CO-198: Precertification/Authorization Limits Exceeded

What Does CO-198 Mean?

CO-198 means the provider exceeded the authorized limit and the financial responsibility falls on the practice. The provider's contract required obtaining additional authorization before delivering services beyond the approved scope, and that step was not completed. The provider cannot bill the patient for the denied amount — it is a contractual write-off unless successfully appealed.

CARC 198 signals that the precertification, authorization, notification, or pre-treatment requirements were exceeded — not missing, but surpassed. An authorization was in place, but the services delivered went beyond its scope. This could mean more visits than approved, more units than authorized, treatment dates outside the authorization window, or medication quantities above the pre-approved amount.

This denial is particularly common in therapy practices (physical therapy, occupational therapy, speech therapy) where initial authorizations cover a limited number of sessions and the patient's condition requires additional treatment. It also appears in behavioral health settings with session caps, DME orders that exceed quantity limits, and surgical cases where intraoperative findings require additional procedures beyond the original authorization scope.

The group code determines who absorbs the financial impact. Under CO, the provider is responsible because the contract required the provider to obtain additional authorization before exceeding the limit. Under PR, the patient is responsible when they have exhausted their plan's benefit limit for that service type (e.g., 20 PT visits per year). The distinction matters because CO means you cannot bill the patient, while PR means you should bill the patient directly.

Common Causes

How to Resolve

Verify which services exceeded the authorization, request a retroactive extension, and appeal if the extension is denied.

1. Review the authorization scope Pull the original authorization and identify the specific limit that was exceeded — number of visits, units, date range, or procedure scope.
2. Request retroactive extension Submit a retro authorization request with clinical documentation showing the patient's progress, current functional status, and why additional services were medically necessary.
3. Appeal if retro extension is denied File a formal appeal with a letter of medical necessity, progress notes from each excess visit, objective outcome measures, and the original treatment plan showing the evolving clinical picture.
4. Write off if all appeals fail If all appeal levels are exhausted, post the excess amount as a contractual write-off and document the outcome for future reference.

Common RARC Pairings

The RARC code tells you exactly what triggered the CO-198:

How to Prevent CO-198

• Implement automated authorization tracking that alerts clinical and billing staff when the patient is approaching the authorized visit or unit limit
• Submit reauthorization requests at least 3-5 visits before the current authorization expires to ensure continuity of coverage
• Review the authorization details (dates, units, CPT codes) at every patient visit to confirm the service is still within the approved scope
• Maintain a centralized authorization log accessible to scheduling, clinical, and billing teams that shows remaining visits and expiration dates
• Train clinicians to document ongoing medical necessity at every visit, which provides the evidence needed for reauthorization requests

General Prevention

• Track authorization utilization actively and set alerts when approaching the authorized visit or unit limit
• Submit reauthorization requests well before the current authorization expires or is exhausted
• Implement automated authorization tracking in your practice management system that flags claims approaching authorization limits
• Review the authorization details (dates, units, CPT codes) before each service delivery to ensure the visit is still within scope
• Maintain a centralized authorization log accessible to scheduling, clinical, and billing staff
• Train clinical staff to document ongoing medical necessity at each visit to support future reauthorization requests

Also Filed As

The same CARC 198 may appear with different Group Codes:

Related Denial Codes