Denial code CO-198: what it means and what to do

On your explanation of benefits or remittance, CO-198 means: precertification/authorization exceeded.

Is there an overturn-rate benchmark for this code?

Honest answer: no. State external-review programs are limited by statute to clinical-necessity disputes, so administrative and financial denial codes like this one never reach external review and no published overturn rate exists. Anyone quoting one for this code is inventing it.

What to do next

• This is usually a paperwork or billing-mechanics issue: it is often fixed by the provider correcting and resubmitting rather than by a patient appeal — call the billing office first and ask them to fix and resubmit.
• Always request an itemized bill and keep everything in writing.