Anyone can diagnose you with something, I can diagnose you if you want but you probably would not want that as I have no training or interest in treating you. But only a pdoc can prescribe meds for you and no matter what your T may decide you are suffering from, your pdoc will make up their own mind. A diagnosis is for insurance and the diagnoser's benefit, so they have a clue what they are trying to treat you for. No one else has to "accept" their diagnosis (except the insurance company, if they are paying the diagnoser). It is not a formal thing except as your treatment team may decide among themselves, etc.