How to appeal a health insurance denial

Your health plan said no. Maybe it denied a claim for care you already got. Maybe it won't approve care you still need.

A denial can feel final, but it isn't. You have the right to ask your plan to look again, and often the right to an independent review.

Few people use these rights. A 2026 KFF analysis of HealthCare.gov plans found that insurers denied 19% of in-network claims in 2024. People appealed fewer than 1% of those denials.

This guide explains how to appeal a health insurance denial, step by step. You'll need your denial letter or your explanation of benefits (EOB), which is your insurer's record of the claim. We cover the deadlines for each kind of coverage, what to send, and where to get help.

Which problem do you have?

Start with the guide that matches your situation.

Why do insurers deny claims?

Most denials fall into 5 groups. Knowing which one you have tells you what to do next.

• Paperwork. The claim had a wrong member ID, a missing code, or it went to the wrong plan. Our guide on what to do when insurance didn't pay a medical bill covers these fixes.
• Coverage. Your plan says the service isn't a covered benefit, or you've used up a benefit limit, like a set number of therapy visits.
• Medical necessity. Your plan agrees the service is covered, but says you didn't need it.
• Network. The provider isn't in your plan's network, so your plan paid less or nothing.
• Prior authorization. The care needed approval ahead of time, and your plan didn't give it.

In the same KFF analysis, administrative reasons made up 25% of denials. Medical necessity made up 5%. That's why reading the reason comes first.

Step 1: Read your denial carefully

Your denial may come as a letter, as an EOB, or both. Federal rules require most private plans to tell you:

• The specific reason for the denial
• The part of the plan it's based on
• The denial code and what it means
• What information would fix the claim, if any
• How to appeal, and your time limits
• Whether you can ask for external review

You can ask for more detail at no cost. That includes copies of the documents in your claim file and the diagnosis and treatment codes.

You can also ask for any rule or guideline your plan used. If the denial says the care wasn't medically necessary, you can ask for the clinical reasons behind it.

Codes on an EOB can be hard to read. Our guide to claim denial codes explained covers the common ones.

Step 2: Decide who needs to fix it

Some denials aren't really decisions about your care. They're mistakes on the claim. The provider can usually correct those and send the claim again. You don't need to appeal.

The provider can often fix:

• A wrong name, birth date, or member ID
• A missing or wrong code
• A claim sent to the wrong plan, or before your other plan paid
• A late claim from an in-network provider, which it often can't bill you for

Our letter asking the provider to bill your insurance helps you ask for a corrected claim. If you have 2 plans, our guide to coordination of benefits explains which one pays first.

Coding problems can also turn a screening into a bill. See our guides on a colonoscopy billed as diagnostic and preventive care billed as diagnostic.

You'll need to appeal when your plan made a decision you disagree with. That includes denials for coverage, medical necessity, experimental treatment, network status, or prior authorization.

Step 3: File an internal appeal

An internal appeal asks your plan to take a full, fair second look at its decision.

For most private plans, you have 180 days from getting the denial notice to file. Your plan then has to decide:

• Within 30 days, for care you haven't gotten yet
• Within 60 days, for care you already got
• Within 72 hours, for urgent care

Some employer plans have 2 levels of internal appeal, with shorter time limits for each. Marketplace and other individual plans have 1 level. Your denial letter explains your plan's steps.

Follow the instructions in your letter. Put your appeal in writing. Include your name, claim number, and member ID. Send it in a way that gives you proof, and keep copies of everything.

You have the right to see your claim file and to add evidence. If your plan finds new evidence or a new reason to deny, it must share it with you before it decides. Our insurance appeal letter gives you a place to start.

What should your appeal include?

A strong appeal answers the exact reason your plan gave. Send:

• A letter from you. Say what was denied, why you disagree, and what you want your plan to do.
• A letter from your doctor. It should explain your diagnosis, why you need the care, and what else you've tried.
• Your medical records. Include test results and notes that back up your doctor's letter.
• Your plan's own words. Quote the part of your plan documents that covers the service.
• The denial. Include a copy of the denial letter or EOB and any bills.

If your plan refused to approve care ahead of time, our prior authorization appeal letter is built for that. Our guide on prior authorization denied walks through the steps.

Federal rules now help here, too. Since 2026, some plans must give a specific reason when they deny a prior authorization request. That includes Medicare Advantage plans, Medicaid, the Children's Health Insurance Program (CHIP), and Marketplace plans on HealthCare.gov. The rule doesn't apply to drugs.

Step 4: Ask for an external review

If your plan says no again, you can often take your case to an independent review organization (IRO). The IRO isn't part of your plan.

• Deadline: You have 4 months after your plan's final denial to ask.
• Timing: The reviewer decides within 45 days, or within 72 hours if your case is urgent.
• Result: If the reviewer sides with you, your plan must accept the decision and pay.
• Cost: The federal process is free. State processes can charge up to $25.

External review covers denials that involve medical judgment. That includes medical necessity, the level or setting of care, and whether a treatment is experimental.

It also covers a plan cancelling your coverage after the fact, and some surprise billing issues. Denials over other issues, like whether you were enrolled, usually don't qualify for the federal process.

You don't always have to finish the internal appeal first. In urgent cases, you can ask for both at the same time. If your plan didn't follow the appeal rules, you may be able to go straight to external review.

Our guide to external review for health insurance explains which comes when. Our external review request letter helps you ask.

What if your plan misses a deadline?

Write down the date your plan got your appeal. If the deadline passes with no decision, call and ask for the status. Then send a short letter that notes the missed date.

A missed deadline can open the next step for you:

• Most private plans: If your plan didn't follow the appeal rules, you may be able to go straight to external review.
• Medicare Advantage: A late decision counts as a denial. Your plan must send your case to the independent review entity.
• Medicaid managed care: If your plan misses its deadline or skips the required notice, you can ask for a state fair hearing right away.

Keep a simple log for every appeal. Note each date, each person you spoke with, and each reference number. Keep copies of everything you send and get.

How do urgent (expedited) appeals work?

An appeal is urgent if the normal wait could seriously harm your life, your health, or your ability to regain function. It's also urgent if your doctor says the wait would cause severe pain that can't be managed.

• Private plans must decide urgent appeals within 72 hours.
• If a doctor who knows your condition tells an employer plan your claim is urgent, the plan must treat it that way.
• You can ask for an urgent external review at the same time as your internal appeal.
• Your plan can't cut or stop an ongoing course of treatment without notice and a chance to appeal first.

Medicare Advantage and Medicaid managed care plans also decide fast appeals within 72 hours.

If you have Medicare, you can also ask for a fast appeal when you think services are ending too soon. That includes care from a hospital, skilled nursing facility, home health agency, or hospice. Your provider should give you a written notice that explains how.

Don't wait on an appeal to get emergency care. If you need care now, talk with your doctor about your options.

How do the rules differ by type of coverage?

Your appeal rights depend on who provides your coverage. Here's a quick comparison.

Employer plans: self-funded or fully insured

A fully insured plan buys coverage from an insurer. State insurance laws apply, and external review usually runs through your state.

A self-funded plan pays claims with the employer's own money. It may hire another company to process claims. State insurance laws generally don't apply.

A federal law, the Employee Retirement Income Security Act (ERISA), sets the rules. External review usually follows a federal process, though some states let these plans use the state process.

After you finish an ERISA plan's appeals, you may have the right to file a lawsuit. Ask your human resources office which kind of plan you have. Our guide to self-funded vs. fully insured plans explains why it matters.

Marketplace plans

Plans from the Health Insurance Marketplace follow the same internal appeal and external review rules. A decision by the Marketplace itself is different. If you disagree with your eligibility for coverage or savings, you can appeal to the Marketplace. You generally have 90 days from your eligibility notice.

Original Medicare

Denials show up on your Medicare Summary Notice (MSN). You have 120 days from getting the MSN to ask for a redetermination. The MSN lists the exact date.

The Medicare contractor usually decides within 60 days.

Original Medicare has 5 levels of appeal. After the first, an independent contractor reviews your case. Next comes a hearing, then the Medicare Appeals Council, then federal court. For 2026, a hearing requires at least $200 in dispute, and federal court requires $1,960.

Our guide to reading a Medicare Summary Notice shows where denials appear.

Medicare Advantage

You have 65 days from the date on your plan's notice to ask for a reconsideration. Your plan must decide within 30 days for care you haven't gotten, 60 days for payment, or 72 hours if it's urgent.

If your plan still says no, even in part, it must send your case to an independent review entity on its own. You don't have to ask. Our guide on how to handle a Medicare Advantage denial appeal covers every level.

Medicaid

If a Medicaid managed care plan denies care, you appeal to the plan first, within 60 days of the date on the notice. The plan must usually decide within 30 days, or 72 hours if it's urgent.

If it still says no, you can ask for a state fair hearing. Your state gives you 90 to 120 days to ask.

Is your plan cutting a service you already get? Ask for an appeal within 10 days of the notice, and ask for your care to continue. Your care can often continue during the appeal, though you may have to repay if you lose. Our guide to the Medicaid fair hearing explains the steps.

Say Priya had a knee MRI in February 2026. Her fully insured employer plan denied the $2,400 claim as not medically necessary. The denial letter arrived on March 4, 2026. Here's how her deadlines lined up.

Date	What happened	The rule behind it
March 4	The denial letter arrived.	Her 180 days to appeal began. Her deadline was August 31.
March 16	She filed an internal appeal with her doctor's letter and her records.	The MRI was already done, so her plan had 60 days, until May 15.
May 1	Her plan's final denial arrived.	Her 4 months to ask for external review began. Her deadline was September 1.
May 8	She asked for external review.	She followed the steps in her final denial letter.
May 15	An IRO received her case.	The reviewer had 45 days to decide.
June 29	This was the latest date for the IRO's decision.	If the IRO sides with Priya, her plan must pay the claim under her plan's terms.

Priya filed each step well before the deadline. That left time to gather records without rushing.

Denials tied to a type of care

Some kinds of care come with their own rules. These guides cover them.

• Cancer treatment, imaging, and infusions. Our hubs on cancer treatment bills, MRI and CT scan denials, and infusion and biologic bills cover the denials and bills for each.
• Mental health care. A federal mental health parity law may apply to your denial. See mental health claim denied.
• Physical therapy. Some plans limit the number of visits. See our guide to physical therapy bills.
• Lab work. A lab you never saw can bill you. See our guide to an unexpected lab bill.

Surprise bills and network problems

A bill from an out-of-network provider isn't always yours to pay. The No Surprises Act protects most people with private insurance from surprise bills for emergency care. It also covers some care at in-network hospitals and surgery centers, and air ambulances.

Our guide on whether the No Surprises Act applies to your bill walks through it. Anesthesia is one place these bills show up. See out-of-network anesthesia at an in-network hospital.

If your plan won't apply these protections, you can appeal. Surprise billing disputes can go to external review.

When to get help

You can handle many appeals yourself. It's worth getting help when:

• The denial is for costly or ongoing care, like cancer treatment.
• Your internal appeal failed, and you're not sure about external review.
• Your plan missed its deadlines or didn't answer.
• You're managing appeals for someone else and you're short on time.

Start with your insurer's member services number, on your insurance card. Your denial letter should list your state's consumer assistance office, if it has one. Your state insurance department can also help with fully insured and Marketplace plans.

For employer plans, the Department of Labor's Employee Benefits Security Administration answers questions at 1-866-444-3272. For Medicare, call 1-800-MEDICARE (1-800-633-4227), or get free counseling from your State Health Insurance Assistance Program. For surprise bills, call the No Surprises Help Desk at 1-800-985-3059.

If you have a serious illness, Patient Advocate Foundation, a nonprofit, offers free case management that can include help with appeals. A medical bill advocate can also take on the calls and letters. For a large claim or a lawsuit over an employer plan, talk with an attorney.