Role of discrimination indices in differentiation of beta thalassaemia trait and iron deficiency anaemia.

Iron deficiency anaemia (IDA) and beta thalassaemia trait (BTT) are the most common causes of microcytic hypochromic anaemias. Several discrimination indices have been introduced to discriminate quickly these similar entities via parameters obtained from automated cell counter. The purpose of the study was to evaluate the value of five discrimination indices in differentiation of BTT and IDA. This study consists of 57 cases of BTT and 72 cases of IDA. Five discrimination indices evaluated in this study for differentiation of BTT and IDA were red blood cell (RBC) count, red blood cell distribution width index (RDWI), Green & King Index (G & K), Mentzer index (MI) and England & Fraser (E & F) index. Sensitivity, specificity, positive and negative predictive values and Youden's index (YI) had been calculated. RBC count and RDWI appears to be reliable and useful index for the differentiation of BTT and IDA, as both of the indices had more than 80% sensitivity, specificity in differentiation of IDA and BTT. Patients with microcytic hypochromic anaemia could be easily screened out for BTT and IDA through these discrimination indices in the absence of other complicated diseases.