The Rh blood group system: RHD update

The Rh blood group system was last reviewed in Immunohematology in 2010 (Chou ST, Westhoff CM. The Rh and RhAG blood group systems. Immunohematology 2010;26:178–86). This update focuses on RHD, RhD structure, alterations in D expression, anti-D alloimmunization, and applications of RHD genotyping for weak and discrepant D phenotypes; identification of RHD genotypes that encode partial D phenotypes; and prevention and management of anti-D in pregnancy. Updates to the RHAG system and to RHCE and its encoded antigens are in recent or upcoming publications of Immunohematology, respectively.