 You may not realize how important three letters can be. For a patient who needs type A, B, or O blood, these letters can mean life. But there simply aren't enough people giving blood. Every two seconds, someone in the U.S. needs it. But only about 3% of the population donates. Without more donors, hospitals may not have the blood needed to save lives. That's why the American Red Cross needs people to help restore the A's, B's, and O's that are depleting each day. When