CARC 50 — "These are non-covered services because this is not deemed a 'medical necessity' by the payer" — is one of the most infuriating denials in healthcare billing. The procedure was clinically indicated. The physician ordered it. The patient needed it. But the payer disagreed.
The good news: CARC 50 denials have one of the highest appeal success rates of any denial type — provided you know what to include in your appeal. Most billing teams file weak appeals, get the same denial back, and write it off. Here's how to do it right.
What Triggers a CARC 50 Denial?
Payers issue CARC 50 when a service doesn't meet their internal medical necessity criteria, which are typically based on:
- Clinical coverage policies (often called Local Coverage Determinations for Medicare, or payer-specific clinical policies for commercial payers)
- Diagnosis codes that don't support the procedure — e.g., billing a high-complexity MRI for a sprained ankle with no neurological symptoms
- Missing or insufficient clinical documentation in the claim record
- Step therapy or prerequisite requirements not met — e.g., prescribing a biologic before trialing conservative treatment
The most common reason appeals fail: the initial claim was submitted without documentation that would have prevented the denial in the first place.
Know the Payer's Criteria Before You Appeal
Before writing a single word, look up the payer's clinical coverage policy for the denied service. For Medicare, these are published as Local Coverage Determinations (LCDs) and National Coverage Determinations (NCDs) on the CMS website. For commercial payers, call Provider Services and ask for the specific medical necessity criteria they applied.
This step is non-negotiable. Your appeal must address their criteria, not your general clinical judgment.
The Five Elements of a Winning CARC 50 Appeal
1. Patient identification and claim details Date of service, claim number, NPI, procedure code(s), diagnosis code(s), and the amount denied. Make it easy for the appeal reviewer to find the original claim.
2. Clear statement of the dispute "We are appealing the denial of [CPT code] for [patient name] on [date of service]. The denial reason cited is CARC 50 (medical necessity). We believe this determination is incorrect and request a full redetermination."
3. Clinical documentation summary Summarize the patient's clinical history as it relates to medical necessity: diagnoses, symptom duration, prior treatments attempted (and their outcomes), functional limitations, and the clinical rationale for the denied service. Do not attach a wall of records — write a concise 1–2 paragraph clinical summary and attach the supporting documents.
4. Direct citation of the payer's own criteria This is the key. Quote the payer's coverage policy back to them and show how the patient meets each criterion. Example: "Per [Payer]'s Clinical Policy Bulletin #XXX, coverage for [service] is indicated when [criteria]. Patient [Name] meets these criteria as demonstrated by [specific documentation]."
5. Call to action Request a specific outcome: "We request that this claim be reconsidered and payment of $[amount] be issued within 30 days."
Sample Appeal Letter: CARC 50 Medical Necessity Denial
[Practice Letterhead]
Date: [Date]
Insurance Company: [Payer Name] Appeals Department Address: [Address]
RE: Appeal of Medical Necessity Denial Patient Name: [Patient Name] Date of Birth: [DOB] Member ID: [ID] Claim Number: [Claim Number] Date of Service: [Date] Procedure Code: [CPT Code] Denial Reason: CARC 50 — Medical Necessity Not Met Amount Denied: $[Amount]
Dear Appeals Coordinator,
We are writing to formally appeal the denial of [CPT code] — [procedure description] — for the above-referenced patient on [date of service]. [Payer]'s explanation of benefits cited CARC 50, indicating that medical necessity criteria were not met. We respectfully disagree with this determination and request a full appeal review.
Clinical Summary:
[Patient Name] is a [age]-year-old [male/female] presenting with [primary diagnosis] (ICD-10: [code]) with an onset date of [date]. The patient has experienced [describe symptoms, severity, functional impact]. Prior to recommending [procedure], the treating physician documented the following conservative treatments:
- [Treatment 1] from [date] to [date] — Result: [outcome]
- [Treatment 2] from [date] to [date] — Result: [outcome]
Given the failure of conservative management and the patient's ongoing functional limitations, [procedure] was recommended as the appropriate next step per [physician name, specialty]'s clinical judgment.
Criteria Analysis:
Per [Payer]'s Clinical Policy Bulletin [number] (effective [date]), [procedure] is covered when the following criteria are met:
- [Criterion 1] — Met. [Explanation with specific clinical data]
- [Criterion 2] — Met. [Explanation with specific clinical data]
- [Criterion 3] — Met. [Explanation with specific clinical data]
Attachments:
- Office visit notes from [date range]
- [Imaging/lab reports] dated [date]
- [Authorization correspondence, if applicable]
- Copy of original EOB
We request that this claim be reconsidered and that payment of $[amount] be issued within [payer's stated timeframe]. If you require additional clinical information, please contact our office at [phone number].
Respectfully,
[Billing Manager Name] [Practice Name] [Phone] | [Fax] | [Email]
Payer-Specific Tips for CARC 50 Appeals
Medicare: Request a Redetermination (Level 1 appeal) — this must be filed within 120 days of the denial notice. Use the CMS-20027 form (Redetermination Request Form). If denied, escalate to Reconsideration (Level 2) with a Qualified Independent Contractor.
UnitedHealthcare: UHC medical necessity appeals can be submitted through the UHC Provider Portal. Attach the clinical notes, the specific coverage criteria, and a physician attestation letter. Peer-to-peer review requests are available within 30 days of the denial.
Aetna: Aetna publishes Clinical Policy Bulletins publicly. Reference the specific bulletin number in your appeal. Attach all supporting documentation upfront — Aetna rarely requests additional information once an appeal is submitted.
Cigna: Cigna requires appeals within 180 days of the EOB date for most services. They also offer a pre-appeal Informal Dispute Resolution (IDR) process, which can resolve straightforward cases without a formal appeal.
What to Do When the Appeal Is Denied
If your first-level appeal fails, you typically have two more bites at the apple:
- Second-level internal appeal — Most payers allow a second internal review, often with a different clinical reviewer.
- External Independent Review — If both internal levels are exhausted, you can request an Independent Medical Review (IMR) through your state's Department of Insurance. These are mandatory for most commercial payers and overturn insurer denials at surprisingly high rates.
Don't stop at the first denial. The work compounds — a well-documented case that reaches external review has a strong record behind it.
The Bottom Line
A CARC 50 denial is not the end of the conversation — it's the beginning of an appeal. The providers who win these consistently are the ones who:
- Know the payer's specific criteria before they appeal
- Organize clinical documentation into a coherent narrative
- Quote the criteria back to the payer
- Follow up relentlessly within the timelines
For a complete appeal template library — pre-filled for the most common CARC codes — join the Arceum waitlist. We'll send you the full template set when we launch.