How you prepare

By Mayo Clinic Staff

Your blood will be tested before a transfusion to determine whether your blood type is A, B, AB or O and whether your blood is Rh positive or Rh negative. Donated blood that is compatible with your blood type will be selected for the transfusion.

You don't need to change your activity levels or diet before a transfusion.

If you've had a reaction to prior blood transfusions, be sure to tell your doctor.

Apr. 26, 2012