Immunologic Diagnosis of α-Thalassemia Traits

Abstract

Frequently it is impossible to diagnose α-thalassemia-2 trait from hematologic findings, since the red cell morphology and the MCV are normal. In such cases, after the neonatal period Hb Bart's is not detectable by conventional electrophoreses and chromatography. Antibody against Hb Bart's was produced in rabbits by repeated injections with Hb Bart's- from Hb Bart's hydropic fetuses. The antibody was specific for Hb Bart's without cross-reaction with Hb s A, A₂, E, F and H. By the capillary tube precipitin test Hb Bart's was demonstrable in 82% of 87 obligatory cases for α-thalassemia traits, 86 % in α-thalassemia-1 trait and 79% in α-thalassemia-2 trait. The test was positive in 21 % of the general subjects, corresponding to the prevalence of α-thalassemia in Bangkok. Thus the immunologic demonstration of Hb Bart's appears to offer a diagnostic screening test for α-thalassemia traits in the postneonatal period.