ACA Marketplace Health Plan Claim Denied: Your Appeal Rights

ACA marketplace health plans — sold through HealthCare.gov or state exchanges like Covered California, NY State of Health, and others — carry mandatory federal appeal rights under the Affordable Care Act. If your marketplace plan denied a claim, Prior Authorization Denied: How to Appeal" class="auto-link">prior authorization request, or essential health benefit coverage, you have the right to an internal appeal and independent External Independent Review: Complete Guide" class="auto-link">external review. Fewer than 1 percent of people who receive denials use these rights — and external reviews overturn insurer decisions at roughly 40 to 50 percent rates. Here is how to use your rights effectively.

Why ACA Marketplace Plans Deny Claims

Medical necessity denials are the most common basis. The insurer's clinical reviewer determines the service does not meet its internal criteria, even when your physician has recommended it and the service falls within an essential health benefit category covered by all marketplace plans under 42 U.S.C. § 18022.

Prior authorization failures: The service required pre-approval that was not obtained before treatment — or the authorization request was denied at the pre-service stage. Prior authorization criteria must be disclosed to members and cannot be more restrictive than generally accepted clinical standards.

Step therapy requirements: The plan requires you to try and fail a less expensive treatment before approving the one your physician recommended. Under the Consolidated Appropriations Act of 2021, plans must have a process to override step therapy requirements when there is a valid clinical reason.

Experimental or investigational designation: The plan denies coverage calling the treatment experimental — even when it has FDA approval or is supported by medical society guidelines. This designation is frequently successfully challenged when clinical evidence supports the treatment.

Out-of-network and network disputes: The service was rendered by an out-of-network provider, or the plan disputes whether the provider was properly in-network. The No Surprises Act (effective January 1, 2022) provides significant protections in emergency and certain non-emergency out-of-network situations.

How to Appeal

Step 1: Analyze the denial notice and request the clinical criteria

The denial notice must cite the specific plan provision and the specific reason for the denial in plain language under ACA regulations at 45 CFR § 147.136. Request the clinical criteria your insurer used to make its decision — you have the right to this information. Understanding exactly what criteria the plan applied is the foundation of a successful appeal.

Step 2: Gather physician documentation targeted to the denial reason

Do not submit a generic physician letter. Your physician must address the specific denial reason point by point — explaining why the service is medically necessary for your specific condition, why alternatives (including any step therapy alternatives) are not clinically appropriate, and citing relevant clinical guidelines from professional medical societies.

Step 3: File the internal appeal within 180 days

Submit your written internal appeal to your insurer within 180 days of the denial notice. Include your policy number, claim number, the denial date, your physician's letter, clinical guidelines, and any relevant medical records. Send by certified mail and through the insurer's online portal. Keep copies and delivery confirmation of everything.

Step 4: Request expedited review for urgent situations

If standard review timelines would cause serious harm, request expedited review. Your insurer must decide within 72 hours. State explicitly: "I am requesting EXPEDITED review because [specific medical urgency]." Have your physician support the expedited request in writing.

Step 5: Request external review after exhausting internal appeals

If the internal appeal fails, immediately request an independent external review under 45 CFR § 147.138. This review is conducted by an IROs) Explained" class="auto-link">Independent Review Organization (IRO) that is not affiliated with your insurer. External review is free to you under the ACA and must be completed within 45 days for standard reviews and 72 hours for expedited reviews. External reviews overturn insurer denials at approximately 40 to 50 percent rates.

Step 6: File complaints with the marketplace and state insurance department

File a complaint with the Health Insurance Marketplace at HealthCare.gov (for federal marketplace plans) or your state exchange (for state-based plans) if you believe your plan violated ACA requirements. File a separate complaint with your state insurance department — state regulators have authority over insurer conduct even for plans sold on the federal marketplace.

What to Include in Your Appeal

• Copy of the denial notice with the specific reason code and plan provision
• Your physician's letter addressing the denial criteria point by point, with clinical guideline citations
• Evidence that the denied service is within an ACA essential health benefit category
• The insurer's own clinical criteria (requested separately) with your analysis showing your case satisfies them
• No Surprises Act documentation for out-of-network billing disputes

Fight Back With ClaimBack

ACA marketplace appeals are free to file, and external review — conducted by independent physicians — has meaningful reversal rates. The process exists specifically to correct wrongful denials. ClaimBack helps you build a complete, well-documented appeal that uses the ACA's own framework to argue for the coverage you are entitled to. ClaimBack generates a professional appeal letter in 3 minutes. Start your free claim analysis → Free analysis · No credit card required · Takes 3 minutes

Related Reading

• How to Write an Insurance Appeal Letter
• What Is Medical Necessity?
• Internal vs External Insurance Appeal