What Does CO-198 Mean?

CO-198 is the common search form for Claim Adjustment Reason Code 198. For this code, the payer is communicating that the billed service exceeded the approved precertification, authorization, notification, or pre-treatment limits.

Common Causes of CO-198

• Billed Services Exceeded the Authorization Limit
  The number of visits, units, days, or services billed exceeded the approved authorization. This often occurs when scheduling, authorization tracking, treatment-plan changes, charge capture, and claim release is not aligned with authorization, notification, and precertification requirements effective for the service.
• Service Continued After the Authorization End Date
  The service continued after the authorization end date. The risk increases when information in the claim is not reconciled with the authorization record, payer approval, scheduling data, treatment plan, and final claim before submission.
• Additional Units Were Provided Before an Extension Request Was Approved
  Additional units were provided before an extension request was approved. If the same code appears repeatedly, compare the authorization number, approved service/code, units, dates, provider, facility, payer product, and billed claim line across recent claims to determine whether the issue is payer-specific or systemic.
• Service Changed After Approval
  The claim billed more units than were actually authorized because of charge-entry or unit errors. A one-time claim correction may not prevent recurrence when the underlying problem sits in scheduling, authorization tracking, treatment-plan changes, charge capture, and claim release.

How to Identify the Exact Reason for CO-198

• Compare Billed Units, Visits, Dates, and Provider With the Authorization
  Compare the authorization record with billed dates, procedure codes, units, visits, and provider. Start by comparing the authorization number, approved service/code, units, dates, provider, facility, payer product, and billed claim line.
• Check How Much of the Authorization Has Already Been Used
  Check how much of the authorization was already used on prior claims. Use the authorization record, payer approval, scheduling data, treatment plan, and final claim to determine whether the discrepancy began in provider-side data or during payer adjudication.
• Review Extension or Additional-Unit Requests
  Review payer portal status for extension or additional-unit requests. Confirm authorization, notification, and precertification requirements effective for the service, because current rules or records may differ from what applied when the claim was processed.
• Confirm Billed Units Match the Documented Service
  Confirm whether the claim units accurately reflect the documented service. If the remittance is not specific enough, use related RARCs, payer portal messages, and claim-history details to isolate the exact discrepancy.

How to Resolve or Appeal CO-198

• Correct Units That Exceed the Documented Service
  Correct billed units when the claim exceeds the documented service. Make a correction only when it is supported by the authorization record, payer approval, scheduling data, treatment plan, and final claim; avoid changing claim data simply to obtain payment.
• Request Additional or Retroactive Authorization When Allowed
  Request additional or retroactive authorization when payer policy allows and clinical criteria are met. Choose the payer’s new-claim, corrected-claim, reprocessing, or appeal route based on whether the submitted claim or the adjudication was wrong.
• Appeal With Authorization History When Approved Units Were Missed
  Appeal with authorization history if the payer failed to recognize approved additional units or dates. Include the relevant evidence from the authorization record, payer approval, scheduling data, treatment plan, and final claim when requesting reprocessing or appeal so the payer can reproduce the expected result.
• Split or Correct Claims That Span Authorized and Unauthorized Services
  Split or correct claims when only part of the service falls within the authorized period. Update scheduling, authorization tracking, treatment-plan changes, charge capture, and claim release if the same root cause could affect other open claims.

How to Prevent CO-198 Denials

• Track Remaining Authorized Visits, Units, and End Dates
  Track remaining authorized visits, units, and end dates in real time. Add a pre-bill or pre-service check that compares the authorization number, approved service/code, units, dates, provider, facility, payer product, and billed claim line before the claim is released.
• Alert Teams Before Authorization Limits Are Reached
  Alert clinical and scheduling teams before authorization limits are reached. Keep authorization, notification, and precertification requirements effective for the service current in billing rules and staff work instructions.
• Start Extension Requests Before Treatment Exceeds Approval
  Start extension requests early enough to avoid treatment continuing without approval. Test scheduling, authorization tracking, treatment-plan changes, charge capture, and claim release after payer, code-set, or system changes so required information is not lost, transformed, or left outdated.
• Reconcile Billed Units With Authorization Balances Before Release
  Reconcile billed units against authorization balances before claim release. Trend this code by payer, service, provider, and location to identify recurring patterns before they become a high-volume denial source.