Detection of alpha thalassaemia in sickle cell trait patients by Hb-Bart's screening & quantitation of Hb-A & Hb-S.

Haemoglobin fractionation in 27 subjects with sickle cell trait revealed 12 (44%) with sickle cell haemoglobin less than 35 per cent (23.4-34.2%, mean 30.4 +/- 3.3%) suggesting an association of alpha thalassaemia. Electrophoresis of 91 samples of cord blood revealed demonstrable amounts of haemoglobin Bart's in 7 (7.7%); six between 5 and 10 per cent and one with less than 2 per cent. It appeared that the six infants with higher amounts of haemoglobin Bart's were homozygous for alpha-thalassaemia + (-a/-a) genotypes and one was heterozygous for alpha-thalassaemia + (-a/aa) Results of haemoglobin electrophoresis done on 2754 blood samples analysed from hospital records, retrospectively did not reveal haemoglobin-H and haemoglobin Constant Spring in any of the samples.