5.1 The Application of PCR base assay to predict Antigen typing for donor and patient To screen for antigen-negative donors /when antibody is weak or not available /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