OA-100: Payment Made to Patient/Insured
Adjustment in a COB or secondary payer context. Review the coordination of benefits details to determine the responsible party.
What Does OA-100 Mean?
When paired with Group Code OA, CARC 100 (Payment Made to Patient/Insured) 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 100 appears on a remittance when the payer applies an adjustment for payment made to patient/insured. Review the group code and any accompanying RARC codes to understand the full context of this adjustment.
Common scenarios that trigger this adjustment include: the provider did not accept assignment on the claim, so the payer sent the payment directly to the patient or insured per non-assigned billing rules; The patient submitted the claim to their insurance company for reimbursement, and the payer issued payment to the patient rather than the provider; The provider is out of network, and the payer's policy is to reimburse the member directly for out-of-network services rather than paying the provider. The group code paired with CARC 100 determines who bears the financial responsibility — OA indicates a coordination of benefits or other payer adjustment, CO places it on the provider as a contractual obligation, PR shifts it to the patient.
Common Causes
| Cause | Frequency |
|---|---|
| Non-assigned claim — payment sent to patient The provider did not accept assignment on the claim, so the payer sent the payment directly to the patient or insured per non-assigned billing rules | Most Common |
| Patient filed the claim directly The patient submitted the claim to their insurance company for reimbursement, and the payer issued payment to the patient rather than the provider | Common |
| Out-of-network provider — payment to member The provider is out of network, and the payer's policy is to reimburse the member directly for out-of-network services rather than paying the provider | Common |
| Assignment of benefits not on file The payer does not have an assignment of benefits (AOB) from the patient directing payment to the provider, so payment defaults to the patient | Common |
How to Resolve
- Review the coordination of benefits Examine the OA-100 adjustment to understand how it fits within the primary/secondary payer relationship or other multi-payer context.
- Verify primary payer adjudication Review the primary payer's EOB to understand the basis for the secondary payer's OA adjustment.
- 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.
- Follow up Monitor the claim status and take additional action as needed based on the COB determination.
This is not a denial. The claim was processed and paid, but payment was issued to the patient/insured. Collect the payment from the patient. To prevent this in the future, ensure assignment of benefits is on file.
Common RARC Pairings
The RARC code tells you exactly what triggered the OA-100:
| RARC | Description |
|---|---|
| N381 | Payment was issued to the patient/insured. Contact the patient to collect your payment. Contact the patient to collect the payment that was sent to them by the insurer → |
| N19 | Claim is covered but payment has been made to the insured Bill the patient for the amount that was paid to them by their insurance → |
How to Prevent OA-100
- Obtain and file assignment of benefits (AOB) forms from all patients at registration
- Verify that AOB is on file with the payer before claim submission
- For non-participating providers, clearly communicate to patients that payment may be sent to them
- Implement a process to check assignment status during the claim submission workflow
- Educate patients about assignment of benefits and why it benefits them to assign benefits to the provider
Also Filed As
The same CARC 100 may appear with different Group Codes:
Related Denial Codes
Sources
- https://www.cms.gov/medicare/claims-appeals/organization-determinations
- https://www.aapc.com/resources/claim-adjustment-reason-code-carc
- https://www.mdclarity.com/denial-code/100
- Codes maintained by X12. Visit x12.org for official definitions.