Final answer:
85% of Americans carry the Rh D agglutinogen on their RBCs, making them Rh positive. This antigen is essential to consider in blood transfusions and pregnancies to prevent hemolytic disease of the newborn.
Step-by-step explanation:
85% of Americans carry the D Rh agglutinogen on their RBCs. The Rh blood group system is significant in transfusions and in pregnancy, with Rh D being the most important antigen. When someone with Rh negative blood (Rh-) is exposed to Rh positive (Rh+) blood, they may produce anti-Rh antibodies. This can lead to complications in subsequent pregnancies with Rh+ fetuses, such as hemolytic disease of the newborn, which is preventable with RhoGAM treatment.