CO-107 Denial Code: Related or Qualifying Claim/Service Not Identified

What does denial code CO-107 mean?

CO-107 is the payer saying: this line depends on another service we cannot find. The official X12 description is "The related or qualifying claim/service was not identified on this claim." The billed procedure is contingent on a qualifying service — a base procedure, a prior surgical claim, or a linked facility claim — that was either missing or not referenced. It carries the CO group code, so the amount is a contractual write-off until you correct it.

It is closely related to bundling denials like CO-97 but distinct: CO-97 says the service is already paid inside another, while CO-107 says the required supporting service is absent.

Why does CO-107 happen?

• Add-on code without its primary — an add-on CPT billed alone or on a separate claim from its base procedure.
• Missing claim reference — a post-op or follow-up service billed without the original surgical claim number.
• Split professional/facility claims — a professional component billed without identifying the related facility claim.

Mini-example: 22614 (additional vertebral segment fusion, an add-on) billed at $1,150 without its primary code 22612 on the same claim. The payer returns the line with CO-107 because there is no qualifying base procedure to attach it to. Rebilling both codes together recovers the $1,150.

How do you fix a CO-107?

1. Identify the qualifying service — the primary CPT for an add-on, or the related prior claim number.
2. Check the accompanying RARC remark codes on the ERA; they often name exactly which reference is missing.
3. Add the base code to the same claim, or populate the referenced claim number in the correct field.
4. Resubmit as a corrected claim; if the qualifying service was billed and paid, appeal with proof of the related claim.

How do you prevent CO-107?

Configure your scrubber to flag add-on codes that appear without their designated primary procedure before submission, and keep the add-on/base pairing list current. When splitting professional and facility billing, verify the linking reference field is populated. Run any unfamiliar remittance code through the denial code lookup, and review RARC remark codes since they usually pinpoint the missing qualifier for a CO-146-style correction.