CO-198 Denial Code: Authorization Exceeded

The official definition

“Precertification/authorization exceeded”

That is the verbatim definition of CARC 198 from the X12 Claim Adjustment Reason Code set, the standardized codes every insurer uses on EOBs and remittance advices. The letters in front of the number are the group code. CO: Contractual Obligation: an adjustment between the provider and the insurer. An in-network provider should not bill you for CO amounts.

What it means in plain English

Authorization existed, but the care went beyond it: more therapy sessions than approved, a longer hospital stay, an extra procedure during surgery. Managing an ongoing authorization (extensions, concurrent review) is the provider's responsibility, and in most scenarios they should be appealing rather than billing you.

What to check on your EOB

• What was authorized vs. what was delivered: sessions, days, procedures.
• Whether anyone told you the authorization was running out before care continued.
• Whether the extra care arose during surgery from emergent findings. Insurers have processes for exactly that.

What to do next

1. If therapy or a hospital stay exceeded the authorization, the provider should have requested an extension. Press them to seek retroactive authorization or appeal, not bill you.
2. If additional procedures were medically necessary mid-surgery, the provider should appeal with documentation of the emergent findings.
3. If you knowingly continued care beyond a stated authorization limit, check your plan documents. Responsibility may be shared.

Who's responsible

Provider, in most cases. Most denials carry a clear owner. Knowing whether the fix belongs to you, your doctor, or the billing office is half the battle. If it's the provider's error, you should not be paying for it.

Want the fundamentals first? Start with how to read an EOB and the 7 most common billing errors. This page is general information about standardized denial codes, not legal or medical advice.