Use of HbA estimation by CE-HPLC for prenatal diagnosis of β-thalassemia; experience from a tertiary care centre in north India: a brief report

Prenatal diagnosis (PND) of beta-thalassemia is offered by DNA based mutation analysis at 10-12 weeks gestation using chorionic villous biopsy specimens. Most centers offering PND search for five common mutations prevalent in India, which cover more than 90% of patients. However in those families where the mutation cannot be identified in the parents, PND becomes difficult by mutation detection. The technique thus followed is estimation of globin chain synthesis ratio in second trimester cord blood samples. However, this technique is cumbersome and not available in most of the centres. We evaluated 112 cord blood samples (74 were informative) for analyzing hemoglobin A (HbA) levels by cation-exchange high performance liquid chromatography (CE-HPLC) using the BioRad beta-thal short program between 18 and 22 weeks of gestation. A normal range for the population was calculated by running 14 cord blood samples of non-thalassemic abortuses of the same gestation. A 6 month post-natal follow-up was possible in 18 cases. All but one of these corroborated their PND.