Beta-thalassaemia trait: Imprecision of diagnosis at birth

Globin chain synthesis was studied at birth in infants who had been tested for haemoglobinopathies with in utero. Subsequent haematological studies showed that five infants were normal, five had β-thalassaemia trait, and two had α-thalassaemia trait. Correct assignment of these diagnoses could not be made in individual cases from globin chain studies at birth, although the β/α ratio was 0.38 in the normal infants, and 0.22 in those with β-thalassaemia trait. Mean (β+γ)/α was 0.90 in the former, and 0.70 in the latter. Specific activity ratios (counts per minute, per absorbance at 280 nm) failed to distinguish thalassaemia trait from normal, as a group or individually. Accurate diagnosis of β-thalassaemia trait required classical haematological studies during the first year of life.