CO-197
CO · Contractual Obligation
CO-197 Denial Code: Required prior authorization or precertification is missing
A required prior authorization, precertification, or notification was not obtained before the service. As a CO adjustment it cannot be billed to the patient unless plan rules allow.
- Group code
- CO - Contractual Obligation
- Code type
- CARC
- Billable to patient?
- No - contractual write-off
- Appealable?
- Sometimes - if an auth exists or retro-auth is allowed
- Category
- Authorization & Precertification
- Common pairing
- N54
On a remittance
CAS*CO*197*125.00On a paper EOB it shows as CO-197.What CO-197 means
CO-197 means the service required prior authorization and the payer has no auth on file. Some are unavoidable write-offs; many are recoverable through a retroactive authorization, by proving an auth existed, or by showing the service was urgent/emergent and exempt from prior-auth rules.
Common causes
- No prior authorization was obtained before a service that required one.
- An authorization existed but the number was missing or wrong on the claim.
- The auth did not match the actual CPT, units, dates, or rendering provider.
- An urgent/emergent service was treated as requiring prior auth when it may be exempt.
How to fix it
- Check whether an authorization actually exists; if so, resubmit a corrected claim with the correct auth number.
- If no auth exists, ask whether the payer allows a retroactive authorization - some do, but often only for urgent/emergent care or narrow circumstances.
- If the service was emergent, appeal citing the emergency exception with documentation.
- Confirm the auth covers the exact codes, units, dates, and provider billed.
How to prevent it
- Maintain a payer-by-service prior-auth matrix and check it at scheduling.
- Verify the auth matches the planned CPT, units, dates, and rendering provider before the service.
- Track auth expiration dates so services do not fall outside the approved window.
Sometimes - if an auth exists or retro-auth is allowedAppealable when an auth exists, a retro-auth is granted, or an emergency exception applies. Attach the auth or the emergency documentation.
Appeal letter template
Fill in the bracketed fields, attach your supporting documentation, and send through the payer's appeal channel. This is a starting point — adjust to your payer's requirements.
Re: Authorization Appeal (CO-197) - Claim [Claim Number] Patient: [Patient Name] | Member ID: [Member ID] Date(s) of Service: [DOS] | Service: [CPT/HCPCS] To Whom It May Concern: Claim [Claim Number] was denied under CO-197 for absent authorization. [Choose: Authorization [Auth Number] was approved on [Date] for this service - see enclosed. / This was an emergent service exempt from prior authorization, as documented in the enclosed records. / We request a retroactive authorization per your policy.] We request reprocessing and payment. Sincerely, [Your Name], [Practice Name] | [Phone] | [NPI/TIN]