From the Guidelines
Platelets should be transfused prophylactically to reduce the risk for spontaneous bleeding in hospitalized adult patients with therapy-induced hypoproliferative thrombocytopenia when the platelet count is 10 × 10^9 cells/L or less. This recommendation is based on the strongest and most recent evidence from the AABB clinical practice guideline 1. The guideline suggests that transfusing hospitalized adult patients with a platelet count of 10 × 10^9 cells/L or less can reduce the risk for spontaneous bleeding.
Key Considerations for Platelet Transfusion
- The standard dose for platelet transfusion is up to a single apheresis unit or equivalent, as greater doses are not more effective and lower doses equal to one half of a standard apheresis unit are equally effective 1.
- For patients undergoing elective central venous catheter placement, prophylactic platelet transfusion is suggested for those with a platelet count less than 20 × 10^9 cells/L 1.
- For patients having elective diagnostic lumbar puncture or major elective nonneuraxial surgery, prophylactic platelet transfusion is suggested for those with a platelet count less than 50 × 10^9 cells/L 1.
- The goal of platelet transfusion is to prevent or stop bleeding by restoring primary hemostasis, and the effectiveness of the transfusion should be assessed with a post-transfusion platelet count.
Special Considerations
- For patients with immune thrombocytopenia (ITP), transfusions are generally reserved for life-threatening bleeding as platelets are rapidly destroyed.
- Refractoriness to platelet transfusions may occur due to alloimmunization, requiring HLA-matched platelets in some cases.
- Platelets have a short lifespan after transfusion (3-5 days), so timing is important for procedures.
From the Research
Indications for Platelet Transfusion
- Platelet transfusions are given to prevent bleeding in thrombocytopenic patients undergoing chemotherapy for malignancy or hematopoietic stem cell transplant 2
- The recommended indication for prophylactic transfusion is a platelet count of 10,000/microL 2
- Transfusion may be helpful to treat serious bleeding, especially in patients with inherited defects of platelet function or acquired defects such as due to drugs or uremia 2
- Platelet transfusion therapy is highly effective in managing bleeding in patients with hypoproliferative thrombocytopenia 3
Thresholds for Platelet Transfusion
- The likelihood of bleeding is the same if half or double the usual dose is given, but half-dose transfusions must be given more often and double-dose transfusions less often than the standard dose 2
- Results from RCTs showed a beneficial effect of prophylactic compared with therapeutic transfusion for the prevention of significant bleeding in patients with hematologic disorders undergoing chemotherapy or stem cell transplantation 4
- There is no difference in significant bleeding events related to the PLT count threshold for transfusion or the dose of PLTs transfused 4
- Universal agreement on the definition of platelet transfusion thresholds has not been reached 5
Special Considerations
- In patients with inherited platelet disorders, platelet transfusion may be ineffective because of competition between transfused and endogenous platelets at the site of vascular injury 3
- In patients on antiplatelet therapy, timing of transfusion and inhibitor mechanism-of-action are key in determining therapeutic success 3
- Platelet transfusion may be used to treat bleeding in patients with disseminated intravascular coagulation (DIC), but the efficacy and safety of this approach have not been objectively assessed 6