En español | Unlike other health insurance, Medicare coverage is divided into four parts: A, B, C and D. This allows you to choose which parts you want and avoid duplicating coverage from other insurance.

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Part A helps pay the costs of a stay in a hospital or skilled nursing facility, home health care, hospice care, and medicines administered to inpatients.

Part B helps pay bills for physicians and outpatient services such as rehab therapy, lab tests and medical equipment. It also covers doctors' services in the hospital and most medicines administered in a doctor's office.

Part C is a different way you can choose to receive your Medicare benefits. It consists of a variety of private health plans, known as Medicare Advantage plans, that cover Part A, Part B and (often) Part D services in one package. (See "Figuring Out Your Choices.")

Part D helps pay the cost of prescription drugs that you use at home, plus insulin supplies and some vaccines. To get this coverage, you must enroll in a private Part D drug plan or in a Medicare Advantage plan that includes Part D drugs. (See"Figuring Out Your Choices.")

Medicare covers most services deemed "medically necessary," but it doesn't cover everything. Except in limited circumstances, it doesn't cover vision, hearing and dental care; nursing home care; or medical services outside the United States.

Exams and checkups:  Medicare doesn’t cover routine physical exams. But when you’re new to Medicare, you’re entitled to a one-time “Welcome to Medicare” exam and medical history review within 12 months of enrolling in Part B. Also, under the new health care law, Medicare now offers annual wellness checkups.  Both are free of charge if provided by a doctor who accepts Medicare reimbursement in full.

Early detection:  Certain lab tests and screenings used to diagnose diseases early are also free of charge.  These include mammograms, pap smears, bone density measurement, and screenings for cardiovascular disease, prostate cancer, HIV and diabetes. Although the tests themselves are free, in most cases you still pay the required copay to see the doctor who prescribes them. 

For more coverage information, see the "Medicare & You" handbook (PDF).

Going to the Doctor

Most doctors accept Medicare patients, but some don't. Be aware that a physician who has opted out of Medicare cannot bill Medicare for treating you, and you will be responsible for the whole cost. It’s also important to find out whether a doctor accepts Medicare “assignment,” which means that he or she has agreed to the Medicare-approved amount as payment in full, or whether the doctor can charge you up to 15 percent above this amount.  (See related article “Seeing a Doctor 'on Assignment.'")

If you need to find a primary care doctor or specialist who accepts Medicare, go to the Medicare website, click on "Resource Locator" and then on "Physician Compare." Or call Medicare at 1-800-633-4227.

Next: What does Medicare cost? »