Medicare Supplement

How Medigap standardized letters work in Des Moines, WA

Des Moines, Washington — If you have Original Medicare and you've ever stared at a hospital bill wondering what "20% coinsurance" actually adds up to, you've bumped into the reason Medicare Supplement insurance exists. Medigap, as it's usually called, is private insurance that helps pay some of the costs Original Medicare leaves behind. It doesn't replace Medicare — it works alongside it.

Here in Des Moines, which sits in King County, Medigap is sold by private insurers but the benefits inside each lettered plan are set by federal rules. That standardization is the part most people don't realize, and it's what makes shopping a little less overwhelming once you know what to look for.

What Medigap actually does

Original Medicare pays a big share of your hospital and doctor bills, but not all of it. You're still on the hook for things like the Part A hospital deductible, the Part B deductible, and typically 20% of the cost of doctor visits, outpatient care, and durable medical equipment — with no yearly cap on what you could owe.

A Medigap policy steps in to help cover those leftover pieces. Depending on the plan letter you pick, it can pay some or all of your coinsurance, copayments, and deductibles. That's the whole job: fill the gaps.

Why the letters matter (and why they're the same everywhere)

Medigap plans are "standardized" by the federal government. That means Plan G from one insurer covers the exact same core benefits as Plan G from another insurer. The price can be different. The customer service can be different. The benefits inside that letter cannot.

There are 10 plan letters available in most states: A, B, C, D, F, G, K, L, M, and N. A few notes worth knowing:

• Plans C and F are only available to people who became eligible for Medicare before January 1, 2020. If you aged in after that, you can't buy them new.
• Plans K and L have lower premiums but ask you to share more of the cost until you hit a yearly out-of-pocket limit.
• Plan N includes small copays for some office and emergency room visits.

Massachusetts, Minnesota, and Wisconsin standardize their Medigap plans a little differently, but Washington follows the standard federal letters.

What Medigap does not cover

This is where people get tripped up. Medigap generally does not pay for:

• Prescription drugs — you'd need a separate Part D plan.
• Routine dental, vision, or hearing care.
• Long-term care (like a nursing home stay for custodial reasons).
• Private-duty nursing.

Medigap also can't be used with a Medicare Advantage plan. You either have Original Medicare plus (optionally) Medigap and Part D, or you have Medicare Advantage. It's one lane or the other.

The enrollment window that quietly matters most

The best time to buy a Medigap policy is during your Medigap Open Enrollment Period — a one-time, 6-month window that begins the first month you're both 65 or older and enrolled in Part B. During that window, insurers must sell you any Medigap policy they offer at their best available rate, and they can't turn you down or charge you more because of your health.

Miss that window, and in most states — Washington included — insurers can use medical underwriting. That means they can ask about your health, and in some cases decline to cover you or charge more. Washington does have some additional consumer protections, and the state's SHIBA program (Washington's SHIP) can walk you through them.

How this fits with Part D and 2026 changes

Because Medigap doesn't cover prescriptions, most people with Medigap also enroll in a stand-alone Part D drug plan. A couple of 2026 program facts worth keeping in mind as you plan:

• Part D has a new $2,100 annual out-of-pocket cap on covered drugs in 2026.
• The maximum Part D deductible is $615.
• The old "donut hole" is gone — Part D now has three phases.
• The Medicare Prescription Payment Plan lets you spread your drug costs across the year in monthly installments if you choose.
• Higher-income beneficiaries may pay an IRMAA surcharge; for a single filer in 2026, that starts above $109,000 in income.

These are Medicare-wide rules, not Medigap features, but they affect the overall picture of what you'll pay.

Plan availability around Des Moines

Medicare plan choices are set at the county level. Des Moines is in King County, where residents typically have a wide selection of both Medicare Advantage plans and stand-alone Part D drug plans to compare during the Annual Enrollment Period (Oct. 15 – Dec. 7). Medigap policies aren't tied to that county-by-county plan menu the same way — insurers offer them across the state — but where you live still affects your premium.