Enhancement of immunofluorescent staining of erythrocytes by saponin hemolysis.

The demonstration of human blood group antigens by the fluorescent antibody technic has been improved by hemolyzing the red cells with saponin. Hemoglobin has a quenching effect on fluorescence. Its removal resulted in dramatic enhancement of the stain. Saponin proved more effective for this purpose than several other common hemolytic agents, all of which caused nonspecific staining. Antigens A, B, M, and N were readily demonstrated when the saponin step was incorporated into the usual two-layer staining procedure. Antigen Rho(D) required the additional enhancement provided by the triple sandwich technic.