How long do I have to appeal a health insurance claim denial?

For employer-sponsored plans under ERISA, you must exhaust internal appeals before going external. Most plans allow 180 days from the denial to file an internal appeal. For individual/marketplace plans, state law governs deadlines — typically 30 to 180 days. Check your Explanation of Benefits (EOB) for the exact deadline.

What is an external review and when can I request one?

An external review is an independent medical review outside of the insurance company. Under the ACA, you can request a free external review after exhausting internal appeals — or immediately for urgent care situations. The external reviewer's decision is binding on the insurer.

My claim was denied for 'not medically necessary.' How do I fight that?

Get a detailed Letter of Medical Necessity from your doctor. Include clinical guidelines from professional societies (ACS, AHA, etc.) and peer-reviewed literature. If your plan has a peer-to-peer review option, have your doctor speak directly with the insurer's medical reviewer — this resolves many denials before an appeal.

What is a prior authorization denial and is it different from a regular claim denial?

Yes. A prior authorization (PA) denial happens before treatment — the insurer says they won't cover a service in advance. A claim denial happens after treatment. For PA denials, you can request an expedited appeal (72 hours for urgent cases). Both types can be appealed through the same internal and external processes.

When should I hire an insurance attorney?

Consider an attorney if your claim exceeds $10,000, if the insurer is acting in bad faith (delaying without reason, misrepresenting your policy), or if you have an ERISA self-funded plan where suing is complex. Many insurance attorneys work on contingency for bad faith cases — no upfront cost.

Health Insurance Claim Denied? Your 2026 Appeal Guide

You paid your premiums. You followed your doctor’s advice. Then your insurance company denied the claim. It feels wrong — because it often is.

Health insurance claim denials are more common than most people realize, and a large portion of them are overturned on appeal. This guide walks you through exactly what to do when your health insurance claim is denied in 2026, from reading your EOB to taking your insurer to an external review.

Why Are Claims Denied? The Most Common Reasons

Understanding the reason for denial is the first step to beating it.

Prior Authorization Not Obtained

Many procedures, specialist visits, and brand-name drugs require prior authorization — advance approval from your insurer. If your provider forgot to get it, the claim gets denied. This is frustrating because it’s often the provider’s administrative error, not a question of whether care was appropriate.

Fix: Ask your provider to request a retroactive authorization or file a “provider error” appeal on your behalf.

Out-of-Network Provider

If you saw a doctor outside your plan’s network, your insurer may deny the claim entirely (HMO) or pay at a lower rate (PPO). Emergency care rules are different — under federal law, you cannot be balance-billed for emergency services, regardless of network.

Watch for: If a facility is in-network but the anesthesiologist or specialist brought in during your procedure is out-of-network, you may have surprise billing protections under the No Surprises Act (2022).

Medical Necessity Dispute

The insurer’s medical reviewer decided the treatment wasn’t “medically necessary” based on their own criteria — often different from your doctor’s clinical judgment. This is the most contested type of denial.

Coding or Documentation Errors

A wrong diagnosis code (ICD-10) or procedure code (CPT) can trigger an automatic denial. This happens more often than you’d expect and is usually fixable with a simple correction.

Pre-Existing Condition (Limited Situations)

Under the ACA, insurers in the individual market cannot deny claims based on pre-existing conditions. However, short-term health plans and grandfathered plans may still apply pre-existing condition exclusions.

Step 1: Read Your Explanation of Benefits (EOB) Carefully

The EOB is not a bill — it’s a statement from your insurer explaining what they will and won’t pay. When a claim is denied, the EOB includes:

The reason code for the denial
The amount denied
Your appeal rights and deadline

Request the specific reason code definition if it’s not clear. Insurers are required to provide a full written explanation upon request.

Also request: the specific clinical criteria or coverage guidelines the insurer used to make the decision. This is the document your appeal needs to directly address.

Step 2: Gather Your Counter-Evidence

Your appeal is only as strong as your documentation.

Letter of Medical Necessity

This is the single most important document. Ask your doctor to write a detailed letter that includes:

Your specific diagnosis and its severity
Why this particular treatment is necessary (not just helpful)
Alternatives considered and why they were ruled out
What happens if the treatment is not approved
Citations to clinical guidelines if possible

Clinical Guidelines and Literature

Look up guidelines from relevant professional societies:

American Medical Association (AMA)
Condition-specific societies (American Cancer Society, American Heart Association, etc.)
UpToDate or published clinical studies

If the guideline recommends the treatment your insurer denied, attach it to your appeal.

Peer-to-Peer Review

Many insurers offer a peer-to-peer (P2P) review — a direct call between your doctor and the insurer’s medical reviewer. Studies show this resolves a significant portion of medical necessity denials before a formal appeal is needed. Ask your provider’s office if they can request a P2P.

Step 3: File the Internal Appeal

Every insurance plan must have an internal appeals process. Here’s how to do it right.

Know Your Deadline

Check your EOB or plan documents. For ERISA plans (employer-sponsored), you typically have 180 days from the denial date. Individual plan deadlines vary by state — often 30 to 180 days.

Do not miss this deadline. Missing it can forfeit your right to appeal.

What to Include in Your Appeal Letter

Your name, member ID, claim number, and date of service
A clear statement that you are appealing the denial
The denial reason and why you believe it is wrong — point by point
Your doctor’s Letter of Medical Necessity
Supporting clinical guidelines or literature
Any relevant medical records
A request for a written decision within the timeframe required by law

Urgent/Expedited Appeals

If your situation is urgent — ongoing treatment, imminent health risk — request an expedited internal appeal. Insurers must respond within 72 hours for urgent cases.

Step 4: Request an External Review

If your internal appeal fails (or is not resolved within 60 days), you have the right to an external review.

Federal External Review (ACA Plans)

Under the ACA, any denial involving medical judgment or rescission of coverage can go to an independent external review organization. This is free, and the reviewer’s decision is binding on the insurer.

To request: Contact your insurer or your state insurance commissioner’s office. You can also go through the federal review process at healthcare.gov if your state doesn’t have its own accredited program.

State Insurance Commissioner

File a complaint with your state’s Department of Insurance (DOI). While the DOI doesn’t override specific claim decisions, they can:

Investigate patterns of bad faith conduct
Apply regulatory pressure
Mediate disputes

Find your state DOI at: naic.org/state-insurance-departments

ERISA and Self-Funded Plans

If your employer self-funds the health plan (common at large companies), ERISA federal law governs — not state insurance law. This is important because:

State external review laws may not apply
You may need to exhaust all ERISA appeals before suing in federal court
The standard of review in court depends on whether the plan gives the insurer discretionary authority

This is where an attorney specializing in ERISA becomes genuinely useful.

Step 5: Recognize Insurer Delay Tactics

Some insurers use delay tactics to wear down claimants. Knowing what to watch for puts you in a stronger position.

Repeated requests for the same documents. Track every submission with date and delivery confirmation. If the same documents are requested twice, note it in writing.

Vague denial reasons. Insurers are legally required to provide specific reasons for denial. If the explanation is vague, push back in writing and request specifics.

Lowball settlement offers. Before an appeal is resolved, you may receive a settlement offer. Know the value of your claim before accepting anything.

Citing policy exclusions that don’t apply. Read the actual exclusion language in your plan documents. Sometimes the cited exclusion doesn’t cover your specific situation.

Step 6: When to Get an Insurance Attorney

Most appeals don’t need a lawyer. But consider hiring one if:

Your denied claim is $10,000 or more
The insurer is clearly acting in bad faith — unreasonable delays, misrepresenting coverage, stonewalling
Your plan is ERISA self-funded and legal nuance matters
You’ve exhausted all appeals and are preparing to sue

Bad Faith Insurance Claims

In most states, insurers have a legal duty to handle claims fairly and promptly. When they deliberately delay, deny without reasonable basis, or fail to investigate, that’s “bad faith.” Bad faith claims can result in damages beyond the original claim amount.

Finding Help Without Upfront Cost

Your state’s insurance department — free complaint and mediation
Patient advocacy organizations — many offer free help navigating appeals (Patient Advocate Foundation: patientadvocate.org)
Legal aid organizations — for income-qualifying individuals
Contingency-fee attorneys — take bad faith cases with no upfront fee

Your Quick-Action Checklist

Read your EOB and note the denial reason code and appeal deadline
Request the full written denial reason and clinical criteria used
Ask your doctor for a Letter of Medical Necessity
Look up relevant clinical guidelines from professional societies
Ask your provider if a peer-to-peer review is possible
File your internal appeal in writing before the deadline
Request external review if internal appeal fails
File a complaint with your state insurance commissioner if needed

A denied claim is not the end of the road. Most insurers count on people giving up after the first denial. The appeal process exists specifically to challenge those decisions — and a well-documented appeal, especially one backed by your doctor’s detailed statement and clinical guidelines, wins more often than you might think.

Start with the EOB, act before the deadline, and escalate if needed.

Health Insurance Claim Denied? Your 2026 Appeal Guide