Platelets are tiny, colorless, disc-shaped particles circulating in the blood, and they are essential for normal blood clotting. Platelets are critically important to the survival of many patients with clotting problems (aplastic anemia, leukemia) or cancer, and patients who will undergo organ transplants or major surgeries like heart bypass grafts. Platelets can only be stored for five days after being collected. Maintaining an adequate supply of this lifesaving, perishable product is an ongoing challenge.