When a person loses a significant amount of blood, or when the blood’s functioning has been impaired, he or she may receive blood through a blood transfusion.
In the United States, nearly all blood that is transfused comes from volunteer donors.
Volunteer blood donors typically give a whole blood donation or apheresis donation. In a whole blood donation, a pint of blood is collected and then divided into its therapeutic components for transfusion. With an apheresis donation, a donor gives a specific therapeutic component(s)—platelets, plasma, or RBCs.
Health care professionals usually transfuse only the specific component(s) needed to treat a certain condition or disease, a process called blood component therapy:
Platelets are used in chemotherapy, cardio-thoracic surgery, general surgery, or trauma treatments. Platelet transfusions also help patients who have a shortage of platelets or whose platelets are not functioning normally. Approximately 1.7 million units of platelets are transfused annually to patients.
Plasma and the proteins it contains are used in liver transplants and for treating burn victims and people with certain bleeding disorders. Approximately 4 million units of plasma are transfused annually to patients.
Red blood cells are used to offset blood loss during surgery or following a severe accident or trauma. They also help treat patients with chronic anemia. As the blood component in greatest demand, with approximately 14 million units transfused annually, RBCs are widely used for people undergoing chemotherapy, open heart surgery, organ transplants, and many other common medical procedures.