How to Appeal a Denied Health Insurance Claim, Step by Step

How to appeal a denied health insurance claim, step 1: read the decision

Start with the denial letter and EOB, rather than the provider's bill alone. Identify the claim or service, date of care, denial reason, and any plan provision or clinical criteria the insurer names. Check whether this is an initial denial or a decision on an appeal already filed.

Call the insurer if the reason is unclear. Ask: "What specific information or plan requirement led to the denial?" Request a written explanation and ask how to obtain the relevant claim materials. For many private-sector employer plans, the Department of Labor's claims guidance explains access to documents relevant to the claim.

A Marketplace eligibility appeal is not the same as an appeal of an insurer's coverage decision. Medicare, Medicaid, and other coverage programs also have their own procedures. Make sure you are following the process for your actual plan.

How to appeal a denied health insurance claim, step 2: check the deadline

Deadlines vary by plan. Check the denial letter for the exact dates. Write down the filing deadline, the address or portal, any required form, and whether delivery must occur by a particular date. Also ask whether more than one internal appeal level applies.

HealthCare.gov describes a general 180-day internal-appeal filing window for the process it covers. That is not a universal deadline for every program or insurance arrangement. Use your notice and plan documents to confirm your own window.

Do not assume that a billing correction, phone call, or request for records extends the deadline. If time is short, contact the plan promptly about how to file a timely appeal and whether supporting information can follow under its rules.

Step 3: Choose evidence that answers the denial reason

The most useful evidence depends on why the claim was denied. For a medical-necessity denial, ask your clinician whether a letter and relevant records can explain the care, prior treatment, and the clinical reasons for the service. The clinical explanation should come from the treating professional, not from a document preparer inventing medical facts.

For an authorization dispute, gather the request, approval or denial notices, and relevant communications. For a coding or eligibility issue, ask the provider or plan administrator for the records showing the correct information.

Organize copies in a simple order:

1. Denial letter and EOB.
2. Relevant coverage language or criteria, if available.
3. Clinician's explanation, when appropriate.
4. Supporting records and correspondence.
5. A document index with labels and dates.

Include what helps address the decision. Unrelated records can make the important evidence harder to find.

Step 4: Write a focused appeal letter

Follow any required plan form first. If a letter is allowed or needed, state which decision you are appealing and what you want reconsidered. Include the identifiers the insurer requires in the actual submission, but do not put member IDs or sensitive records into a public contact form.

Describe the reason given for the denial and explain which documents address it. Refer to the evidence by its label or page number. Keep factual statements tied to the records. A respectful, specific request is more useful than threats, unsupported claims, or promises that a rule must apply.

For example, the structure could be: "I am requesting reconsideration of the decision on this claim. The notice says the service was denied because of [stated reason]. The enclosed [record or clinician's letter] addresses that reason by explaining [documented information]. Please review these materials and provide a written decision."

That is an organizational example, not a legal argument or a substitute for your plan's instructions.

Step 5: Submit the complete packet and keep proof

Check the required destination, signature, forms, and any authorization needed if another person is helping you. Use the method the plan accepts. Keep a copy of the exact letter and attachments, along with the portal receipt, fax confirmation, or delivery record.

Ask the insurer to confirm that the appeal was received, whether anything is missing, and when it expects to decide. Record the appeal reference number. If you send additional documents later, keep proof of those submissions too.

Step 6: Follow up and read the next decision

Put the expected response date on your calendar. Ask the insurer about the decision window that applies to your claim. Rules can differ for care already received, care requested in advance, and urgent situations.

If the insurer upholds the denial, read the new notice carefully. It may describe another internal level, external review, or a different next step. Not every denial qualifies for external review. Our external review guide explains the distinction, and External Review, Explained: The Appeal Step Most People Never Take walks through how that step works. If you are still sorting out the original notice, read what to do when a health insurance claim is denied.

If waiting would create a serious health risk, ask your care team and insurer immediately about expedited procedures. Do not wait for a routine packet service to respond before seeking time-sensitive help.

This guide provides general information about organizing an insurance appeal. It is not legal advice. Check your denial notice and plan documents for the procedure that applies to you.

What KFF reports about denials and appeals

KFF's 2024 Marketplace analysis found a 19% in-network claim denial rate among insurers offering qualified health plans on HealthCare.gov. Fewer than 1% of denied in-network claims were internally appealed. The findings do not cover every U.S. health plan.

In that analysis, insurers upheld 66% of internal appeals. That means the denials remained in place, not that two thirds of people won. KFF could not calculate an external-review outcome rate from the reported data. A focused appeal is worth understanding, but no population statistic guarantees approval.

Want the packet prepared for you?

Cura's paid Denial Appeal Packet service is for denied claims of $3,500 or more. We prepare an appeal letter to the insurer's stated reason, a deadline sheet, an indexed evidence appendix, and a submission and follow-up checklist from the records you provide. The internal appeal packet is $349. If it goes to external review, the price is $599. You submit it, and we track the deadlines with you. We are not lawyers and this is not legal advice.

A person reviews your case, and you keep every dollar you win back.

Start your Denial Appeal Packet

Not sure what the bill or explanation of benefits is saying? Start with Bill Help or use Cura's medical bill and EOB explainer.