Your Action Plan: Insurance Denial Appeal
Time-sensitiveMost denials can be overturned. The insurance company is counting on you not to appeal.
In your favor
Fewer than 1% of patients ever appeal a denied claim. But when patients do appeal, the results are striking: studies show that 75% of Medicare Advantage appeals result in the denial being overturned. While success rates vary by plan type and denial reason, the data consistently shows that appeals succeed far more often than most patients expect. Filing an appeal costs you nothing.
Appeal deadlines are strict. Check your denial letter or EOB for your specific deadline. For ACA and employer plans, internal appeal deadlines are typically 180 days. For Medicare, the deadline is 120 days.
Key Facts
75% of Medicare Advantage insurance denials that are appealed are overturned. Success rates vary by plan type.
HHS OIG, 2022
Fewer than 1% of patients ever file an appeal when their claim is denied.
KFF, 2025
13% of Medicare Advantage prior authorization denials met coverage rules but were denied anyway.
HHS OIG, 2022
93% of physicians say prior authorization delays necessary care.
AMA, 2024
Your Action Steps
Read your denial letter carefully. It contains the specific reason for denial, the clinical criteria the insurer used, and your appeal deadline. This letter is the roadmap to overturning the denial. If you did not receive a denial letter, you can request one — your insurer is required to provide it in writing.
Request the insurer's clinical criteria in writing. You have the right to see the specific medical policy or clinical guideline the insurer used to deny your claim. Call the number on your denial letter and say: "I'd like a copy of the clinical criteria or medical policy used to deny my claim." Having this document lets you address their exact reasoning in your appeal.
Ask your treating doctor for a letter of medical necessity. This is the single most important piece of your appeal. Your doctor can explain why the treatment was medically necessary, cite clinical guidelines that support it, and address the insurer's specific denial reason. Doctor involvement dramatically improves appeal outcomes.
File an internal appeal with your insurance company. Include the letter of medical necessity from your doctor, relevant medical records, the insurer's own clinical criteria (if it supports your case), and a written explanation of why the denial is wrong. Send everything by certified mail or the insurer's designated appeals submission method. Keep copies of everything.
If the internal appeal is denied, request an external review. For ACA-compliant plans, external review is conducted by an independent organization and the decision is binding on the insurer — they must comply. For employer (ERISA) plans, external review is also available. For Medicare, the next step is an Administrative Law Judge hearing. File external review promptly; deadlines vary by plan type.
For out-of-network emergency care denials, the No Surprises Act (effective January 2022) protects you from balance billing. If your denial involves emergency care from an out-of-network provider, invoke this protection — the hospital cannot bill you beyond your in-network cost-sharing amount.
Consider requesting a peer-to-peer review. This is a call between your treating doctor and the insurer's medical director to discuss your case directly. Peer-to-peer reviews can resolve denials without a formal appeal, particularly for "not medically necessary" denials. This option is generally available for commercial and employer plans but is not part of the standard Medicare appeals process. Ask your doctor's office if they can initiate one.
File a complaint with your state insurance department if the insurer is obstructing or delaying your appeal. Every state has an insurance commissioner who oversees insurer conduct. Filing a complaint creates a regulatory record and can accelerate resolution. You can find your state insurance department through the National Association of Insurance Commissioners (NAIC).
Contact the Patient Advocate Foundation (800-532-5274) for free case management if your appeal is complex or involves a serious medical condition. They specialize in navigating insurance denials and can help with the appeals process at no cost.
Learn More
Free Resources
Free case management and appeals assistance for patients dealing with insurance denials, especially for serious or chronic conditions.
Find your state insurance department to file a complaint about claim denial practices.
Official Medicare appeals process information, including deadlines and forms for each level of appeal.
Information about appeal rights for employer-sponsored (ERISA) health plans.
Educational Information Only
This information is educational and does not constitute legal, medical, or financial advice. Laws and programs vary by state and change over time. For complex situations — particularly lawsuits, wage garnishment, or situations involving large sums — consult a qualified attorney, patient advocate, or other professional. We connect you with free resources that can help.