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N405 Remark Code: Donor's Insurance Must Pay First

N405 means the payer covers this service only when the donor's own insurance does not. It appears on donor-related services, such as organ or tissue donation workups, where the donor's plan must be billed and must decline before this payer will consider the claim.

Quick facts

Code
N405 (RARC N405)
Status
Active In use since August 1, 2007.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • OA (Other Adjustment): The payer is signalling that another plan (the donor's) should be billed first. The amount is not a final patient liability while the donor's coverage is unresolved.
  • CO (Contractual Obligation): Some payers deny the line as a contractual adjustment until proof of the donor plan's decision is supplied. Do not bill the donor or recipient for it at this stage.
Official description
This service is only covered when the donor's insurer(s) do not provide coverage for the service.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N405 means

N405 shows up on donor-related services, most often in transplant cases where testing, evaluation, harvesting, or follow-up care for a living donor is billed. The payer that sent N405 is saying it acts as a fallback: it will consider the charge only after the donor’s own health plan has declined it or has been shown not to exist.

The remark usually rides with CARC 22 (care may be covered by another payer) or CARC 109 (not covered by this payer). Neither is a medical necessity decision. The payer simply wants the donor’s insurer to go first.

Common causes

  • The claim for donor services was billed straight to the recipient’s plan, even though the donor has active coverage.
  • The donor’s insurance was never collected at registration because the donor was treated as a secondary party to the transplant case.
  • The donor’s plan did respond, but its denial or EOB was not sent with the claim.
  • Donor and recipient services were combined in one account, so the payer could not tell which person’s coverage should apply.

How to fix it

  1. Confirm who the donor is and whether they had coverage on the date of service. Verify eligibility directly with the donor’s plan.
  2. Bill the donor’s insurer under the donor’s own demographics and member ID if that has not happened.
  3. Collect the donor plan’s response. A denial, an EOB showing no benefit, or written confirmation that the donor is uninsured is typically what the fallback payer needs.
  4. Refile with the other plan’s result. If you are replacing the original claim, submit a corrected claim with resubmission code 7 and the original claim number; otherwise follow the payer’s instructions for a new submission.
  5. Call the payer’s transplant or case management unit if the case involves a contracted transplant arrangement. These cases often follow special billing rules that differ from standard claims.

How to prevent it

Build a donor intake step into transplant workflows so the donor’s insurance is captured separately from the recipient’s. Keep donor and recipient charges on separate accounts, and check the transplant contract or benefit terms for which plan pays donor costs before the first claim is sent. For more on sorting out payer order, see eligibility and COB denials.

Codes that may appear with N405

  • OA-22 (This care may be covered by another payer per coordination of benefits.): Another payer may be responsible under coordination of benefits; N405 identifies that payer as the donor's insurer.
  • CO-109 (Claim/service not covered by this payer/contractor.): The service is not covered by this payer and should go to the correct one, which N405 points to as the donor's coverage.
  • CO-16 (Claim/service lacks information or has submission/billing error(s).): Some payers treat the missing donor-plan decision as missing claim information.
  • N406 (This service is only covered when the recipient's insurer(s) do not provide coverage for the service.): The mirror image: the service is covered only when the recipient's insurer does not cover it.
  • N479 (Missing Explanation of Benefits (Coordination of Benefits or Medicare Secondary Payer).): Used when the payer needs the other plan's explanation of benefits, which is often the follow-up once the donor plan has responded.
  • OA-23 (The impact of prior payer(s) adjudication including payments and/or adjustments. (Use only with Group Code OA)): Shows the effect of a prior payer's adjudication once the donor plan has processed its share.

N405 FAQ

Who is the 'donor' in N405?

The person donating an organ, tissue, bone marrow, or similar material. N405 means the service was billed to a plan other than the donor's own, and that plan wants the donor's coverage to respond first.

What if the donor has no insurance?

Tell the payer that the donor has no coverage, in writing if it asks. Many transplant benefits are designed to cover donor costs through the recipient's plan when the donor has none, but the exact rule depends on the plan.

Should I appeal an N405 denial?

Usually not at first. The quicker path is to get a decision from the donor's insurer and send that to this payer. Appeal only if you already supplied that proof and the claim was still denied.