OA-163: Attachment/Documentation Referenced on Claim Not Received

What Does OA-163 Mean?

When paired with Group Code OA, CARC 163 (Attachment/Documentation Referenced on Claim Not Received) is processed as an adjustment outside the standard CO/PR classifications. This typically occurs in secondary payer or coordination of benefits scenarios. Review the remittance details and the COB arrangement to determine financial responsibility and appropriate next steps.

CARC 163 is used when the payer determines that attachment/documentation referenced on claim not received. The claim could not be processed as submitted because required information was absent, incomplete, or did not meet the payer's submission standards.

Common scenarios that trigger this adjustment include: the claim indicated that supporting documentation was attached, but the payer did not receive the referenced attachment with the electronic or paper claim; The documentation was sent separately from the claim and was lost, misfiled, or not linked to the claim during payer processing; The attachment control number on the claim does not match the control number on the submitted documentation, preventing the payer from linking them. The group code paired with CARC 163 determines who bears the financial responsibility — CO places it on the provider as a contractual obligation, OA indicates a coordination of benefits or other payer adjustment, PR shifts it to the patient.

How to Resolve

1. Review the coordination of benefits Examine the OA-163 adjustment to understand how it fits within the primary/secondary payer relationship or other multi-payer context.
2. Verify primary payer adjudication Review the primary payer's EOB to understand the basis for the secondary payer's OA adjustment.
3. Determine the responsible party Based on the COB review, identify whether the adjustment should be absorbed, billed to another payer, or if additional documentation is needed.
4. Appeal or resubmit if needed If the OA adjustment appears incorrect based on the COB arrangement, submit an appeal or corrected claim with the appropriate documentation.
5. Follow up Monitor the claim status and take additional action as needed based on the COB determination.

How to Prevent OA-163

• Maintain accurate coordination of benefits information
• Verify secondary payer requirements before claim submission

Also Filed As

The same CARC 163 may appear with different Group Codes:

Related Denial Codes