CO-226 fires when the payer requested information about the provider — licence, enrolment, revalidation, ownership disclosure — and did not receive it within its window. It attaches to the claim but originates in the enrolment relationship.
What CO-226 means
Payers periodically revalidate provider records, and the requests go to the address on the enrolment file rather than to the billing address. When they lapse, claims begin denying with codes that look like claim problems. Nothing on the claim can fix it. Restoring the enrolment record is the resolution, and until it is restored every claim will deny the same way.
Why CO-226 fires
- A revalidation or credentialing request lapsed unanswered.
- The request went to the enrolment address on file rather than the billing address.
- A licence or certification on file expired and was not updated.
- An ownership or disclosure update the payer requires was not filed.
Is CO-226 worth appealing?
Sometimes worth appealing
How to resolve or appeal CO-226
- 1
Contact provider enrolment, not claims
Establish what is outstanding and when it was requested.
- 2
Ask for bulk reprocessing
Once the record is current, request reprocessing of every claim denied for this reason rather than resubmitting individually.
CO-226 — frequently asked
Why did claims start denying without warning?
Will resubmitting help?
Reason-code meanings are paraphrased from the X12 Claim Adjustment Reason Code list for plain-language reference; they are not reproduced verbatim. This is general information, not legal, coding, or medical advice — always confirm against the payer's remittance and policy.
Turn this CO-226 denial into a signed appeal
Upload the denied EOB and Merits builds a complete CO-226 appeal — the argument, the payer's own coverage criteria, and your federal appeal rights, every claim cited to a named source. $9 a letter. No account.