Denial code · CARC 170
CARC 170 (CO-170): provider type not paid for the service
What CO-170 means for counselors, therapists, associates, peer specialists and technicians, Medicare's 2024 change for family therapists and mental health counselors, and how to fix or appeal it.
By the ClaimParrot editorial team · Who we are · Reviewed · 4 min read · 4 cited sources
Quick answer
CARC 170 means the payer does not pay for the service when the type of provider on the claim performs or bills it. In behavioral health it hits license types a plan does not recognize, associates billing under their own NPI, peer specialists, and technicians billing analyst-level codes. Correct who is billed if the payer's rules allow it; otherwise appeal with the license and the plan's rules.
| Item | Detail |
|---|---|
| Code | CARC 170 · Active on the X12 list; checked October 14, 2026 |
| Plain meaning | The payer does not pay for this service when the type of provider on the claim, such as a counselor, an associate or a peer specialist, performs or bills it. |
| Group codes seen | CO (contractual obligation), PR (patient responsibility) |
| Common remark codes | N95, N808, N665, M143 |
| Where it shows up in BH | Outpatient therapy, Partial hospitalization (PHP), ABA therapy, Residential SUD (ASAM levels) |
| Usual next step | Correct the billing provider if allowed; otherwise appeal with license and plan rules |
| Related codes | CARC 185, CARC 16, CARC 4 |
What does CARC 170 mean?
CARC 170 is about the category of provider, not the individual. The payer's rules say this service is not payable from this provider type, such as a license level or specialty, however well the person did it. Compare CARC 185, which concerns one specific rendering clinician's eligibility.
Medicare changed the picture in 2024: since January 1, 2024, marriage and family therapists and mental health counselors, including qualifying addiction counselors, can enroll and bill Medicare directly. Medicare also allows behavioral-health services by auxiliary personnel incident to a physician or practitioner under general supervision.
What do CO-170 and PR-170 mean for who pays?
CO-170 is the usual form: recognized provider types are a contract and credentialing matter, so the amount stays with the provider and is not billed to the patient. A PR-170 can appear when a member chose an out-of-network provider type the plan does not cover; check the plan terms before billing.
| Group + reason | What it signals | Who usually carries the balance |
|---|---|---|
| CO-170 | This provider type is not paid for the service | Provider; not the patient |
| PR-170 | Plan assigns the cost to the member (out of network) | Patient, within the plan terms |
Which remark codes come with CARC 170?
These remark codes explain which provider rule the payer applied.
| Remark code | What it adds | What to check |
|---|---|---|
| N95 | Providers of this type or specialty may not bill this service. | The payer's list of provider types for the code |
| N808 | Not covered when provided by this provider type or specialty. | Coverage rules by provider type or specialty |
| N665 | Services from a provider without the required license are not paid. | Licensure of the clinician who delivered the service |
| M143 | The provider needs to update its license information with the payer. | License information on file with the payer |
Where does CARC 170 show up in behavioral health?
Behavioral-health 170 denials come from mismatches between who did the work and whom the payer pays. Typical cases are associate-level clinicians billing under their own NPI, license types a plan does not recognize, peer and paraprofessional staff billing restricted codes, and Medicare rules for counselors in hospital programs.
| Care setting | Typical trigger | Check first |
|---|---|---|
| Outpatient therapy | Associate or pre-licensed clinician billed as the rendering provider | The plan's rules for supervised clinicians |
| Partial hospitalization (PHP) | Counselor services to Medicare PHP or IOP patients billed under the counselor benefit | Medicare pays these through the hospital or CMHC program instead |
| ABA therapy | Technician session billed under a code meant for the supervising analyst | Who delivered the session and the code's provider requirement |
| Residential SUD (ASAM levels) | Peer or paraprofessional service billed by a provider type the state does not allow | The state's provider-type rules for the service |
Corrected claim, reconsideration or appeal: which fits CARC 170?
First check whether the service could be billed correctly another way: under a supervising clinician where the payer allows it, or incident to a physician or practitioner where Medicare rules permit. If so, send a corrected claim. If the payer misread the provider's license or type, appeal with the license and the plan's own rules.
- 01Confirm the clinician's license, the payer's recognized provider types and its supervision rules.
- 02Allowed alternative: correct the rendering and billing provider and resubmit.
- 03Misclassification: appeal with the license, the scope of practice and the payer's provider-type policy.
What evidence resolves a CARC 170?
The evidence is about the provider, not the patient: the license and its scope, the payer's provider-type and supervision rules, and the enrollment or credentialing record. Clinical notes help only to show who actually delivered the service and under whose supervision it happened.
- The clinician's license and scope of practice
- The payer's provider-type and supervision policy
- Enrollment or credentialing records for the clinician and group
- Notes showing who delivered and who supervised the service
- The claim's rendering and billing provider fields
How do Medicare, Medicaid and commercial plans differ on CARC 170?
Medicare recognizes a defined list of practitioners for behavioral-health services, which grew in 2024; Medicaid programs set provider types by state rule, often with modifiers; commercial plans set them in credentialing and payment policies. The same clinician can be payable under one program and not another.
| Program | What differs |
|---|---|
| Medicare (Original) | Family therapists and mental health counselors can enroll and bill since January 1, 2024; their services to hospital PHP and IOP patients are paid through the program, not their own benefit. |
| Medicaid | States define which provider types may deliver each service; Ohio Medicaid, for example, bars one provider type from billing SBIRT codes. |
| Commercial and ERISA plans | Credentialing and payment policies define recognized license types and how supervised clinicians are billed. |
CO-170 on an associate counselor's sessions
A fictional practice billed an associate counselor's sessions under her own NPI to a plan that pays only independently licensed clinicians. The lines came back CO-170 with N95.
The plan's manual allowed supervised associates' services to be billed under the supervising clinician with a modifier, so the practice corrected the claims, kept the supervision notes with each session and updated its billing rules for that payer.
Names, dates, payers and amounts are invented for illustration.
What a ClaimParrot packet does here
- When CARC 170 needs an appeal rather than a corrected claim, an appeal packet answers the payer's stated reason.
- A person checks every packet: $29, or $99 for level of care, and the first is free (pricing).
- No remittances, records or PHI are sent: just the reason and a de-identified summary (Trust & security).
Every draft is reviewed and approved by your team. ClaimParrot does not make medical-necessity determinations or give legal advice.
Frequently asked questions
Can mental health counselors and family therapists bill Medicare?
Yes, since January 1, 2024, if they meet Medicare's qualifications and enroll. Addiction counselors who meet the mental health counselor requirements can enroll in that category.
What is the difference between CARC 170 and CARC 185?
170 concerns the provider type: this kind of provider is not paid for the service. 185 concerns the specific rendering clinician, for example someone not enrolled or credentialed with the payer on that date.
Can we bill an associate's sessions under the supervisor?
Only where the payer's rules allow it, and Medicare's incident-to rules have their own conditions. Billing under a supervisor without meeting the payer's requirements is a compliance risk.
Can we bill the patient after a CO-170?
No. CO keeps the amount with the provider. Correct the billing where the rules allow, or appeal the provider-type decision.
Primary sources and references
- Claim Adjustment Reason Codes (CARC) code list · X12 · checked
- Remittance Advice Remark Codes (RARC) code list · X12 · checked
- MLN1986542, Medicare & Mental Health Coverage (March 2026) · CMS Medicare Learning Network · checked
- Ohio Medicaid Behavioral Health Provider Requirements and Reimbursement Manual, v1.28.1 (March 2026) · Ohio Department of Medicaid · checked
General information, not legal or medical advice. Payer rules change; confirm deadlines and requirements in the notice and the plan documents. Read our editorial policy.
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