Glycosylated haemoglobin HbA1c and HbS1c in non-diabetic Nigerians.

Normal glycosylated haemoglobin levels were determined by the Bio-Rad Haemoglobin A1c by Column Assay, in a large series of non-diabetic Nigerians. Subjects having normal haemoglobin genotype (HbAA) and the common haemoglobinopathies, namely heterozygous sickle cell trait (HbAS) and homozygous sickle-cell anaemia (HbSS) were studied. The group mean uncorrected %HbS1c levels in the HbSS subjects were significantly higher than %HbA1c levels in the HbAA (p less than 0.02) and HbAS (p less than 0.001). However, after correction for HbS and HbF the sickle-cell trait group had a %HbA1c value significantly higher than the %HbS1c value in the HbSS subjects (p less than 0.001). Since the haemoglobinopathies influence the glycosylated haemoglobin results, hence its interpretation, the need to correct observed results for the presence of abnormal haemoglobin has been emphasised. Only then would the application of a glycosylated haemoglobin test be truely meaningful in the management of diabetic patients with the 'S' haemoglobin.