Newborn screening for hemoglobin abnormalities. A comparison of methods.

Peripheral blood from 1,000 newborn infants of black (641) and Southeast Asian (359) ancestry were screened for hemoglobin variants. Results obtained from the combination of cellulose acetate (CAC) and citrate agar (CAG) electrophoresis were compared with isoelectric focusing (IEF) electrophoresis. There was complete agreement between the two methods on assignment of Hb S trait, Hb C trait, Hb E trait, and homozygous Hb E. IEF identified small amounts of Hb A in two newborn infants with Hb S-beta + thalassemia; the CAC and CAG electrophoretic patterns were indistinguishable from sickle cell anemia. One hundred twenty newborn infants with Hb Bart's were detected by IEF; 51 of these were found on CAC. Although IEF was more sensitive in detecting small amounts of hemoglobin, it is not clear if the improvement in detection warrants adopting this form of electrophoresis for routine screening of newborn infants.