▪ To identify a fetus at risk or not for hemolytic disease of the fetus and newborn (HDFN)

▪ When antibody is weak or not available (eg, anti-Do^a, -Do^b, -Js^a, -V/VS)

▪ Who has been recently transfused to aid in antibody identification and selection of RBCs for adsorption

▪ To distinguish an alloantibody from an autoantibody (eg, anti-e, anti-Kp^b)

▪ To help identify alloantibody when a patient’s RBCs type antigen-positive and a variant phenotype is suspected (eg, anti- D in a D-positive, anti-e in a e-positive)

▪ Whose RBCs are coated with immunoglobulin (+DAT)

▪ Who has received an allogeneic stem cell transplant

▪ To detect weakly expressed antigens where the patient is unlikely to make antibodies to transfused antigen-positive RBCs

▪ Identify molecular basis of unusual serological results, especially Rh variants

▪ To determine zygosity

▪ Mass screening to increase antigen-negative inventory

▪ To find donors whose RBCs lack a high-prevalence antigen

▪ To resolve blood group A, B, D, C, and e discrepancies

▪ To detect genes that encode weak antigens

▪ To type donors for reagent RBCs for antibody screening cells and antibody identification panels