Most denied claims can be successfully appealed — but only if you follow the right process. Here's exactly what to do.
Follow these steps in order. Each step builds on the last. Skipping steps is the most common reason appeals fail.
Your denial letter must state the specific reason for denial and cite the plan provision used. Look for the denial reason code, the clinical rationale, and whether the denial is a coverage exclusion, medical necessity issue, or administrative error. This determines your appeal strategy.
You have the right to request the coverage determination guidelines (CDGs) and clinical policy bulletins your insurer used to deny your claim. Submit a written request citing ERISA §503 (employer plans) or ACA §2719. Insurers must provide these documents free of charge.
A Letter of Medical Necessity (LMN) from your treating physician is the cornerstone of most successful appeals. The letter should cite your specific diagnosis, why the treatment is medically necessary, the consequences of denial, and reference peer-reviewed clinical guidelines supporting the treatment.
Strengthen your case with peer-reviewed studies, clinical practice guidelines (e.g., NCCN, ADA, AHA), and your complete medical records. If your insurer cited a specific policy bulletin, find published evidence that contradicts their criteria. The stronger the clinical evidence, the higher your odds of success.
Submit your appeal in writing (not by phone) and send by certified mail or via the insurer's online portal with a confirmation receipt. Include: your appeal letter citing the denial reason, the LMN, clinical evidence, your EOB, and the insurer's own clinical policy. Keep copies of everything.
Under the ACA, if your internal appeal is denied, you have the right to request an Independent External Review from an accredited Independent Review Organization (IRO). This process is free, legally binding on the insurer, and succeeds approximately 72% of the time. Request it in writing within 4 months of the internal appeal denial.
If external review fails or your plan is self-funded (ERISA), escalate to your state insurance department, the Department of Labor (ERISA), or file a complaint with CMS. In the UK, escalate to the Financial Ombudsman Service. In Australia, AFCA. In Singapore, FIDReC. These bodies have authority to compel insurer compliance.
Assemble all of these before filing. Missing even one key document is a common reason for appeal failure.
Missing your appeal deadline forfeits your right to appeal. Check your country and plan type carefully.
Deadlines may vary by plan type within each country. Use our Appeal Deadline Calculator for your specific situation.
In the US, you typically have 180 days from the date of denial to file an internal appeal under ACA and ERISA rules. For Medicare Advantage plans, the deadline is 60 days. For urgent medical situations, you can request an expedited appeal within 3 days. Deadlines vary by country — in the UK you have 6 months from the insurer's final response to contact the Financial Ombudsman Service.
According to KFF 2023 data, 63% of appealed marketplace claims are overturned. When claims reach independent external review under the ACA, the overturn rate reaches approximately 72%. The key factor is documentation: appeals that include a Letter of Medical Necessity and peer-reviewed clinical evidence succeed significantly more often than those that do not.
To appeal a denied insurance claim you need: (1) the original denial letter, (2) your Explanation of Benefits (EOB), (3) a Letter of Medical Necessity from your treating physician, (4) your complete relevant medical records, (5) your insurer's clinical policy bulletin used to deny the claim, and (6) published peer-reviewed clinical guidelines supporting your treatment.
Yes. Most insurance appeals are filed by patients directly, without legal representation. The process involves gathering medical documentation, writing a formal appeal letter that cites the denial reason and regulatory grounds, and submitting within the deadline. Tools like ClaimBack can generate a regulation-citing appeal letter in minutes. For complex ERISA disputes or claims over $50,000, consulting an insurance attorney may be worthwhile.
An independent external review (also called an Independent Medical Review or IMR) is a legally mandated second opinion from an accredited Independent Review Organization (IRO), separate from your insurer. Under the ACA (42 U.S.C. § 300gg-19), all ACA-compliant plans must offer external review. It is free for consumers, typically completed within 45 days (or 72 hours for urgent cases), and the IRO's decision is legally binding on the insurer.
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