EOB denial code CO-197: what it means

What it means

A required prior authorization or pre-certification was not on file before the service, so the claim was denied.

Contractual Obligation — an adjustment the provider agreed to by contract. The patient is generally not billed for CO amounts.

Official X12 description

“Precertification/authorization/notification/pre-treatment absent”

Typical cause

The service needed advance approval from the insurer and none was obtained, or the approval was not linked to the claim.

What to do next

1. 1Check whether authorization was actually obtained — sometimes it exists but was not attached to the claim.
2. 2If it was an emergency, many plans waive prior authorization; point that out in an appeal.
3. 3Ask your provider to request a retroactive authorization, and file an internal appeal if denied.