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N105 Remark Code: Misdirected Claim for RRB Beneficiary

N105 means the claim was sent to the wrong Medicare contractor because the patient is a Railroad Retirement Board (RRB) beneficiary. Part B claims for RRB beneficiaries are handled by a dedicated RRB contractor, so the claim must be resubmitted there.

Quick facts

Code
N105 (RARC N105)
Status
Active In use since January 29, 2002; last modified July 1, 2017.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): A routing denial. The patient does not owe the amount; the claim needs to go to the RRB contractor.
Official description
This is a misdirected claim/service for an RRB beneficiary. Submit paper claims to the RRB carrier: Palmetto GBA, P.O. Box 10066, Augusta, GA 30999. Call 888-355-9165 for RRB EDI information for electronic claims processing.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N105 means

Medicare beneficiaries who qualify through the railroad retirement system have the same Part B benefits as other beneficiaries, but their Part B claims are processed by a single nationwide specialty contractor rather than the regional contractor for your area. N105 means your claim reached a regional contractor, which recognized the patient as an RRB beneficiary and sent it back.

The official remark identifies the RRB contractor and gives a mailing address and an EDI phone line. Use the details on your remittance rather than an address copied from an old record.

Common causes

  • The patient’s Medicare coverage was not identified as RRB at registration.
  • The eligibility check returned RRB information, but the billing system still routed the claim to the local contractor.
  • The practice has not set up electronic submission to the RRB contractor, so claims default to the regional payer ID.

How to fix it

  1. Confirm RRB status with an eligibility check.
  2. Set up the RRB payer in your practice management system and clearinghouse, including any EDI enrollment the RRB contractor requires.
  3. Submit a new claim to the RRB contractor. The original was not processed on its merits, so a replacement claim to the regional contractor is not the right route.
  4. Watch timely filing. The standard Medicare filing limit still applies; see the timely filing guide.

How to prevent it

Add an RRB flag to the patient’s insurance record so claims route to the correct payer ID automatically. A quick eligibility check before billing any Medicare patient for the first time will usually reveal railroad coverage.

Codes that may appear with N105

  • CO-109 (Claim/service not covered by this payer/contractor.): Not covered by this contractor; send it to the correct one. N105 names the RRB contractor as the destination.
  • N104 (This claim/service is not payable under our claims jurisdiction area.): A general Medicare jurisdiction mismatch not tied to railroad coverage.
  • N127 (This is a misdirected claim/service for a United Mine Workers of America (UMWA) beneficiary.): A misdirected claim for a United Mine Workers of America beneficiary.
  • CO-B11 (The claim/service has been transferred to the proper payer/processor for processing.): Used when a claim was transferred to the proper processor rather than returned.

N105 FAQ

How can I tell a patient is an RRB beneficiary?

Their Medicare card and eligibility response identify Railroad Retirement Board coverage. Ask about it at registration if the patient worked in the railroad industry or is a family member of someone who did.

Do I need a separate enrollment for RRB claims?

Providers generally use their existing Medicare enrollment, but electronic submission to the RRB contractor may need its own EDI setup. The remark text includes contact details for RRB EDI information.

Where do paper claims go?

The remark itself lists the RRB contractor's mailing address. Use the address on your current remittance, since contractor details can change.