What type blood do you transfuse to an AB if have no blood?

If there is no available AB blood, the next best option would be to transfuse O Negative blood. O Negative blood is often referred to as the "universal donor" because it can be safely transfused to individuals with any blood type, including AB. This is because O Negative blood does not contain any of the A, B, or Rh antigens that can cause an immune reaction in recipients with different blood types. While transfusing O Negative blood is not an ideal solution for AB individuals, it can provide life-saving support until compatible AB blood becomes available.