What they probably meant was that it wasn't a diagnosis that warranted ER treatment; in other words, it should be handled outpatient. However, if the diagnosis reflects suicidality somehow (not sure how they code this but they know how), it will likely be covered. The insurance company is playing a game here in order not to pay out. Hospital should know how to code it so they will be paid. Somebody screwed up on the hospital end and insurance is taking advantage of it. Always, always, always question medical bills if insurance doesn't seem to be paying properly. They deliberately play dumb and go ONLY by whatever coding is in front of them (they don't have detailed hospital records).