My mom has Medicare part F (supposed to cover everything) as a supplemental insurance. She's a widow on a fixed income and had an agent come over her to give her the best plans available. Yesterday she received a $232.00 bill fora Vit D. test that her doc had ordered back in June. She has High Vit D and High calcium. They determined from that second set of labs, that she has some sort of granular disease, most likely sarcoidosis.
Called insurance guy yet again today after many such bills have rolled in since this plan began. Insurance guy says that because Medicare deemed the test unecessary, neither Medicare nor her insurance would cover it. The way it is right now, any insurance co. can legally deny you anything that Medicare denies. Whether or not they choose to do so or not, is up to them.
However, it also depends on where the services are performed. By law, hospitals that charge for anything more than Medicare says is necessary, insurance companies are not allowed to pay for it. The cost falls on the patient.
By the same token they also have to provide services that they don't think are necessary, or right, if Medicare says that they need to. When these services are not performed, insurance can deem the entire visit/appt. as inappropriate and refuse to pay.