Role of Hematological Indices as a Screening Tool of Beta Thalassemia Trait in Eastern Uttar Pradesh: An Institutional Study.

A large majority of microcytic hypochromic anemia have defects in cellular hemoglobin synthesis due to either iron deficiency or thalassemia trait; both differing in management and prognosis. HPLC and serum iron profile as confirmatory tests are unavailable at health care centers. Blanket therapy of iron supplements is therefore given in all such cases which may cause iron overload in thalassemia cases. Easy to use and cost effective screening methods are desirable. The present study was undertaken to evaluate the diagnostic accuracy of twelve indices to effectively screen cases of thalassemia trait and differentiate them from iron deficiency anemia. Routine samples from the hematology lab with Hb < 13 gm/dl, MCV < 80 fl and MCH < 27 pg were screened. Taking HPLC and serum ferritin as gold standard, out of total 1353 cases, 98 cases of thalassemia trait (HbA2 > 3.5 on HPLC) and 1102 cases of iron deficiency anemia (serum ferritin < 12 g/ml) were evaluated using discrimination indices. Diagnostic accuracy for each index was calculated. While few indices showed a sensitivity of 100%, their specificity was low which meant more number of false positive cases. Based on Youden's Index, which measures the diagnostic tests ability to balance sensitivity and specificity, the best three indices in the decreasing order of their efficacy in our study were Ricerca Index (RI), Green and King Index (GKI) and Mentzer Index (MI). MI is considered a reliable index by many clinicians since a long time, however RI and GKI were found to have a better diagnostic accuracy based on our study.