Laboratory medicine parameter. Utilizing monospecific antihuman globulin to test blood-group compatibility

When using polyspecific antihuman globulin (AHG) reagents to detect unexpected antibodies or for crossmatching, reactivity in the AHG phase may be due exclusively to the AHG anticomplement component. A lengthy evaluation may be needed to prove that the reactivity is caused by a "nuisance" antibody, one that is clinically insignificant. Clinically significant transfusion intolerance is rare when caused by blood group alloantibodies, which are detected only with AHG sera that contain anticomplement activity. Using monospecific anti-IgG AHG reagents to detect unexpected antibodies offers reliability while avoiding interference from some common and clinically insignificant IgM complement-fixing antibodies, and thereby saves time and expense.