I've only requested an interpreter once - last year, when I had a bad mastoid infection and was getting ready for surgery. The receptionist I spoke to was happy to help, but she couldn't get past ASL - as a non-signer, I wanted either oral interpreting or CART, but "deaf patient" immediately made her think "ASL". Grr, especially since this was in the ENT department. I ended up just writing notes, and clarifying things later with the relative I was going to appointments with - very irritating.
It's amazing how these supposed specialists just don't make the connection. Right now, I'm talking to a cochlear surgeon about implantation, and she made various comments about how "you must be an excellent lip reader" after looking at my chart - then, not 10 minutes later, turned her back to me and kept talking. She turned towards me when I pointed this out, but I was surprised she didn't apologize or seem embarrassed.