Hi lostwonder,
When I pay and check out after my pdoc appt, I get the receipt from the front desk person (the insurance invoice) and it has the diagnostic code on it at the very bottom. I know that I have more than one diagnosis however, so that is where it gets tricky if your pdoc is not forthcoming with you as you may only get partial info from it...you definitely have a right to know your diagnosis!
ETA: Wanting to know you diagnosis isn't avoiding anything IMO...I would be uncomfortable with a pdoc trying to hide something from me! It would be like going to any other dr. and them refusing to tell you what they think you have.