What does denial code CO-197 mean?

CARC 197 is 'Precertification/authorization/notification/pre-treatment absent.' The payer required prior authorization, precertification, notification, or pre-treatment approval for the service and did not find it on the claim.

CO-197 Denial Code: Prior-Authorization Denials & How to Appeal (2026)

Q: How do I appeal a CO-197 denial?

If authorization was obtained, appeal with the authorization number and the approval documentation attached, and reference the date it was granted. If authorization was not required for the service or plan, cite the payer's own policy. If a retroactive authorization is allowed, request it within the payer's timeframe.

Q: Can CO-197 be prevented?

Largely, yes — by verifying authorization requirements before the service, obtaining and recording the authorization number, and confirming it is attached to the claim at submission. The denials that remain are the ones where authorization existed but the payer failed to match it, which are appealable.

"Authorization absent" is one of the most common — and most overturnable — denials, because so often the authorization wasn't absent at all.

CARC CO-197 reads, verbatim, "Precertification/authorization/notification/pre-treatment absent." The payer required prior approval for the service and didn't find it on the claim. It's a high-volume denial — and a high-value one, because a meaningful share of CO-197 denials land on claims where the authorization was obtained. When your record shows the auth on file, this denial is appealable.

What causes CO-197

Authorization was genuinely never obtained before the service.
Authorization was obtained, but the number wasn't attached to the claim, or the payer failed to match it.
The service didn't actually require authorization for that plan — a payer or plan-loading error.
The authorization expired or covered a slightly different code or tooth than billed.
Notification (not full prior-auth) was the requirement, and it was made but not recorded.

When the payer is wrong

The appealable cases are the ones where your record contradicts the denial:

Authorization on file. You have the authorization number and approval date. This is the clearest win — attach it.
Authorization not required. The payer's own policy didn't require prior-auth for that service or plan. Cite the policy.
Retroactive authorization allowed. Some payers grant retro-auth for urgent or emergency care within a set window. Request it.
Notification, not authorization. If only notification was required and it was made, document it.

ClaimZen checks every CO-197 denial against the practice's own records — surfacing the claims where the authorization number is on file, and drafting the appeal with the authorization cited and attached. Nothing is sent without your approval.

How to appeal

Keep it factual and evidence-first: "Claim #… was denied CO-197 for absent authorization. Authorization #… was obtained on … for this service and is attached. We request reprocessing for payment." Attach the approval. If authorization wasn't required, quote the payer's policy instead. See the full step-by-step appeal guide, and mind the timely-filing window on the appeal itself — see timely filing limits.

How to prevent it

Verify authorization requirements before the service, capture the authorization number in the chart, and confirm it's attached to the claim at submission. Prevention closes most of the gap; the denials that remain — auth obtained, payer didn't match it — are exactly the ones worth appealing.

Frequently asked questions

What does CO-197 mean?

"Precertification/authorization/notification/pre-treatment absent." The payer required prior approval for the service and didn't find it on the claim.

How do I appeal a CO-197 denial?

If auth was obtained, appeal with the authorization number and approval documentation attached. If it wasn't required, cite the payer's policy. If retro-auth is allowed, request it within the window.

Can CO-197 be prevented?

Largely — verify auth requirements beforehand, record the number, and confirm it's attached at submission. The remaining denials (auth obtained, payer didn't match it) are appealable.

Sources

X12, Claim Adjustment Reason Codes: CARC 197, "Precertification/authorization/notification/pre-treatment absent."

General information, not billing, legal, or coding advice.

CO-197: prior-authorization denials, and when the payer is wrong