Blood transfusion Blood transfusion Blood transfusion is generally the process of receiving blood or blood products into one's circulation intravenously. Transfusions are used for various medical conditions to replace lost components of the blood. Early transfusions used whole blood, but modern medical practice commonly uses only components of the blood, such as red blood cells, white blood cells, plasma, clotting factors, and platelets. Red blood cells contain hemoglobin and increase iron levels by improving the amount of oxygen found in the body. White blood cells, are not commonly used during transfusion but are related to the immune system and to fight infections.
Packed red blood cells are kept with a minimal amount of fluid. Generally, an additive solution of citrate, dextrose, and adenine is mixed with the cells to keep them alive during storage. This process is sometimes done as automated apheresis, where the centrifuging and mixing take place at the donation site. Red blood cells are sometimes modified to address specific patient needs. The most common modification is leukoreduction, where the donor blood is filtered to remove white cells, although this is becoming increasingly universal throughout the blood supply (over 80% in the US, 100% in Europe). The blood may also be irradiated, which destroys