Top Reasons Health Insurance Claims Are Denied (And How to Appeal Each One)
Few things are more frustrating than getting medical care you need—only to open your mail or insurance portal and see the words “CLAIM DENIED.”
Unfortunately, health insurance claim denials are extremely common. Millions of claims are denied every year, not because the care was unnecessary or inappropriate, but because of documentation issues, technical mistakes, or how the claim and appeal were presented.
The good news? Many denials can be appealed—if you know why the claim was denied and how to respond correctly.
This guide breaks down the top reasons health insurance claims are denied, explains what insurers are really saying, and shows you how to fix each issue through a strong, properly written appeal.
Why Health Insurance Claims Get Denied So Often
Insurance companies process claims using:
Strict policy definitions
Internal guidelines
Automated systems
Limited medical reviews
They are not evaluating whether care was helpful or fair. They are asking:
“Does this claim meet our coverage rules exactly as written?”
If the answer is unclear—or poorly documented—the claim is denied.
1. “Not Medically Necessary”
Why This Denial Happens
This is one of the most common denial reasons.
Insurers may argue that:
The treatment was unnecessary
A cheaper alternative should have been used
Clinical criteria were not met
Documentation didn’t clearly justify the service
Often, the insurer is not disputing your diagnosis—just whether the specific treatment met their standards.
How to Appeal It
A successful medical necessity appeal should:
Tie the diagnosis directly to the treatment
Explain why the treatment was appropriate for you
Address why alternatives were ineffective or inappropriate
Reference accepted clinical guidelines when possible
Simply stating “my doctor says it was necessary” is not enough.
This is where a professionally structured, attorney-written appeal template is especially powerful, because it prompts you to include the precise medical reasoning insurers expect.
2. Service Is “Excluded Under the Policy”
Why This Denial Happens
Insurance policies are filled with exclusions, limitations, and exceptions.
Claims are often denied because:
A service is listed as excluded
The insurer claims the treatment falls outside coverage
The wrong section of the policy was applied
Sometimes insurers misinterpret their own policy—or rely on overly broad exclusions.
How to Appeal It
To challenge an exclusion-based denial, your appeal should:
Cite the exact policy language used to deny the claim
Identify exceptions or carve-outs that apply
Clarify how the treatment actually fits covered benefits
Show how the insurer misapplied the exclusion
Appeals that don’t cite policy provisions are easy for insurers to dismiss.
Attorney-written templates help you structure appeals around policy language, not just personal explanations.
3. Prior Authorization Was Missing or Denied
Why This Denial Happens
Insurers may deny claims when:
Prior authorization wasn’t obtained
Authorization was incomplete
Authorization was retroactively denied
Even when the care was urgent or medically necessary, insurers often enforce authorization rules strictly.
How to Appeal It
Depending on the situation, a strong appeal may argue:
The service was urgent or emergent
Authorization was requested but delayed
The insurer failed to respond timely
The provider reasonably relied on approval
These appeals are procedural, meaning structure and timelines matter more than emotion.
Using a customizable appeal template ensures you don’t miss critical procedural arguments.
4. Out-of-Network Care
Why This Denial Happens
Claims are commonly denied because:
The provider was out-of-network
The insurer claims in-network care was available
Emergency exceptions weren’t recognized
Patients often have no control over this—especially in emergencies.
How to Appeal It
Out-of-network appeals often rely on:
Emergency care exceptions
Lack of available in-network providers
Continuity-of-care arguments
Improper application of network rules
These appeals require clear, factual explanations tied to policy terms.
Appeal templates designed for out-of-network denials help frame these arguments correctly.
5. Diagnosis / Procedure Mismatch (Coding Errors)
Why This Denial Happens
A claim can be denied even when the care was appropriate if:
The diagnosis code doesn’t match the procedure
The wrong billing code was used
Documentation doesn’t align with submitted codes
These are some of the most fixable denials—but only if handled correctly.
How to Appeal It
Your appeal may need to:
Clarify the clinical rationale
Correct coding inconsistencies
Include supporting provider documentation
Insurers often rely on these mismatches because many people don’t challenge them.
A structured appeal template helps ensure technical errors are clearly explained and corrected.
6. Claim Filed Too Late or Appealed Improperly
Why This Denial Happens
Claims and appeals can be denied for:
Missed filing deadlines
Incorrect appeal submission
Missing signatures or forms
Submitting to the wrong address or portal
These are procedural denials—not judgments on your care.
How to Appeal It
Fixing procedural denials may involve:
Showing good cause for delay
Demonstrating insurer notice failures
Arguing compliance with appeal rules
These appeals require precision.
Attorney-written templates guide you through procedural compliance so nothing critical is overlooked.
7. “Insufficient Documentation”
Why This Denial Happens
Insurers may claim:
Records were incomplete
Notes didn’t support the claim
They didn’t receive key documents
This denial is often vague—and strategic.
How to Appeal It
A strong appeal should:
Include a complete, organized record
Clearly explain how documents support coverage
Reference specific pages or exhibits
Simply resending documents without explanation often fails.
Templates help you present documentation in a way insurers can’t easily dismiss.
8. Experimental or Investigational Treatment
Why This Denial Happens
Insurers may deny coverage by labeling a treatment:
Experimental
Investigational
Not widely accepted
This is common with newer treatments or off-label uses.
How to Appeal It
Appeals may focus on:
Medical literature
Clinical acceptance
Standard-of-care arguments
Misclassification of the treatment
These appeals are nuanced and benefit greatly from structured legal-style arguments.
Why Many DIY Appeals Fail
Most people:
Write emotional letters
Repeat the same appeal after denial
Don’t cite policy language
Miss key arguments
Insurance companies expect appeals to follow their rules and logic, not personal narratives.
How Attorney-Written Appeal Templates Can Help
My health insurance appeal templates are:
✔ Written by an insurance attorney
✔ Built from years of experience fighting insurance companies
✔ Designed for common denial scenarios
✔ Customizable to your diagnosis, treatment, and policy
✔ Structured to meet insurer expectations
They help you:
Avoid common mistakes
Present strong, organized arguments
Meet deadlines with confidence
Improve your chances of overturning denials
If your claim was denied, using a proven appeal structure can make the difference between payment and permanent denial.
Start With the Free Health Insurance Appeal Guide
Before filing your appeal, it’s critical to understand:
How insurers evaluate claims
What must be included in the appeal record
What you can’t add later
📘 Download the FREE Health Insurance Appeal Guide to learn how the process works and how to use appeal templates effectively.
Ready to Take Action?
If your health insurance claim was denied, don’t guess and don’t give up.
👉 Choose the appeal template that matches your denial reason, customize it to your situation, and submit a strong appeal written by an insurance attorney with years of experience fighting insurance companies.
Health insurance denials are rarely about fairness. They are about rules, documentation, and structure.
Understanding the reason for denial—and responding correctly—can turn a “no” into a paid claim.
With the right strategy and a professionally written appeal, many denials can be successfully overturned.
