What does CO-97 actually mean?

The payer believes it already paid for this work as part of another service on the claim, so it will not pay separately. Whether that is right depends on whether the two services were genuinely distinct.

Can I bill the patient for a bundled service?

No. CO-97 is a contractual write-off, so the amount cannot be balance-billed to the patient.

What makes a CO-97 appeal succeed?

Documentation that shows the services as separate work — different session, different site, or a distinct clinical indication. If the note reads as one continuous service, the appeal is unlikely to change the outcome.

CO-97Sometimes worth appealing

CO-97 denial: service already included in another payment

The payer treated this service as already paid for as part of another service on the claim.

Official X12 description

The benefit for this service is included in the payment/allowance for another service/procedure that has already been adjudicated.

What the CO group code means

CO — Contractual Obligation

The amount is written off under your contract with the payer. You cannot bill the patient for it.

Is it worth appealing?

Worth appealing when the services really were distinct and independently documented. The whole case rests on whether the record shows them as separate work — which is a documentation question, not a coding one.

Why payers issue CO-97

01The payer's edits treat the two services as inherently bundled.
02A global period from a prior procedure was still running.
03The services were genuinely distinct but the record did not clearly show them as separate.
04The payer applied a bundling edit that its own policy does not actually support.

What to gather before you appeal

The full operative or encounter note for each service in question.
The payer's bundling or global-period policy for the services involved.
Documentation establishing separate sites, sessions, or clinical indications.
The remittance showing which service the payer considered inclusive.

Arguments that work

The services were distinct and independently documented — the record shows separate work.
The service fell outside the global period of the earlier procedure.
The payer's own policy does not bundle these services, contrary to the edit that fired.

The deadline

Standard first-level appeal windows apply — commonly 90–180 days from the remittance date. The remittance advice governs.

Common questions about CO-97

What does CO-97 actually mean?: The payer believes it already paid for this work as part of another service on the claim, so it will not pay separately. Whether that is right depends on whether the two services were genuinely distinct.
Can I bill the patient for a bundled service?: No. CO-97 is a contractual write-off, so the amount cannot be balance-billed to the patient.
What makes a CO-97 appeal succeed?: Documentation that shows the services as separate work — different session, different site, or a distinct clinical indication. If the note reads as one continuous service, the appeal is unlikely to change the outcome.

Draft the CO-97 appeal in about three minutes

Upload the denial. Undeny reads it, drafts a payer-specific appeal letter citing this code and the record, and tracks the deadline until the money comes back.

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