agree with the other poster. i had $60k worth of emergency surgery and a three day stay over the summer. billing has been nothing short of a shitshow. question everything they send you, read it carefully, read it again, have your shit buttoned up when you call them (take notes of who you spoke to on what day, keep good records of payments etc).

edited to add that asking for an itemized bill is the bare minimum of patient proactivity, you and everyone else who receives a large bill from any provider should absolutely be asking for one.