I have been doing ambulance billing for over 6 years here in Nevada. We have actually trained our dispatchers to ask the facility for a PCS prior to transport. That is required for all of our non emergent calls. If we do not have a PCS for billing, then per the federal register, we fax the request to the requesting doctor and ask for signature. If we do not receive a signed copy within 21 days, we then send it certified mail with return receipt. With this documentation, we are then allowed to bill Medicare.

As far as documentation, a lot of insurance companies are allowing electronic submission. This makes billing a lot easier.

Let me know if you have any other questions, I'll be happy to try and help.
:rollin