What does CO-204 mean?
CARC code 204 is similar to CO-96 but more specific — the particular service is not covered under this patient's benefit plan. Review the plan documents to confirm the exclusion. For behavioral health, consider whether the Mental Health Parity Act applies. If a comparable medical/surgical service would be covered but the behavioral health service is excluded, this may violate parity requirements. Otherwise, the overturn rate is low at approximately 15%, and the balance may be the patient's responsibility.
How to appeal CO-204
Check the RARC code
The RARC (Remittance Advice Remark Code) on your ERA provides specific details about why the claim was denied. This tells you exactly what needs to be fixed.
Gather clinical documentation
Compile clinical notes, treatment plans, and any relevant guidelines that support the medical necessity of the service provided.
Submit a formal appeal letter
Write a detailed appeal letter that references clinical guidelines, payer policies, and includes supporting documentation. Submit via the payer's preferred method (fax, portal, or mail).
Key notes for behavioral health
Benefit exclusion. Review plan documents. Low overturn unless parity laws apply.