Denial code library
The denial codes chiropractors actually see.
Not a generic CARC dictionary. This library covers the codes that land on real chiropractic remittances, what each one means in a chiropractic context, and the specific next step for each, drawn from the denial logic our own three location practice runs on every ERA, every day.
| Code | What it means | The move |
|---|---|---|
| CO-16 | Claim lacks information | Correct and resubmit |
| CO-11 | Diagnosis inconsistent with the procedure | Correct and resubmit |
| CO-4 | Procedure code inconsistent with the modifier | Correct and resubmit |
| CO-97 | Bundled into another service | Correct and resubmit |
| CO-50 | Not deemed medically necessary | Reconsider or appeal |
| CO-29 | Timely filing expired | Write off, appeal only with proof |
| CO-45 | Charge exceeds fee schedule | Contractual write off, not a denial |
| CO-22 | Coordination of benefits, another payer may be primary | Recheck eligibility |
| CO-151 | Frequency of services not supported | Reconsider or appeal |
| CO-167 | Diagnosis not covered | Reconsider or appeal |
| CO-197 | Preauthorization absent | Correct and resubmit |
| CO-204 | Not covered under the patient plan | Recheck eligibility |
| PR-119 / CO-119 | Benefit maximum reached | Patient responsibility, switch to cash |
| PR-100 / CO-100 | Payer paid the patient, not the practice | Bill the patient immediately |
| PR-242 / CO-242 | Out of network | Verify credentialing, then appeal or bill |
| PR-170 / CO-170 | Not paid to this type of provider | Patient responsibility with waiver, or write off |
| PR-96 | Non covered service | Patient responsibility |
| OA-18 | Duplicate claim | Do not rebill, investigate the original |
| CO-140 | Patient and insured information mismatch | Recheck eligibility |
| CO-31 | Patient cannot be identified as insured | Correct and resubmit |
| B11 | Claim forwarded to another processor | Hold, do not rebill |
| CO-109 | Not covered by this payer, wrong payer billed | Recheck eligibility |
| PR-200 | Coverage lapsed on the date of service | Recheck eligibility |
| PR-26 / PR-27 | Service before coverage began, or after it ended | Recheck eligibility |
| CO-181 | Procedure code invalid on the date of service | Correct and resubmit |
Related billing references
Use the chiropractic payer quirks guide alongside the remittance and the payer’s instructions when investigating a recurring denial.
Why a chiropractic specific denial library
The same code means different things in different specialties. CO-97 in a hospital is a coding department problem; in a chiropractic office it is almost always 97140 billed with same day CMT. A generic CARC lookup tells you the definition. This library tells you the fix. Inside Cervica, this same logic runs automatically: every denied claim on an ERA is triaged by code into a worklist with the suggested fix attached, so a biller works denials instead of researching them.
Where the denials start
Most of these codes trace back to a specific box on the claim form. The CMS-1500 box by box reference maps each box to the denials it produces.
General information for billing teams, not legal or payer specific advice. CARC definitions belong to X12; payer policies vary and control. Verify against the payer contract before acting on any individual claim.