CO-B20: Service Partially or Fully Furnished by Another Provider
CO-B20 means another provider already billed for this service. Use appropriate modifiers to distinguish your portion or coordinate billing to resolve the overlap.
What Does CO-B20 Mean?
When paired with Group Code CO, the overlapping provider billing is a contractual adjustment. The provider absorbs the denied portion and cannot collect from the patient. Rebill with proper modifiers if the provider furnished a distinct portion of the service.
CARC B20 indicates the payer denied or reduced the claim because another provider has already billed for part or all of the same service for the same patient on the same date. The payer detected an overlap in billing between two providers.
This commonly occurs with shared surgical services where multiple surgeons or assistants participated, transfer of care situations where both the outgoing and incoming providers billed for overlapping services, facility vs. professional component overlap, and locum tenens billing conflicts.
The resolution depends on the nature of the overlap. If the providers genuinely shared the service, appropriate modifiers must be used to distinguish each provider's contribution. If one provider's billing was in error, the incorrect claim should be corrected or withdrawn.
Common Causes
| Cause | Frequency |
|---|---|
| Another provider already billed for the service A different provider has already submitted and been paid for the same or substantially similar service for the same patient on the same date | Most Common |
| Shared surgical services not properly coordinated Multiple providers participated in a surgical procedure but billing was not coordinated with appropriate modifiers (62, 66, 80, 81, 82) | Common |
| Transfer of care billing overlap During a transfer of care, both the transferring and receiving providers billed for services that overlap in time or scope | Common |
| Facility and professional component overlap The facility billed the global service while the physician also billed the technical or professional component, creating an overlap | Common |
| Locum tenens billing conflict Both the regular physician and locum tenens billed for services on the same date without proper modifier usage | Occasional |
How to Resolve
- Identify the overlap Determine which provider billed and what services overlap.
- Apply correct modifiers Use modifiers 62, 80, 81, TC, or 26 as appropriate.
- Coordinate billing Work with the other provider to resolve the overlap.
- Resubmit with documentation Rebill with operative reports showing your provider's distinct contribution.
Appeal with documentation showing the specific portion of the service your provider furnished. Include operative reports, procedure notes, and modifier documentation (62 for co-surgery, 80/81 for assistant surgeon). If the services were distinct, provide documentation differentiating the two providers' contributions.
Common RARC Pairings
The RARC code tells you exactly what triggered the CO-B20:
| RARC | Description |
|---|---|
| M86 | Service denied because payment already made for same/similar procedure within set time frame. Identify the other provider's claim and determine if modifiers are needed to distinguish the services → |
| M15 | Separately billed services/tests have been bundled. Review bundling rules between providers sharing a service → |
How to Prevent CO-B20
- Coordinate billing with other providers involved in shared or transferred care
- Use appropriate surgical modifiers (62, 66, 80, 81, 82) for shared surgical services
- Verify whether another provider has already billed before submitting your claim
- Implement transfer of care protocols that clearly define billing responsibilities
- Use the TC (technical component) and 26 (professional component) modifiers correctly for split billing
Also Filed As
The same CARC B20 may appear with different Group Codes:
Related Denial Codes
Sources
- https://x12.org/codes/claim-adjustment-reason-codes
- https://www.cms.gov/regulations-and-guidance/guidance/manuals
- Codes maintained by X12. Visit x12.org for official definitions.