Warm autoantibodies (WAA) are usually IgG antibodies that target a patient's own red blood cell surface antigens. They react best at body temperature (37ºC). WAAs tend to demonstrate panagglutination on panels, where the patient's plasma reacts with all the donor cells and the patient's own cells, as seen in the autocontrol. WAA can also show specificity to antigens, especially antigens of the Rh group system.
WAA can make a blood bank workup difficult and time-consuming. It is imperative to ensure that there are no underlying alloantibodies in the patient's plasma prior to a blood transfusion.
