Are you an O Negative blood donor? Did you know you’re considered a Universal Blood Donor? Your blood can be transfused to anyone in need. This is particularly important in emergencies, when hospitals may not have time to determine a patient’s specific blood type. It is also why O Negative blood is always in short supply. Our Universal O- Heroes Club rewards donors who make the commitment to donate whole blood at least 4 times throughout the calendar year with an exclusive, Universal Hero T-shirt.