Medicare Supplement

A plain-English guide to Medigap letters for Madisonville

MADISONVILLE, Ky. — If you're new to Medicare — or helping a parent sort through the mail piling up on the kitchen table — you've probably run into the term "Medigap." It's also called Medicare Supplement insurance, and it works alongside Original Medicare to help pay some of the costs Medicare doesn't cover. The confusing part? Medigap plans are sold under letter names: A, B, D, G, K, L, M, and N. Here's a plain-English look at what these plans do, what they don't, and how to avoid a few common mistakes.

What Medigap actually does

Original Medicare covers a big share of your hospital and doctor costs, but not everything. You're still responsible for deductibles, coinsurance, and copays — and there's no yearly limit on what you might owe out of pocket. Medigap fills in some of those gaps. Depending on the letter you pick, it can help pay things like the Part A hospital deductible, the 20% coinsurance under Part B, and costs for extra hospital days.

Medigap does not replace Medicare. It rides along with it. You keep paying your Part B premium, and you pay a separate premium for the Medigap policy.

How the standardized letters work

In most states, including Kentucky, Medigap plans are standardized by the federal government. That means Plan G from one insurance company covers the same core benefits as Plan G from any other company. The difference is price and customer service — not the benefits themselves.

There are eight lettered plans available to new enrollees today: A, B, D, G, K, L, M, and N. (Plans C and F are no longer sold to people who became eligible for Medicare on or after January 1, 2020, because they covered the Part B deductible, which newer rules don't allow.)

Plans K and L are cost-sharing plans with lower premiums but higher out-of-pocket limits. Plan N has some copays for office and emergency room visits. Plan G is often chosen for its broader coverage. The right fit depends on your budget, your health, and how you like to pay — a little more each month, or a little more when you use care.

What Medigap does not cover

This is where people get tripped up. Medigap policies generally do not cover:

• Prescription drugs (you'd add a stand-alone Part D plan)
• Routine dental, vision, or hearing care
• Long-term care, like a nursing home stay for custodial care
• Hearing aids or eyeglasses

Medigap also can't be used with a Medicare Advantage plan. It's an either-or choice: Original Medicare plus Medigap (and usually Part D), or Medicare Advantage. Madisonville is in Hopkins County, where residents have both routes available, but you can only use Medigap on the Original Medicare side.

The enrollment window that matters most

Timing is everything with Medigap. Your Medigap Open Enrollment Period is a one-time, six-month window that starts the month you're 65 or older and enrolled in Part B. During this window, insurance companies must sell you any Medigap policy they offer at their best available rate, regardless of your health history.

Miss that window, and in most cases insurers can use medical underwriting — meaning they can charge you more, or turn you down, based on your health. A few limited "guaranteed issue" rights exist outside that window (for example, if a plan you had leaves the market), but they're narrower than most people expect.

This is different from the Annual Enrollment Period (October 15 – December 7) and the Medicare Advantage Open Enrollment Period (January 1 – March 31). Those windows deal with Part D and Medicare Advantage — not Medigap.

A few facts worth knowing for 2026

Even if you have Medigap, you'll still deal with Part D for drug coverage. For 2026, the Part D out-of-pocket cap is $2,100, and the maximum Part D deductible is $615. The old "donut hole" coverage gap was eliminated in 2025, so Part D now has three phases instead of four. If paying drug costs in one hit is hard, the Medicare Prescription Payment Plan lets you spread those costs across the year in monthly amounts.

Higher earners should also know about IRMAA — an income-related surcharge that starts above $109,000 for a single filer in 2026. IRMAA applies to Part B and Part D premiums, not Medigap.

Common mistakes to avoid

• Assuming Medigap covers drugs. It doesn't. You need Part D separately.
• Waiting too long to buy. Once your six-month window closes, coverage isn't guaranteed.
• Trying to stack Medigap on a Medicare Advantage plan. It's not allowed.
• Comparing plans by benefits alone. Since plans of the same letter are standardized, price and the insurer's reputation matter more than the fine print of the benefits.