Correlation between transfusion requirement, blood volume and haemoglobin level in homozygous beta-thalassaemia.

We examined the relationship between blood volume, mean haemoglobin maintained and transfusion requirement in an extensive series (166 cases) of uniformly treated patients with homozygous beta-thalassaemia. The blood volume is increased in all the subjects and this increase appears inversely proportional to the mean haemoglobin level maintained. When this is above 12 g/dl, the blood volume is nearly normal. The transfusion requirement of patients kept between 10 and 14 g/dl is constant. Maintenance of a high haemoglobin level in thalassaemic patients inhibits erythropoiesis to a considerable degree with a reduction of the haemopoietic tissue and hence of the total blood volume.