The American Red Cross is the single largest supplier of blood in the United States, providing approximatley 40 percent of the nation's blood supply. Blood and platelets are needed for many different reasons--accident and burn victims, heart surgery patients, organ transplant patients, and those receiving treatment for leukemia, cancer or sickle cell disease may all need blood. Anyone age 17 and over - weigh at least 110 lbs - in good health - can donate blood.