Denial Code Decoder
CO-97 — Bundled into another paid service
The payer considers this service part of another service already adjudicated — bundled under coding edits or included in a global period. The question is always whether the bundling is correct, or whether a distinct, separately payable service was performed.
Billable to the patient? No — bundled services are not patient liability.
Where this denial is born
- Front desk
- Coding
- Claim build
- Submission
- Adjudication
This denial is usually created at the highlighted stage — that is where prevention lives.
Answer the questions — follow the path
The same questions an experienced biller asks, in order. Your answers draw the route to the right action.
Was the service genuinely distinct from the one it was bundled into?
Different session, site, or a service beyond the usual pre/post work of the primary procedure.
The full decision tree
Was the service genuinely distinct from the one it was bundled into?
Different session, site, or a service beyond the usual pre/post work of the primary procedure.
- Yes →
Does documentation support a distinct-service modifier?
- Yes →
Resubmit with the appropriate modifier. Append the modifier that reports the distinct service, exactly as documented, and resubmit as a replacement claim. Expect the payer to request records — have them ready.
- No →
Accept the bundling. Correct bundling is not recoverable. Feed the pattern back to charge entry so the combination stops being billed separately.
- Yes →
- No →
Accept the bundling. Correct bundling is not recoverable. Feed the pattern back to charge entry so the combination stops being billed separately.
Prevention
Run claims against bundling edits before submission and track global periods on procedures, so separately-payable work gets its modifier at charge entry.
Related reading
The code list, and when it was last checked
X12 maintains the Claim Adjustment Reason Codes list, where this code is listed as 97. The list carries the number alone: the CO in front of it is the adjustment group the payer chose for this line, which decides who owes the balance, and the same code can arrive under a different group from a different payer. It has been on the list since January 1, 1995, and X12 last revised its entry on July 1, 2017.
Checked against the list revision dated November 1, 2025 on August 7, 2026, where it reads as an active code.
Sources
The paragraphs behind the guidance above. A page that tells you what to do about money should show you what the instruction rests on.
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