CARC 163: Attachment/other documentation referenced on the claim was not received.
Attachment/other documentation referenced on the claim was not received.
CARC 163 is the code your insurance company used to explain why your claim was reduced, denied, or paid less than expected. It appears on your Explanation of Benefits (EOB) — the statement your plan sends after a claim is processed. Here's what it means for you and what you can do about it.
What CARC 163 means
The official X12 description is: “Attachment/other documentation referenced on the claim was not received.”
In plain language: Attachment/other documentation referenced on the claim was not received.
What to do next 163
Appeal with documentation specific to this code. The provider's billing office can help clarify what the carrier wants.
DenialHelp helps organize a source-linked draft from the denial notice and confirmed case facts. The patient and treating clinician must verify the governing review rule, current payer policy, clinical sources, attachments, destination, and deadline.
CARC 163 group codes explained
On the 835 ERA, CARC 163 appears alongside a group code that signals who is financially responsible for the adjustment. CO (Contractual Obligation) — Contractual write-off. The provider agreed to the rate. Patient does NOT owe this amount.
Frequently asked questions
What does CARC 163 mean?
Attachment/other documentation referenced on the claim was not received. In plain language: Attachment/other documentation referenced on the claim was not received.
Is CARC 163 appealable?
Yes — CARC 163 is one of the codes that commonly supports an appeal. Appeal with documentation specific to this code. The provider's billing office can help clarify what the carrier wants.
Which group code does CARC 163 appear under?
CARC 163 most often appears under: CO (Contractual Obligation) — Contractual write-off. The provider agreed to the rate. Patient does NOT owe this amount.
How do I appeal a CARC 163 denial?
Appeal with documentation specific to this code. The provider's billing office can help clarify what the carrier wants.
Related resources
Sources
Appeal a CARC 163 denial
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