Identification of abnormal hemoglobins in cord blood by an immunoblot technique.

Variant hemoglobins S, C, and FHull were identified in newborn cord blood hemolysates with an immunoblot procedure. The abnormal hemoglobins were originally detected in cord blood hemolysates by cellulose acetate electrophoresis and presumptively identified according to their mobilities. Hemolysates that contained a hemoglobin variant again underwent electrophoresis and were transferred to nitrocellulose membranes. For identification, the membrane was treated with the appropriate rabbit monospecific antiserum and developed with peroxidase-conjugated anti-rabbit IgG or peroxidase-conjugated protein A. After the addition of substrate, a violet reaction developed at the site of the hemoglobin band, signifying an antigen-antibody reaction or a positive reactivity. The use of monospecific antisera in an immunoblot technique allows for confirmed identification of variant hemoglobins in cord blood samples in as little as 5 hours. In some cases in which the variant is near the limits of detectability by protein staining, the immunoblot allows an unequivocal identification.