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N226 Remark Code: Invalid ADA Certificate of Recognition

N226 means the American Diabetes Association (ADA) Certificate of Recognition supplied for the diabetes self-management training program was incomplete or invalid, so the payer could not confirm the program's accreditation.

Quick facts

Code
N226 (RARC N226)
Status
Active In use since August 1, 2004.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The training was denied because program accreditation could not be verified. The provider must resolve it; the patient should not be billed.
Official description
Incomplete/invalid American Diabetes Association Certificate of Recognition.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N226 means

Diabetes self-management training (DSMT) is usually covered only when delivered by an accredited program. The ADA’s Education Recognition Program is one of the recognised accreditations, and the certificate is the proof. N226 says the certificate the payer has, or the one you sent, is incomplete or no longer valid.

The remark tends to pair with CARC B7, which says the provider was not eligible for payment on that date, or with CARC 252.

Common causes

  • The recognition period expired before the date of service and renewal was pending or lapsed.
  • The certificate lists a parent organisation or another site rather than the billing entity or location.
  • The payer’s enrollment file has an outdated certificate.
  • The copy sent was partial or illegible.

How to fix it

  1. Check the recognition dates and the site listed on your current certificate.
  2. If recognition was active on the date of service, send the payer a complete copy and ask it to update its file.
  3. If the certificate covers a different site or entity, work with the accrediting organisation to confirm which locations are recognised.
  4. Once the payer’s records are updated, request reprocessing or submit a corrected claim with resubmission code 7.
  5. If recognition had lapsed, services in that gap are unlikely to be payable; review with your compliance lead.

How to prevent it

Track accreditation expiry dates and begin renewal early. When the program adds a site or changes its legal entity, confirm with both the accrediting body and payers that the new arrangement is recognised before billing.

Codes that may appear with N226

  • CO-B7 (This provider was not certified/eligible to be paid for this procedure/service on this date of service.): The provider was not certified or eligible to be paid for this service on the date of service.
  • CO-252 (An attachment/other documentation is required to adjudicate this claim/service.): Documentation, the accreditation certificate, is required to adjudicate the claim.
  • CO-16 (Claim/service lacks information or has submission/billing error(s).): The claim or its support has an information error.
  • M142 (Missing American Diabetes Association Certificate of Recognition.): The ADA Certificate of Recognition was missing entirely.
  • CO-170 (Payment is denied when performed/billed by this type of provider.): Payment denied when performed or billed by this type of provider.

N226 FAQ

Why do payers need the ADA certificate?

Many payers, including Medicare, cover diabetes self-management training only from programs accredited by a recognised national organisation. The ADA's recognition is one such accreditation.

What makes the certificate invalid?

An expired recognition period, a certificate issued to a different entity or location, or a copy that is missing identifying details.

What if our program is accredited by another organisation?

Some payers also accept accreditation from the Association of Diabetes Care and Education Specialists. Send that accreditation and ask the payer to update its records.