CO-97 Denial Code: Service Bundled Into Another Adjudicated Service

What Does CO-97 Mean?

CO-97 means the payer considers this service part of another service already paid — the benefit is 'included in the payment/allowance for another service.' It is the classic bundling denial, driven by NCCI edits, global surgical packages, and payer-specific bundling rules.

Code group: CO (Contractual Obligation) · Appealable: Yes, when services were genuinely distinct and documentation proves it. Not appealable for modifier indicator '0' pairs or true package components.

Why CO-97 Happens

NCCI Procedure-to-Procedure edits: the two CPT codes billed together are bundled, and the column-2 code denies unless a valid modifier applies.
Global surgical package: an E/M visit or wound check billed during the 10- or 90-day global period of a surgery is included in the surgical payment.
An E/M billed with a procedure on the same day without modifier 25 — or supplies, trays, and local anesthesia that are never separately payable.
Payer-proprietary bundling that goes beyond NCCI — some commercial payers bundle more aggressively than Medicare.

How to Fix a CO-97 Denial — Step by Step

Look up the code pair in the NCCI edit tables. Check the modifier indicator: '1' means a modifier can unbundle when clinically justified; '0' means never.

Determine whether the services were genuinely distinct — different session, different site, different lesion, separate injury. If yes, resubmit with the correct modifier (59 or the more specific X-series (XE, XS, XP, XU) modifiers, 25 for E/M, 79 for unrelated procedure in global).

If the service falls inside a global period but was unrelated to the surgery, append modifier 79 (unrelated procedure) or 24 (unrelated E/M) with documentation.

If the bundling is correct, write it off — and stop billing that combination.

Never append modifier 59 just to force payment — undocumented unbundling is a top audit trigger and repayment risk.

CO-97 Appeal Letter Template

Adapt this wording to your claim — replace the bracketed fields and attach the documentation it references:

CPT [code A] and CPT [code B] were performed as distinct services on [DOS]: [separate sessions/sites/lesions, times documented]. Per NCCI guidance, modifier [59/XS/XE] appropriately identifies the distinct procedural service, and supporting documentation is attached. We request reprocessing with separate payment for [code B].

How to Prevent CO-97

Run NCCI edits in your scrubber before submission, updated quarterly.
Train providers to document distinct sites, sessions, and times when performing multiple procedures.
Keep a global-period tracker so post-op visits are billed (or not) correctly.

Related Denial Codes & Guides

Modifier 59 — the NCCI bypass CO-45 — Exceeds fee schedule CO-4 — Modifier missing CO-234 — Not paid separately CO-18 — Duplicate

← Back to the full denial code library

Reviewed by the LegitMedBilling denial management team. This guide is general billing information, not legal or payer-specific advice — always verify against your payer contract and current policy.

Winning a CO-97 Appeal: Prove the Service Was Distinct

CO-97 says the service is already included in the payment for another service billed the same day. The appeal therefore turns on a single question: was this a genuinely separate service, or part of the one already paid? Arguing that the work took extra effort will not succeed. Demonstrating separateness will.

Separateness is shown in three ways, and the strongest appeals use whichever the record actually supports. A different anatomical site — documented by side and location, which is what the X-series modifiers exist to communicate. A different encounter — separate times recorded in the note, not merely a claim that the visits were distinct. A different clinical purpose — a problem addressed that was unrelated to the procedure performed, which is the basis for modifier 25 on a same-day evaluation and management service.

The modifier must have been supportable at the time of service, not appended afterwards to rescue a denial. If the documentation does not show separateness, the correct outcome is a write-off rather than an appeal — and pursuing it anyway is how practices attract attention they do not want. Where the service genuinely was distinct and the modifier was simply omitted, that is a corrected claim, not an appeal.

Frequently Asked Questions

What's the difference between modifier 59 and the X modifiers?

The X-series (XE, XS, XP, XU) modifiers (XE separate encounter, XS separate structure, XP separate practitioner, XU unusual non-overlapping service) are more specific versions of modifier 59. Medicare prefers them; many commercial payers accept either. Using the precise X modifier strengthens both payment and audit defense.

Can we bill the patient for a bundled service?

No — CO-97 is a contractual obligation adjustment. The payer considers the payment for the primary service to include the bundled one, and in-network providers must write it off.

Why did an office visit deny when we did a procedure the same day?

Same-day E/M with a minor procedure is bundled unless the visit was significant and separately identifiable — a genuinely distinct evaluation beyond the procedure's built-in work. When it is, append modifier 25 to the E/M and make sure the documentation shows separate medical decision-making.

How do I win a CO-97 appeal?

Prove the service was distinct rather than arguing it took more work. Show a different anatomical site, a different encounter with separate documented times, or a different clinical purpose. The supporting modifier must have been justified at the time of service, not added afterwards to reverse a denial.

Do you have a CO-97 appeal letter template?

Yes. The CO-97 Appeal Letter Template section on this page provides wording you can adapt, and the free appeal letter generator will produce a complete CO-97 bundling appeal with your payer and claim details inserted.