Red cells, serum iron and total iron-binding capacity in three population groups in Natal.

Male blood donors from three population groups (Indian, Black, White) who showed neither microcytosis nor levels of serum ferritin or transferrin saturation suggestive of iron deficiency were matched in 3's 1 from each population, for age, number of previous blood donations, and serum ferritin. Three groups of individuals of similar iron status were thus obtained, in whom mean serum iron and total iron-binding capacity as well as red cell indices were compared. The Indian group had smaller red corpuscles, and more of them, than either of the other groups; they also had significantly higher mean total iron-binding capacity. The Black group had a lower mean level of serum iron than the other two, coupled with a total iron-binding capacity greater than in the Whites but less than in the Indians; as a result, both the Indian and Black groups had a lower mean transferrin saturation than the White. The mean level of haemoglobin was significantly lower in the Black group than in the other two. It is unlikely that any of these differences is due to iron deficiency.