Official CARC description: “The procedure/revenue code is inconsistent with the patient's age.” Here’s what it actually means, why it fires, and how to get the claim paid.
The CPT has an age range and the patient's recorded age falls outside it — either an age-specific code was misapplied or the DOB on file is wrong.
Liability group: CO = Contractual Obligation — the provider absorbs it — the amount cannot be billed to the patient. If the denial is wrong, the money is recovered by correcting or appealing the claim, not by balance-billing.
Also written: CO-6, CO6, “denial code 6”, “6 denial code” or “reason code 6” — same CARC, different ERA formatting.
Verify the patient's DOB first — the cheapest fix
Select the age-appropriate code from the family; corrected claim
Age-banded preventive visits: check the exact age rules (some run on birthdays, some plan years)
If the code has no age limit and the edit is wrong: dispute with CPT descriptors
Appeal only payer-edit errors (attach CPT descriptor language). Data and code-choice errors are corrected claims.
Fill in the denial facts — use placeholders, never real patient data (the letter keeps [PATIENT NAME]-style fields so you can merge real details privately). A payer-ready draft with an enclosure checklist comes back in ~20 seconds.
Your appeal letter draft will appear here.
The official CARC description for CO 6 is: “The procedure/revenue code is inconsistent with the patient's age.” In practice: The CPT has an age range and the patient's recorded age falls outside it — either an age-specific code was misapplied or the DOB on file is wrong.
Denial code 6 under the CO group (Contractual Obligation) means: The procedure/revenue code is inconsistent with the patient's age. The number is the reason; the CO prefix decides who is liable — the provider absorbs it — the amount cannot be billed to the patient. If the denial is wrong, the money is recovered by correcting or appealing the claim, not by balance-billing.
Yes. CO 6, CO-6, CO6 and “denial code 6” are the same CARC — clearinghouses, payer portals and PM systems just print it differently. Only the group prefix (CO, PR, OA or PI) changes the meaning, because it changes who has to absorb the amount.
CO stands for Contractual Obligation — the provider absorbs it — the amount cannot be billed to the patient. If the denial is wrong, the money is recovered by correcting or appealing the claim, not by balance-billing.
Appeal only payer-edit errors (attach CPT descriptor language). Data and code-choice errors are corrected claims.