CO-97: Payment Adjusted Due to Bundling Rules
CO (Contractual Obligation)What is CO-97?
CO-97 is a Contractual Obligation code indicating the payment was adjusted because the billed service is included (bundled) in another service or procedure already paid on the same claim. NCCI edits and payer-specific bundling rules are the primary triggers.
Why Does CO-97 Occur?
- NCCI column 1/column 2 edit. The procedure code is bundled into a more comprehensive code on the same claim per CMS NCCI rules.
- Payer-specific bundling rule. The payer has additional bundling logic beyond CMS NCCI that groups the codes together.
- Global surgical package. The service falls within the global surgery period and is included in the surgical fee.
- E/M bundled with procedure. The evaluation and management service on the same day is considered part of the procedure unless modifier 25 is applied.
How to Fix CO-97 Denials
- Check the CMS NCCI editing tool to confirm if the code pair is bundled. Note whether a modifier is allowed to override the edit.
- If a modifier override is permitted, add modifier 59 or the appropriate X-modifier (XE, XS, XP, XU) with documentation supporting the distinct service.
- If the bundling is within the global surgical period, check the postoperative day count. Submit modifier 24 (unrelated E/M during global period) or modifier 79 (unrelated procedure during global period) if the service is clinically unrelated.
- Appeal with operative notes or clinical documentation if the payer denies the unbundled claim.
CO-97 by Payer
| Payer | Common RARC | Appeal Deadline | Notes |
|---|---|---|---|
| UnitedHealthcare | M15 | 60 days from remittance | UHC follows NCCI edits and adds proprietary bundles. Check both. |
| Anthem | M15 | 365 days from denial notice | Anthem's bundling varies by state. Verify with your regional plan. |
| Aetna | M15 | 180 days from denial | Aetna requires documentation for all modifier 59 overrides. |
| Cigna | M15 | 180 days from denial | Cigna's bundling logic may differ from CMS NCCI for certain specialties. |
| Medicare | M15 | 120 days (redetermination at MAC) | CMS NCCI tool is the definitive source. Quarterly updates apply. |
Related CARC Codes
If you are seeing CO-97, check these related codes: CO-4 (incompatible coding), CO-16 (claim differs from payer records), CO-25 (code edit mismatch).
Related CPT Modifiers
Modifier 59 (Distinct Procedural Service), Modifier 25 (Significant, Separately Identifiable E/M).
Common Questions About CO-97
What does bundled mean in medical billing?
Bundling means two or more procedure codes are grouped together because the payer considers them part of a single service. The payment for the comprehensive code includes the bundled code, so only the comprehensive code is reimbursed.
When can I unbundle a CO-97 denial?
You can unbundle when the services were performed at different anatomic sites, during separate encounters, by different providers, or are otherwise clinically distinct. Document the distinction and apply modifier 59 or an X-modifier.
Altair catches CO-97 denials before submission with NCCI bundling analysis. See how pre-submit claim scoring works.