EOB denial code · CO group
CO-197: Prior Authorization Not Obtained — Meaning & Fix
CO-197 means your insurer required prior authorization for the service and it wasn't obtained before the service was provided. The provider is usually responsible for securing authorization, not you. The fastest fix is a retro-authorization request: providers can ask the insurer to authorize the service after the fact with clinical documentation, and payers routinely grant them when the care was appropriate.
What “CO-197” means on your EOB
Prior authorization(s) or pre-certification(s) not obtained.
Who pays? CO — Contractual Obligation
CO (contractual) — payment is denied because the pre-approval step was skipped. Depending on contract terms, the provider may be barred from billing you if they failed to obtain the required authorization.
What to do next: Retro-authorization is the first move: your provider submits the same clinical information with a request to authorize the service after the fact. When that fails, appeal with the argument that (1) the provider was responsible for authorization and (2) the service was clinically appropriate and would have been approved prospectively. Many states have laws protecting patients from 'no authorization obtained' denials when the service was medically necessary and the fault was administrative.
Why this denial happens
- The provider never submitted the prior-authorization request.
- The authorization was approved for a different date, code, or location than the service delivered.
- The service was ordered by a specialty office but performed by a facility that didn't check authorization.
- An authorization expired while wait times delayed the appointment.
What to do now
- Ask your provider for the authorization tracking number or whether one was ever requested.
- Have the provider submit a retro-authorization request with the clinical documentation — this resolves a large share of CO-197 denials.
- If denied, appeal citing that the provider was contractually responsible for obtaining authorization and the service was medically necessary.
- Check your state: some states bar the provider from billing you after a no-authorization denial.
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Generate an appeal letter →Whose fault is a CO-197 denial?
Almost always administrative — the provider's office failed to get the pre-approval. Some states and provider contracts prohibit billing the patient when the provider caused the missed authorization.
What is retro-authorization?
A request to the insurer to approve the service after it was performed, using the same clinical documentation. Many insurers grant these when the care was appropriate but the paperwork was late.
Can I appeal instead?
Yes — after retro-authorization fails, appeal formally. The strongest angle: the service was medically necessary AND the failure was the provider's administrative error, not yours.