My question involves federal public health law (Medicare and Medicare Advantage)
Do Medicare subscribers have the right, under the law or under the rules, to have an insurance pre-authorization before a surgery? Hospitals require patients to sign forms stating that they are financially responsible for paying the bill. If senior citizens have surgery and it turns out not to be covered by the Medicare plan (in my case, Medicare advantage), such patients would incur bills that they can't pay. Is there something in the law and the rules that gives the patient the right to a pre-authorization so that patients can make a decision based on specific dollar amounts from the insurance company? Is the hospital required to send a pre-authorization form in response to a patient's request? Is the insurance company required to process the request?

What agency enforces the rules? Is it ERISA?

Thank you for any information on the laws and rules.