What does denial code CO-226 mean?

CO-226 means the payer requested additional information from the provider and did not receive it within its response window. The claim was never adjudicated on its merits, so the service itself may well have been payable.

Can I still get paid after a CO-226 denial?

Often yes. Find the original request, send exactly what was asked in the format the payer specified, and submit it against the claim. If the response window has closed, file an appeal with the documentation attached and explain why the request went unanswered.

CO-226: Requested information was not received from the provider

CO-226 is entirely self-inflicted and entirely avoidable, which is what makes it worth tracking as a process metric rather than a denial category. The payer asked for records and nobody answered inside the window. The claim was not judged on its merits at all, so the underlying service may well have been payable. The recovery is straightforward - send what was asked - but the window for doing so is narrower than a standard appeal deadline and closes quietly.

What it means: The payer asked the billing or rendering provider for additional information and did not receive it within its response window.
Who pays the balance: Contractual - failing to respond to a documentation request is an administrative lapse on the provider's side.
Group code CO: Contractual Obligation - the provider absorbs the balance and cannot bill the patient

Why CO-226 happens

The records request went to an address or fax the practice no longer monitors.
The request was received but routed to a queue nobody owns, such as a general correspondence inbox.
Records were sent but not in the format or to the destination the payer specified, so they were never matched to the claim.
The request named specific documentation and the response sent something else, which the payer treats as no response.
The response was sent after the payer's response window had already closed.

How to fix a CO-226 denial

1
Locate the original request and read exactly what was asked
Payers deny for a non-responsive answer as readily as for no answer. Sending the whole chart when a specific operative note was requested often fails a second time.
2
Submit the documentation the way the payer specified
Portal upload, a specific fax line, and a claim-specific cover sheet are frequently required for records to be matched to the claim. Sending correctly addressed records the wrong way loses them.
3
Appeal with the records if the response window has closed
Once the window is gone, the route is an appeal rather than a records submission. Include the documentation and explain that the original request was not received or not routed.
4
Find out where the request went
This denial repeats until the intake gap is closed. Confirm the addresses and fax numbers the payer has on file for medical records requests and correct them.

Deadlines depend on the payer

Filing limits and appeal windows for CO-226 vary by payer and often by plan type within the same payer. Look up the specific payer to see its verified deadlines and the source document they came from.

Browse payer billing references

Preventing CO-226 denials

Maintain a single owned queue for payer correspondence with an accountable owner and a service level, rather than a shared inbox.
Verify the records request address and fax number each payer holds for the practice and update them after any move.
Log every records request against the claim so an unanswered one is visible before the response window closes.

CO-226 frequently asked questions

What does denial code CO-226 mean?: CO-226 means the payer requested additional information from the provider and did not receive it within its response window. The claim was never adjudicated on its merits, so the service itself may well have been payable.
Can I still get paid after a CO-226 denial?: Often yes. Find the original request, send exactly what was asked in the format the payer specified, and submit it against the claim. If the response window has closed, file an appeal with the documentation attached and explain why the request went unanswered.

Related denial codes

CO-16 CO-252 CO-50 CO-197

Last reviewed August 5, 2026.

Denial code explanations are original plain-English summaries written for reference and are not the official X12 code descriptions. Payer handling of any code varies by contract - always verify against the remittance advice and your payer agreement before adjusting a claim.