Denial code · group CO
CO-226: The payer asked you for records or information and did not get a usable response
Short answer
CO-226 means the payer had asked the billing or rendering provider for something, usually medical records, an invoice or a completed questionnaire, and the response was late, incomplete or never arrived. It often follows a CO-252 or a development letter that nobody acted on. Send exactly what was requested through the channel the payer named, with the claim number, and ask for a reopening or file a reconsideration.
Look up other codes in the denial code library.
Last reviewed by the Remitwright billing team. Editorial policy
Group CO means contractual obligation: the balance is written off, not billed to the patient. The number is the reason; the two-letter group says who carries the balance.
Remark codes that usually come with CO-226
- N4
- The explanation of benefits from the prior insurer is missing, incomplete or not valid
Common causes
The request letter never reached the person who works denials
Development letters go to the correspondence address on the payer's enrollment record, which is often an old suite, a lockbox or a former billing company. The deadline passes while the letter sits in a pile, and the claim denies.
The records sent were incomplete
The visit note went without the order, the plan of care went without the signature page, or the pages covered the wrong date of service. The payer treats a partial packet as no response and does not call to ask for the rest.
The response arrived after the payer's deadline
Each letter states a response window. Records faxed a few days late are logged as untimely and the claim denies CO-226 even though the payer now has everything.
The response went through the wrong channel
Records faxed to the general provider services number instead of the medical review fax, uploaded to the wrong portal queue, or mailed when the letter asked for a portal upload do not get matched to the claim.
The request was for something other than clinical records
Payers also ask providers for the primary payer's EOB on a secondary claim, an itemized invoice for a drug or DME item, an accident questionnaire, or a certificate of medical necessity. Each of these, unanswered, produces the same code.
How to fix it and resubmit
- 1
Retrieve the original request before sending anything
Find the letter in the payer portal or ask provider services to read it to you. You need the exact list of items, the claim numbers it covered, the deadline and the submission route. Guessing at what was wanted produces a second CO-226.
- 2
Build the packet the letter asked for
Signed and dated notes for the dates of service, the order or referral, the authorization, the invoice or the EOB, with the claim number and patient identifier on every page. Include a cover sheet listing what is enclosed.
- 3
Submit through the payer's reopening or appeal route
Most payers treat CO-226 as appealable once the documentation is attached: a reopening or reconsideration request with the records, filed inside the appeal window. A corrected claim without records returns the same denial.
- 4
Do not send a new claim
A fresh claim for the same service hits the duplicate edit and comes back CO-18. It also does nothing to answer the records request, which stays open against the original claim.
- 5
Keep proof of the response
Save the fax confirmation, portal receipt or tracking number with the claim. If the payer says the records were not received, that proof is what gets the claim reopened.
How to prevent it
- Correspondence address, fax and portal contacts kept current with every payer, and incoming payer mail opened by someone who logs records requests the same day
- A records-request log with claim numbers, items requested, due date, owner, send date and proof of transmission
- Pre-built documentation packets for the service types payers review most, such as DME orders and proof of delivery, therapy plans of care and daily notes, and home care visit notes with the signed plan of care
- Secondary claims sent with the primary payer's 835 data attached so the EOB is never requested after the fact
A CO-226 on home care visits after a missed letter
A home care agency receives a payer letter asking for visit notes and the signed plan of care for a month of home health aide visits. The letter goes to the agency's previous address and is forwarded weeks later, after the deadline. The claims deny CO-226. The biller pulls the letter from the payer portal, assembles the notes and the signed plan of care with each claim number, files a reconsideration through the portal, and updates the correspondence address on the agency's enrollment record. This is a hypothetical example.
Official text: the X12 claim adjustment reason code list. The meaning above is our paraphrase for billers; the list is the authority.
FAQ
Questions about CO-226
Is CO-226 a final denial?
What is the difference between CO-226 and CO-252?
Should I resubmit the claim with the records?
Can the patient be billed for a CO-226?
How do I prove the records were sent on time?
Next step
Seeing a lot of CO-226?
Tell us the payer and the volume. Three quick questions, no patient data, a written answer from a biller who works that queue.
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While you wait: see the sample weekly report or read how to work claim denials. You can also download the sample weekly report (PDF).