My son is 4 years old. His weight is 14. 2 kg.he is very energetic but fussy eater. He have frequent infections. On routine examination s doctor find his spleen palpable. But in ultrasound it comes normal. Doctor done his CBC and GBP. His Hb is 12 and other parameter s Normal. Blood picture shows mild microcytic anemia and d/d is iron deficiency anemia and thalassemia trait. How should I differentiate between the two above please advice.