CO-97 means the payer considers the service part of another service on the same claim or date, so it is paid as zero. The provider absorbs the amount. Sometimes that is correct bundling and should be written off. Sometimes the service really was separate, and a supported modifier and corrected claim will get it paid.
What does CO-97 mean?
CARC 97 is officially described as “The benefit for this service is included in the payment/allowance for another service/procedure that has already been adjudicated.” The wording is published in the X12 Claim Adjustment Reason Code list (opens in a new tab).
Most CO-97 denials come from bundling edits. Medicare and many commercial payers use the CMS National Correct Coding Initiative (NCCI) procedure-to-procedure edits, which list code pairs that should not be paid separately for the same patient on the same date. Surgical global periods cause many of the rest: routine visits after surgery are already included in the surgical payment.
Common causes of CO-97
| Cause | Where to look |
|---|---|
| Two codes form an NCCI pair and no modifier shows they were separate | NCCI procedure-to-procedure edit tables |
| An E/M billed with a minor procedure without modifier 25 | Visit note and the procedure note |
| A post-operative visit inside the global period | Surgery date and global days for the procedure |
| A service that is a component of a more complete code | CPT code descriptors |
| Payer-specific bundling rules | Payer policy and the 835 policy reference, if sent |
How to fix a CO-97 denial
- Identify which paid service the denied line was bundled into. The 835 may include a policy reference.
- Check the code pair in the current NCCI edits (opens in a new tab) and whether a modifier is allowed for that pair.
- Read the documentation. A modifier is only valid if the note shows a separate site, session, encounter or significant, separately identifiable service.
- If it is supported, send a corrected claim with the right modifier (for example 25, 59 or XE, XS, XP, XU). If it is not, record the adjustment as a write-off.
Correct, appeal or write off CO-97?
Correct the claim when a valid modifier was missing. Appeal when the modifier was already on the claim and the documentation clearly supports it. Write off when the bundling is correct. Adding modifiers only to get past edits is a compliance risk, and payers audit modifier 59 and 25 use.
How to prevent CO-97
- Run claims through a scrubber that applies current NCCI edits.
- Train providers on what documentation supports modifiers 25 and 59.
- Flag claims within surgical global periods before they go out.
- Review CO-97 by code pair monthly to spot one recurring pattern.
Frequently asked questions
Is CO-97 the same as a duplicate claim denial?
No. Duplicates are reported with CARC 18. CO-97 means the service was included in another one, not billed twice.
Can I bill the patient for CO-97?
No. Group code CO means the provider is responsible for the amount.
Does modifier 59 always fix CO-97?
No. It is only appropriate when the services were truly distinct, and some code pairs do not allow a modifier at all.
Related denial code guides
- How to read a claim denial: CARCs, RARCs and group codes
- CO-16 denial code
- CO-197 denial code
- CO-50 denial code
- CO-4 denial code
- PR-1 denial code
Code descriptions are quoted from X12 at the time of writing and are revised from time to time. Payer policies and your contracts decide what is billable and appealable.
Losing revenue to bundling edits?
We review your CO-97 denials by code pair and tell you which are fixable and which are correct bundling.