What does CO-197 mean?

CO-197 is a Contractual Obligation (CO) denial: "Precertification/authorization/notification/pre-treatment absent." The service required prior authorization (or notification) that wasn't obtained before it was provided, so the payer denied it.

CO · Contractual ObligationCARC 197

Denial Code CO-197

Q: Is CO-197 the patient's responsibility or a provider write-off?

CO-197 carries the CO group code (Contractual Obligation): Provider/contractual responsibility — not billable to the patient while denied. A CO adjustment is the provider's responsibility, not the patient's: balance-billing the patient for a CO amount is a contract (and often compliance) violation. But CO does not automatically mean “write it off.” When the cause is fixable — missing information (CO-16), a modifier problem (CO-4), or NCCI bundling (CO-97) — you correct and resubmit, or appeal with documentation. You only truly write the amount off when it is a final contractual adjustment, such as the fee-schedule difference on CO-45.

Precertification/authorization/notification/pre-treatment absent.

Source: X12 Claim Adjustment Reason Codes (CARC) & Group Codes. Maintained by the D3rx Clinical Billing Team.

What CO-197 means

The service required prior authorization (or notification) that wasn't obtained before it was provided, so the payer denied it.

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CO group code: who absorbs the charge

Contractual Obligation — Provider/contractual responsibility — not billable to the patient while denied.

A CO adjustment is the provider's responsibility, not the patient's: balance-billing the patient for a CO amount is a contract (and often compliance) violation. But CO does not automatically mean “write it off.” When the cause is fixable — missing information (CO-16), a modifier problem (CO-4), or NCCI bundling (CO-97) — you correct and resubmit, or appeal with documentation. You only truly write the amount off when it is a final contractual adjustment, such as the fee-schedule difference on CO-45.

Why CO-197 happens

Prior authorization was required but never obtained before the service
Authorization was obtained but the auth number wasn't placed on the claim
The authorization expired before the date of service
The service performed differed from what was authorized (different code, site, or units)

What to do when you get CO-197

1Check whether a valid authorization actually exists; if so, add the auth number and resubmit a corrected claim
2If the auth covered a different code/units, compare it to what was performed
3If no auth exists, request a retroactive authorization with clinical documentation (many payers allow a short window)
4Document medical necessity to support a retro-auth or appeal

Appeal, correct, or write off CO-197?

If authorization existed and was simply left off the claim, that is a corrected-claim fix, not an appeal. If no authorization was obtained, appeal or request retroactive authorization with clinical records showing the service was medically necessary — and, where applicable, that it was urgent/emergent (many plans waive prior auth for true emergencies). The strongest appeals attach the documentation that would have supported the auth in the first place.

Timing & deadlines

Retro-authorization and appeal windows are short and payer-specific — act within days, not weeks. Standard appeal anchors apply (Medicare redetermination 120 days from the remittance; commercial ~180 days), but many payers cap retro-auth requests at a small number of business days after the service or denial.

Example

An advanced imaging study (e.g., an MRI) is scheduled and performed, but the ordering office never obtained the required prior authorization. The payer returns CO-197. The practice requests a retroactive authorization with the clinical notes; if granted, it resubmits with the auth number.

Prevent CO-197 going forward

Build a prior-auth check into scheduling for every auth-required service
Maintain a payer-by-service prior-authorization grid and keep it current
Verify the auth covers the exact code, units, site, and date before the visit
Track auth expiration dates so they don't lapse before the service

Code families most affected

Advanced imaging (CT/MRI/PET, 70000-series)
Elective surgeries and procedures
High-cost drugs/biologics and DME
Specialty services with payer auth requirements

Related codes

Denial codes you'll often see alongside CO-197

CO-16 PR-204 CO-50

Payer notes

Which services need prior authorization varies widely by payer and plan and changes frequently, so a current payer-specific auth list is essential. Many payers route auth through third-party benefit managers (e.g., for imaging or musculoskeletal care), and some offer 'gold card' programs that waive auth for high-performing providers.

Turn this CO-197 denial into a sent appeal

D3rx drafts a ready-to-send, e-signable appeal letter for CO-197 from your claim details — free, backed by CMS, Medicare, and major-payer data.

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Medical billing disclaimer

CARC/RARC definitions are the standardized X12 set; group-code semantics follow the X12 Claim Adjustment Group Code standard. Filing and appeal windows vary by payer — the standard anchors shown (Medicare redetermination 120 days from the remittance; Medicare timely filing 12 months from date of service; most commercial payers ~90-180 days) are general references, not a guarantee for any specific plan. Always confirm the rule in the payer's provider manual before acting. D3rx is not responsible for claim outcomes.