Medicare Summary Notice: How to Read Your MSN, Spot Errors and Appeal

The number on a Medicare Summary Notice that matters most is in the "Maximum You May Be Billed" column ("Max You May Be Billed" on Medicare's sample). Medicare's own sample MSN defines it as the total amount the provider is able to bill you. If a bill from the doctor's office is higher than that number, don't pay it until you've asked why.

The Medicare Summary Notice (MSN) is the statement Original Medicare sends for Part A and Part B claims. It is not a bill. It shows what each provider billed Medicare, what Medicare approved and paid, and what you may still owe, per Medicare.gov. It's also where your appeal clock starts and one of the best places to catch billing errors and fraud, if you actually read it. Here's how to read one line by line, how it differs from the Explanation of Benefits that plans send, and who to call in Washington when something looks wrong.

Source: Medicare.gov, Medicare Summary Notice; 42 CFR 405.942; Medicare.gov, Medicare costs; CMS newsroom (checked November 14, 2026).

When the MSN arrives, and the faster electronic version

Paper MSNs come every 6 months, and only if you had services or supplies billed to Medicare in that period. No claims, no MSN (Medicare.gov). Some handouts, including one from Washington's SMP, still say "quarterly." Medicare.gov's current page says 6 months, and that's what I go by.

Six months is a long time to wait to find out a lab billed Medicare for a test you never had. The electronic MSN fixes that. Once you switch, you get an email with a link to your MSN for any month you have a processed claim, and paper copies stop. To sign up, log into your Medicare account (you can now use ID.me, CLEAR or Login.gov), open "My account settings," find "Email and document settings," choose "Edit" next to Medicare Summary Notices, pick "Electronically," and save (Medicare.gov, Go digital).

The account helps even if you keep paper. According to the Medicare & You 2027 handbook, claims generally show up online within 24 hours after processing, and you can download your claims data. The Washington OIC's Senior Medicare Patrol handout says the account lets you review bills processed within the past 36 months (OIC).

Two housekeeping points. MSNs come in large print or Braille if you need them. And the MSN goes to the address Social Security has on file, so an address change goes through Social Security (or the Railroad Retirement Board if you get RRB benefits), not Medicare.

How to read an MSN, page by page

Medicare's sample Part B MSN has four pages, and the Part A version uses the same layout for hospital, skilled nursing, hospice and home health claims. This is what's on each page and what I'd actually check.

Source: Medicare.gov sample Part B MSN; sample Part A MSN; Washington OIC / Senior Medicare Patrol, Medicare Statements.

"This is not a bill." Medicare means it. Nobody pays Medicare off an MSN. The provider sends you a separate bill, and the MSN is what you check that bill against.

Assigned vs. unassigned. Each Part B claim is marked one or the other. On an assigned claim the provider has agreed to take the Medicare-approved amount as full payment and can charge you only the deductible and coinsurance. On an unassigned claim from a non-participating provider, Medicare pays you rather than the provider (42 CFR 424.53(e)), you may have paid the full charge at the visit, and the provider can charge more than the approved amount: in many cases up to 15% more, called the limiting charge (Medicare & You 2027). I covered how that plays out in Part B excess charges in Washington.

QMB status. If you're in the Qualified Medicare Beneficiary program, the MSN says so. QMB members can't be billed for Part A or Part B deductibles, coinsurance or copayments (a small Medicaid copay may apply), and the handbook suggests handing a provider a copy of your MSN to prove it.

A hypothetical claim, worked through

Here's a made-up set of four Part B claims, so you can see how the columns relate. Assume 2026 rules, providers who accept assignment, no Medigap or other coverage, and that these are the first Part B claims of the year, so the full $283 deductible is still unmet.

Hypothetical illustration, not a real claim. Rules from Medicare.gov, Medicare costs: $283 Part B deductible (2026), then usually 20% of the approved amount; $0 for covered clinical lab services. Real claims can include adjustments this example leaves out.

Walk through it. The first visit's approved amount is $150, all of which goes to the deductible, so Medicare pays nothing and you owe $150. That leaves $133 of deductible. The specialist visit is approved at $400: you pay the remaining $133, then 20% of the other $267, which is $53.40, for $186.40. Medicare pays $213.60. The lab test costs you nothing. By the follow-up visit the deductible is met, so you owe 20% of $120, or $24.

Notice what the "Charged" column does for you: nothing. On assigned claims the charge is the provider's list price, and the approved amount is what counts. If the specialist's office sends a bill for $520, or even for $400, that's the moment to call them with the MSN in hand. The most you owe on that line is $186.40, less anything you already paid at the front desk.

MSN vs. Explanation of Benefits

If you're in a Medicare Advantage plan, you don't get MSNs for the care the plan covers. The plan sends an Explanation of Benefits (EOB) instead. Federal rules (42 CFR 422.111(k)) require it to show the billing code and amount billed, what the plan approved, the plan's share and your share, plus year-to-date totals toward your deductible and out-of-pocket maximum. Plans send it monthly, or quarterly with a notice for each claim.

A stand-alone Part D drug plan sends its own EOB for any month you fill a covered prescription, no later than the end of the following month (42 CFR 423.128(e); Medicare.gov). And if you have a Medigap policy, that insurer sends an EOB showing what Medicare paid and what the Medigap policy paid (OIC).

Source: Medicare.gov, MSN; Medicare.gov, EOB; eCFR 42 CFR 422.111(k), 423.128(e); Medicare.gov, Reporting fraud.

The row that trips people up is the appeal clock. A Medicare Advantage EOB has to flag a denied claim and describe your appeal rights, but the regulation says plainly that it does not replace the plan's denial notice. In a plan, the 60-day appeal window runs from that written notice (Medicare.gov states it as 65 days from the date on the notice; Medicare.gov). Keep both.

When a claim is denied: the 120-day clock

A denied line on an MSN is Medicare's initial determination. You have 120 days from the day you receive the MSN to ask for a redetermination, and the rule presumes you received it 5 days after the date printed on it (42 CFR 405.942). The request counts as filed when the contractor receives it, not when you mail it. Page 4 of the MSN prints the date your appeal must be received; use that date.

Hypothetical: an MSN dated December 1, 2026 is presumed received December 6, 2026, so the appeal has to reach the contractor by April 5, 2027.

Before you appeal, call the provider's billing office. Medicare.gov says to make sure they submitted the correct information, and if they didn't, the office may resubmit. A wrong code fixed that way is faster than any appeal. If the provider says the claim was right, appeal. The 2027 handbook lays out the low-tech way: circle the item on the MSN, write why you disagree (on the MSN or a separate page), add your name, phone number and Medicare Number, keep a copy, and send it to the Medicare Administrative Contractor listed on the MSN. Form CMS-20027 works too. Miss the deadline and you can still ask, but you'll have to show good cause.

Source: eCFR 42 CFR 405.942, 405.950, 405.962, 405.1002, 405.1102, 405.1130; Federal Register amount-in-controversy notices for CY2026 and CY2027. Each deadline runs from when you receive the prior decision. 2027 minimums apply to requests filed on or after January 1, 2027.

The contractor generally decides a level 1 appeal within 60 days (405.950), and a win shows up on your next MSN. Deadlines, decision clocks and the Medicare Advantage and Part D tracks are all in the full Medicare appeal process.

Using the MSN to catch errors and fraud

The 2027 Medicare handbook gives the same advice I'd give: write down the dates you get care, save receipts, and check every MSN against them. Medicare.gov says the same, and Washington's Senior Medicare Patrol handout calls reviewing your statements one of the best ways to catch errors, fraud and abuse (OIC).

Source: Medicare & You 2027; Medicare.gov, Reporting fraud; Washington OIC, Report Medicare fraud; OIC SMP fact sheet; HHS-OIG.

The handbook says a provider you know should give you an itemized statement within 30 days of your request. If you suspect Medicare is being charged for something you didn't get, or you don't know the provider on the claim, call 1-800-MEDICARE (1-800-633-4227). If you're in a Medicare Advantage or drug plan, the Investigations Medicare Drug Integrity Contractor (I-MEDIC) takes tips at 1-877-7SAFERX (1-877-772-3379).

One of the seven schemes the OIC's fact sheet lists: calls saying you qualify for free medical supplies like back or knee braces, or genetic testing. Hang up. In Original Medicare you need a doctor's prescription and a Medicare-contracted supplier (OIC). If braces show up on your MSN anyway, that's exactly what the Senior Medicare Patrol wants to hear about. More schemes and how to report them: Medicare fraud in Washington.

One more thing to watch: dates. Providers must file Original Medicare claims within 12 months of the date of service (Medicare.gov). If a visit from last spring still isn't on your MSN or in your account, ask the office whether it was filed.

The deductible and coinsurance behind the numbers

Part B's deductible is $283 in 2026. After that, you usually pay 20% of the Medicare-approved amount for each covered service, when the provider accepts assignment (Medicare.gov). There's no yearly out-of-pocket cap in Original Medicare. Part A works differently: a $1,736 deductible for each benefit period in 2026, which is why the Part A MSN shows when your benefit period began.

The 2027 numbers aren't out yet. When I checked the CMS newsroom on November 14, 2026, there was no 2027 Part B premium and deductible announcement, and Medicare.gov's costs page still showed 2026 amounts. For reference, CMS published the 2026 figures on November 14, 2025. Until it does, any 2027 deductible you see quoted is a projection.

The deductible line on page 1 of your MSN is the easy way to track where you stand. If you have a Medigap policy, compare the MSN with the Medigap insurer's EOB, which also lists what Medicare paid; the two Medicare figures should match. Policy details: Medicare Supplement insurance in Washington.

Free help in Washington

SHIBA, the Statewide Health Insurance Benefits Advisors program run by the Office of the Insurance Commissioner, gives free, unbiased and confidential help with Medicare: 800-562-6900, 8:30 a.m. to 4:30 p.m., Monday through Friday (OIC). A volunteer can sit down with your MSN and walk through it, which is worth doing the first time if you're helping a parent in Yakima or Everett sort a stack of them. Here's how SHIBA works.

SHIBA is also Washington's Senior Medicare Patrol, the federally funded program that helps people spot and report Medicare fraud. The OIC has an online "Report Medicare fraud to SHIBA" form, or you can call the same number (OIC; SMP locator).

Know which door to use. A denied Medicare claim goes through the Medicare appeal process. A Medigap insurer refusing to pay its share of a claim Medicare approved is a state matter: file a complaint with the OIC (OIC).

My read: open every MSN or eMSN the week it arrives, compare it with your calendar, and check page 4 for a date. Ten minutes catches most problems while they're still easy to fix. Coverage basics for this state are in Medicare in Washington.

Questions

How often do you get a Medicare Summary Notice?

Every 6 months, if you had Part A or Part B services or supplies billed to Medicare in that period. If you sign up for electronic MSNs, you get an email for any month with a processed claim.

Is a Medicare Summary Notice a bill?

No. It shows what providers billed Medicare, what Medicare paid and the maximum you may be billed. Your provider bills you separately; compare that bill with the MSN.

What is the difference between an MSN and an EOB?

Medicare sends the MSN for Original Medicare Part A and Part B claims. A Medicare Advantage or Part D plan sends an Explanation of Benefits for the claims it covers. An MSN denial starts the 120-day appeal clock; in a plan, the plan's separate written denial notice starts it.

How long do I have to appeal a claim on my MSN?

120 days from when you receive the MSN, presumed 5 days after the date printed on it. The appeal must be received by the date shown on the MSN's last page.

Federal Medicare rules and your own plan or policy documents control your situation, and the dates printed on your notices govern. Confirm the details with SHIBA, 1-800-MEDICARE, a licensed agent, or (for legal questions) an attorney.

Sources

1. Medicare.gov: Medicare Summary Notice
2. Medicare.gov: Sample Part B Medicare Summary Notice (PDF)
3. Medicare.gov: Sample Part A Medicare Summary Notice (PDF)
4. Medicare.gov: MSN envelope guide (PDF)
5. Medicare.gov: Go digital (electronic MSNs)
6. Medicare & You 2027 handbook (PDF)
7. Medicare.gov: Explanation of Benefits
8. Medicare.gov: Medicare costs
9. Medicare.gov: Filing a claim
10. Medicare.gov: Reporting Medicare fraud and abuse
11. Medicare.gov: Appeals in Medicare health plans
12. CMS newsroom
13. CMS: 2026 Medicare Parts A & B premiums and deductibles (Nov 14, 2025)
14. eCFR: 42 CFR 422.111, disclosure requirements (MA explanation of benefits)
15. eCFR: 42 CFR 423.128, dissemination of Part D plan information (Part D EOB)
16. eCFR: 42 CFR 424.53, unassigned claims
17. eCFR: 42 CFR 405.942, time frame for filing a redetermination
18. eCFR: 42 CFR 405.950, time frame for making a redetermination
19. eCFR: 42 CFR 405.962, time frame for filing a reconsideration
20. eCFR: 42 CFR 405.1002, right to an ALJ hearing
21. eCFR: 42 CFR 405.1102, request for Council review
22. eCFR: 42 CFR 405.1130, judicial review
23. Federal Register: Amount in Controversy Threshold Amounts for CY2026 (Dec 4, 2025)
24. Federal Register: Amount in Controversy Threshold Amounts for CY2027 (Sept 16, 2026)
25. Washington OIC / SMP: Medicare Statements, tips for protecting yourself (PDF)
26. Washington OIC: Report Medicare fraud
27. Washington OIC: SMP fact sheet, Be safe during Medicare Open Enrollment (PDF)
28. SMP Resource Center: Washington
29. HHS-OIG: Report fraud
30. Washington OIC: Get free Medicare help from SHIBA
31. Washington OIC: Appealing a Medicare coverage or payment decision