Lots of things you could say in this situation Dan. How about:
"You know, I used to think it was a simple question about "Blood" vs. "No Blood" but it's really not. Whole blood is almost never transfused anymore. Blood is broken down soon after donation because the components individually are worth much more than whole blood.
The question today is which components we must refuse and which ones we can accept. I'm pretty clear on some of them, but the others are confusing. Some of the ones we can accept are actually administered as transfusions! If I ever met a doctor at the door who wanted to argue, I'm not sure I could give an answer that makes any kind of sense.
I guess it would depend on the medical situation and what blood component was needed"