Medicare Advantage Denials Guide
Medicare Advantage Denials Guide: Overview
MA denials follow CMS-standardized rules using consistent CARC and RARC codes. Redetermination window: 60 days from denial. Most denials stem from missing prior authorizations, insufficient documentation, or medical necessity concerns. Understanding denial codes and required evidence is critical for effective appeals.
Key Requirements
- Obtain Prior Authorization: Submit PA requests before service delivery for any service listed as requiring authorization in the MA plan's medical policy.
- Verify Medical Necessity: Ensure submitted documentation (clinical notes, test results, specialist recommendations) supports the medical necessity of the treatment.
- Check Coverage Limits: Confirm the service is not subject to frequency limits, age restrictions, or quantity caps that would trigger denial.
- File Timely Claims: Submit claims within the MA plan's filing deadline (365 days per Medicare rules). Late claims are denied for untimely filing.
- Use Correct Coding: Verify the CPT, HCPCS, and ICD-10 codes on the claim match the authorization and the service rendered.
Timeline & Process
Step 1: Receive Denial . MA plan sends electronic remittance or EOB with denial code.
Step 2: Identify Code . Reference CARC code (CO-16, CO-4, CO-50) to determine issue.
Step 3: Gather Evidence . Compile medical records, physician orders, and clinical justification.
Step 4: File Appeal . Submit within 60 days. Plans respond in 7 days (standard) or 72 hours (expedited).
Common Medicare Advantage Denials
| CARC Code | Description | Prevention |
|---|---|---|
| CO-16 | Claim/service not authorized | Obtain prior authorization before service; verify coverage rules |
| CO-4 | Lack of required information | Submit complete clinical documentation, authorization numbers, medical necessity supporting evidence |
| CO-50 | Not covered as billed; frequency limit exceeded | Check coverage rules; verify frequency/duration limits in MA policy before billing |
Appeal Process
File redetermination within 60 days of denial. Include claim number, denial code, and clinical evidence. Plans respond within 7 days (standard) or 72 hours (expedited). If denied, escalate to Independent Review Organization (IRO).
Common Questions
How long do I have to appeal a Medicare Advantage denial?
60 calendar days from the denial date. Submit a written redetermination request with supporting clinical documentation to the MA plan's appeals department.
What is the most common Medicare Advantage denial?
CO-16 (Claim/service not authorized) and CO-4 (Lack of required information). Many can be prevented by obtaining prior authorization and verifying coverage before service delivery.
Can I bill the patient after a Medicare Advantage denial?
Only if the patient was notified in advance and agreed to be financially responsible. An Advance Beneficiary Notice (ABN) must be signed before service delivery for non-covered services.
Altair checks Medicare Advantage requirements before submission . flagging missing authorizations and coding mismatches in real time. See how Altair works.
This reference is for informational purposes. Payer policies change frequently. Always verify against Medicare Advantage plan and CMS documentation. Last updated: 2026-03-16.
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