Evidence-based platelet transfusion guidelines.

Transfused platelets (plts) are either pooled random-donor platelet (plt) concentrates or single-donor apheresis plts. When stored for 5 days, all of these products are equally efficacious. A 10,000/microL prophylactic plt transfusion trigger has been documented to be both hemostatically efficacious and cost effective in reducing plt transfusion requirements. The optimal plt dose/transfusion is being evaluated in an ongoing clinical trial. Therapeutic plt transfusions to control or prevent bleeding with trauma or surgical procedures require higher transfusion triggers of 100,000/microL for neurosurgical procedures and between 50,000/microL and 100,000/microL for other invasive procedures or trauma. Leukoreduction has been documented to reduce plt alloimmunization rates, cytomegalovirus (CMV) transmission by transfusion, and febrile transfusion reactions. Whether it reduces immunomodulatory effects of transfusion (i.e., decreases infection rates and cancer recurrence) is still controversial, as is universal leukoreduction. Poor responses to plt transfusions are often multifactorial. For alloimmune plt refractoriness, HLA matching, cross-matching, and identification of the specificity of the patient's antibodies with avoidance of mismatched donor antigens are all equally effective in identifying compatible plts for transfusion. Other causes of poor plt responses are splenomegaly, ABO mismatching, females with 2 or more pregnancies and males, use of heparin or amphotericin, bleeding, fever, graft-vs-host disease (GVHD), and vaso-occlusive disease (VOD).