Claim adjustment reason code
Denial code CO-163 meaning
CARC 163, usually seen as CO-163: An attachment or record referenced on the claim did not arrive.
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- Reason code
- CARC 163
- Short name
- Attachment not received
- Plain meaning
- An attachment or record referenced on the claim did not arrive.
- Group codes
- CO-163: Contractual obligation. The provider absorbs the amount under its contract or the payer's rules. Do not bill the patient for it.
Plain-English summary written by Rivvi. X12 owns the CARC list and its exact wording, which is not reproduced here. Read it on the X12 CARC list (list dated November 1, 2025, checked October 23, 2026). This page does not decide how a claim is paid.
Common causes
- The paperwork indicator was set but the attachment was not sent, or did not match the claim.
What to check before resubmitting
- Send the attachment with the claim's control number and the payer's attachment ID.
Related reason codes
Related pages
Questions
What does denial code CO-163 mean?
An attachment or record referenced on the claim did not arrive. This is Rivvi's plain-English summary of CARC 163. X12's exact wording is on x12.org.
How do I fix CO-163?
Send the attachment with the claim's control number and the payer's attachment ID.
Can I bill the patient for CO-163?
With group code CO, no. CO means the provider absorbs the amount under its contract or the payer's rules.
Which group codes come with CARC 163?
Most often CO (contractual obligation). The group code, not the reason code, says who owes the amount.
What is the difference between a CARC and a RARC?
A claim adjustment reason code (CARC) says why a claim line was paid differently than billed. A remittance advice remark code (RARC) adds detail, such as which field is missing.