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CO-17 Denial Code (Deactivated): Requested Info Missing

CO-17 meant the payer asked for information and it was not sent, or what arrived was incomplete. A remark code had to explain what was missing. X12 deactivated it; payers now use codes such as 226, 227, and 228 depending on who owed the information.

X12 deactivated CARC17 on July 1, 2009. Payers should no longer use it on new remittances, but it can still appear on older ERAs, corrected claims, and appeals.

Quick facts

Code
CO-17 (CARC 17)
Status
Deactivated StoppedJuly 1, 2009 (in use since January 1, 1995).
Code set
Claim Adjustment Reason Codes (CARC)
Group codes
  • CO (Contractual Obligation): The provider carried the adjustment because the requested information had not been supplied.
Official description
Requested information was not provided or was insufficient/incomplete. At least one Remark Code must be provided (may be comprised of either the Remittance Advice Remark Code or NCPDP Reject Reason Code.)
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What CO-17 meant

CARC 17 was a follow-up denial. The payer had already asked for something, such as medical records, an accident questionnaire, or an itemized bill, and either nothing came back or the response did not answer the question. The code itself never said what was requested. That detail lived in the remark code the payer was required to attach.

What replaced it

The official text does not name one replacement, but today’s code set separates these denials by who was supposed to respond:

  • CO-226 for information the billing or rendering provider did not send, sent late, or sent incomplete.
  • CO-227 for information owed by the patient, insured, or responsible party.
  • CO-228 when the missing information was owed to a prior payer.

If the problem is simply a gap on the claim form rather than an unanswered request, payers generally use CO-16 instead.

If you still see CO-17

Old ERAs and aged A/R reports are the usual source. If a payer is still sending CO-17 on current claims, ask them which active code they intend and what exactly they are waiting for.

For the claim itself, find the original request letter or portal message, gather the requested documents, and send them using the payer’s attachment or correspondence process, referencing the claim number. If the patient was the one who needed to respond, contact them and help them complete it. Keep proof of what you sent and when, since a missed response window is often the reason these denials stick.

  • CO-226 (Information requested from the Billing/Rendering Provider was not provided or not provided timely or was insufficient/incomplete.): Information requested from the billing or rendering provider was not provided, late, or insufficient.
  • CO-227 (Information requested from the patient/insured/responsible party was not provided or was insufficient/incomplete.): Information requested from the patient or insured was not provided or was incomplete.
  • CO-228 (Denied for failure of this provider, another provider or the subscriber to supply requested information to a previous payer for their adjudication): A provider or subscriber failed to supply information to a previous payer.
  • CO-16 (Claim/service lacks information or has submission/billing error(s).): Information missing from the claim itself, rather than from a follow-up request.

CO-17 FAQ

How is CO-17 different from CO-16?

CO-16 points to data missing from the claim as submitted. CO-17 was about a separate request the payer made afterward, such as a records request or questionnaire, that went unanswered or was answered incompletely.

What should I look at first on an old CO-17 denial?

The remark code that came with it. CO-17 required at least one, and that remark is the only place the ERA told you what document or data the payer wanted.