A while ago, an acquaintance saw her dermatologist for an annual check. She said, "oh, by the way, take a look at the place on my foot where we removed a wart a while ago." The doctor looked at her foot, said everything is fine, then finished the exam. Checking the bill, there was a $400 extra charge for the wart examination!
This nice audio story from NPRs "third coast festival" tells the story of billing codes. Answer: As insurers and medicare/medicaid reduce payment for services, doctors respond by writing up every billing code they legally can. There are whole conferences devoted to billing code maximization. It's a lovely unintended-consequences story. Good luck with that "cost control."
The piece quotes the Institute of Medicine that there are 2.2 people doing billing for every doctor, at a $360 billion dollar cost. I couldn't find the source of these numbers. If any of you can, post a comment.
Of course, being NPR, the program leaves the impression that all this will be fixed in our brave new world of the ACA. But it wasn't even that heavy handed on the point. Perhaps experience is gaining on hope.