Did they tell you that they were going to do the testing on that visit? If not, it will probably just be a consultation, and then they will schedule the testing for later. If they didn't tell you that your appointment would take quite a while, you probably aren't going to be tested on that visit.
When they do test you, they will either do it on your back or your forearms. I've had it both places. It doesn't really hurt, but it gets kind of annoying after a little while.