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When can I use modifier 59 to override a CO-97 denial?

Modifier 59 (or the X{EPSU} modifiers) can only be used when NCCI allows it (modifier indicator = 1) and clinical documentation supports that the services were separate and distinct (different session, different site, different provider, or separate procedure). Never use modifier 59 as a default — only when documentation supports it.

What is the difference between modifier 59 and X{EPSU} modifiers?

Modifiers XE (separate encounter), XS (separate site), XP (separate practitioner), and XU (unusual non-overlapping service) were introduced by CMS as more specific alternatives to modifier 59. They provide more detail about why the services are separate. Some payers accept them; Medicare prefers them.

Can I appeal a CO-97 denial if NCCI says no override is allowed?

If NCCI has a modifier indicator of 0, the bundling cannot be overridden with any modifier. Appeals are generally not successful unless the payer applied an incorrect edit. You would need to prove the code pair is not subject to NCCI bundling.

How do I know which code was bundled into which?

Review the ERA/EOB. The code with the CO-97 adjustment is the one that was bundled. The other code on the claim (or same date of service) was paid. The EOB should show which code received payment.

Are CO-97 denials the same as CO-11 denials?

No. CO-97 means the service is bundled into another paid service. CO-11 means the diagnosis is inconsistent with the procedure (medical necessity). They are different denial types with different resolution approaches.

Home Payer Denial Intelligence CO-97UnitedHealthcare

CO-97UnitedHealthcare

How to Work CO-97 for UnitedHealthcare

Master Denial Codes CO-97 Overview

Quick Answer

CO-97 (Payment Bundled Into Another Service): Payment is included in the allowance for another service/procedure. Read the accompanying RARC codes on the ERA/EOB to identify the specific missing or incorrect information, then correct and resubmit as a corrected claim or file a formal appeal.

Key Takeaways

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CO-97 is a CO denial code — payment bundled into another service.

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Always read the accompanying RARC codes for specific detail about what is missing or incorrect.

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Most denials are resolved via corrected claim submission, not formal appeal.

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Document all follow-up actions and track the claim to resolution within timely filing limits.

Denial Code Definition

CO-97 is a CARC indicating that the payment for the billed service is bundled or included in the payment for another service/procedure already paid on the same claim or date of service. The payer considers the service a component of the more comprehensive service and does not pay it separately.

Official Description

Payment is included in the allowance for another service/procedure.

Why This Denial Occurs

This denial occurs when a payer applies bundling rules — either National Correct Coding Initiative (NCCI) edits or payer-specific bundling logic. The service is considered integral to another service on the same claim or date of service. Common examples include surgical assistants, pre-operative evaluations bundled into global surgical packages, and certain lab panels that include individual test components.

UnitedHealthcare-Specific Causes

UHC generally follows NCCI but also applies its own bundling logic for certain code combinations. UHC is particularly strict about same-day E/M and procedure bundling. Preventive and problem-oriented visits on the same day require modifier 25 to be paid separately.

1UHC-specific bundling logic (may differ from NCCI)
2Bundling of preventive and problem-oriented E/M visits on the same day
3Bundling of lab panel components into comprehensive panels
4Bundling of E/M into procedural services on the same date

Required Documentation

NCCI edit documentation showing whether the code pair has a modifier indicator
Operative report or clinical documentation supporting separate billing
Coding guidelines supporting unbundling (if applicable)
ERA/EOB showing which code was paid and which was bundled

Investigation Workflow

1Identify which code was paid and which was bundled (CO-97) on the EOB.
2Check the NCCI edits for the code pair to determine if a modifier can override the bundling.
3Review the clinical documentation to determine if the services were truly separate and distinct.
4Determine if the bundled code was correctly bundled or if a modifier (59, XE, XP, XS, XU) is warranted.
5Verify whether the denial is based on NCCI edits or payer-specific bundling rules.

Resolution Steps

1If the bundling is correct per NCCI and clinical documentation: write off the adjustment.
2If a modifier is appropriate (separate site, separate session, separate provider): submit a corrected claim with the appropriate modifier (59, XE, XS, XP, or XU).
3If the payer's bundling logic differs from NCCI and you disagree: file a formal appeal with clinical documentation supporting separate billing.
4If the code pair has a NCCI modifier indicator of 0 (cannot be overridden): accept the denial and write off.

Appeal Guidance

CO-97 appeals are only successful when clinical documentation supports that the services were truly separate and distinct. If NCCI allows a modifier override (indicator = 1), append the appropriate modifier and resubmit. If NCCI does not allow an override (indicator = 0), appeals will not succeed unless the payer's edit is incorrect. Include operative notes, clinical documentation, and coding rationale with any appeal.

UnitedHealthcare Appeal Tip

For UHC CO-97 appeals, determine if the denial is based on NCCI or UHC-specific logic. If UHC's edit differs from NCCI and you have documentation supporting separate billing, appeal with clinical notes and coding rationale. Use modifier 25 for same-day E/M and procedure.

Prevention Strategies

Integrate NCCI edit checking into your claim scrubbing software.
Train coders on NCCI bundling rules and appropriate modifier usage.
Use the correct modifier (59, XE, XS, XP, XU) only when documentation supports separate billing.
Audit CO-97 denials weekly to identify patterns and coder training needs.
Maintain current NCCI edit files — CMS updates them quarterly.
Educate providers on documentation that supports unbundling (separate sites, sessions, etc.).

Real-World Scenario: UnitedHealthcare

Situation

A provider billed CPT 99213 (problem-oriented E/M) and CPT 17000 (destruction of premalignant lesion) on the same date without modifier 25. UHC denied the E/M with CO-97, bundling it into the procedure.

Resolution

The coder reviewed the clinical notes and confirmed the E/M was significant and separately identifiable from the procedure. She resubmitted with modifier 25 appended to the E/M code. UHC paid both services within 14 days.