Getting a claim denied by your health insurance company is frustrating, but it is not the end of the road. Insurance companies deny claims for a wide variety of reasons, and a significant number of those denials get overturned when the enrollee appeals. The process takes some effort, but it is well worth it when the bill in question is substantial. Here is how the appeals process works, what your rights are, and how to build the strongest possible case for getting your claim approved.

Understand Why the Claim Was Denied

Before you can appeal, you need to understand the specific reason for the denial. Your insurer is required to send you an Explanation of Benefits, commonly called an EOB, that explains why the claim was not paid. Common denial reasons include the service being deemed not medically necessary, the provider being out of network, a required prior authorization not being obtained in advance, or the claim being submitted with a coding error. Each of these has a different appeal strategy. A denial based on medical necessity requires clinical documentation from your doctor. A coding error can often be corrected by the provider’s billing office and resubmitted without a formal appeal at all.

Start With an Internal Appeal

Your first step is always an internal appeal, which means asking the insurance company to reconsider its decision. You have at least 180 days from receiving a denial to file an internal appeal under federal law, though checking your plan documents for any shorter deadlines is important. Write a clear appeal letter that states the date of the denial, the service in question, and why you believe the claim should be covered. Attach supporting documentation including your doctor’s letter explaining medical necessity, any relevant treatment records, and the specific language from your plan’s benefits documents that you believe covers the service. Keep copies of everything you submit.

Get Your Doctor Involved

A letter of medical necessity from your treating physician is one of the most powerful pieces of evidence in any appeal. The letter should explain your diagnosis, why the specific treatment or service was necessary given your condition, and why alternative options that may be cheaper or in-network were not appropriate for your situation. Physicians are usually willing to write these letters because they have a direct interest in their patients getting the care they ordered. Ask your doctor’s office to submit the letter directly to the insurance company and to keep a copy for your shared records.

Request an Expedited Appeal When Timing Is Urgent

If a denied service is urgently needed for an ongoing medical situation, you can request an expedited internal appeal. Insurers are required to respond to expedited appeals within 72 hours. This is particularly relevant when a denial involves insurance after job loss or a coverage transition, where delays in care can have serious consequences. In urgent care situations, you can also request a simultaneous external review rather than waiting for the internal appeal to conclude first. Tell your insurer explicitly that the situation is urgent and ask for expedited processing in writing.

File an External Appeal If the Internal One Fails

If your internal appeal is denied, you have the right to request an independent external review. An external review is conducted by an Independent Review Organization that has no connection to your insurance company. Their decision is binding on the insurer. For most plans covered under federal law, you can request external review within four months of receiving the internal appeal denial. Some state laws provide even stronger external review rights. If your plan is fully insured, meaning you get coverage through an employer who buys insurance from a carrier, your state insurance department may also have its own external appeal process with additional protections.

Use Your State Insurance Commissioner as a Resource

Your state’s department of insurance or insurance commissioner is a free resource that can help you understand your rights, file a complaint against an insurer, or escalate an appeal that seems to be going nowhere. Filing a complaint with the department of insurance often prompts insurers to take a second look at a denied claim more seriously. You can find your state insurance department’s contact information and complaint portal through the National Association of Insurance Commissioners website at naic.org.

A denied claim is a starting point, not a final answer. The appeals process exists precisely because denials are often wrong, and the system gives you multiple opportunities to push back. Start with an internal appeal, gather your doctor’s supporting documentation, and escalate to external review if the internal process does not resolve the issue. Most people who see the full appeals process through to the end are glad they did, and the financial stakes are usually significant enough to make every step worth the effort.