Neonatal screening of β‐thalassemias by thin layer isoelectric focusing

As an alternative to the recently proposed screening for β‐thalassemias by isoelectric focusing (IEF) of denatured globin chains in urea‐detergent gels [6], IEF of intact hemoglobins, obtained from umbilical cord blood in neonatal units, is reported here. For maximum separation, IEF should be performed in nonlinear pH gradients, in gels containing 0.2 M β‐alanine and 0.2 M 6‐amino caproic acid, which flatten the pH gradient around pH 7, thus increasing the resolution between HbA and HbF ac . The method can unambiguously detect homozygous and heterozygous β‐thalassemic conditions. A bimodal distribution of HbA at birth has been found: In heterozygous patients, HbA values of 9.02% (range 6.8–9.98%) have been found while in normal newborns HbA levels of 20.34% (range 11.02–30.6%) have been demonstrated.