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CARC 50 · CO-50

CARC 50 Denial: These are non-covered services because this is not deemed a 'medical necessity'… — How to Fix and Appeal

QuickIntell editorial content · Legacy registry date · Review not verified

Updated

TL;DR

CARC 50 (X12 These are non-covered services because this is not deemed a 'medical necessity' by the payer). CARC 50 is a medical-necessity denial — the payer does not believe the clinical record supports the service you billed.

Official X12 description

“These are non-covered services because this is not deemed a 'medical necessity' by the payer.”

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 50 actually means

CARC 50 is a medical-necessity denial — the payer does not believe the clinical record supports the service you billed. This is the classic denial where an appeal is usually warranted: if the chart documents the medical indication, pull the note, cite the applicable LCD or commercial medical-policy section, and submit a first-level appeal. Medicare CARC 50 denials are tied to a specific NCD or LCD; commercial CARC 50 denials reference the payer's published medical policy.

Common root causes

  • Diagnosis on the claim is not on the payer's covered-diagnosis list (overlaps heavily with CARC 11 and 167).
  • Ordering provider did not meet a payer prerequisite (e.g., conservative therapy tried first for back surgery).
  • Clinical documentation does not support the level of service billed (e.g., E/M billed higher than the note supports).
  • Frequency limit exceeded (e.g., routine physical more than once per year).

Prevention checklist

  • Front-end medical-necessity scrubbing against LCDs and commercial medical policies.
  • Prior-authorization workflow for any service where the payer's policy flags it as medically-necessity-reviewed.
  • Clinical-documentation-improvement (CDI) program for high-risk services (spine surgery, advanced imaging, sleep studies).

Appeal strategy — step by step

Most CARC 50 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. 1Submit a first-level appeal with the full clinical record — the office note, any relevant imaging reports, prior conservative-therapy notes, and specialist consultations.
  2. 2Cite the payer's specific medical policy or LCD and quote the criterion your documentation satisfies.
  3. 3Include peer-reviewed literature for emerging or guideline-based indications where the policy is stale.
  4. 4If peer-to-peer review is offered, use it before written appeal — often faster and equally effective.
Sample appeal-letter language for CARC 50
[Provider letterhead] Re: Appeal of CARC 50 — Claim #{claim_number} Member: {member_name} · Member ID: {member_id} Date(s) of Service: {dos} On {remittance_date} this claim was adjusted with CARC 50: "These are non-covered services because this is not deemed a 'medical necessity' by the payer." We respectfully request reconsideration. The X12 External Code List definition of CARC 50 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 50 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 50?

Search demand rank
#6

Out of 306 seeded CARCs, ranked by combined US monthly search volume for "CARC 50", "CO-50 denial", and "denial code 50".

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 50

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.
Prevent denials before submission →Work and appeal denialsBook a demo

CAQH CORE code combinations for CARC 50

Under the CAQH CORE Payment and Remittance Uniform Use rule, health plans may pair CARC 50 only with the remark codes and group codes below for the defined business scenario 3 (Billed service not covered by the health plan). A combination outside this list on an 835 is itself a payer compliance issue worth raising.

CORE-required CARC/RARC/CAGC combinations for CARC 50
RARCRemark descriptionGroup codeScenario
(no RARC)CARC used without a remark codeCO, PI or PR3
M1X-ray not taken within the past 12 months or near enough to the start of treatment.CO, PI or PR3
M25The information furnished does not substantiate the need for this level of service. If you believe the service should have been fully covered as billed, or if you did not know and could not reasonably have been expected to know that we would not pay for this level of service, or if you notified the patient in writing in advance that we would not pay for this level of service and he/she agreed in writing to pay, ask us to review your claim within 120 days of the date of this notice. If you do not request an appeal, we will, upon application from the patient, reimburse him/her for the amount you have collected from him/her in excess of any deductible and coinsurance amounts. We will recover the reimbursement from you as an overpayment.CO, PI or PR3
M26The information furnished does not substantiate the need for this level of service. If you have collected any amount from the patient for this level of service /any amount that exceeds the limiting charge for the less extensive service, the law requires you to refund that amount to the patient within 30 days of receiving this notice. The requirements for refund are in 1824(I) of the Social Security Act and 42CFR411.408. The section specifies that physicians who knowingly and willfully fail to make appropriate refunds may be subject to civil monetary penalties and/or exclusion from the program. If you have any questions about this notice, please contact this office.CO, PI or PR3
M31Missing radiology report.CO, PI or PR3
M51Missing/incomplete/invalid procedure code(s).CO, PI or PR3
M60Missing Certificate of Medical Necessity.CO, PI or PR3
M64Missing/incomplete/invalid other diagnosis.CO, PI or PR3
M76Missing/incomplete/invalid diagnosis or condition.CO, PI or PR3
M85Subjected to review of physician evaluation and management services.CO, PI or PR3
M127Missing patient medical record for this service.CO, PI or PR3
M135Missing/incomplete/invalid plan of treatment.CO, PI or PR3
MA126Pancreas transplant not covered unless kidney transplant performed.CO, PI or PR3
N10Adjustment based on the findings of a review organization/professional consult/manual adjudication/medical advisor/dental advisor/peer review.CO, PI or PR3
N40Missing radiology film(s)/image(s).CO, PI or PR3
N45Payment based on authorized amount.CO, PI or PR3
N115This decision was based on a Local Coverage Determination (LCD). An LCD provides a guide to assist in determining whether a particular item or service is covered. A copy of this policy is available at www.cms.gov/mcd, or if you do not have web access, you may contact the contractor to request a copy of the LCD.CO, PI or PR3
N124Payment has been denied for the/made only for a less extensive service/item because the information furnished does not substantiate the need for the (more extensive) service/item. The patient is liable for the charges for this service/item as you informed the patient in writing before the service/item was furnished that we would not pay for it, and the patient agreed to pay.PR3
N129Not eligible due to the patient's age.CO, PI or PR3
N130Consult plan benefit documents/guidelines for information about restrictions for this service.CO, PI or PR3
N161This drug/service/supply is covered only when the associated service is covered.CO, PI or PR3
N163Medical record does not support code billed per the code definition.CO, PI or PR3
N170A new/revised/renewed certificate of medical necessity is needed.CO, PI or PR3
N178Missing pre-operative images/visual field results.CO, PI or PR3
N180This item or service does not meet the criteria for the category under which it was billed.CO, PI or PR3
N206The supporting documentation does not match the information sent on the claim.CO, PI or PR3
N214Missing/incomplete/invalid history of the related initial surgical procedure(s)CO, PI or PR3
N227Incomplete/invalid Certificate of Medical Necessity.CO, PI or PR3
N229Incomplete/invalid contract indicator.CO, PI or PR3
N237Incomplete/invalid patient medical record for this service.CO, PI or PR3
N238Incomplete/invalid physician certified plan of careCO, PI or PR3
N240Incomplete/invalid radiology report.CO, PI or PR3
N242Incomplete/invalid radiology film(s)/image(s).CO, PI or PR3
N244Incomplete/Invalid pre-operative images/visual field results.CO, PI or PR3
N362The number of Days or Units of Service exceeds our acceptable maximum.CO, PI or PR3
N372Only reasonable and necessary maintenance/service charges are covered.CO, PI or PR3
N383Not covered when deemed cosmetic.CO, PI or PR3
N386This decision was based on a National Coverage Determination (NCD). An NCD provides a coverage determination as to whether a particular item or service is covered. A copy of this policy is available at www.cms.gov/mcd/search.asp. If you do not have web access, you may contact the contractor to request a copy of the NCD.CO, PI or PR3
N429Not covered when considered routine.CO, PI or PR3
N443Missing/incomplete/invalid total time or begin/end time.CO, PI or PR3
N455Missing Physician Order.CO, PI or PR3
N456Incomplete/invalid Physician Order.CO, PI or PR3
N607Service provided for non-compensable condition(s).CO, PI or PR3
N646Reimbursement has been adjusted based on the guidelines for an assistant.CO, PI or PR3
N658The billed service(s) are not considered medical expenses.CO, PI or PR3
N661Documentation does not support that the services rendered were medically necessary.CO, PI or PR3
N721This service is only covered when performed as part of a clinical trial.CO, PI or PR3
N734The patient is eligible for these medical services only when unable to work or perform normal activities due to an illness or injury.CO, PI or PR3
N789Clinical Trial is not a covered benefit.CO, PI or PR3
N794Payment adjusted based on type of technology used.CO, PI or PR3
Source: CAQH CORE-required Code Combinations v3.10.0 (2026-02).

The rule behind CARC 50

CARC 50 is a medical-necessity denial: the diagnosis on the claim is not on the covered list of the governing NCD or LCD. Find the contractor's LCD for the service, check the national policy where one exists, and compare the claim's diagnosis with the covered list.

Frequently asked questions — CARC 50

What does CARC 50 mean?

CARC 50 is an X12 Claim Adjustment Reason Code. The official definition is: "These are non-covered services because this is not deemed a 'medical necessity' by the payer." In plain English, the payer is telling you cARC 50 is a medical-necessity denial — the payer does not believe the clinical record supports the service you billed. This is the classic denial where an appeal is usually warranted: if the chart documents the medical indication, pull the note, cite the applicable LCD or commercial medical-policy section, and submit a first-level appeal. Medicare CARC 50 denials are tied to a specific NCD or LCD; commercial CARC 50 denials reference the payer's published medical policy.

How do I resolve a CARC 50 (CO-50) denial?

Start with the most common root cause: Diagnosis on the claim is not on the payer's covered-diagnosis list (overlaps heavily with CARC 11 and 167). First step: Submit a first-level appeal with the full clinical record — the office note, any relevant imaging reports, prior conservative-therapy notes, and specialist consultations. See the full remediation and appeal checklist on this page before filing a formal appeal.

Is CARC 50 patient responsibility?

No — CARC 50 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 50 look like on an EOB or 835 remittance?

On the 835 ERA, CARC 50 appears in Loop 2110 CAS segment as "CAS*CO*50*{amount}". On a paper EOB the same code prints in the Adjustment/Denial Reason column with the X12 description: "These are non-covered services because this is not deemed a 'medical necessity' by the payer." — usually paired with one or more RARC remark codes in the same remittance line for additional context.

Which RARC is paired with CARC 50?

CARC 50 is commonly observed with RARC N115, N130, N386. 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.