CO-P8: Claim Under Investigation — P&C Only
CO-P8 means the claim is under investigation. Cooperate with the investigation, respond to requests, and redirect to health insurance in the interim.
What Does CO-P8 Mean?
When paired with Group Code CO, the investigation hold prevents the carrier from processing the claim. This is a temporary status — payment may be released after the investigation. Cooperate with the investigation and redirect to health insurance in the interim.
CARC P8 applies to property and casualty claims and indicates the claim is under investigation, with payment withheld pending the outcome. The investigation may involve potential fraud review, liability determination, Special Investigation Unit (SIU) referral, or subrogation investigation to determine if another party is liable.
This is a hold status, not a final denial. Payment may be released once the investigation concludes favorably. The provider should cooperate fully with the investigation, respond promptly to requests for information, and consider billing the patient's health insurance in the interim if the investigation is expected to take an extended period.
Common Causes
| Cause | Frequency |
|---|---|
| Fraud investigation The P&C carrier has flagged the claim for potential fraud investigation and payment is withheld pending the outcome | Most Common |
| Liability investigation The carrier is investigating liability (fault) for the incident and cannot process the claim until liability is determined | Most Common |
| Special Investigation Unit (SIU) referral The claim was referred to the carrier's SIU for review due to suspicious patterns, unusual charges, or other red flags | Common |
| Subrogation investigation The carrier is investigating whether another party is liable, potentially allowing subrogation recovery | Common |
How to Resolve
- Contact adjuster Get investigation details and timeline.
- Respond to requests Provide documentation promptly.
- Redirect to health insurance Bill health insurance in the interim.
- Monitor status Follow up regularly.
- Appeal if denied Appeal the denial after investigation concludes if warranted.
If the investigation results in a denial, appeal with documentation supporting the legitimacy of the claim. Include all medical records, billing documentation, and any evidence contradicting the investigation findings. File through the P&C carrier's formal appeal process.
Common RARC Pairings
The RARC code tells you exactly what triggered the CO-P8:
| RARC | Description |
|---|---|
| N381 | Alert: Consult your contractual agreement for restrictions, billing, and payment information. Contact the P&C adjuster for investigation details and timeline → |
How to Prevent CO-P8
- Submit complete and accurate claims documentation to avoid triggering investigation flags
- Bill at rates consistent with standard charges to avoid fraud flags
- Maintain thorough documentation of all services provided
- Respond promptly to carrier requests for additional information to minimize investigation duration
- Ensure compliance with all P&C billing regulations
Also Filed As
The same CARC P8 may appear with different Group Codes:
Related Denial Codes
Sources
- https://x12.org/codes/claim-adjustment-reason-codes
- https://www.cms.gov/medicare/coordination-benefits
- Codes maintained by X12. Visit x12.org for official definitions.