transfusion

Transfusion is the medical procedure of transferring blood or blood components from a donor to a recipient. It aims to replace blood loss, treat anemia, or correct coagulation disorders. The main components are red blood cells, plasma, and platelets; whole blood is rarely used today except in limited situations. Blood is donated voluntarily, screened for infectious diseases, typed for compatibility, and processed into components. ABO and Rh typing, along with crossmatching, are used to minimize immune reactions. Leukoreduction and irradiation may be applied for selected patients.

Administration is carried out in hospitals by trained clinicians. Indications include acute blood loss from trauma or surgery; symptomatic anemia; coagulopathy requiring plasma; or thrombocytopenia requiring platelets. Dosing depends on clinical status, laboratory values, and product type. Informed consent is obtained, and patients are monitored for reactions during and after transfusion.

Potential risks range from mild allergic reactions to severe acute hemolytic transfusion reactions due to ABO incompatibility. Other risks include febrile nonhemolytic reactions, transfusion-related acute lung injury (TRALI), transfusion-associated circulatory overload (TACO), and very rarely infection, though screening has greatly reduced risk.

Storage and supply vary by component: red blood cells are stored at 1–6 C for up to 42 days; platelets at 20–24 C with gentle agitation for about 5 days; plasma is frozen within 24 hours of collection and stored at -18 C or colder for up to one year. Autologous transfusion uses the patient’s own blood; allogeneic transfusion uses donor blood.