PPO
In health insurance in the United States, a preferred provider organization (or "PPO", sometimes referred to as a participating provider organization or preferred provider option) is a managed care organization of medical doctors, hospitals, and other health care providers who have covenanted with an insurer or a third-party administrator to provide health care at reduced rates to the insurer's or administrator's clients.
The idea of a preferred provider organization is that the providers will provide the insured members of the group a substantial discount below their regularly-charged rates. This will be mutually beneficial in theory, as the insurer will be billed at a reduced rate when its insured utilize the services of the "preferred" provider and the provider will see an increase in its business as almost all insureds in the organization will use only providers who are members. Even the insured should benefit, as lower costs to the insurer should result in lower rates of increase in premiums. Preferred provider organizations themselves earn money by charging an access fee to the insurance company for the use of their network. They negotiate with providers to set fee schedules, and handle disputes between insurers and providers. PPOs can also contract with one another to strengthen their position in certain geographic areas without forming new relationships directly with providers.
HMO
A health maintenance organization (HMO) is a type of managed care organization (MCO) that provides a form of health care coverage in the United States that is fulfilled through hospitals, doctors, and other providers with which the HMO has a contract. Unlike traditional indemnity insurance, an HMO covers only care rendered by those doctors and other professionals who have agreed to treat patients in accordance with the HMO's guidelines and restrictions in exchange for a steady stream of customers.
Most HMOs require members to select a primary care physician (PCP), a doctor who acts as a "gatekeeper" to direct access to medical services. PCPs are usually internists, pediatricians, family doctors, or general practitioners (GPs). Absent a medical emergency, patients need a referral from the PCP in order to see a specialist or other doctor, and the gatekeeper cannot authorize that referral unless the HMO guidelines deem it necessary.
Primary care doctor: In most HMOs you must have a main doctor, called a primary care physician, or PCP. This doctor gives you most of your care and refers you for other services when you need them. Usually, you must see this doctor first before you can see a specialist. Your primary care doctor must be in the HMO’s network.
Medical group: Your medical group is the group of doctors and other providers that your primary care doctor is in. The medical group has a contract with the HMO to provide your care.
Networks and medical groups: Each HMO has a network of doctors, medical groups, labs, hospitals, and other providers who work for the HMO or have a contract with it. You must get approval from your HMO to get care from a provider outside the network, unless it’s an emergency, or you need urgent care and are outside your plan’s area. Most of the providers you see are also in your medical group. Ask the plan to mail you a copy of its provider directory. Or look on the plan’s website.
Referrals and pre-approval: You must have a referral to see a specialist or get most other services. Your HMO or medical group must approve many of your services before you can get them. Usually it is your doctor who gives you a referral and asks for pre-approval