Background: Iron deficiency anaemia (IDA) and β thalassemia trait (βTT) are the two most common causes of microcytic hypochromic anaemia. βTT is an important differential diagnosis of IDA . It is important to distinguish between these two conditions for appropriate treatment. Red blood cells (RBCs) indices are a simple, easy and cost
effective method. Red cell distribution width index (RDWI) can be easily derived from these parameters helps in diagnosis. Objective: We aimed at finding out reliable and cost effective method in the differentiation of iron deficiency anaemia and beta thalassemia trait in the adult population. Methods: A total of 110 cases (age range 20–45 years) from the hospital record are taken into the study. Cases diagnosed as IDA and βTT on the basis of serum iron, ferritin levels and Hb electrophoresis. Haemoglobin, RBC count, MCV, MCH, MCHC and RDW was noted from Swelab Alfa analyser value, whereas RDWI was calculated for all the samples. Results: A total of 110 individuals with microcytic hypochromic anemia, 60 were diagnosed having IDA, whereas 50 were having βTT. There is female preponderance is seen in both types of anaemia. RBC count is higher in βTT. In both IDA and βTT haemoglobin and ranges from 6–7g/dl. The derived index RDWI showed better discriminative effect between βTT and IDA, as this index had both sensitivity and specificity equal or more than 85%. Conclusion: RDWI is simple cost effective and reliable index for differentiation of IDA and βTT.

Keywords: Iron deficiency anaemia; β thalassemia trait; RDWI.