Health Maintenance Organization (HMO)
This is a type of Medicare Advantage Plan in which you are required to use the physicians, or other health care providers, and hospitals within your insurer’s network (except in an emergency) when receiving medical care. You may be required to get a referral from your primary care doctor to see a specialist. In some cases you might be able to go out-of-network for some services, this is called an HMO with a point-of-service (POS) plan.
As Bill’s physician was not part of the Health Maintenance Organization‘s network, he either had to find a new plan, a new physician, or pay for the services of his preferred doctor out of his own pocket.