What does denial code CO-170 mean?

CO-170 means the payer does not pay this service when it is performed or billed by your provider type. It commonly affects mid-level providers billing services a payer restricts to physicians, and ancillary provider types with limited payable service lists.

Can I rebill a CO-170 under a different provider?

Only where an eligible provider genuinely performed or properly supervised the service and that supervision is documented. Changing the rendering provider on a claim to someone who was not involved is a compliance exposure rather than a correction, regardless of the revenue at stake.

CO-170: This provider type may not be paid for this service

CO-170 is a policy restriction on who may be paid, not a question of whether the service happened or was necessary. It falls most often on claims billed under mid-level providers for services a payer restricts to physicians, and on ancillary provider types with narrow payable service lists. The important consequence is structural: if the restriction is genuine, no correction to this claim helps, and the practice needs to change who bills the service going forward or accept the write-off every time.

What it means: The payer's policy does not permit payment for this service when it is performed or billed by a provider of this type.
Who pays the balance: Contractual - billing under an ineligible provider type is a submission decision, not a patient one.
Group code CO: Contractual Obligation - the provider absorbs the balance and cannot bill the patient

Why CO-170 happens

A nurse practitioner or physician assistant billed a service the payer pays only to a physician.
The service was performed under physician supervision but billed directly under the mid-level provider rather than incident to the physician.
An ancillary provider type billed outside the narrow list of services the payer pays it for.
A facility-based provider type billed a service the payer expects the facility itself to bill.
The payer's policy changed and the practice's billing pattern did not change with it.

How to fix a CO-170 denial

1
Find the payer's policy on who may bill this service
Provider-type restrictions are published in the payer's provider manual or reimbursement policy. This tells you whether any billing arrangement makes the service payable at all.
2
Check whether incident-to or supervision billing applies
Where the service was genuinely supervised by an eligible provider and the supervision requirements were met and documented, billing under the supervising provider may be correct and the claim can be corrected.
3
Do not simply rebill under a different provider
Changing the rendering provider on a claim to one who did not perform or properly supervise the service is a compliance problem, not a billing fix. The supervision has to have actually happened and be documented.
4
Change the service model if the restriction is absolute
Where the payer will not pay this provider type for this service under any arrangement, the decision is operational - who performs it going forward - rather than something the A/R team can resolve.

Preventing CO-170 denials

Map each payer's provider-type restrictions against the services your mid-level providers actually deliver, before scheduling rather than after denial.
Document supervision contemporaneously wherever incident-to billing is used, since the documentation is what makes it defensible.
Review payer reimbursement policy updates for provider-type changes, which are among the least announced and most costly.

CO-170 frequently asked questions

What does denial code CO-170 mean?: CO-170 means the payer does not pay this service when it is performed or billed by your provider type. It commonly affects mid-level providers billing services a payer restricts to physicians, and ancillary provider types with limited payable service lists.
Can I rebill a CO-170 under a different provider?: Only where an eligible provider genuinely performed or properly supervised the service and that supervision is documented. Changing the rendering provider on a claim to someone who was not involved is a compliance exposure rather than a correction, regardless of the revenue at stake.

Related denial codes

CO-8 CO-185 CO-183 CO-16

Last reviewed August 5, 2026.

Denial code explanations are original plain-English summaries written for reference and are not the official X12 code descriptions. Payer handling of any code varies by contract - always verify against the remittance advice and your payer agreement before adjusting a claim.