Rapid mid-trimester prenatal diagnosis of beta-thalassaemia and other haemoglobinopathies using a non-radioactive anion exchange HPLC technique--an Indian experience.

Anion exchange high performance liquid chromatography (AX-HPLC) has been widely used for separating and quantifying various haemoglobin fractions especially in the haemoglobinopathies. We have evaluated the reliability of this technique to measure low concentrations of adult haemoglobin (HbA) in fetal blood to enable differentiation between affected and unaffected fetuses at risk for beta-thalassaemia (85) and other haemoglobinopathies such as delta beta/beta-thalassaemia (1), E-beta-thalassaemia (2), S-beta-thalassaemia (1), and sickle cell anaemia (1). The HbA values obtained ranged between 0 and 9.51 per cent. The HbA for 27 affected fetuses was 0 per cent, while two showed a HbA value of 0.5 per cent. The mean HbA for 61 unaffected fetuses was 4.8 +/- 2.08 per cent. Thirty cord blood samples (cord abortus in cases of affected fetuses and cord full term in cases of unaffected fetuses) were analysed to reconfirm the diagnosis. Ten babies between 8 and 18 months of age could be followed up for confirmation. AX-HPLC was found to be a simple and rapid procedure with high sensitivity and there was a good correlation between the HbA values obtained by AX-HPLC and the diagnosis by carboxymethyl cellulose (CMC) chromatography.