Kp(a) antigen
The Kp(a) antigen belongs to the Kell antigen system. It is present on the red cells of 2.0% of white and <0.1% of black patients. Kp(a) antibody appears to be red cell stimulated, it is often IgG and best reactive by indirect antiglobulin testing (IAT). This antibody has the ability to cause transfusion reactions and hemolytic disease of the fetus and newborn (HDFN).