CO-39: Services denied at the time authorization/pre-certification was requested.
The payer already denied this service when the provider requested prior authorization, before it was even performed. The claim denial here simply reflects that earlier utilization review decision.
What the group code means
- CO
- Contractual Obligation. The provider is responsible and the amount cannot be billed to the patient.
Why it fires
- The prior authorization request was denied for medical necessity, non-covered benefit, or missing information at the utilization review stage
- The service was performed anyway despite the authorization denial
- The authorization denial was never appealed or overturned before the service was rendered
Corrective actions, ranked
- 1
Pull the original UM denial letter
Review the specific reason the authorization was denied, since it will be the same basis for the claim denial.
- 2
File a UM appeal or peer-to-peer review
If the authorization denial was clinically wrong, pursue the payer's utilization management appeal or peer-to-peer review process directly.
- 3
Prevent recurrence
Establish a policy of not proceeding with denied-authorization services unless urgent, or obtaining a signed financial waiver from the patient beforehand.
Is it worth appealing
Appeal through the payer's utilization management or authorization appeal process with clinical justification. A generic claims appeal alone usually will not overturn this without addressing the original UM denial.
Retrieved 2026-07-18.
Do not let this happen again
Scrub the claim against NCCI PTP and MUE edits before you submit, free and in your browser.
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.