Medicare covers between 42 million and 45 million Americans, making it the largest single payer of healthcare in the nation. Medicare has traditionally been the plan for senior citizens aged 65 and older, the primary patient population covered by Medicare. Nearly 15% of Medicare recipients are actually under the age of 65, however, with most being disabled or having one of a small number of specified diseases that Medicare covers.
Medicare is divided into four parts, labeled Part A, Part B, Part C, and (you guessed it) Part D. Each has a separate funding source, although all are ultimately funded by the federal government. Each part also has a different coverage purpose, so it is important for Medicare patients to be aware of how the different parts may cover different services. Medicare reimbursement can vary greatly by the type of service and Medicare's detailed rules and guidelines, and while your provider can help you with some questions, it makes sense to have a good understanding yourself.
Part A is the hospital insurance, covering inpatient hospital stays, skilled nursing, and hospice care. While Part A may not be the most frequently used portion of Medicare, it is certainly the most costly.
Part B is the outpatient and physician insurance, often called the Supplementary Insurance because it is optional for the patient. In order to receive Part B, a patient must pay a premium which can range from $96 to $116 based on income. Part B is what would cover most routine and preventative care that is not done on an inpatient basis.
Part C is also known as Medicare Advantage, the private HMO plans that administer Medicare benefits to some patients instead of them accessing Parts A and B directly through Medicare. Medicare Advantage is something that a patient would opt in to if they chose -- it only accounts for less than 1 on 5 Medicare patients.
Part D is the prescription drug benefit, which was enacted in 2006. Part D is also optional and requires a modest monthly premium to participate.
Since Medicare doesn't cover all of the costs associated with medical care -- long-term care isn't included past just a few days, skilled nursing days are limited, and dental is not covered -- many patients have a secondary policy to help cover the "gap". MediGap policies have become popular ways to pay for uncovered services as well as offset the costs of deductibles, and some patients have plans as part of a retirement package that cover the portion of cost that Medicare doesn't pay.