a point-of-entry physician who determines the need for additional services. Clients must go through this "gatekeeper" first. HMOs often use a Point of Service (POS) plan. In this plan:
*Primary care MD is the gatekeeper for hospital admission, specialist, emergency, & other services. The physician authorizes the referrals to these other physicians or service providers.
*There is a fixed fee for service.
*If client chooses to go outside of provider network, he pays the full cost.