Clinical Transfusion Medicine: Anemias, Thrombocytopenias, and Coagulation Disorders
Core concepts
Red cell transfusion decisions rest on clinical status plus hemoglobin, not a single number. Restrictive thresholds (Hb 7 g/dL; 8 g/dL in cardiac surgery or symptomatic CAD) are supported by trials. In chronic anemia, calculate the expected rise: one unit of red cells raises adult Hb by ~1 g/dL (Hct ~3%).
Thrombocytopenia: prophylactic platelet transfusion at <10,000/µL is standard; higher thresholds (20,000) for procedures or fever; 50,000 for major surgery; 100,000 for CNS or ocular surgery. Platelet refractoriness-poor increment after two transfusions-suggests alloimmunization (HLA) or nonimmune causes (sepsis, splenomegaly, DIC).
Coagulation: plasma (FFP or thawed plasma) for multiple factor deficiencies or warfarin reversal when PCC unavailable; cryoprecipitate for fibrinogen <150 mg/dL (or <100 in obstetric bleeding), factor XIII, and von Willebrand disease when concentrates unavailable. DIC management treats the underlying cause; component support guided by bleeding and labs.
Traps
- Do not transfuse red cells for asymptomatic chronic anemia without assessing volume status.
- Platelet count alone does not determine need in immune thrombocytopenia (ITP)-platelets are consumed.
- FFP is not a volume expander; 10–15 mL/kg dosing.
Rule of thumb
"One unit, one gram" for red cells; "one apheresis platelet raises count ~30,000–50,000/µL" in an average adult; "10–15 mL/kg plasma" for factor replacement.