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M11 Remark Code: Bill DME to Patient's DME MAC

M11 means the claim for durable medical equipment, orthotics, or prosthetics went to the wrong contractor. It must be billed to the DME contractor that covers the patient's ZIP code.

Quick facts

Code
M11 (RARC M11)
Status
Active In use since January 1, 1997.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The line is not paid by this contractor. Rebilling to the correct DME contractor is the path to payment; the patient is not billed.
  • OA (Other Adjustment): Some contractors report the misrouting as an informational adjustment with no liability assigned.
Official description
DME, orthotics and prosthetics must be billed to the DME carrier who services the patient's zip code.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What M11 means

Medicare processes durable medical equipment, prosthetics, orthotics, and supplies through regional DME Medicare Administrative Contractors (DME MACs). Which one handles a claim depends on where the patient lives, not where the supplier is located. M11 tells you the claim reached a contractor that does not cover the patient’s ZIP code, or went to a Part A/B contractor instead of a DME contractor.

The pairing is usually CARC 109, which says the claim is not covered by this payer or contractor.

Common causes

  • The patient moved, and the address on file is outdated.
  • The patient’s temporary address (for example, a seasonal residence) was used instead of the permanent one.
  • DME items were included on a claim sent to the Part A/B contractor.
  • Clearinghouse routing was set by the supplier’s location rather than the patient’s.

How to fix it

  1. Verify the patient’s permanent address and ZIP code.
  2. Identify the correct DME contractor for that address.
  3. Submit a new claim to that contractor. This is not a corrected claim to the original contractor.
  4. Update the patient record and clearinghouse routing so future claims go to the right place.

How to prevent it

Confirm patient addresses at every order, and route DMEPOS claims by the patient’s residence. Keep DME items off Part A/B professional claims. For a primer on claims sent to the wrong payer, see claim rejection vs denial and timely filing denials.

Codes that may appear with M11

  • CO-109 (Claim/service not covered by this payer/contractor.): The claim is not covered by this payer or contractor and should be sent to the correct one.
  • CO-16 (Claim/service lacks information or has submission/billing error(s).): The claim information, such as the patient address, did not support processing by this contractor.
  • N558 (This claim/service is not payable under our service area.): The claim must be filed with the plan whose service area the equipment was received in.
  • CO-109 (Claim/service not covered by this payer/contractor.): The reason code that usually carries the wrong-payer decision M11 explains.
  • MA130 (Your claim contains incomplete and/or invalid information, and no appeal rights are afforded because the claim is unprocessable.): A broader instruction that the claim contains incomplete or invalid information and must be resubmitted as a new claim.

M11 FAQ

How do I know which DME contractor to bill?

For Medicare, the jurisdiction is based on the patient's permanent residence address. Use the patient's current address to find the matching DME MAC.

Is this a denial I can appeal?

Generally no. It is a routing problem. Submit a new claim to the correct contractor instead.

Does rebilling to the right contractor affect timely filing?

The timely filing clock usually still runs from the date of service, so rebill promptly.