Andy Polhamus's parents never thought about the importance of blood donations until Andy nearly lost his life after a bike accident severed his liver five years ago. Today Andy is a healthy 12-year-old boy, but had he not received more than twenty units of blood, he would have died.

Accident victims like Andy Polhamus often need blood transfusions to replace blood lost in the trauma that he or she experienced. But blood is also used for life-saving cancer treatments and for patients undergoing surgery. All heart, liver and kidney transplant patients need red blood cells during the transplant procedure to ensure that their new organs function correctly. Some transplant patients also require plasma, another component of blood, while in surgery.

In the United States, a blood transfusion is needed about every two seconds. Cancer patients most often receive platelets, the portion of blood that causes blood to clot. Patients undergoing treatment for leukemia, one type of cancer, sometimes need up to six units of red blood cells and up to eight units of platelets daily for two to four weeks. Red blood cells carry oxygen throughout the body.

Sickle cell disease patients are another population that greatly benefits from blood transfusions. Sickle cell disease, which disproportionately affects African-Americans, causes red blood cells to be misshapen and less able to transport oxygen. Normal red blood cells are doughnut-shaped and can pass easily through small blood vessels in the body. Sickle red blood cells become hard, sticky and shaped like sickles used to cut wheat. When these hard and pointed red cells try to pass through small blood vessels, they clog the flow of blood and often break apart. This can cause severe pain and a low red blood cell count, or anemia. The pain episodes are treated with transfusions of normally-shaped red blood cells.