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CARC 170 · CO-170

CARC 170 Denial: Payment is denied when performed/billed by this type of provider — How to Fix and Appeal

Reviewed by QuickIntell RCM Editorial Team · Last reviewed

Updated

TL;DR

CARC 170 (X12 Payment is denied when performed/billed by this type of provider). CARC 170 denies the service because the billing or rendering provider type is not eligible to bill this code under the payer's policy — common examples are PTs billing an MD-only code, NPs billing without their supervising MD rule met, or ancillaries billing a procedure restricted to the primary…

Official X12 description

“Payment is denied when performed/billed by this type of provider.”

Source: X12 Claim Adjustment Reason Codes. The X12 External Code Lists are the single authoritative source for every CARC descriptor — always verify against the current release before building a claim-scrub rule.

What CARC 170 actually means

CARC 170 denies the service because the billing or rendering provider type is not eligible to bill this code under the payer's policy — common examples are PTs billing an MD-only code, NPs billing without their supervising MD rule met, or ancillaries billing a procedure restricted to the primary provider. Verify taxonomy/scope and rebill from the correct provider or appeal with scope documentation.

Common root causes

  • CPT/HCPCS restricted by provider taxonomy (surgery-only, MD-only, PT-only).
  • Split/shared or incident-to billing rules not met for mid-level providers.

Prevention checklist

  • Coder training on taxonomy-provider eligibility per the payer's policy.
  • Incident-to / split-shared checklist at the point of charge capture.

Appeal strategy — step by step

Most CARC 170 denials clear faster with the right remediation than with a formal appeal. Work the steps in order and escalate only when a lower-effort path has been ruled out.

  1. 1Appeal with the provider's taxonomy enrollment, or rebill from the correct provider's NPI if another eligible provider rendered/participated.
Sample appeal-letter language for CARC 170
[Provider letterhead] Re: Appeal of CARC 170 — Claim #{claim_number} Member: {member_name} · Member ID: {member_id} Date(s) of Service: {dos} On {remittance_date} this claim was adjusted with CARC 170: "Payment is denied when performed/billed by this type of provider." We respectfully request reconsideration. The X12 External Code List definition of CARC 170 does not apply to this claim for the following reasons: 1. [Cite the clinical / coding / policy fact that rebuts the adjustment] 2. [Cite the supporting documentation attached — op note, EOB, LCD/NCD citation, NCCI edit indicator, modifier rationale] 3. [Cite the payer's own policy where applicable] Attached: {list supporting documents} Please process payment under the member's benefits. If additional information is required, contact the billing office at {provider_phone} or {provider_email}. Sincerely, {billing_manager_name}, {credentials}

Edit the bracketed fields before sending. This template is a starting point; a payer-specific appeal form may still be required — check the provider portal first.

Payer-specific notes

Payer-specific behavior for CARC 170 publishes here as the QuickIntell anonymized denial ETL ingests sufficient volume. In the meantime, consult the payer directory for the relevant provider manual and appeal form.

How common is CARC 170?

Search demand rank
#47

Out of 306 seeded CARCs, ranked by combined US monthly search volume for "CARC 170", "CO-170 denial", and "denial code 170".

Platform frequency
Pending ETL

Platform frequency ranks publish once the anonymized denial-rate pipeline reaches the publication threshold (strategy §12 Phase 2).

How QuickRCM prevents CARC 170

QuickRCM catches the root causes above before the 837 leaves the clearinghouse:

  • Claim-scrub rules fire on every root cause listed above — the scrub references the same X12 CAS segment logic that drives the denial, so what the payer checks, QuickRCM checks first.
  • When a denial lands, QuickRCM routes it to the correct worker with the documentation bundle already attached (op note, LCD citation, modifier rationale, EOB, primary 835).
  • Appeal templates tuned to each CARC (including this one) pull the supporting facts from the claim and fill the bracketed fields automatically.
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Frequently asked questions — CARC 170

What does CARC 170 mean?

CARC 170 is an X12 Claim Adjustment Reason Code. The official definition is: "Payment is denied when performed/billed by this type of provider." In plain English, the payer is telling you cARC 170 denies the service because the billing or rendering provider type is not eligible to bill this code under the payer's policy — common examples are PTs billing an MD-only code, NPs billing without their supervising MD rule met, or ancillaries billing a procedure restricted to the primary provider. Verify taxonomy/scope and rebill from the correct provider or appeal with scope documentation.

How do I resolve a CARC 170 (CO-170) denial?

Start with the most common root cause: CPT/HCPCS restricted by provider taxonomy (surgery-only, MD-only, PT-only). First step: Appeal with the provider's taxonomy enrollment, or rebill from the correct provider's NPI if another eligible provider rendered/participated. See the full remediation and appeal checklist on this page before filing a formal appeal.

Is CARC 170 patient responsibility?

No — CARC 170 is typically carried under CO (Contractual Obligation) or OA (Other Adjustment), which means it is the provider's responsibility, not the patient's. Do not bill the patient unless the 835 CAS group code is PR.

What does CARC 170 look like on an EOB or 835 remittance?

On the 835 ERA, CARC 170 appears in Loop 2110 CAS segment as "CAS*CO*170*{amount}". On a paper EOB the same code prints in the Adjustment/Denial Reason column with the X12 description: "Payment is denied when performed/billed by this type of provider." — usually paired with one or more RARC remark codes in the same remittance line for additional context.

Which RARC is paired with CARC 170?

CARC 170 is commonly observed with RARC N95. The RARC narrows the reason — for example, pointing at a missing modifier, an LCD citation, or a specific policy. Fix the underlying CARC first; the RARC usually clears with the corrected claim.

Disclaimer

This page is operational reference for medical-billing professionals. It is not legal, clinical, or contractual advice. X12 code descriptors are maintained by the X12 External Code Lists; always verify against the current X12 release and the payer's own published policy before submitting or appealing a claim.