A single donation may be used by as many as three different people. Red blood cells can be kept for 42 days. Red cells are usually used by trauma or surgery patients. Plasma the liquid part of the blood, is usually kept as frozen plasma and can be stored for up to one year. Plasma may be administered to patients with clotting problems.
Platelets cause clotting when cuts or other open wounds occur.
Donated platelets expire after five days. Leukemia and transplant patients often needs platelet transfusions.