What does denial code CO-97 mean?

CO-97 means the payer considers the billed service to be included in another service already adjudicated for the same patient and date, so it is not separately payable. It is a contractual adjustment and cannot be billed to the patient.

How do I fix a CO-97 bundling denial?

Run an NCCI Procedure-to-Procedure check on the two codes. If the edit's modifier indicator is 0, the bundle cannot be bypassed and the line is written off. If the indicator is 1, a distinct-service modifier such as 59 or an X-series modifier may be appended - but only when the documentation genuinely supports a separate service.

Is modifier 59 always the answer for CO-97?

No. Modifier 59 only applies when the services were genuinely distinct, and it cannot bypass an edit with modifier indicator 0. Routine use of modifier 59 to clear bundling denials is a recognized audit trigger.

CO-97: Service is bundled into another service already adjudicated

CO-97 is a bundling denial and is the code where an NCCI Procedure-to-Procedure edit check is the actual next step rather than a guess. The payer has decided one code is included in another. The question to answer is whether a National Correct Coding Initiative edit genuinely pairs those two codes and, if it does, whether the edit's modifier indicator permits a bypass with documentation.

What it means: The payer considers this procedure an component of another procedure billed for the same patient and date, so it is not separately payable.
Who pays the balance: Contractual - a bundled service cannot be billed to the patient.
Group code CO: Contractual Obligation - the provider absorbs the balance and cannot bill the patient

Why CO-97 happens

An NCCI PTP edit pairs the two codes and no modifier was appended.
The service falls inside another procedure's global surgical period.
An evaluation and management visit was billed on the same day as a procedure without modifier 25.
A component code was billed alongside a comprehensive code that already includes it.
The payer applies its own proprietary bundling logic that is stricter than NCCI.

How to fix a CO-97 denial

1
Run an NCCI PTP check on the two codes
Determine whether an edit actually exists and, critically, what its modifier indicator is. Indicator 0 means the edit can never be bypassed - append no modifier and write it off. Indicator 1 means a modifier may bypass it when the documentation supports a distinct service.
2
Append a modifier only when the record genuinely supports it
Modifier 59 or the more specific X-series modifiers (XE, XS, XP, XU) for a distinct procedural service; modifier 25 for a significantly separate E/M on the same day. Appending modifier 59 reflexively to clear bundling edits is a well-known audit trigger and a false-claims risk.
3
Check the global period before appealing
If the service falls in another procedure's global period, the correct fix may be modifier 24, 78, or 79 rather than a distinct-service modifier.

Check the NCCI edit for your code pair

CO-97 turns on whether a published National Correct Coding Initiative edit applies and what its modifier indicator allows. Rette checks the live CMS edit tables and tells you whether a modifier can bypass the edit at all.

Run an NCCI edit check

Preventing CO-97 denials

Run bundling edits inside the encounter workflow rather than discovering them on the remittance.
Train coders on when the X-series modifiers are more defensible than a blanket modifier 59.
Audit modifier 59 usage rates by provider - an outlier rate attracts payer attention.

CO-97 frequently asked questions

What does denial code CO-97 mean?: CO-97 means the payer considers the billed service to be included in another service already adjudicated for the same patient and date, so it is not separately payable. It is a contractual adjustment and cannot be billed to the patient.
How do I fix a CO-97 bundling denial?: Run an NCCI Procedure-to-Procedure check on the two codes. If the edit's modifier indicator is 0, the bundle cannot be bypassed and the line is written off. If the indicator is 1, a distinct-service modifier such as 59 or an X-series modifier may be appended - but only when the documentation genuinely supports a separate service.
Is modifier 59 always the answer for CO-97?: No. Modifier 59 only applies when the services were genuinely distinct, and it cannot bypass an edit with modifier indicator 0. Routine use of modifier 59 to clear bundling denials is a recognized audit trigger.

Related denial codes

CO-236 CO-151 CO-18

Denial code explanations are original plain-English summaries written for reference and are not the official X12 code descriptions. Payer handling of any code varies by contract - always verify against the remittance advice and your payer agreement before adjusting a claim.