CO-6: The procedure/revenue code is inconsistent with the patient's age.
The code billed is restricted to a specific age range, such as pediatric or adult, and the patient's age on the date of service falls outside that range.
What the group code means
- CO
- Contractual Obligation. The provider is responsible and the amount cannot be billed to the patient.
Why it fires
- The code is designated for a specific age bracket, such as a well-child code billed for an adult patient
- The patient's date of birth was entered incorrectly, making the age appear wrong
- The provider intended a different, age-appropriate code but selected the wrong one
Corrective actions, ranked
- 1
Verify the patient's date of birth
Confirm the DOB on file matches the patient's ID or insurance card. A data entry error is common here.
- 2
Correct the code if needed
If the age restriction is accurate and the wrong code was used, identify and rebill the age-appropriate equivalent.
- 3
Resubmit the corrected claim
Once the DOB or code is fixed, resubmit rather than appeal.
Is it worth appealing
Not an appeal. This is a data or coding correction, so fix the DOB or code and resubmit.
Retrieved 2026-07-18.
Do not let this happen again
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DenialPath provides billing and administrative guidance based on published CMS and X12 sources. It is not medical advice, not a coverage determination, and not a guarantee of payment. NCCI and MUE edits are republished quarterly and payer policies vary by contract. Always confirm against the payer's own current policy before submitting or appealing.