Platelet transfusion and respecting patient D type

Current guidance allows transfusing D-mismatched platelets to D negative recipients when necessitated by logistic constraints. Although the D antigen is not expressed on the platelet membrane, platelet concentrates are still labeled by their D antigen status because the platelet concentrates contain a small quantity of red blood cells. D matching is currently recommended to prevent D alloimmunization based on frequencies of D alloimmunization after transfusing platelet concentrates obtained from whole blood collections of up to 18.7%.

The content of red blood cells is higher in pooled platelet concentrates prepared from whole blood collections (range: 0.036-0.59 ml) than in platelet concentrates obtained from apheresis devices (range: 0.00017-0.009 ml). Large retrospective studies with long follow-up suggest that it is not possible to rule out a secondary immunization in D negative patients who developed an alloanti-D within 4 weeks after receiving the first D-mismatched platelet transfusion, and the frequency of D alloimmunization after D-mismatched platelet transfusions ranges between 0 and 7.1%.

Based on the reported frequencies of D alloimmunization and data from some recent large studies, we recommend administering Rh Immune Globulin, if D-mismatched platelet concentrates prepared from whole blood collections are transfused to D negative females of childbearing potential.