It depends on what your insurance plan requires. I had called my insurance and requested a copy of my benefits for weight loss surgery and thats how I found out my information. My insurance is also BCBS PPO and they required me to have 6 months of documented primary care doctors visit and a copy of the diet my pcp had me on, along with all the testing that was required in order for BCBS to approve the surgery. I started the process in February 2012 and my insurance didn't approve the surgery until December.
Everyones insurance is different.