How to Appeal a Denied Medical Claim in 2025: Complete Guide

When your insurance company denies a claim, it feels like the end of the road. But here's something important to know: studies show that up to three-quarters of denied claims that are appealed are eventually approved.

The appeal process can be intimidating, especially when you're already stressed about health issues or caring for someone who is. But it's often worth the effort. This guide will walk you through the process step by step.

Before You Start: Understanding Your Denial

The first thing you need to do is understand exactly why your claim was denied. Your insurance company is required to send you a letter—called an Explanation of Benefits (EOB)—that explains their decision.

Look for these key pieces of information:

• The specific reason for denial
• The date of the denial decision
• Your deadline to file an appeal (this is critical—miss this and you lose your right to appeal)
• Instructions for how to submit an appeal
• Contact information for questions

Don't throw this letter away, even if you're frustrated. You'll need it throughout the appeals process.

Step 1: Contact Your Insurance Company

Before you file a formal appeal, call your insurance company. Sometimes denials are based on simple errors or missing information that can be resolved with a phone call.

What to ask:

• "Can you explain exactly why this claim was denied?"
• "What additional information or documentation would you need to approve this claim?"
• "Is this a denial or a rejection?" (Rejections can often be corrected and resubmitted without a formal appeal)
• "What is my deadline for appealing this decision?"

Important: Take notes during this call. Write down:

• The date and time you called
• The name of the person you spoke with
• Their reference number or employee ID
• Everything they told you

These notes might become important later.

Step 2: Contact Your Doctor's Office

Your healthcare provider's office can be your strongest ally in the appeals process.

Call the billing department and explain that your claim was denied. Ask them:

• If they're aware of the denial
• If they can provide additional documentation supporting the medical necessity of the service
• If there might have been a coding error
• If they'll write a letter of medical necessity to support your appeal

Many denials happen because the insurance company needs more detailed information about why the treatment was necessary. Your doctor can provide this.

Step 3: Gather Your Documentation

A strong appeal includes supporting documentation. Here's what you might need:

Always include:

• A copy of your denial letter
• Your appeal letter (we'll discuss this next)
• A letter from your doctor explaining why the service was medically necessary

May also include:

• Medical records supporting the need for treatment
• Research or medical studies supporting the treatment approach
• Photos or documentation of your condition
• Records of previous treatments that didn't work (showing this treatment was the next logical step)

Step 4: Write Your Appeal Letter

Your appeal letter is your opportunity to make your case. Here's how to structure it:

Opening paragraph:

• State that you're appealing the denial
• Include your claim number, dates of service, and patient information
• Briefly state why you believe the denial was incorrect

Body paragraphs:

• Explain why the service was medically necessary
• Address the specific reason given for the denial
• Include relevant facts from your medical history
• Reference your doctor's recommendation and attached letter

Closing paragraph:

• Clearly state what you're asking for (approval of the claim)
• Include your contact information
• Thank them for reviewing your appeal

Tone tips:

• Be factual, not emotional
• Stick to medical facts and your doctor's recommendations
• Be polite but firm
• Keep it concise—usually one to two pages

Step 5: Submit Your Appeal

Most insurance companies allow you to submit appeals by:

• Mail (send it certified mail with return receipt requested)
• Fax (keep the confirmation sheet)
• Online portal (save confirmation and screenshots)

Critical: Submit your appeal before the deadline. Most insurance companies give you 180 days to appeal, but some deadlines are much shorter. If you miss the deadline, you lose your right to appeal.

Step 6: Follow Up

After submitting your appeal:

• Keep copies of everything you sent
• Note the date you submitted it
• Call to confirm receipt within a week
• Ask about the timeline for a decision (usually 30-60 days)

If Your First Appeal Is Denied

Don't give up. Most insurance companies have multiple levels of appeal:

Level 1 (Internal Review): Your first appeal, reviewed by the insurance company.

Level 2 (Internal Review): If denied, you can usually appeal again to a higher level within the insurance company.

External Review: If internal appeals fail, you can request an independent external review by a third party not affiliated with your insurance company. This is often your best chance at overturning a denial.

State Insurance Commissioner: You can also file a complaint with your state's insurance department.

Timeline Expectations

The appeals process takes time:

• Urgent/Expedited appeals (for emergency or critical care): Usually decided within 72 hours
• Standard appeals: Typically 30-60 days for a decision
• External review: Can take 60-90 days

When to Get Help

The appeals process can be exhausting, especially if you're dealing with serious health issues or caring for someone else. Some situations where outside help makes sense:

• Complex medical cases with multiple denials
• You're too sick or overwhelmed to manage the process
• You've tried appealing on your own without success
• The claim amount is very large

Some people use patient advocacy services or attorneys specializing in insurance appeals. Others use services like HealthLock that monitor claims automatically and can guide you through the appeals process, helping you gather documentation and craft effective appeals.

Your Rights in the Appeals Process

You have the right to:

• Appeal any denial
• See all information the insurance company used to make their decision
• Present your case in writing and sometimes in person
• Bring someone with you to help
• Request an expedited review if your health is at serious risk

Success Stories

Real patients have successfully appealed denials for expensive treatments that insurance companies initially refused to cover. One patient's liver transplant was approved after appeal. Another patient's expensive infusion therapy was covered after providing additional documentation about previous failed treatments.

The key in most successful appeals is persistence and good documentation.

The Bottom Line

Appealing a denied claim takes effort, but it's often successful. Most people don't appeal because they assume the insurance company's decision is final or because the process seems too complicated.

But insurance companies are counting on you not to fight back. When you do appeal—with good documentation and clear explanations of medical necessity—you have a real chance of getting the coverage you deserve.

Get Help Fighting Denials

Appealing a denied claim takes time and expertise most patients don't have. HealthLock monitors your claims automatically and alerts you to denials immediately, giving you the best chance to fight back successfully. HealthLock's members have saved over $243 million by catching billing errors, denied claims, and fraud before they became major problems.

Learn more about HealthLock →

Disclaimer: We're not medical billing experts or attorneys—we're patients and caregivers sharing resources to help you navigate a broken system. This information is for educational purposes only and should not be considered medical or legal advice.

Affiliate Disclosure: This site may contain links to services like HealthLock that help monitor medical claims and billing. We may earn a commission if you sign up through our links, at no extra cost to you. We only recommend services we believe can genuinely help.