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CO-250 Denial Code: Wrong Attachment Received

CO-250 means the attachment or other documentation the payer received was the wrong document, and the expected attachment is still missing. A remark code identifies what the payer actually needs.

Quick facts

Code
CO-250 (CARC 250)
Status
Active In use since September 30, 2012; last modified June 1, 2014.
Code set
Claim Adjustment Reason Codes (CARC)
Group codes
  • CO (Contractual Obligation): The provider is responsible for sending the correct documentation. The amount generally cannot be billed to the patient.
Official description
The attachment/other documentation that was received was the incorrect attachment/document. The expected attachment/document is still missing. At least one Remark Code must be provided (may be comprised of either the NCPDP Reject Reason Code, or Remittance Advice Remark Code that is not an ALERT).
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What CO-250 means

CARC 250 says the attachment or other documentation that was received was the incorrect attachment or document. The expected attachment is still missing. Something did arrive, and the payer looked at it, but it was not what the claim or the payer’s request called for.

This usually comes from a workflow slip rather than a clinical problem: the wrong file was uploaded, pages from another patient’s chart were attached, or a standard cover letter was sent in place of the actual record. X12 requires a remark code, which tells you which document the payer is still waiting for.

Example: a payer asks for the operative report for a surgical claim. The practice uploads the office visit note from the same date. The claim is denied CO-250 with a remark code for the missing medical record.

Common causes

  • Wrong document selected from the chart or document management system.
  • Wrong patient’s document attached, which is also a privacy concern.
  • Attachment control number mismatch, so the payer linked the claim to a different submission.
  • Generic packet sent, such as a cover letter or face sheet, instead of the requested record.
  • Misreading the request, such as sending an invoice when a certificate of medical necessity was needed.

How to fix it

  1. Read the remark code and any request letter to identify the exact document needed.
  2. Check what you sent. If another patient’s information was sent, involve your privacy officer.
  3. Send the correct document through the payer’s attachment channel, with the claim number and attachment control number matching the claim (the 837 PWK segment for electronic claims).
  4. Ask how the payer will reopen the claim: automatically on receipt, via corrected claim, or through a reconsideration.
  5. Track the resubmission and follow up if the claim is not reprocessed in a reasonable time.

How to prevent it

  • Use a checklist for common attachment types that shows exactly which document each request needs.
  • Confirm patient name, date of service, and document type before uploading.
  • Generate attachment control numbers systematically and match them to the PWK segment on the claim.
  • Have a second person review high-dollar attachment submissions.
  • See CO-16 missing or invalid information for related documentation and data problems.

Remark codes that may appear with CO-250

  • M127 (Missing patient medical record for this service.): The payer needs the medical record for the service.
  • N706 (Missing documentation.): The expected documentation is missing.
  • N753 (Missing/incomplete/invalid Attachment Control Number.): The attachment control number is missing, incomplete, or invalid, so the payer may have matched the wrong document.
  • CO-251 (The attachment/other documentation that was received was incomplete or deficient.): The right type of document arrived but was incomplete or deficient.
  • CO-252 (An attachment/other documentation is required to adjudicate this claim/service.): An attachment is required and none has been received yet.
  • CO-163 (Attachment/other documentation referenced on the claim was not received.): An attachment referenced on the claim was not received at all.
  • CO-226 (Information requested from the Billing/Rendering Provider was not provided or not provided timely or was insufficient/incomplete.): Information requested from the provider was not provided or was insufficient.

CO-250 FAQ

How is CO-250 different from CO-251?

CO-250 means the document was the wrong one entirely, like an invoice sent when an operative report was needed. CO-251 means the right kind of document arrived but was missing pages or information.

What does the payer want after a CO-250?

Check the remark code. It names the document still needed, such as medical records, an itemized bill, or a certificate of medical necessity.

Do I need to resubmit the claim?

It depends on the payer. Some reopen the claim when the correct attachment arrives with the right reference number; others want a corrected claim or reconsideration. Follow the payer's instructions.

Can the wrong attachment cause a privacy breach?

Yes, if it contained another patient's information. Report it to your privacy officer, who can decide whether breach notification rules apply.