METHODS: Haemoglobin A(2) and HbF were determined in healthy adults who have haemoglobin A genotype by elution after electrophoresis and alkaline denaturation methods respectively.
RESULTS: The mean HbA(2) among the subjects was 3.3% (range 2.0-5.6%) while the mean HbF was 2.6% (range 0.4-8.8%). Twenty-six percent of the subjects had HbA(2) values higher than 3.9% while 86% had HbF values greater than 1%, twenty-four percent had elevated HbA(2) and HbF. The mean HbA(2) value was 2.7% among those with HbF <1%, 3.6% among those with HbF 1-3% and 3.1% among those with HbF >3%.
CONCLUSIONS: These findings confirm that the frequency of beta thalassaemia in western Nigeria is higher than previously thought and that many of the individuals studied may be silent carriers of the beta thalassaemia trait. Its presence may also have been masked by the high prevalence of alpha thalassaemia in the same environment. It is therefore important to consider beta thalassaemia trait as a differential diagnosis in patients who present with haemolytic anaemia in this environment.