Influence of iron deficiency anaemia on haemoglobin A(2) levels: possible consequences for beta-thalassaemia screening

Iron deficiency modulates the synthesis of HbA(2), resulting in reduced HbA (2) levels in patients with iron deficiency anaemia. The diagnosis heterozy gous beta-thalassaemia is based on a raised HbA(2) level. Patients with bet a-thalassaemia and concomitant iron deficiency can show normal HbA(2) level s. It is of clinical importance to know the quantitative effect of iron-def icient erythropoiesis on the levels of HbA(2) in order to be able to determ ine which iron-deficient patients with normal HbA(2) levels have to be rete sted after iron therapy in thalassaemia screening programmes. In this study , HbA(2) levels in 150 patients with iron-deficiency anaemia and 71 healthy controls have been measured. A linear correlation is found in the patient group between HbA(2) and Hb, HbA(2) and MCV, and HbA(2) and erythrocyte zin c protoporphyrin (ZPP). In future studies, the correlation between HbA(2) a nd erythrocyte parameters in patients with heterozygous beta-thalassaemia a nd concomitant iron deficiency has to be examined. We recommend that ZPP be measured in these studies too, as ZPP levels may be a better indicator of concomitant iron deficiency than Hb or MCV in thalassaemic patients.