When DAT is performed, the typical presentations of AIHA are as follows. Warm-type AIHA shows a positive reaction with antisera to IgG antibodies with or without complement activation. Cases may also arise with complement alone or with IgA, IgM or a combination of these three antibody classes and complement. Cold-type AIHA usually reacts with antisera to complement and occasionally to the above antibodies. This is the case in both cold agglutinin disease and cold paroxysmal hematuria. In general, mixed warm and cold AIHA shows a positive reaction to IgG and complement, sometimes IgG alone, and sometimes complement alone. Mixed-type can, like the others, present unusually with positive reactions to other antisera.