Which of the following is NOT a requirement for autologous transfusion testing?

In the context of autologous transfusion, which involves using a patient’s own blood for transfusion, specific testing requirements are in place to ensure safety and compatibility. Crossmatching is primarily utilized in allogeneic transfusions (between different individuals), to confirm the compatibility of donor blood with the recipient's blood type. In the case of autologous transfusion, since the blood is coming from the same patient, there's no need for a crossmatch because the patient’s own blood is already known to be compatible with their body.

On the other hand, ABO testing, Rh typing, and antibody screening are essential components in this process. ABO testing ensures that the blood group of the patient's own stored blood is identified, Rh typing confirms whether the blood is Rh-positive or Rh-negative, and antibody screening checks for any unexpected antibodies that could lead to complications upon reinfusion, even if the blood is from the same patient. These tests help to ensure that the autologous blood transfusion is safe and effective. Thus, crossmatch is not a requirement for autologous transfusion testing.