I work for a PPO currently, and have worked for TPA and insurance company. Also have done independent case management. Okay, I've done some of everything except work as a showgirl.
With the PPO I work with, we have several different insurance companies that access our network and some that also use our utilization management services. When I get a call, the first thing I have to ask is what insurance the patient has. I need to know this because not everyone requires prior authorization for the same thing. For instance: one insurance company does not require prior auth for outpatient diagnostic tests. Another requires authorization for any tests over $300. Another requires prior auth for only CT's, MRI's, EMG/NCS's. We have ONE form for all the providers to fill out that tells us what we need to know in order to process the request. Right now we have everything done the same day.
Most PPO's should have a directory of their participating providers. Most should now have access to their providers on a website.
TPA - Third Party Administrators: Say you own a large doughnut shop. You want to stay very hands on with the management of your doughnut shop and don't want to have to get bogged down in trying to see if the medical care you have for your workers is getting out of control or not. You want to save as much as you can by not having to pay their medical costs out of your own pocket. You hire a TPA to review your employee's medical claims for medical necessity, and pay the claims out of a fund you have set up through the TPA. The TPA may further help you by saying, "look, we can also help you with your workers compensation costs in the same way, let us help you (for a few extra bucks) and we'll throw in some case management to help contain your costs". So while you are trying to contact the doughnut shop for the needs of the worker, they may refer you to their TPA because they have hired the TPA to handle those things for them.
Hope that helps!