A point-of-service plan (POS) is a type of managed care plan that is a hybrid of HMO and PPO plans. Like an HMO, participants designate an in-network physician to be their primary care provider. But like a PPO, patients may go outside of the provider network for health care services. When patients venture out of the network, they’ll have to pay most of the cost, unless the primary care provider has made a referral to the out-of-network provider. Then the medical plan will pick up the tab.