How do I appeal when my health insurer denies a claim?

Why was my claim denied?

The denial letter, or your explanation of benefits, gives the reason. Read it first, because the reason decides what you send with your appeal.

Common reasons include:

• the plan says the service isn't covered;
• the provider is out of network;
• the plan needed to approve the care first (prior authorization);
• the plan says the care was not medically necessary;
• a code, a date or your details are wrong on the claim.

A wrong code or detail can be a simple mistake. Ask the provider's billing office to check the claim and send it again before you appeal.

Challenging a bill can work. In a survey of insured working-age adults who got a bill for care they thought their plan should cover, the share of those who challenged it and got the bill lowered or removed was 38% (Commonwealth Fund, Gupta et al., April 18 to July 31, 2023).

What kind of plan do I have, and why does it matter?

Your type of plan decides which rules and deadlines apply and who reviews your appeal. Check your plan card, your plan documents or your employer's benefits office.

• Job-based plans and plans you buy yourself, including Marketplace plans. If the plan is not grandfathered, it must offer an internal appeal and an independent external review Source 22. Ask your plan whether it is grandfathered: a grandfathered plan offers external review only for questions about surprise bills Source 22.
• Original Medicare. Medicare has its own appeal steps. You file the first appeal by the date on your Medicare Summary Notice Source 33.
• Medicaid. You ask your state Medicaid agency for a fair hearing. The notice gives the deadline, which can be no later than 90 days (42 CFR 431.221(d) (eCFR), published 2026) from the date the notice is mailed, and some states give less time Source 44.

How do I file an internal appeal, and by when?

File in writing before the deadline in your denial letter. Job-based plans must give you at least 180 days (45 CFR 147.136 (eCFR); 29 CFR 2560.503-1(h)(3)(i), published 2026) after the denial notice to appeal Source 22. Other plans and programs set their own deadlines, so go by the date in your letter.

1. Call the plan and ask it to explain the reason for the denial and what information would change its decision.
2. Ask your doctor for a letter that explains why you needed the care. This matters most when the plan says the care was not medically necessary.
3. Write a short appeal letter: your name, plan ID number and claim number, the service and its date, why the plan should pay, and a list of what you attach.
4. Send it the way the plan asks. Keep copies and proof that you sent it.
5. Write down every call: the date, the name of the person and what they said.

What is an external review?

An external review is a decision by an independent reviewer outside your plan. If your plan turns down your internal appeal, you can usually ask for one Source 22.

You must ask within a set number of months after the denial notice. That number is 4 (45 CFR 147.136 (eCFR); 29 CFR 2560.503-1(h)(3)(i), published 2026). Your plan's final denial letter explains how to ask and who to send it to.

What if my care is urgent?

Say so, in writing and by phone. Urgent cases must be handled faster than other appeals Source 22. Ask your doctor to tell the plan that waiting could harm your health, and ask the plan for its fastest review.

In an emergency, go to the nearest emergency room. Don't wait for the plan.

Should I pay the bill while I appeal?

You can ask the provider to wait. Tell its billing office in writing that you are appealing, send a copy of your appeal and ask it to put the bill on hold until the plan decides. Pay any part of the bill that you agree you owe, such as a copay.

• State law may make collectors wait. In New Jersey, a creditor or collector that knows you are appealing the insurance decision behind a medical debt has to wait. While the appeal is pending, it may not try to collect from you, sue you or send the debt to a collector (P.L.2024, c.48).
• If the bill is from a nonprofit hospital, you can also apply for financial assistance. Once the hospital has your complete application, it must stop its extraordinary collection actions while it decides Source 55. Our guide to charity care explains how to apply.

Who can help me for free?

• Consumer assistance programs. CMS keeps a state-by-state list of programs that help people with health insurance problems, and for states without one it points to other help, such as the state insurance department Source 66. Find yours on the CMS consumer assistance list.
• Patient Advocate Foundation. It says its case managers give free help to patients with a serious health condition, including with insurance denials and prior authorizations. It has eligibility rules, among them a diagnosis, being in treatment, and U.S. citizenship or permanent residence, and it limits how many new cases it takes each day Source 77.
• For surprise bills, call the federal No Surprises help line at 1-800-985-3059 Source 88. Our guide to the No Surprises Act explains those protections.
• For Original Medicare, Medicare's appeals page explains each step Source 33.