OK, so rereading the definition of pass through billing, I understand what you are thinking. I have seen pass through billing mostly with labs. The provider billing the insurance for the labs doesn't perform the tests, but sends the bills in for a much higher amount than they paid the lab that did the testing. So with the radiology, I was thinking they are billing for the global service, but paying someone to read the xray. So it seemed different. But after rereading the definition I see that it really is the same thing. I am not a legal expert so I would advise that someone with experience in legal medical issues be consulted on this question. I tried to research it more, but couldn't find anything.