved to be a more reliable tool for differentiating BTT from IDA than the Mentzer index. Given its high sensitivity, specificity, and affordability, the Patra index is an effective screening tool for primary care physicians, particularly in resource-limited settings. Its low cost and ease of sample transport make it a valuable method for initial screening, with positive cases confirmed by high-performance liquid chromatography (HPLC) using the same EDTA-anticoagulated blood sample.