Haematological status of blood-donors with sickle cell trait and alpha thalassaemia in northern Nigeria.

Northern Nigeria is an endemic area for sickle haemoglobin (HbS), and it is common practice in many hospitals to accept blood for transfusion from donors with sickle cell trait (HbAS). In 212 healthy HbAS blood donors, the proportion of HbS was found to range between 24-47%. The HbS levels less than 38% were presumably due to the interaction of sickle-cell gene with the alpha + thalassaemia gene. Low HbS levels and presumed alpha + thalassaemia were associated with significant microcytosis and relatively low Hb A2 and Hb F, but differences were minimal. Carriers of sickle cell trait, with or without alpha + thalassaemia, appear to be acceptable as blood donors. Beta thalassaemia was not detected amongst 710 blood-donors.