Our names just come up on a large screen on the wall, it makes a sound so you know to look up and see who is being called in. I always knock on the doctor or nurse's door before I go in.
Yes, i always have done, but recently ive changed doctors and he comes out to the patients in the waiting room and walks back into his consulting room with you, so i dont need to knock anymore.
I always knock and go in.
Once when my doctor changed rooms I got up to leave and opened a cupboard. I didn't get chance to check whether there was a nurse hidden in there. :)
Whether it be a doctor or not, if you are directed to see someone whose door is closed it is a matter of simple courtesy to knock before entering. There is no need to wait for a "come in", as you know the person is free to see you, but to me to enter someone's room by opening the door without knocking is the height of discourtesy.
I'd always knock if called in by an intercom like at past places.
At my current one they come out and get you and walk in with you as all the doctors and nurses are behind a keycoded door so you can't get in unless anyone lets you in.