A blood transfusion infuses, or adds, donated blood to your own blood. Blood transfusions can supplement various components of your blood, including platelets and white blood cells. A blood transfusion boosts blood levels that are low, either because your body isn't making enough blood cells or because blood has been lost during surgery, injury or disease. Blood has several components, including red cells, white cells, plasma and platelets. Whole blood means the blood contains all its parts, but whole blood is rarely used for transfusion. You'll receive a transfusion that provides the part or parts of blood that will be most helpful for you. This procedure may also be performed for patients who are being treated for anemia, bleeding disorders and infections, as well as patients who are undergoing cancer treatments.