Claim Adjustment Code Guide
CO-197 means the payer says required precertification, authorization, or notification was missing. The CO prefix matters because it can indicate a contractual obligation between the payer and provider rather than automatic patient responsibility.
Standard Definition
Precertification/authorization/notification/precertification absent.
Financial Liability
For many in-network claims, CO-197 points to an authorization workflow failure by the participating provider or facility. The patient should compare the EOB patient-responsibility column with any provider bill and challenge attempts to collect a contractual denial from the member.
Out-of-network claims may be handled differently, and similar authorization denials can appear with patient-responsibility language. If the EOB assigns the balance to the patient, the appeal should address network status, emergency exceptions, and retrospective medical necessity.
Check Your EOB First
Find the patient-responsibility column on the Explanation of Benefits for this claim before deciding what to do next.
No, patient responsibility shows $0
A CO-197 denial with no balance assigned to you is typically a provider-side administrative issue. The in-network provider or facility usually has to request retrospective authorization or correct the claim. Provider correction does not automatically extend your own appeal deadline, so keep watching it.
Yes, or the EOB is unclear
If the plan is holding you responsible for the denied amount, or you cannot tell from the EOB, a member appeal may be the right next step.
Find Where to Send Your AppealAdministrative Defenses
A strong CO-197 response checks the billing liability first, then documents the authorization exception or retrospective clinical basis.
Verify whether the provider was in-network and whether the EOB lists the denial as CO-197. If the provider attempts to bill the member anyway, the appeal should dispute the balance as a provider-side authorization failure.
If the service followed an emergency presentation, prior authorization requirements may not apply the same way. The appeal should document triage notes, admission path, presenting symptoms, and urgent clinical facts.
When the authorization issue cannot be resolved administratively, the appeal should show that the service would have met medical necessity standards if reviewed before care occurred.
Action Protocol
Challenging this specific ANSI code requires precise legal and provider checks. Work through the steps in order.
You must review your EOB and verify whether the denial is listed as CO-197 or PR-197. You must also check whether the patient-responsibility column shows $0.00 or assigns a balance to you.
If an in-network provider bills you for a CO-197 denial, you must call their billing office to dispute the charge and manually draft a complaint referencing their participating provider agreement.
If the care was emergent, you must contact the hospital, request your emergency room triage notes, and manually isolate your presenting symptoms and vitals to support an emergency-care exception.
You must compile the EOB, denial notice, provider bill, clinical records, authorization history, HIPAA authorization, and representative forms into one complete appeal packet and submit it via standard mail.
EOB Notes
Next Step
Answer a few questions about your denial and get an editable appeal letter you can review and send yourself.
Create Free Appeal LetterThis guide provides general administrative information for health insurance appeals and EOB review. It is not legal or medical advice, and liability rules can vary by plan, provider contract, waiver language, state, and service type.
