It's slightly complicated. I chose to have straight Medicare rather than an Advantage plan for several reasons. I worked as a P.T. for 25 years and I saw how poorly patients were often treated by advantage plans. They are for-profit companies trying to do everything the cheapest way, with networks of preferred providers, limitations on out-of-local area coverage, ability to deny coverage, etc. You have less choice in many cases. I know they work out for a lot of people. I am in favor of single payor non-profit medical care, so I'm walking my talk with my choice. In the case of the infusion, I don't have to wait for authorization because there is no pre-authorization but the doctor has to use the correct code to get it covered. If it is a covered Medicare item there is no chance for denial. This is the first expensive item I have needed so I asked for an estimate of cost in case I somehow ended up getting billed. The billing people are just covering their butts when they told me they can't make any guarantees about what insurers will do. It turned out the doctor coded it correctly, I didn't need to worry about it. If I had less knowledge and experience I probably wouldn't have worried about it.