How do I resolve a CO-171 denial?

Verify the rendering provider taxonomy code and NPI submitted on the claim: Compare the submitted provider type and place of service code against the payer's contract terms to confirm the mismatch Check the Healthcare Policy Identification Segment (loop 2110 REF) in the 835 file: This segment will contain the specific policy reference explaining which provider or facility types are authorized for this service Process the contractual write-off and update credentialing or billing workflows: Ensure future claims for this service type are billed under an appropriate contracted provider or facility to prevent recurrence

835 Denial Combination

CO-171

Contractual Obligation · Service-Line Level Adjustment

Coding Error

What This Combination Means

This denial indicates a provider type or facility type mismatch for the billed service under the contract. The payer is denying payment because the service was performed by a provider type or in a facility type that is not authorized to bill for this particular service under the terms of the provider agreement. The provider must contractually absorb this as a write-off.

Financial Responsibility

provider writeoff

The provider must write off the denied amount as a contractual obligation and cannot balance bill the patient. This is a contract limitation on which providers or facilities may bill for specific services.

N/A

Appeal Success

Immediate (write-off)

Avg. Resolution

Easy

Difficulty

Appealable

Step-by-Step Resolution

Steps tailored specifically to this CO-171 combination — not generic advice.

Not Appealable:This is a contractual limitation defining which provider or facility types may bill for services, not a coding error that can be corrected or a medical necessity determination that can be challenged.

1
Verify the rendering provider taxonomy code and NPI submitted on the claim
Compare the submitted provider type and place of service code against the payer's contract terms to confirm the mismatch
2
Check the Healthcare Policy Identification Segment (loop 2110 REF) in the 835 file
This segment will contain the specific policy reference explaining which provider or facility types are authorized for this service
3
Process the contractual write-off and update credentialing or billing workflows
Ensure future claims for this service type are billed under an appropriate contracted provider or facility to prevent recurrence

Specialty Context

How CO-171 typically presents across different practice types.

Dental

May occur when general dentists bill for specialist procedures (e.g., endodontics, periodontics) that the plan restricts to specialists only, or when billing from a non-contracted facility type

Medical

Common when mid-level providers (NPs, PAs) bill for services restricted to physicians, when hospital outpatient departments bill for services only allowed in physician offices, or when non-facility providers use facility codes

Behavioral Health

May occur when LCSWs or counselors bill for services restricted to licensed psychologists or psychiatrists, or when telehealth services are billed by provider types not authorized for virtual care under the contract

Individual Code References

View the standalone definition for each code in this combination.

CARC 171

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Synthesized from official definitions — not from training data

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