Evaluation of the diagnostic reliability of Mentzer index for Beta thalassemia trait followed by HPLC

Abstract

Introduction: The individuals having thalassemia trait usually have an asymptomatic course and have mild microcytic hypochromic anemia. Since the other cause of microcytic anemia is iron deficiency, it is important to differentiate it from ???? thalassemia trait. Though the definitive diagnosis of thalassemia trait is possible only by HPLC, the Mentzer index is such an index that can differentiate between thalassemia trait and iron deficiency anemia. Objectives: This study aims at figuring out the diagnostic value and reliability of the Mentzer index in the differentiation of iron deficiency anemia and thalassemia carrier compared with the results of HPLC. Methods: This was a hospital-based retrospective observational study done on 1236 patients of all age groups. Mentzer index of all the patients was calculated and the results were analyzed and further compared with HPLC. Results: Out of 1236 patients, 741 (59.9%) patients are of iron deficiency anemia and 495 (40.1%) patients are of β thalassemia trait. Mentzer index was found to be more reliable to detect true positive cases for β thalassemia trait with a sensitivity of 89.0%, specificity of 87.9%. Positive predictive value for β thalassemia trait is 83.2% and Negative predictive value is 92.3% with Youden’s Index 76.9. Conclusion: Iron deficiency anemia and thalassemia have different effects on blood indices. In resource-poor and developing countries like that of India, it can be used as a screening tool. In doubtful cases, the diagnosis can be confirmed by HPLC.