Service partly or fully furnished by another provider
The payer already paid someone else for all or part of this service (for example the facility was paid for the technical component, or another physician was paid for the global surgery).
CO = Contractual Obligation. The provider owes the difference. The patient cannot be billed for this amount. The same reason code can appear with a different group code; the group decides who may be billed.
Usual causes
- Technical and professional components billed by two parties without 26 and TC modifiers.
- Two providers billing the same global surgical package (surgeon and a post-operative care provider without modifiers 54, 55, 56).
- Purchased diagnostic test billed by both the performing and the billing provider.
The fix
Add the correct component or split-care modifier and send a corrected claim. If both claims are complete and yours is correct, appeal with documentation showing who did what.
Appeal or corrected claim?
Corrected claim with modifiers when the split was not shown; appeal with records otherwise.
Deadline to watch
Timely filing limit; appeal window per payer.
Exact limits are in your payer contract or provider manual. When in doubt, send the correction or appeal this week.
CO-B20 in short
What does CO-B20 mean?
The payer already paid someone else for all or part of this service (for example the facility was paid for the technical component, or another physician was paid for the global surgery). The official X12 text reads: "Procedure/service was partially or fully furnished by another provider."
What usually causes a CO-B20 denial?
Technical and professional components billed by two parties without 26 and TC modifiers. Two providers billing the same global surgical package (surgeon and a post-operative care provider without modifiers 54, 55, 56). Purchased diagnostic test billed by both the performing and the billing provider.
How do I fix CO-B20?
Add the correct component or split-care modifier and send a corrected claim. If both claims are complete and yours is correct, appeal with documentation showing who did what.
Should I appeal CO-B20 or send a corrected claim?
Appeal. Corrected claim with modifiers when the split was not shown; appeal with records otherwise.
What deadline applies to CO-B20?
Timely filing limit; appeal window per payer.