Appendix 13. A3, Ax, and B3 weak subgroups


Some of the most important characteristics of the three weak subgroups (A3, Ax, and B3) are shown. A3 and B3 phenotypes are most well-characterized by mixed-field agglutination patterns under the microscope, where some cells exhibit agglutination and others do not. The Ax RBCs are not agglutinated by anti-A reagents, but are weakly agglutinated with anti-A,B reagents. There seems to be heterogeneity among the cases in the same subgroups.