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CARC 155 · CO-155

CARC 155 Denial: Patient refused the service/procedure — How to Fix and Appeal

Reviewed by QuickIntell RCM Editorial Team · Last reviewed

Updated

TL;DR

CARC 155 (X12 Patient refused the service/procedure). CARC 155 denies the charge because the documentation indicates the patient refused the service.

Official X12 description

“Patient refused the service/procedure.”

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 155 actually means

CARC 155 denies the charge because the documentation indicates the patient refused the service. Verify the documentation and bill only for the portion that was actually rendered before refusal, or appeal if the documentation is inaccurate.

Common root causes

  • Clinical note explicitly shows patient refused or did not complete the service.

Prevention checklist

  • Clinical documentation training: refusal events documented as refusal, not as completed service.

Appeal strategy — step by step

Most CARC 155 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. 1If service was actually rendered, appeal with corrected documentation.
  2. 2Otherwise accept the denial.
Sample appeal-letter language for CARC 155
[Provider letterhead] Re: Appeal of CARC 155 — Claim #{claim_number} Member: {member_name} · Member ID: {member_id} Date(s) of Service: {dos} On {remittance_date} this claim was adjusted with CARC 155: "Patient refused the service/procedure." We respectfully request reconsideration. The X12 External Code List definition of CARC 155 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 155 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 155?

Search demand rank
#187

Out of 306 seeded CARCs, ranked by combined US monthly search volume for "CARC 155", "CO-155 denial", and "denial code 155".

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 155

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 155

What does CARC 155 mean?

CARC 155 is an X12 Claim Adjustment Reason Code. The official definition is: "Patient refused the service/procedure." In plain English, the payer is telling you cARC 155 denies the charge because the documentation indicates the patient refused the service. Verify the documentation and bill only for the portion that was actually rendered before refusal, or appeal if the documentation is inaccurate.

How do I resolve a CARC 155 (CO-155) denial?

Start with the most common root cause: Clinical note explicitly shows patient refused or did not complete the service. First step: If service was actually rendered, appeal with corrected documentation. See the full remediation and appeal checklist on this page before filing a formal appeal.

Is CARC 155 patient responsibility?

No — CARC 155 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 155 look like on an EOB or 835 remittance?

On the 835 ERA, CARC 155 appears in Loop 2110 CAS segment as "CAS*CO*155*{amount}". On a paper EOB the same code prints in the Adjustment/Denial Reason column with the X12 description: "Patient refused the service/procedure." — usually paired with one or more RARC remark codes in the same remittance line for additional context.

Can CARC 155 be appealed successfully?

Yes — when the root cause does not apply to the specific claim. Overturn rates are strongest when the appeal cites the X12 definition, the payer's own published policy, and documentation that rebuts the payer's rationale. The sample appeal language block above is a starting point; always adapt it to the payer's reconsideration form.

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.