Last time my doctor had to bill my insurance he said he would just run it immediately, because apparently "routine denial" is a thing where they just automatically deny it because if you really need it the doctor will then have his office try again with more justifications. He hated this a lot, because it basically meant he had to just assume first denial for no real reason and then his staff had to take the time to almost always go back and resubmit. He said sometimes he would submit it with the info, it would be denied, and then he would resubmit it two more times and suddenly it would be approved.

Like seriously, what the fuck. But only does that hold up necessary care, it also makes doctors do more bureaucratic work and hire more staff, which, of course, makes medicine more expensive. Brilliant.