Preferred Provider Organization or PPO: PPOs allow patients to seek medical care from in-network or out-of-network health providers; however, patients pay less when in-network providers are used. To see a specialist, the patient does not need a referral from a primary care provider. For certain services, patients, must obtain prior authorization from the insurer. Members of PPOs may be required to pay deductibles, copays, and co-insurance. PPOs are similar to indemnity plans in that both are paid by the fee-for-service method. In a fee-for-service plan, the medical service provider is paid a pre-set fee for each type or unit of service given. An office visit, laboratory tests, x-rays, or other services are paid individually according to a pre-determined fee schedule. This type of payment method enables health care providers to receive the maximum reimbursement for each service rendered.