Medigap plans work with Original Medicare, but if you do not take out a plan when you first become eligible, you may be subject to medical underwriting, which could cost you more money or plan eligibility.

If you have Original Medicare, you can take out a Medigap plan to cover some of Original Medicare’s out-of-pocket costs.

Several Medigap plans are available, which private insurers administer on Medicare’s behalf.

You’re usually eligible for Medigap coverage when you first become eligible for Medicare Part B. But if you do not enroll, you may become ineligible for a plan or have to pay more.

When you apply for some health insurance plans, you may need to complete a medical history form to disclose all the medical conditions you have, medical investigations, and any other medical information that may be relevant to the application.

The insurer may then review this information and decide when to exclude specific health conditions from coverage, apply specific rules to those health conditions, charge a higher premium, or deny coverage.

In 2022, around 42% of people with Original Medicare had a Medigap plan. However, many people miss out on plan benefits due to the limited enrollment windows.

Medigap plans cannot use your medical history to decide plan coverage or cost if you enroll when you are first eligible, which is during the Medigap open enrollment period, or if you have guaranteed issue rights.

The Medigap open enrollment period lasts for 6 months from the time you’re 65 years or older and have Medicare Part B. It is a one-time period that does not come around annually like many other Medicare enrollment periods.

During this time, you can:

  • enroll in any Medigap policy for which you’re eligible
  • often get the best premium prices
  • often have more Medigap plan choices
  • purchase almost any Medigap plan available in your state.
    • Reminder: During this time, an insurance company cannot use medical underwriting to decide whether to sell you a plan. They cannot deny you coverage due to preexisting health conditions.
  • shorten or avoid waiting periods for preexisting conditions (when you buy a Medigap plan to replace creditable coverage)

Once you are outside the Medigap open enrollment period, you may be unable to buy a Medigap plan, or it may cost more.

Generally, your Medigap plan may start on the first of the month after you apply. However, you can decide when you want it to begin.

Guaranteed issue rights

Guaranteed issue rights are specific circumstances that allow you to enroll in a Medigap plan outside the open enrollment period.

Medigap plans can include coverage of the following benefits:

  • Part A coinsurance
  • Part A hospital costs up to an extra 365 days after you use your Medicare benefits
  • Part B coinsurance or copayment
  • the first 3 pints of blood you may need
  • Part A hospice coinsurance or copayment
  • skilled nursing facility coinsurance
  • Part A deductible
  • Part B deductible
  • Part B excess charge, which is a charge that a doctor or healthcare professional may charge above the Medicare-approved amount
  • foreign travel emergency care

Not all plans are available in all areas, and not all plan providers offer all plan types.

You can use Medicare’s helpful plan finder tool to find available plans in your area.

In some circumstances, Medicare supplement (Medigap) plan providers may use medical underwriting to decide whether they can sell you a policy, exclude medical conditions, or charge more for the plan.

However, insurers cannot use your medical history this way if you are within the Medigap open enrollment period or have guaranteed issue rights.

Enroll in a Medigap plan as soon as you become eligible to ensure you get the right plan for you.