USEFULNESS OF RED CELL INDICES IN DIFFERENTIATING MICROCYTIC HYPOCHROMIC ANEMIAS

Background: Iron Deficiency Anemia and beta-thalassemia trait are the two most common causes of microcytic hypochromic anemia. In this study we compared the validity of the various indices to differentiate between these two conditions. Material & Methods: A total of 312 patients from 7th December 2007 to 4th April 2009 were studied retrospectively by calculating seven discrimination indices i.e. Mentzer, Shine & Lal, Srivastava, England & Fraser, Ricerca, Green & King and Red cell Distribution Width Index (RDWI). The study included 213 BTT cases (HbA2>3.5% and <8.0%) and 89 non BTT cases (HbA2 < 3.5%). The number of correctly identified cases were determined and sensitivity, specificity, positive and negative predictive value and Youden index of each discrimination index were calculated. Results: None of the discrimination index showed 100% sensitivity and specificity. The percentage correctly diagnosed is highest for RDWI (88.14%) followed by Mentzer index (86.85%). Youden index is also highest for RDWI (72) and Shine & Lal (72) followed by Mentzer (70). Conclusion: RDWI, Mentzer and Shine & Lal are the most reliable formulae in discrimination between iron deficiency anemia and beta-thalassemia trait.