What is "exchange transfusion"

n. slow removal of a person's blood and its replacement with equal amounts of a donor's blood

An exchange transfusion, also known by several other names, is a blood transfusion in which the patient's blood or certain components of it are exchanged with (that is, replaced by) other blood or blood products. In contrast, most simple blood transfusions involve adding blood or blood products without removing any. A typical example of an exchange transfusion is when apheresis is used to remove the patient's red blood cells or platelets and replace them with cells from blood donors.

Exchange transfusion is used in the treatment of a number of diseases, including sickle-cell disease, thrombotic thrombocytopenic purpura, and hemolytic disease of the newborn. Partial exchange might be required for polycythemia.

Nearly all exchange transfusions are allogeneic (that is, the new blood or blood products come from another person or persons, via donated blood); autologous exchange transfusion is possible (using autologous blood banking), but there are not many situations in which a need for it arises, as most autologous transfusions involve no exchange.