When Original Medicare processes a claim for health care services you received, the claim is detailed in a Medicare Summary Notice (MSN). The MSN is a summary of claims for health care services Medicare processed for you during the previous three months. The MSN is not a bill.

MSNs are mailed four times a year and contain information about submitted charges, the amount that Medicare paid, and the amount you are responsible for.

The most important fields on your MSN explain:

• The total amount your doctor or other provider may bill you. The "You May Be Billed" field indicates the total amount that the provider is allowed to bill you (balance billing). It deducts the amount you already paid. In many instances, Medicare forwards your MSN to your supplemental insurer, which may pay this amount in full or in part. Sometimes, you may be responsible for a portion of the balance which neither Medicare nor your supplemental insurance has paid. Note: You should ignore the "Amount Charged" field.
  To learn about supplemental insurance, click on the link in the GO TO box.

• Non-covered charges, if any. The "Non-Covered Charges" field shows the portion of charges for services that are denied or excluded (never covered) by Medicare. A $0.00 in this field means that there were no denied or excluded services. If you disagree with a non-covered charge, you can appeal.
  To learn how to appeal, click on the links in the GO TO box.

Try to save your MSNs for about seven years. You might need them in the future to prove that payment was made if a provider sends you a bill or that services were received if you claimed a medical deduction on your taxes. If you have lost your MSN or you need a duplicate copy, call 800-MEDICARE. You will be redirected to the Medicare carrier who originally issued the MSN and can send you a copy.