Skip to main content

N480 Remark Code: Primary EOB Incomplete or Invalid

N480 means the secondary payer received the primary payer's explanation of benefits but could not use it. The EOB may be for the wrong patient, dates, or services, may be missing pages or amounts, or may not agree with the claim.

Quick facts

Code
N480 (RARC N480)
Status
Active In use since July 1, 2008.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The payer could not complete secondary processing because the prior payer information was unusable. The provider should correct it.
  • OA (Other Adjustment): Reported by some payers as an other adjustment tied to coordination of benefits data. Correct and resubmit rather than billing the patient.
Official description
Incomplete/invalid Explanation of Benefits (Coordination of Benefits or Medicare Secondary Payer).
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N480 means

You did send primary payer information, but the secondary payer rejected it as incomplete or invalid. This is the companion to N479 (EOB missing entirely). The payer is still trying to coordinate benefits, either between two regular plans or under Medicare Secondary Payer rules, and it cannot calculate its share from what arrived.

Common causes

  • Line mismatch. The EOB shows different procedure codes, modifiers, units, or dates than the secondary claim.
  • Wrong document. An EOB for another patient, another date, or an earlier processing of the claim was attached.
  • Partial copy. Pages with the payment summary or adjustment codes were cut off.
  • Electronic data errors. Other-payer amounts in the 837 do not balance, for example paid plus adjustments not equaling the billed charge.
  • Stale information. The primary later reprocessed the claim, and the secondary received the outdated version.

How to fix it

  1. Pull the primary’s current remittance and compare it line by line to the secondary claim.
  2. Correct whichever side is wrong. If your secondary claim differs from what the primary processed, correct the claim. If the primary processed it incorrectly, resolve that with the primary first.
  3. Check the math on electronic COB data so each line’s billed charge, primary payment, and adjustments reconcile.
  4. Resubmit as a corrected claim (resubmission code 7 in box 22 on paper, or the electronic equivalent) or through the payer’s attachment process.
  5. Keep a copy of exactly what was sent in case you need to appeal.

How to prevent it

Post the primary remittance before creating the secondary claim so the COB data comes from actual adjudication, not from what you expected to be paid. An ERA Analyzer review of secondary denials can show whether N480 is clustering around one primary payer or one billing workflow.

Codes that may appear with N480

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): The claim had invalid information, and the invalid element is the prior payer EOB data.
  • CO-251 (The attachment/other documentation that was received was incomplete or deficient.): The attachment received, here the EOB, was incomplete or deficient.
  • OA-22 (This care may be covered by another payer per coordination of benefits.): The payer is coordinating benefits with another plan and still needs usable primary results.
  • N479 (Missing Explanation of Benefits (Coordination of Benefits or Medicare Secondary Payer).): No EOB was received at all.
  • N48 (Claim information does not agree with information received from other insurance carrier.): The claim does not agree with information received from the other insurance carrier.
  • N245 (Incomplete/invalid plan information for other insurance.): Plan information for the other insurance is incomplete or invalid.
  • N4 (Missing/Incomplete/Invalid prior Insurance Carrier(s)): The general prior-carrier EOB remark, used by many payers in place of N479 or N480.

N480 FAQ

What does the secondary payer check on the primary EOB?

Typically the patient and subscriber, dates of service, service lines, billed and allowed amounts, the primary's payment, patient responsibility, and the adjustment reason codes. Any mismatch with the secondary claim can trigger N480.

Can I just resend the same EOB?

Only if the problem was a missing page or unreadable copy. If the EOB lines do not match your claim, fix the claim or get the correct EOB first.

Does N480 mean the secondary plan will not pay?

No. It means secondary processing stopped because the primary information was not usable. Once corrected, the claim can be reconsidered under the patient's secondary benefits.