CO-198 means an authorization existed, but the claim went beyond it: more visits or units than approved, or a date outside the approved window. Ask the payer for an extension or update, then resubmit. Track visits against every authorization.
The official wording
The X12 Claim Adjustment Reason Code list defines 198 as: "Precertification/notification/authorization/pre-treatment exceeded."
The letters in front are the group code. CO means contractual obligation (the provider absorbs it), PR means patient responsibility, and OA is other adjustment. The same reason code can come with different group codes, so always read both.
Common causes
- More visits or units than approved, common in therapy and behavioral health.
- Services after the authorization's end date.
- A different code billed than the one authorized.
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How to fix it
- Compare the claim with the authorization: codes, units, dates.
- Ask the payer to extend or update the authorization, with clinical notes.
- Resubmit with the updated authorization number.
One case that ran past its authorization
A payer approves 12 physical therapy visits from March 1 to April 30. The patient comes 14 times before April 30.
| Visit | Status | Result |
|---|---|---|
| Visits 1 to 12 | Inside the approval | Paid |
| Visit 13 | Over the approved count | CO-198 |
| Visit 14 | Over the approved count | CO-198 |
Visits 13 and 14 can still be paid if the payer extends the authorization. Ask before the window closes.
CO-198 vs CO-197
| Code | What it means | Usual fix |
|---|---|---|
| CO-197 | No authorization on file at all | Find the auth, ask for retro auth, or appeal. See our CO-197 guide. |
| CO-198 | An authorization exists, but the claim went past it | Ask for an extension or update, then resubmit |
Remark code that often comes with CO-198
| Remark code | Official wording | What to do |
|---|---|---|
| N54 | "Claim information is inconsistent with pre-certified/authorized services." | Compare the CPT codes, units, dates and provider on the claim with the approval. |
How to track authorizations so CO-198 stops
- Enter each authorization in your system with codes, units, start date and end date.
- Count units and visits used after every visit.
- Set an alert when 2 visits or 20% of units are left.
- Ask for an extension with updated notes before the last approved visit.
- Put the new authorization number on later claims.
CO-198 checklist
- ☐ Visits and units used are counted against the approval.
- ☐ The date of service is inside the approved dates.
- ☐ The CPT code billed is the code approved.
- ☐ Extensions are requested before the approval runs out.
Questions people ask about CO-198
Can I bill the patient for CO-198?
Generally no for in-network services.
How do I prevent CO-198?
Track visits and units used against each authorization and request an extension before the last approved visit.
What is the difference between CO-197 and CO-198?
CO-197 means no authorization was on file. CO-198 means one was on file but the claim went past its visits, units, dates or codes.
Can the payer extend an authorization after the visit?
Some do, if you ask quickly and send notes showing the care was needed. Check the payer's rules.
Which services get CO-198 the most?
Therapy, behavioral health, home health and other services approved in a set number of visits or units.
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All denial code guides
PR-1 · PR-2 · PR-3 · CO-4 · CO-5 · CO-11 · CO-15 · CO-16 · OA-18 · CO-22 · OA-23 · CO-24 · CO-26 · CO-27 · CO-29 · CO-31 · CO-45 · CO-49 · CO-50 · CO-59 · PR-96 · CO-97 · CO-109 · CO-119 · CO-129 · CO-140 · CO-146 · CO-151 · CO-167 · CO-170 · CO-181 · CO-185 · CO-197 · CO-198 · PR-204 · CO-234 · CO-236 · CO-242 · CO-252 · CO-253 · CO-288 · CO-A1 · CO-B7 · MA130 · N130 · N23 · N290
Timely filing limits by payer: Cigna timely filing limit · HealthSpring timely filing limit · Aetna timely filing limit · UnitedHealthcare timely filing limit · Humana timely filing limit · corrected claim timely filing limits
Sources: X12 Claim Adjustment Reason Code list (198), read October 27, 2026; CMS Medicare guidance where Medicare rules are mentioned; X12 Remittance Advice Remark Code list (N54), read October 27, 2026. Last reviewed October 27, 2026. General information, not coding or legal advice. Payer rules differ, so check the remark code and the payer's own policy.