If the DAT is positive, Hb and bilirubin should also be measured. If the cord blood DAT is positive, antibody elution from the red cells can be performed to confirm the identity of the antibody coating the cord red cells. Antibody titre less than 32. Usually involves anti-D. Different RBC antigens between mother and father. ABO antigens are poorly developed in the fetus.
ABO incompatibility is rare.
ABO antibodies readily cross the placenta. Normal oxygen-carrying capacity. Washed cells from clotted blood specimen. EDTA blood specimen. Heparinised blood cells.