In an emergency, would he be safe to receive O RhD positive blood?
Well done, correct.
This patient can receive the donor blood.
The potential donor's blood is O RhD Positive.
Our patient's blood is A RhD Positive.
It is generally best to match donor and recipient ABO and RhD types exactly. But if this were an emergency, and the only donor type was O RhD positive (a common situation in small hospitals), the patient could receive this blood safely.
Note: O RhD negative blood is the 'universal donor' blood and small stocks situated in all fridges where blood may be needed at short notice, before the blood group is determined (e.g. A&E, delivery suites, rescue teams).
Remember: Type O blood has neither A nor B antigens on the surface and is hence a universal donor blood.