Adverse Effects Of Blood Transfusion Practice Test

Refractoriness to platelet transfusion happens when the platelets you transfuse don’t produce the expected rise in the patient’s platelet count. The most common mechanism is alloimmunization against HLA antigens on donor platelets. After prior exposure to non-self HLA antigens through transfusions or pregnancies, a patient can develop antibodies to HLA class I antigens. When new platelets are transfused, these anti-HLA antibodies bind to the HLA on the donor platelets and mark them for rapid destruction by the spleen and other phagocytes, leading to a poor post-transfusion platelet count increment despite adequate transfusion. Other possibilities exist, but they’re less likely the primary cause. Rh incompatibility of platelets isn’t a common driver since platelets express little Rh antigen and aren’t targeted the same way red cells are. Anti-D antibodies mainly affect red blood cells rather than platelets. Decreased platelet pH during storage can affect platelet function, but refractoriness is defined by failure to achieve a sufficient count rise, which is most often due to immune clearance from anti-HLA antibodies rather than storage-related dysfunction.