Denial code CO-97
CO-97 Denial in Dermatology: Bundled Into Another Service
CO-97 says the payer considers this line already paid for inside another line on the same claim. In dermatology it is the most common denial by volume, because the standard encounter combines an evaluation with one or more procedures across several sites, and almost every combination of those has a bundling rule attached to it. Fixing CO-97 is rarely about resubmitting — it is about deciding, honestly, whether the services were genuinely distinct.
What the payer is saying
The benefit for this service is included in the payment for another service already adjudicated.
The three shapes CO-97 takes in dermatology
- E/M bundled into a same-day minor procedure. The payer read the evaluation as the assessment inherent in doing the procedure. This is a modifier 25 question.
- One procedure bundled into another under an NCCI pair edit — a biopsy into a destruction, a repair into the excision that created the defect. This is a modifier 59 or X-series question, and only where the sites were genuinely separate.
- A service bundled into a global surgical period, where a visit falls inside the post-operative window of an earlier procedure and is not separately payable unless it is unrelated.
Work out which one you have before you touch the claim
The remittance advice names the line that absorbed the payment. Start there rather than at the denied line: if the absorbing line is a procedure performed on the same lesion, the bundling is almost certainly correct and the claim should not be appealed. If the absorbing line relates to a different lesion at a different site, the edit is overridable and the note should already prove it.
Check the NCCI modifier indicator for the pair before appealing. An indicator of 0 means no modifier will release the edit, and appending one to force payment converts a denial into a repayment liability with an audit trail attached.
The appeal, when the appeal is right
- Submit the encounter note with the separately identifiable work or the separate anatomical site marked, not highlighted in isolation.
- State the distinct site or distinct problem in one sentence in the cover letter. Reviewers read the letter first and the note only if the letter gives them a reason to.
- Include the operative detail per lesion — site, technique, indication. 'Two lesions treated' does not release the edit.
- Do not resubmit the same claim with a modifier added and no documentation change. That is the pattern that turns a routine denial into a records request.
The structural fix
A practice with a high CO-97 rate almost never has an appeals problem. It has a documentation-template problem: a note that does not force per-lesion site capture, or a protocol that appends modifier 25 automatically. Appeals recover some of last month's money and none of next month's.
We track CO-97 by provider and by code pair rather than as a single rate, because the remedy differs completely between a provider whose site documentation is thin and a provider whose modifier logic is being applied by the system rather than by them.
Frequently asked questions
Can we just add modifier 59 to release CO-97?
Only where the services were genuinely distinct and the documentation shows it. Adding it to force payment on correctly bundled services is exactly what post-payment reviews look for.
Why does one payer bundle a pair another pays?
NCCI is the national baseline; commercial payers layer their own edits on top and some are more aggressive. The pair may also carry a different modifier indicator under that payer's policy.