Table 2.

Applications of PCR-based assays to predict a blood group antigen.

Antigen Typing a Patient

■ 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-Doa, -Dob, -Jsa, -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-Kpb)

■ 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

Antigen Typing for Donors

■ 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