With my insurance, I was "approved", then they kicked back my file saying they needed more documented evidence of my medical conditions. So basically I wound up sending them a 3" thick copy of my complete medical history. In my case they just wanted to verify that I had been going to/ through treatment for my infertility, that the docs couldn't find any other reason other than my weight, and that I had been on a medically supervised weight loss program. Each insurance company and surgeon's office does things a little differently. It can be frustrating!!
Today I am finally going into my surgeon's office for my pre-op evals/tests, and it took us a lot of hair pulling to get to this point.