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N490 Remark Code: Referral Form Incomplete or Invalid

N490 means the payer received a referral form but found it incomplete or invalid for the claim. The referral may have expired, named a different provider, covered other services or fewer visits, or lacked required information such as a signature or date.

Quick facts

Code
N490 (RARC N490)
Status
Active In use since July 1, 2008; last modified March 14, 2014.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The provider should resolve the referral problem. Under most network contracts the amount is not billable to the patient.
  • PR (Patient Responsibility): Occasionally assigned to the member when the plan decides the member did not follow referral rules. Confirm plan rules before billing.
Official description
Incomplete/invalid referral form.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N490 means

There is a referral, but it does not cover this claim. N490 separates that situation from N489, where no referral exists at all. Referrals are specific: they typically name the provider or group, a date range, and sometimes a number of visits or a type of service. When the claim falls outside any of those limits, the plan treats the referral as invalid for that service.

Common causes

  • Expired dates. The visit happened after the referral’s end date.
  • Wrong provider. The referral named a different specialist, location, or group NPI than the one on the claim.
  • Visits used up. Earlier claims consumed all the visits the referral allowed.
  • Scope mismatch. The referral covered a consultation, but the claim includes procedures or testing.
  • Missing elements. No signature, date, diagnosis, or referral number where the plan requires one.

How to fix it

  1. Compare the referral to the claim field by field: patient, referring and receiving provider, dates, visit count, and scope.
  2. Correct the claim if the error is on your side, such as the wrong referring provider in box 17 or a mistyped referral number.
  3. Ask the referring office for an updated referral if the original was too narrow or expired. Confirm whether the plan will apply it to past dates.
  4. Resubmit with a corrected claim (resubmission code 7 in box 22) or through the plan’s reconsideration process.
  5. Appeal if the referral was valid as written and the plan misapplied it.

How to prevent it

Record each referral’s end date, visit limit, and scope in the practice management system, and warn schedulers when a patient is close to either limit. Front-desk checks against the plan portal catch most N490 issues before the visit.

Codes that may appear with N490

  • CO-288 (Referral absent): The plan treats the service as lacking a valid referral.
  • CO-287 (Referral exceeded): The referral existed but the services billed went beyond it.
  • CO-251 (The attachment/other documentation that was received was incomplete or deficient.): The referral document was received but was deficient.
  • N489 (Missing referral form.): No referral form was received.
  • N476 (Incomplete/invalid completed referral form.): Incomplete or invalid completed referral form, a near-identical remark.
  • N335 (Missing/incomplete/invalid referral date.): Only the referral date is missing or invalid.

N490 FAQ

What makes a referral invalid?

Typical reasons include an expired referral, a named specialist or group different from the billing provider, a visit limit already used, services outside the referral's scope, or missing signatures or dates.

Can the referral be extended?

Usually the referring provider can request an extension or issue a new referral. Whether it applies to dates already past depends on the plan.

Should I rebill the claim after fixing the referral?

Follow the plan's instructions. Some reprocess automatically once a valid referral is on file; others want a corrected claim or reconsideration request.