Which of the following haemoglobin (Hb) estimation will be diagnostically helpful in a case of beta thalassemia trait -

Ans. is 'c' i.e. HbA2 Hemoglobin A2 o In hemoglobin A., the polypepties consists of two a and two 8 chains i.e. the p chain of the normal adult hemoglobin is replaced by the 8 chain. o In normal adults hemoglobin A2 is present in trace amounts. It accounts for 1.5% to 3.5% of the normal adult hemoglobin. Clinical implication of HbA2 o HbA2 levels have special application in the diagnosis of beta thalassemia trait. Elevation of HbA, is present in these cases even through the peripheral blood smear is normal. Microcytosis and other morphological characteristic of [3-thalassemia trait are also seen in iron deficiency but unlike 3 thalassemia trait HbA2 level is decreased.