The effectiveness of antihuman globulin (AHG) in enhancing the detection of antibodies during a crossmatch is particularly significant for low titer IgG4 antibodies. The AHG test is designed to detect antibodies that are bound to red blood cells, and IgG antibodies are typically the most clinically significant in terms of transfusion reactions.
Low titer IgG4 antibodies, while often not causing immediate hemolytic reactions, can still signal potential issues in crossing blood from donors to recipients. AHG works by binding to the Fc portion of IgG antibodies that are attached to red blood cells. This binding enhances the visibility of these antibodies through agglutination reactions in the testing phase, making it easier to identify a potential incompatibility.
Other antibody types mentioned, such as IgM, IgA, or complement binding antibodies, do not respond to AHG in the same way. IgM typically activates complement more efficiently and is usually detected via different methodologies. High titer IgA antibodies are generally not a primary concern in crossmatching and may not require the use of AHG for detection. Similarly, while complement binding antibodies can be detected using AHG, the specific case of low titer IgG4 antibodies represents a scenario where the