How long does an insurance appeal take?

Internal appeals must be decided within 30 days for pre-service claims and 60 days for post-service claims. Urgent care appeals must be decided within 72 hours. If you request an expedited external review, that decision also comes within 72 hours.

How often are insurance appeals successful?

Studies consistently show that 40-67% of internal appeals result in partial or full reversal. External reviews by independent medical experts overturn insurer decisions at rates of 30-50%. Filing an appeal is almost always worth the effort rather than accepting the denial.

What is an external review and who qualifies?

External review is an independent review of your insurer's decision by a third-party medical expert not employed by your insurer. Most people with employer-sponsored or individual market health plans have the right to request external review after exhausting internal appeals. Both ERISA plans and ACA marketplace plans are subject to external review requirements.

What is the difference between a denial and an exclusion?

A denial means the insurer refused to cover a claim it theoretically could cover — this is appealable. An exclusion means the service is explicitly not covered under your plan's terms. Exclusions are harder to appeal, though you can still request an exception or seek external review if a medical necessity argument applies.

Can I appeal a denial for out-of-network care?

Yes. Out-of-network denials are among the most commonly appealed and successfully overturned claim types. The No Surprises Act provides additional protections for emergency care and some non-emergency care at in-network facilities. Reference these protections specifically in your appeal letter when applicable.

How to Appeal a Health Insurance Denial: A Step-by-Step Guide

April 27, 2026 · Tips · 5 min read

Health insurance denials are reversed in 40-67% of cases when patients file formal appeals — yet most people accept the denial and pay out of pocket. The appeals process has defined deadlines, required steps, and specific documentation that significantly increases your success rate when used correctly.

Why Claims Get Denied

Understanding the denial reason is the most important first step, because it determines your entire appeal strategy. The most common denial reasons include:

Medical necessity: The insurer determined the service wasn't medically necessary. This is the most appealable denial type — a detailed letter from your physician explaining clinical rationale overturns these frequently.
Prior authorization not obtained: The provider failed to get prior approval. Appeal on the basis that the service was urgent, or that authorization was obtained but not recorded correctly.
Out-of-network provider: The provider isn't in your plan's network. Appealable when emergency care was involved or in-network alternatives weren't reasonably available.
Experimental or investigational: The insurer classified a treatment as experimental. Often overturned with peer-reviewed evidence and a specialist letter.
Coding error: The claim was billed with incorrect medical codes. Resubmitting with corrected codes from the provider often resolves this without a formal appeal.

Request your Explanation of Benefits (EOB) and locate the denial reason code. Your insurer must provide the specific reason in writing — if the EOB is vague, call member services and ask for the exact clinical or administrative basis. Learning how to read your medical bill and EOB before you call makes this conversation significantly faster.

Step 1: Know Your Deadlines

Deadlines are the most common reason appeals fail. Most plans allow 180 days from the date of the denial notice to file an internal appeal — but some plans use shorter windows. Calendar the deadline the same day you receive a denial.

Internal appeal filing deadline: Typically 180 days from denial notice (check your specific plan documents)
Internal appeal decision deadline (insurer): 30 days pre-service, 60 days post-service, 72 hours for urgent care
External review request deadline: 4 months after receiving the final internal appeal denial

Step 2: File Your Internal Appeal

The internal appeal goes to the insurer's appeals department — a different team than the one that issued the denial. You must exhaust internal appeals before requesting external review in most cases.

What to Include in Your Appeal Letter

An effective appeal letter is specific, medical, and well-documented. Include:

Your member ID, claim number, and date of service — reference exactly which claim you're appealing
A clear statement of what you're requesting: "I am requesting reconsideration of the denial of [service] for [date] and asking that the claim be paid as a covered benefit"
A letter from your treating physician explaining why the service was medically necessary, referencing the specific diagnosis codes (ICD-10) and clinical guidelines that support the treatment — this is the single most important document
Peer-reviewed literature if the denial was based on "experimental" classification — PubMed abstracts showing standard-of-care status can overturn this
Your plan's own coverage criteria — download the plan's medical policies from the insurer website and cite the criteria your case meets
Records of prior authorization (if applicable) including the authorization reference number

Send via certified mail or through your insurer's secure member portal so you have a timestamped record of submission.

Step 3: Request an Expedited Appeal If Necessary

If your health is at serious risk and the care cannot wait 30-60 days, you have the right to request expedited review — the insurer must decide within 72 hours. To qualify, your physician must document why the standard timeline poses a significant health risk. This applies most often to pre-service authorizations for urgent procedures, ongoing treatment denials for serious illness, and mental health treatment continuation denials.

Step 4: Request External Review

If internal appeals fail, you can request an independent external review. An external reviewer is a board-certified physician not employed by your insurer who evaluates whether the denial was medically appropriate.

External review overturns insurer denials 30-50% of the time
You typically have 4 months from the final internal denial to request it
The external review is free — the insurer bears the cost by law
The external reviewer's decision is binding on the insurer under the ACA

Step 5: File a State Insurance Commission Complaint

Every state has an insurance commissioner with authority to investigate insurer practices. Filing a complaint costs nothing and frequently prompts insurers to reconsider denials they would not otherwise revisit. For employer-sponsored plans governed by ERISA, file with the Department of Labor's Employee Benefits Security Administration (EBSA) at 1-866-444-3272 instead — ERISA plans are not subject to state insurance commissioner jurisdiction.

Know Your ACA Rights

The Affordable Care Act strengthened appeal rights significantly. Key protections: the right to a full and fair review, access to your claims file, an independent external reviewer, and a plain-language explanation of denial reasons. These apply to most employer and individual market plans.

Understanding your plan structure affects your appeal strategy — the HMO vs PPO vs EPO guide explains how plan type affects your network appeal rights specifically.

When to Hire a Patient Advocate

Professional patient advocates specialize in navigating insurance denials and typically charge $100-$250/hour or a percentage of the successfully appealed claim. For complex denials — cancer treatments, experimental therapies, large out-of-network claims — the investment is frequently worthwhile. The Patient Advocate Foundation also provides free case management for qualifying patients.

Ready to find healthcare providers with strong insurance acceptance? Browse our directory by city or find clinics near you with verified insurance participation and patient ratings.

Frequently Asked Questions

How long does an insurance appeal take?: Internal appeals must be decided within 30 days for pre-service claims and 60 days for post-service claims. Urgent care appeals must be decided within 72 hours. If you request an expedited external review, that decision also comes within 72 hours.
How often are insurance appeals successful?: Studies consistently show that 40-67% of internal appeals result in partial or full reversal. External reviews by independent medical experts overturn insurer decisions at rates of 30-50%. Filing an appeal is almost always worth the effort rather than accepting the denial.
What is an external review and who qualifies?: External review is an independent review of your insurer's decision by a third-party medical expert not employed by your insurer. Most people with employer-sponsored or individual market health plans have the right to request external review after exhausting internal appeals. Both ERISA plans and ACA marketplace plans are subject to external review requirements.
What is the difference between a denial and an exclusion?: A denial means the insurer refused to cover a claim it theoretically could cover — this is appealable. An exclusion means the service is explicitly not covered under your plan's terms. Exclusions are harder to appeal, though you can still request an exception or seek external review if a medical necessity argument applies.
Can I appeal a denial for out-of-network care?: Yes. Out-of-network denials are among the most commonly appealed and successfully overturned claim types. The No Surprises Act provides additional protections for emergency care and some non-emergency care at in-network facilities. Reference these protections specifically in your appeal letter when applicable.