How to Appeal a Health Insurance Denial: Internal and External Review

Quick answer

Most private health plans must offer an internal appeal and, if that fails, an independent external review. The denial notice explains your rights and deadlines. Gather the plan documents and claim file, get a supporting letter from your clinician, file in writing before the deadline, and ask for expedited handling if delay could harm your health. The rules differ by plan type and state.

• Read the denial notice first. It must explain why the claim was denied and how to appeal.
• Federal guidance for many plans gives at least 180 days for an internal appeal, and a separate window for external review.
• A supporting letter from your treating clinician and relevant records often matter more than a long argument.
• Your plan type decides which rules and which regulator apply, so identify it early.

Why a health claim denial is worth a second look

A denial from a health plan can feel final, particularly when it arrives with codes and abbreviations you do not recognize. It often is not. Plans make mistakes, paperwork gets lost, a service gets coded incorrectly, or a reviewer applies a rule without the clinical details that a treating clinician would add. HealthCare.gov explains that if your insurer refuses to pay a claim or ends your coverage, you have the right to appeal and have the decision reviewed by a third party.

This guide walks through how appeals usually work for people with private health coverage in the United States: what kind of denial you have, which rules apply to your plan, how to meet deadlines, how to prepare an appeal and what to do if the first appeal fails. Health coverage is regulated by both federal and state law, and different plan types follow different procedures, so some details here will not match your plan exactly. Where a rule comes from a named source, this article says so. For everything else, use the denial notice and your plan documents as the final word, and verify current rules for your plan and state.

Nothing in this article is medical or legal advice. Your clinician is the right person to discuss medical questions, and a licensed attorney can advise on your specific rights.

Identify the kind of denial you have

Start by pinning down what was actually denied, because the strategy differs.

• A claim denial after care. The plan refuses to pay all or part of a bill for a service you already received. The notice is often an explanation of benefits, or EOB, with a reason code.
• A prior authorization or pre-service denial. The plan will not approve a procedure, medication or device before you receive it.
• A denial based on medical necessity. The plan says the service is not medically necessary under its criteria. These denials involve medical judgment.
• An experimental or investigational denial. The plan says the treatment is not yet accepted as standard.
• A network or coverage denial. The plan says the provider was out of network, the service is excluded or the benefit has a limit.
• A cancellation or rescission. The plan ends coverage, sometimes claiming incorrect information was given at enrollment. This is more serious and worth prompt advice.
• A billing or coding error. Sometimes the denial is not about coverage at all but about an incorrect code, a missing referral or a duplicated claim, which a provider's billing office can often correct by resubmitting.

Call your provider's billing office early. A surprising number of denials are corrected by a resubmission, and the office may also know how the plan usually responds to similar requests.

Find out which rules apply to your plan

Health plans are not all regulated the same way, and this determines your deadlines, your reviewer and your regulator.

• Individual and marketplace plans. Plans you buy yourself, including through the marketplace, generally follow the internal appeal and external review process that HealthCare.gov describes, and are regulated by your state insurance department.
• Employer-sponsored plans. Many are governed by federal law administered by the Department of Labor's Employee Benefits Security Administration (EBSA). Its guide explains claims and appeals procedures for these plans.
• Fully insured vs. self-funded employer plans. In a fully insured plan, an insurer takes the risk and state insurance law applies in part. In a self-funded plan, the employer pays claims directly and federal law mostly governs, which can change which regulator handles complaints. Your summary plan description or your employer's benefits office can tell you which you have.
• Medicare, Medicaid and other government programs. These have their own appeal processes and deadlines that differ from those described here. The denial notice explains them.

Write down the plan name, whether it is through an employer or purchased individually, the member ID and the plan's appeals address. These details determine everything that follows.

Find and calendar the deadlines

Deadlines are the most time-sensitive part of an appeal. For the private insurance plans it describes, HealthCare.gov states that an internal appeal generally must be filed within 180 days (about six months) of receiving notice that your claim was denied. It also states that internal appeals must be completed within 30 days if the appeal is for a service you have not yet received, and within 60 days if it is for a service you have already received. A written request for an external review generally must be filed within four months of the date you receive a final determination from your insurer.

For employer plans, the Department of Labor's guide states that you have at least 180 days to file an appeal, and that your plan may provide a longer period. It describes decision timeframes that depend on the kind of claim, from a short period, such as 72 hours for urgent care, to longer periods for other claims, and says plans must notify you if they extend any period.

These are general federal timeframes, and your plan or state may provide more time or different steps. Do not rely on a summary, including this one. The denial notice is required to describe your appeal rights, so find the date on the notice, compute the earliest deadline and set reminders well ahead. Our explainer on statutes of limitation and claim deadlines describes how these clocks differ from deadlines for going to court.

Gather the paperwork

A strong appeal is built from documents. Collect:

1. The denial notice or EOB, including the date, reason, codes and appeal instructions.
2. Your plan documents, such as the summary of benefits, the certificate of coverage or the summary plan description, to see what the plan says about the service and the appeal process.
3. The claim file information. The EBSA guide states that for employer plans, the plan must provide copies of documents, records and other information relevant to your claim free of charge if you request them, and that you can ask for the identity of any medical or vocational expert whose advice was obtained. Ask in writing, and keep a record of when you asked.
4. Medical records related to the service: notes, test results, imaging, prior treatments tried and outcomes.
5. Provider statements, including a letter from your treating clinician.
6. Billing records: itemized bills, payment records and prior authorization numbers.

Our guide on how to document a claim explains how to organize and back up this material. Keep a contact log of every call to the plan, with names, dates and reference numbers.

Build the appeal

An appeal does not need legal language. It needs to be clear, complete and supported.

A supporting clinical letter. For denials based on medical necessity or experimental status, a letter from your treating clinician is often the most important document. It typically explains your diagnosis, what treatments have been tried, why the requested service is needed, what could happen without it and why alternatives are not suitable, and may cite clinical guidelines or published evidence the clinician relies on. Your clinician's office may also be able to arrange a peer-to-peer conversation, in which your clinician speaks directly with the plan's reviewer.

A short cover letter from you. Include your name, member ID, claim number, date of the denial, the service involved and a clear statement that you are appealing. Explain in a few sentences why you disagree, pointing to specific reasons stated in the denial and specific documents that answer them. For example: "The denial states that physical therapy was not medically necessary. The enclosed letter from Dr. [name] explains that conservative treatment for six weeks did not improve the condition."

What to attach. Include the denial notice and all supporting records. List the enclosures in your letter so nothing is missed.

How to send it. Follow the instructions on the notice. Use a method with proof of delivery, such as certified mail with a return receipt or an online portal that provides a confirmation, and keep a full copy.

The internal appeal process

After you file, the plan must review its decision. For plans covered by the rules HealthCare.gov describes, this is an internal appeal, and the insurer must give you a written decision at the end. The EBSA guide explains that for employer plans, appeals must be reviewed by someone new, who looks at all the information submitted and consults with qualified medical professionals when medical judgment is involved, and who is not the person who made the initial decision or that person's subordinate.

Some plans have one level of internal appeal; others have two. After each level, you should receive a written decision explaining the result and what to do next. If the decision is still a denial, the notice must explain how to request further review. Keep all letters. If the plan misses its own deadlines or does not respond, note the dates and follow up in writing; a missed deadline may change your options, and a regulator can help.

When the situation is urgent

If waiting for a standard review could seriously jeopardize your health or your ability to regain maximum function, you can ask for expedited handling. HealthCare.gov states that in urgent situations you can file an expedited appeal, and that you may be able to file an internal appeal and an external review request at the same time. The EBSA guide describes shorter decision timeframes for urgent care claims.

Ask your clinician to state in writing that the situation is urgent and why. Contact the plan by phone and in writing, label the request "expedited" or "urgent," and keep a record of the call. If the urgent matter involves an emergency, seek care first; appeals can follow.

External review

If the plan upholds its denial after internal appeals, many plans must offer external review, in which an independent reviewer outside the insurer examines the dispute. HealthCare.gov explains that there are two steps: you file a written request for external review within four months after receiving the final determination, and an external reviewer issues a decision that either upholds the insurer's decision or decides in your favor. It states that the insurer is required by law to accept the external reviewer's decision.

Types of denials that can go to external review include denials involving medical judgment where you or your provider may disagree with the plan, determinations that a treatment is experimental or investigational, and cancellations of coverage based on a claim that false or incomplete information was given at application. The final denial notice should say where to send the request. Some plans participate in a federal external review process and others use state-run or state-approved organizations, depending on the plan and state. If you need help, HealthCare.gov notes that your state's Consumer Assistance Program or Department of Insurance may be able to assist.

Getting help along the way

You do not have to do this alone.

• State consumer assistance programs and insurance departments. They may help you understand a denial, file an appeal or start an external review. The National Association of Insurance Commissioners explains how to find your state department and how complaints work; see also our guide to filing a complaint with your state insurance regulator.
• EBSA benefits advisors can assist participants in many employer plans.
• Your clinician's office and the hospital or clinic billing office, who often know the plan's process.
• Patient advocates and legal aid organizations, some of which help with insurance appeals at no cost.
• A licensed attorney, particularly when large amounts, coverage cancellation or complex plan terms are involved.

Example scenario (hypothetical)

A patient's plan denies a prior authorization request for an imaging study as "not medically necessary." The patient reads the notice, finds the appeal deadline and puts it on a calendar. She calls the clinic, which offers a peer-to-peer call and a letter explaining why the study is needed after earlier treatments did not resolve her symptoms.

She requests the plan's criteria and the documents relevant to the claim in writing, files a short appeal with the letter and records attached, sends it with delivery confirmation and notes the date. When the plan upholds the denial, she files a written request for external review within the period stated in the notice. Nothing here is a prediction of the outcome. It simply shows how the steps fit together: read, calendar, document, file and escalate.

Common mistakes

• Missing the deadline because the notice was set aside.
• Appealing by phone only without a written request.
• Not asking for the documents the plan relied on.
• Sending only a personal letter without a clinician's supporting statement.
• Arguing about fairness rather than addressing the stated reason.
• Skipping the billing office, where a coding error may be quickly fixed.
• Not keeping copies or proof of delivery.
• Giving up after the first denial without asking about further levels or external review.
• Overlooking plan type, and following rules that belong to a different kind of plan.

An appeal checklist

1. Read the denial notice and identify the reason and the appeal deadline.
2. Identify your plan type, and whether it is insured or self-funded.
3. Call the provider's billing office to rule out a coding or paperwork error.
4. Request your plan documents and the claim file in writing.
5. Ask your clinician for a letter, and a peer-to-peer call if available.
6. Write a short, specific appeal letter and attach the records.
7. File before the deadline, with proof of delivery, and keep copies.
8. Ask for expedited review if delay could harm your health.
9. If denied again, ask about further internal levels and external review, and calendar that deadline.
10. Contact your state insurance department, consumer assistance program or EBSA if you need help.

When legal help may be appropriate

Consider talking with a licensed attorney in your state if your coverage has been cancelled, if a high-cost treatment is at stake, if the plan has not followed its own procedures, or if you are close to a deadline and unsure of the process. See our overview of why insurance claims are denied for how to read a denial against a policy, our guide to medical bills, liens and injury settlements for how reimbursement works when an injury is involved, and our guide on finding and vetting a licensed attorney.

Frequently asked questions

What is the difference between an internal appeal and an external review?

An internal appeal asks your health plan to reconsider its own decision. An external review sends the dispute to an independent organization outside the plan. For plans that offer it, the external reviewer's decision is binding on the insurer, according to HealthCare.gov.

Can I ask for a faster decision if the situation is urgent?

Yes. HealthCare.gov explains that in urgent situations you can ask for an expedited appeal, and you may be able to request an external review at the same time as the internal appeal. Ask your clinician to confirm the urgency in writing.

Does my employer's plan follow the same rules as a marketplace plan?

Not exactly. Employer plans are generally covered by the Department of Labor's claims procedure rules, while individual marketplace plans follow the procedures described by HealthCare.gov, and state insurance law can add protections. Your plan documents explain which applies.

When to consult a licensed attorney

This article is general information. It cannot account for the facts of your situation, the wording of your policy or contract, or the law where you live. Consider speaking with an appropriately licensed attorney in your jurisdiction if any of the following applies:

• A deadline may be running, or you are unsure whether one applies.
• You have been seriously injured, or a large amount of money or property is involved.
• You have been asked to sign a release, waiver or settlement agreement.
• A claim has been denied and you do not understand why, or you believe you are being treated unfairly.

Legal aid organizations, bar association referral services and court self-help centers may offer free or low-cost help. See our guide to finding and vetting a licensed attorney.

Important legal notice

Verdicairn is an independent informational publication, not a law firm. Content is general educational information, not legal advice, and reading it does not create an attorney-client relationship. Laws vary by jurisdiction and change over time, so information may be out of date. For advice about your situation, consult an appropriately licensed attorney. Read the full disclaimer.

Sources and further reading

1. How to appeal an insurance company decision — HealthCare.gov. Accessed September 29, 2026
2. Internal appeals — HealthCare.gov. Accessed September 29, 2026
3. External review — HealthCare.gov. Accessed September 29, 2026
4. Filing a Claim for Your Health Benefits — U.S. Department of Labor, Employee Benefits Security Administration. Accessed September 29, 2026
5. How to File a Complaint and Research Complaints Against Insurance Carriers — NAIC. Accessed September 29, 2026
6. An Employer's Guide to Health and Disability Benefit Claims — U.S. Department of Labor, Employee Benefits Security Administration. Accessed September 29, 2026

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