Understanding Your Medicare Summary Notice (MSN): A Line-by-Line Guide

Your Medicare Summary Notice shows every claim and payment. Learn how to read it, spot errors, and protect yourself from billing mistakes.

Every three months, Medicare sends you a Medicare Summary Notice (MSN) — a detailed statement showing all the services and supplies billed to Medicare on your behalf. Think of it as your Medicare "bank statement." Yet many beneficiaries toss it aside without reading it, missing potential billing errors, fraud, or opportunities to appeal denied claims. Here's how to read and use your MSN.

What Is a Medicare Summary Notice?

The MSN is NOT a bill. It's a summary statement that shows what services you received, what Medicare paid, what your provider is allowed to charge, and what you may owe. It's mailed every three months (quarterly) and covers all Part A and Part B claims processed during that period.

MSN vs. EOB

If you have Original Medicare, you receive a Medicare Summary Notice (MSN). If you have a Medicare Advantage plan, you receive an Explanation of Benefits (EOB) from your plan instead. Both serve the same purpose but come from different sources.

MSN Sections Explained

How to Spot Errors and Fraud

Your MSN is your first line of defense against billing errors and Medicare fraud. Review each claim carefully and watch for these red flags:

Services you never received — if a claim shows a doctor visit or procedure you didn't have, this could be fraud
Duplicate charges — the same service billed more than once on different dates
Wrong dates — claims showing services on days you didn't see a provider
Incorrect provider — claims from doctors or facilities you've never visited
Higher charges than expected — services billed at a higher level than what was performed
Equipment you didn't receive — durable medical equipment charges for items you never got

Report Suspected Fraud

If you spot services you didn't receive or charges that look fraudulent, report it immediately. Call 1-800-MEDICARE (1-800-633-4227) or contact the HHS Office of Inspector General at 1-800-HHS-TIPS (1-800-447-8477). You may be eligible for a reward of up to $1,000 for reporting fraud.

Common MSN Terms Explained

What to Do with Your MSN

Open it as soon as it arrives — don't let it pile up
Compare each claim to your own records (appointment calendar, receipts, etc.)
Look for any services you don't recognize or didn't receive
Check denied claims and decide whether to appeal
Verify that "You May Be Billed" amounts match what your providers actually charge you
File it with your medical records — keep MSNs for at least one year
Report any suspected fraud to 1-800-MEDICARE