Red blood cells contain hemoglobin and serve as the primary agent for transport of oxygen to tissues. Transfusion of red blood cell (RBC) components and whole blood, which also contains red blood cells, increase the recipient’s oxygen-carrying capacity by increasing the mass of circulating red blood cells.
Whole blood is prepared when 400-550 mL of blood is collected into an FDA-approved container with the appropriate volume of anticoagulant solution. The primary red-cell-containing transfusion component is RBCs. This RBC component is prepared by centrifugation or sedimentation of whole blood to remove much of the plasma. RBC components can also be prepared by automated apheresis methods, which are continuous collection systems that remove blood from a donor, collect RBCs and return the remaining blood and plasma to the donor.
Whole blood transfusion may be indicated in life-threatening hemorrhage where oxygen-carrying capacity, coagulation factors, platelets and volume expansion are needed. Whole blood contains approximately 150 mL of plasma, which provides the patient with volume expansion and non-labile clotting factors. Whole blood contains platelets which, when stored up to 14 days, may contribute to hemostasis. The transfusing facility must have policies and procedures in place addressing specific indications for use, product specifications, administration instructions and volumes that may be transfused prior to considering whole blood an alternative to component therapy. Whole blood transfusions must be ABO identical unless there are procedures in place to address titer cut-off for anti-A and anti-B, specific indications for use and a defined maximum number of units to be transfused per patient.
For more information refer to the AABB Technical Manual and the Circular of Information for Blood and Blood Components.