CO-97 Denial Code: What Bundling Means and How to Fight It

CO-97 is a frequent denial code that appears when an insurer decides one service is already included in the payment for another service performed on the same day. This is known as bundling. In 2026 understanding exactly why bundling denials happen and how to challenge them can recover significant revenue that would otherwise be written off. This guide explains what CO-97 means, why it occurs, and the exact steps to fight it successfully. What CO-97 actually means CO-97 stands for “The benefit for this service is included in the payment or allowance for another service or procedure that has already been adjudicated.” It is a contractual adjustment under the CO group code. The insurer is telling the provider that the separate charge should have been bundled into a single comprehensive code. Why bundling denials happen Common triggers include: National Correct Coding Initiative (NCCI) edits that bundle certain procedure pairs. Same-day services that the insurer considers part of one global procedure. Missing or incorrect modifiers on the claim. Unbundling attempts where separate codes were billed for components of a single service. Step-by-step process to fight a CO-97 denial Review the Explanation of Benefits and remittance advice Identify the bundled code and the primary procedure it was bundled into. Note any remark codes for additional clues. Check for appropriate modifiers Determine whether a modifier such as 59 (distinct procedural service), 25 (significant separate evaluation and management), or an X-modifier should have been used. If the documentation supports separate billing, the modifier may resolve the denial. Gather supporting documentation Obtain operative notes, procedure reports, or chart notes that clearly show the services were distinct and medically necessary as billed. Submit a corrected claim or formal appeal If a modifier was simply omitted, file a corrected claim. If the payer applied bundling incorrectly, submit a written appeal with the documentation and a clear explanation of why the services qualify for separate payment. Escalate if the first appeal is denied Move to the second level of internal appeal or request an external review. Provide any additional clinical evidence or reference to payer-specific policies. Prevention tips for future claims Review NCCI edits before submitting claims that involve multiple procedures on the same date. Use the correct modifier when documentation supports separate billing. Confirm payer-specific bundling rules, as some insurers have stricter policies than national guidelines. Next steps with Bill Advantage Stop manually researching bundling rules or drafting appeal letters. Use Bill Advantage’s Denial Letter Translator (available in the Member tier and above). Enter the CO-97 denial text, and the tool explains the bundling issue in plain English and generates a ready-to-send appeal or corrected-claim letter. For repeated bundling patterns from the same payer, check the Denial Pattern Reporter on your dashboard. You can also review the full CO-97 explanation and appeal tips on the new Denial Code Reference page at billadvantage.com/denial-codes/CO-97.

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Bill Advantage is a document literacy tool. Nothing in this article constitutes legal or medical advice.