Aetna Claim Denied: A Complete Guide to Appealing Your Denial

Aetna, now a subsidiary of CVS Health, is one of the three largest health insurers in the United States. Aetna covers members through employer-sponsored plans, ACA marketplace plans, Medicare Advantage, and Medicaid managed care. Regardless of which Aetna product you have, a claim denial is not the end of the road — it is the beginning of a formal appeal process you have a legal right to use.

This guide covers everything you need to know to appeal an Aetna claim denial effectively.

Why Aetna Denies Claims

Aetna denies claims for a range of reasons, and identifying the exact reason is the first step in building a successful appeal. Common denial reasons include:

• Medical necessity: Aetna determined the service was not clinically required for your condition
• Prior Authorization Denied: How to Appeal" class="auto-link">Prior authorization not obtained: The service required advance approval that was not requested or was denied
• Out-of-network provider: You received care from a provider outside Aetna's network without an exception
• Timely filing: Aetna received the claim after its filing deadline (typically 90 to 365 days from date of service, depending on your plan)
• Coordination of benefits: A dispute about which insurer is primary when you have multiple policies
• Billing or coding errors: The claim contained incorrect diagnosis codes, procedure codes, or provider information
• Experimental or investigational: The treatment is not considered proven under Aetna's clinical policy bulletins

Your EOB)" class="auto-link">Explanation of Benefits (EOB) will list the reason code for the denial. Call Aetna Member Services at 1-800-872-3862 or use the member portal at aetna.com to get the full denial letter and the specific clinical criteria applied.

Step 1: Review Your Denial Letter and EOB Carefully

Before filing an appeal, understand exactly what was denied and why. Request the complete adverse benefit determination letter if the EOB does not contain full details. Aetna is required under federal law to provide:

• The specific reason for denial in plain language
• The clinical criteria or plan provision applied
• Instructions for how to file an appeal
• Your deadline to appeal

Also check whether the denial is a billing or administrative error — sometimes what appears to be a substantive denial is actually a coding mistake or duplicate claim. Confirm the claim details with your provider's billing department before spending time on a clinical appeal.

Step 2: File a First-Level Internal Appeal

Aetna offers multiple levels of internal review. The first-level appeal is reviewed by a clinical staff member different from the person who made the initial decision.

ACA plan timelines:

• Expedited (urgent) appeal: 72 hours
• Pre-service appeal: 30 days
• Post-service appeal: 60 days

ERISA employer plan timelines:

• Pre-service: 15 days (urgent) or 15 days (non-urgent)
• Post-service: 60 days

You typically have 180 days from the date of the denial to file your first-level appeal. Submit via:

• Online: Aetna member portal at aetna.com
• By mail: Aetna Appeals, P.O. Box 14463, Lexington, KY 40512 (verify current address on your denial letter)
• By fax: Use the fax number on your denial letter

Include in your appeal package:

• A written appeal letter referencing the denial date and claim number
• A physician letter of medical necessity addressing Aetna's specific denial criteria
• Relevant medical records (office notes, labs, imaging, specialist consultations)
• Published clinical guidelines from specialty societies
• A copy of the EOB and denial letter

Step 3: Peer-to-Peer Review

Before or during the formal appeal, your physician can request a peer-to-peer review — a clinical call with the Aetna Medical Director who reviewed the claim. This is especially effective for medical necessity denials and prior authorization disputes. Ask your doctor's office to call Aetna Provider Services to schedule one.

Step 4: Second-Level Internal Appeal

For most Aetna plans, a second internal appeal level is available if the first-level appeal is denied. A physician reviewer with the appropriate specialty will conduct the second review. This is your last internal step before External Independent Review: Complete Guide" class="auto-link">external review.

Step 5: External Independent Review

Once you exhaust internal appeals, you can request an external independent review by an accredited IROs) Explained" class="auto-link">Independent Review Organization (IRO) that has no affiliation with Aetna. The IRO's decision is binding.

• ACA plans: Request external review within 4 months of the final internal denial
• External review standard decisions: 45 days
• Expedited external review: 72 hours

Aetna must arrange and pay for the external review. You submit your documentation to the IRO, and Aetna must also submit its documentation and rationale.

Filing a Complaint with State Regulators

If Aetna violated procedural requirements — missed deadlines, failed to provide criteria, or handled your appeal improperly — file a complaint with your state insurance department. Find your state regulator at naic.org.

For ERISA self-funded employer plans, contact the Department of Labor's Employee Benefits Security Administration (EBSA) at 1-866-444-3272 or dol.gov/agencies/ebsa.

Aetna Member Rights

Aetna publishes a Member Rights and Responsibilities policy. You have the right to:

• Request and receive all criteria used to evaluate your claim
• Appeal any adverse benefit determination
• Be represented by an authorized representative
• Request a second opinion
• File a complaint with your state insurance commissioner

Fight Back With ClaimBack

Aetna's appeal system is multi-layered, and each stage requires the right documentation to succeed. ClaimBack helps you organize your evidence, write a compelling appeal letter, and track your case through every level of review.

Start your appeal with ClaimBack

Related Reading

• How to Write an Insurance Appeal Letter
• Internal vs. External Insurance Appeals
• Common Reasons Insurance Claims Are Denied