CO-198: Precertification/notification/authorization/pre-treatment exceeded.
An authorization or precertification did exist, but the service billed exceeded what was actually approved, whether in units, visits, or scope.
What the group code means
- CO
- Contractual Obligation. The provider is responsible and the amount cannot be billed to the patient.
Why it fires
- More units or visits were billed than the authorization approved
- The service performed exceeds the scope of what was originally authorized, such as being authorized for evaluation but a procedure was also performed
- The authorization expired before all approved services were rendered, and services rendered afterward exceeded its validity period
Corrective actions, ranked
- 1
Compare billed units to authorized units
Pull the authorization approval letter and compare exactly what was approved versus what was billed.
- 2
Request an authorization extension or amendment
If clinically justified, contact the payer's utilization management department to expand or extend the existing authorization to cover the additional services.
- 3
Bill only the authorized portion
If the excess truly is not covered, consider billing only up to the authorized amount and addressing the remainder separately, with patient responsibility only if permitted.
Is it worth appealing
Appeal when the additional units or services were medically necessary and documentation supports expanding the original authorization scope.
Retrieved 2026-07-18.
Do not let this happen again
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DenialPath provides billing and administrative guidance based on published CMS and X12 sources. It is not medical advice, not a coverage determination, and not a guarantee of payment. NCCI and MUE edits are republished quarterly and payer policies vary by contract. Always confirm against the payer's own current policy before submitting or appealing.