The ABCDs of Medicare: An overview

There’s a lot to learn about Medicare, starting with the different parts (plans): ABC and D. Read on for an overview of Medicare plans and an invitation to learn more at a free class.

  • An overview of Medicare Parts A, B, C and D
  • Tips on how to enroll in Medicare plans
  • A word about Medicare supplemental plans


In 1965, the Medicare bill was signed into law as a basic insurance program for Americans who didn’t have a health plan. The original program included Part A, which is hospital insurance, and Part B, which is medical insurance. These two parts are now called “Original Medicare,” although you don’t have to sign up for both.

Over the years, Medicare has changed to include:

  • People 65 and older who select Medicare coverage
  • People under 65 with certain disabilities
  • People with end-stage renal disease (ESRD), who need dialysis or a kidney transplant     

With all the choices available, Medicare plans certainly aren’t one-size-fits-all. It can be confusing, but it helps to start with the basics. Here’s a quick primer about the various parts (plans) of Medicare — think of them as the ABCDs of the program.

The four parts of Medicare

The first two plans — Part A and Part B — are known as Original Medicare. The two other plans, Part C and Part D, were added later as Medicare offerings expanded. 

Medicare Part A

This plan helps cover:

  • Inpatient care in hospitals
  • Critical access hospitals
  • Skilled nursing facilities
  • Some home health care
  • Hospice care

As a beneficiary who receives health care insurance through the Medicare program, you need to meet certain conditions. Also, if you or a spouse have already paid toward Medicare through payroll while working, you usually won’t pay a premium for Part A.

Although there’s no monthly premium, you may have out-of-pocket costs for coinsurancecopayments and deductibles.

Medicare Part B

This plan helps cover:

  • Doctors' services, such as office visits
  • Flu shots
  • Lab tests
  • Flu shots
  • X-rays
  • Cancer screenings
  • Physical and occupational therapy
  • Some home health care

Part B also covers other health care services that Part A doesn't. Part B helps pay for covered services and supplies such as physical and occupational therapists and some home health care. Most people pay a monthly premium and a yearly deductible for Part B.

Medicare Part C

Part C is most often called Medicare Advantage. This type of Medicare health plan is offered by private insurance companies that are approved by Medicare. In other words, it’s not provided through the government, like Original Medicare is. Think of it as an all-in-one option over and above Original Medicare — meaning, “bundled" plans that include Part A, Part B and usually D.

The private health plan company contracts with Medicare to provide you with all of your Part A and B benefits. Different types of plans fall under the umbrella of Medicare Advantage and include:

  • Health maintenance organizations (HMOs)
  • Preferred provider organizations (PPOs)
  • Private fee-for-service plans

If you enroll in a Medicare Advantage plan, most of your Medicare services will be covered through that plan. Most Medicare Advantage plans offer prescription drug coverage and also help cover things that Original Medicare doesn’t, including:

  • Vision
  • Hearing
  • Dental
  • Wellness programs such as gym memberships

Part C plans may have lower out-of-pocket costs than Original Medicare. Most of the time you'll need to use doctors who are in the plan's network.

Other things to keep in mind: Even if you’re in a Medicare Advantage plan, Original Medicare will still cover hospice care costs and certain new Medicare benefits. And whichever type of Medicare Advantage plan you have, you're always covered for emergency care and urgent care.

Medicare Part D

This Medicare prescription drug coverage benefit is offered to everyone who has Medicare, but you can choose not to sign up for it. However, it’s important to note that if you decide not to get Medicare drug coverage when you're first eligible and then you choose to join later, you'll most likely pay a late enrollment penalty.

If you want Medicare Part D drug coverage, you need to join a Medicare plan that offers it. These plans can have different costs and types of drugs that are covered.

How to enroll in Medicare plans

To sign up for either Part A or Part B or both (Original Medicare)

  • If you already get benefits from Social Security, you will receive Original Medicare automatically when you first become eligible. You don't need to sign up. Medicare will send you a "Welcome to Medicare" packet three months before you turn 65.
  • If you’re not already getting benefits from Social Security and you’re 65 or over, or turning 65 in the next three months, you will not get Medicare automatically. You need to sign up to get Original Medicare.

To sign up for Part C (Medicare Advantage)

Since Medicare Advantage is offered through private health plan companies that are approved by Medicare, it’s best to compare Medicare plans where you live. Once you decide to join a plan, you can use Medicare's Plan Finder.

Then visit that plan's website to see if you can join online or if you’ll need to (or want to) fill out a paper enrollment plan. All plans must offer the paper form. You can also call the plan you want to join by getting your plan’s contact information.

To sign up for Part D (prescription drug coverage)

Since Medicare prescription drug coverage is a choice offered to everyone who has Medicare, you need to join a Medicare plan that offers prescription drug coverage if you want it.

Once you choose either Original Medicare or a Medicare Advantage plan, you can get prescription drug coverage by enrolling on the Medicare Plan Finder or on the private health plan's website; filling out a paper enrollment form; or by calling the plan.

A word about Medicare supplemental plans

Let’s say you have Original Medicare and you want help to pay some of the healthcare costs that Original Medicare doesn’t cover. These may include coinsurance, copayments, deductibles and medical care when you travel outside the country.

A Medigap policy isn’t the same as a Medicare Advantage plan. Here’s why:

  • A Medicare Advantage plan offers Medicare benefits.
  • A Medigap policy only supplements Original Medicare benefits.

With Original Medicare, when you buy a Medigap policy, Medicare will pay its share of the Medicare-approved amount for covered healthcare costs. After that, your Medigap policy will pay its share.

You’re invited to learn more about Medicare

There’s so much to learn and so many choices! That’s why we’re offering free Medicare 101 classes at our Oregon and Southwest Washington locations. Providence Medical Group invites you to join us, where we’ll discuss Medicare A, B, C and D and Medicare Supplements, help you understand your choices and benefits, and tell you how to sign up.

Register now, because space is limited.

Find a doctor

The team of experts at Providence understand the important role Medicare plays in making your health care accessible and affordable. Find a doctor covered by your plan in our provider directory. Or use one of the regional directories below:






Related resources

Take Advantage of Your Annual Wellness Visit glossary

Medicare Advantage Plans

How to get prescription drug coverage

Find a 2020 Medicare plan

Ask others about their experiences with Medicare and share your own at #medicare and with #aging readers @psjh.

This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.

About the Author

From how to identify and treat heart diseases to exercise tips to maintain an active lifestyle, the Providence Senior's Health team is committed to providing real-world advice that is hyper-relevant to helping those 65+ find ways stay young at heart

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