A 5 year old girl presents with pallor, abdominal examination shows hepatosplenomegaly. Which of the following test is most appropriate in making the diagnosis?

The child is showing features of beta thalssemia intermedia. Definitive diagnosis of this condition can be made by hemoglobin electrophoresis which shows HbF in the range of 10-50%, High HbA2 >4%. Criteria for diagnosing beta thalassemia intermedia includes: Clinical: Late presentation 2-5years, with relatively high hemoglobin 8 -10 g/dl and moderate bone changes and hepatosplenomegaly. Serum electrophoresis showing HbF in the range of 10-50%, High HbA2 >4% Genetics: One or both parents can be a silent carrier, absence of heterozygosity for beta thalassemia or presence of high HbF beta thalassemia. Molecular: Mild beta thalassemia mutation, Co inheritance of alpha thalassemia, co inheritance of high fetal hemoglobin. Ref: Harrison's Internal Medicine, 18th Edition, Page 859 ; Kochars Clinical Medicine for Students By Dario.M.Torre, Page 582