Medicare Supplement Insurance: What Is It?

Medicare Insurance

Medicare is the government’s health insurance program for adults age 65 and over, and for those with kidney failure or certain other serious disabilities. It offers fairly comprehensive coverage for doctor’s visits, hospital stays, and medications, but it doesn’t cover everything. You’re still responsible for many out-of-pocket costs, including deductibles, copayments, and coinsurance. That’s where Medicare supplement insurance comes in.

How Do Health Insurance Deductibles Work?

What Is Medicare Supplement Insurance?

Medicare supplement insurance is an add-on to Medicare Parts A and B. It’s also called Medigap insurance, because it fills in for Medicare cost gaps. When you buy Medigap insurance, it will cover many of the out-of-pocket costs Medicare won’t pay for along with a few extras.

Is Medigap the Same as a Medicare Advantage Plan?

No. Medigap is not the same as a Medicare Advantage Plan (Part C). Medicare Advantage plans are an alternative to Medicare Parts A and B coverage. Medigap is an add-on to Parts A and B.

Types of Medicare Supplement Insurance Policies

Medigap comes in an alphabet of plans from A through N. Each policy offers a specific set of benefits. Insurance companies don’t have to carry every single kind of Medigap plan, but they all must at least carry Plan A.

What Does Medicare Supplement Insurance Cover?

Medicare supplement insurance pays for costs you would normally be responsible for under Medicare, including:

  • Deductibles: The amount you must pay before Medicare coverage kicks in.
  • Coinsurance: Your share of the cost for a medical service.
  • Copayments: A set percentage of the costs for drugs and some health services.

Medigap may also pay for some services Medicare doesn’t cover, including the costs of medical care when you travel outside of the U.S.

What Doesn’t Medicare Supplement Insurance Cover?

Any new Medigap policy you buy won’t cover prescription drugs. You’ll need to sign up for Medicare Part D to get prescription coverage.

Your plan also won’t cover:

  • dental care
  • eyeglasses
  • hearing aids
  • long-term care
  • private nursing
  • routine vision care

How Medicare Supplement Insurance Works

You buy Medicare supplement insurance coverage through a private insurance company. Then you’ll pay that company a monthly premium on top of the premium you already pay Medicare.

Each individual must have their own Medicare supplement insurance policy. So if you’re married, you and your spouse will have to buy separate policies.

When you see your doctor or stay in the hospital, your Medicare Part A or B coverage will kick in first. Then, your supplement insurance will cover any leftover costs.

Can I Have Medigap and a Medicare Advantage Plan?

No. You can’t have both Medicare supplement insurance and a Medicare Advantage Plan. Medicare supplement insurance can’t be used to pay for deductibles, copayments, and other fees from a Medicare Advantage Plan. If you want Medicare Advantage, you’ll need to switch back to a regular Medicare Part A and B plan.

Can I Be Denied for Medicare Supplement Insurance?

The private insurance company you choose can deny your request for Medicare supplement insurance because of a pre-existing health condition. However, once you have a plan, the insurance company has to renew it no matter what health problems you develop.

Insurance companies can’t sell you a Medigap policy if you:

  • don’t already have Medicare Parts A and B
  • have a Medicare Advantage Plan, unless you’re planning to leave that plan
  • have Medicaid

How Do I Sign up for Medicare Supplement Insurance?

Your best option is to sign up during a Medigap open enrollment period. This 6-month period starts the first month you’re covered under Medicare Part B. During this time, you’ll get the best prices and the most coverage options.

You can buy Medicare supplement insurance from any licensed private insurance company in your state. To find a policy in your area, visit:

Costs and coverage can vary quite a bit from plan to plan. Read each policy carefully, and compare different plans until you find one that best fits your medical needs and budget.

Read This Next

When Should I Apply for Medicare: Timeline and Strategies
What You Should Know About the Medicare Fee Schedule
Medicare Requirements: Who Is Eligible?
Medigap Plans
Heading for Retirement? What You Can Do Now to Improve Your Health