The presence or
absence of A and/or B antigens and antibodies, as outlined in the graph below,
is the basis for determining ABO type compatibility between patient and donor.
ABO antibodies develop naturally starting at approximately 3 months of age,
whereas antibodies against Rh occur in Rh negative individuals only after
exposure to Rh positive blood. When assessing the compatibility of blood and
components, both patient and donor antigens and antibodies must be considered.
|O||Neither A nor B||Anti A and Anti B|
|AB||A and B||Neither Anti A nor Anti B|