How to Read Your Medicare Summary Notice

When a thick envelope arrives from Medicare, most people put it in a drawer. That's a missed opportunity. Your Medicare Summary Notice (MSN) is your receipt — it shows every claim submitted in your name and is your first defense against billing errors and fraud. The MSN arrives every 3 months and covers all Part A and Part B services. Here's how to read each section: Section 1 — "Did Medicare Approve All Claims?" A quick yes/no summary. If anything was denied, it'll say "See Claims" with details below. Section 2 — "Claim Details." For each service: the date, provider name, description of service, amount billed by the provider, Medicare-approved amount (often less than billed), amount Medicare paid, and the amount you may owe. Section 3 — "Deductible and coinsurance." Shows where you stand on your Part B deductible and any coinsurance owed. What to look for: Services you don't recognize — this could be fraud. Ask yourself: did you see this doctor on this date? Duplicate charges — the same service billed twice. Denied claims — the MSN will include a reason code. Common ones: not medically necessary (CO-50), billing error (CO-16), or bundled service (CO-97). Higher "you may owe" amounts than expected — compare with your provider's bill. If something looks wrong: call the provider first (billing errors are common). If unresolved, call 1-800-MEDICARE. If you suspect fraud, call the OIG hotline at 1-800-HHS-TIPS. Keep MSNs for at least one year. If you're appealing a denial, you'll reference the MSN as part of your evidence.