Why Insurance Says a Treatment Is “Not Medically Necessary” (And How to Appeal)
If your health insurance claim was denied because the treatment was deemed “not medically necessary,” you are not alone—and this denial does not mean your care was unnecessary or inappropriate.
Medical necessity denials are one of the most common reasons insurers deny claims, and they affect everything from MRIs and surgeries to specialty drugs, physical therapy, and mental health treatment. Many patients are shocked to learn that a treatment ordered by their doctor can still be rejected by an insurance company.
What most people don’t realize is that medical necessity denials are often procedural, guideline-driven, or automated—and many can be overturned with a properly written appeal.
This guide explains:
What “medical necessity” really means to insurers
Why these denials happen so often
Why most appeals fail
What you must include in an appeal
How to challenge a medical necessity denial effectively
And most importantly: what to do next if your claim was denied.
What Does “Medical Necessity” Mean to Insurance Companies?
Insurance companies do not define medical necessity the same way doctors do.
While your physician makes decisions based on clinical judgment and patient needs, insurers rely on:
Internal coverage guidelines
Medical policies written by the insurer
Utilization review criteria
Algorithms and automated screening tools
A treatment can be:
Appropriate
Widely accepted
Supported by medical evidence
…and still be denied because it does not fit the insurer’s specific definition of “medically necessary.”
This disconnect is why so many legitimate claims get denied.
Why Insurance Companies Deny Claims as “Not Medically Necessary”
Medical necessity denials often happen because:
1. Insurer Guidelines Are Narrow
Insurers frequently rely on internal medical policies that are:
More restrictive than standard medical practice
Based on outdated assumptions
Written to control costs, not outcomes
If your case doesn’t fit neatly into their criteria, the claim may be denied—even when the treatment is reasonable.
2. Automated or Incomplete Reviews
Many medical necessity denials are issued after limited or automated review, not a full evaluation of your medical records.
These systems may:
Review only diagnosis and procedure codes
Ignore treatment history
Miss comorbid conditions
Overlook physician notes
As a result, critical details are never considered.
3. Insurers Expect Patients Not to Appeal
Medical necessity denials are common because insurers know:
Many patients won’t appeal
Others will appeal incorrectly
Deadlines and complexity discourage follow-through
This makes medical necessity denials an effective cost-containment tool.
Common Situations Where Medical Necessity Denials Occur
Medical necessity denials often involve:
MRIs or CT scans ordered after conservative treatment
Surgery recommended after failed alternatives
Specialty drugs or biologic medications
Infusions or advanced therapies
Mental health treatment or extended therapy
Durable medical equipment (DME)
In many cases, the denial is based on how the justification was presented, not the actual need for care.
Why Most Medical Necessity Appeals Fail
Many patients try to appeal—and still lose—because the appeal:
❌ Repeats What Was Already Denied
Appeals that simply resubmit the same information rarely succeed. Insurers are looking for new clarification, not repetition.
❌ Relies on Emotion Instead of Structure
Statements like “My doctor said I need this” or “This treatment helped me” feel compelling—but they don’t address insurer criteria.
Medical necessity appeals must be clinical, organized, and policy-based.
❌ Doesn’t Address Insurer Guidelines
If the appeal does not directly respond to the insurer’s medical necessity criteria, the denial is likely to stand.
❌ Misses Critical Evidence
Key elements are often missing, such as:
Failed conservative treatments
Patient-specific risk factors
Why alternatives were ineffective
Clinical intent of the procedure
Here is the most important thing to understand:
Anything missing from your appeal may never be added later.
If your appeal is denied and the appeal record closes, insurers may refuse to consider new information—even if it proves coverage should have been approved.
A Real-Life Example of a Medical Necessity Denial
A patient with worsening back pain and neurological symptoms was referred for an MRI of the lumbar spine billed under CPT code 72148. The claim was submitted with ICD-10 code M54.50 (low back pain) and denied as “not medically necessary.” The insurer’s explanation stated that the diagnosis did not support advanced imaging. The patient later received a bill for $4,800.
What the insurer did not consider was that the patient had already failed conservative treatment and exhibited symptoms consistent with nerve involvement. When the appeal properly explained the medical rationale, referenced additional diagnoses such as lumbar radiculopathy (M54.16), and clarified the clinical purpose of the MRI, the claim was reprocessed and paid.
The denial was not about the MRI being unnecessary—it was about how the case was explained.
What a Strong Medical Necessity Appeal Must Do
A successful appeal must:
Explain why the treatment is medically necessary for this patient
Address insurer guidelines directly
Clarify clinical intent and treatment history
Connect medical records to policy criteria
Present information in a structured, professional format
This is where many DIY appeals fall short.
Why Writing a Medical Necessity Appeal Is Harder Than It Looks
Medical necessity appeals are not simple letters.
They are technical documents that require:
Understanding how insurers evaluate claims
Knowing what arguments matter
Structuring information logically
Avoiding procedural mistakes
Many people turn to generic templates or AI-generated letters. The problem? These often:
Miss insurer-specific criteria
Ignore policy language
Use incorrect tone or structure
Leave out key arguments
A weak appeal can permanently kill an otherwise valid claim.
A Smarter Way to Appeal a Medical Necessity Denial
If your claim was denied for medical necessity, you don’t need to start from scratch.
The Medical Necessity Appeal Letter Template offered here was written by an insurance attorney with years of experience fighting insurance companies.
It gives you a clear, customizable framework designed specifically for medical necessity denials.
What the Medical Necessity Appeal Letter Template Helps You Do
This attorney-written template helps you:
✔ Present a structured medical necessity argument
✔ Address insurer guidelines directly
✔ Explain why alternatives failed or were inappropriate
✔ Tie your records to coverage requirements
✔ Avoid the mistakes that cause repeat denials
You customize it with your:
Diagnosis
Treatment details
Provider information
Insurance plan language
The logic and structure are already done for you.
Why This Matters Financially
Medical necessity denials often involve:
Imaging studies
Surgical procedures
Specialty medications
Ongoing therapy
These claims can easily involve bills of:
$3,000
$10,000
$25,000 or more
This appeal template costs $29.
For many people, that’s the difference between:
Giving up, or
Submitting a serious appeal that demands review
$29 is small compared to accepting a denial that could have been overturned.
👉 Denied for Medical Necessity? Take Action Now
If your claim was denied as “not medically necessary,” don’t guess—and don’t rely on generic letters.
👉 Download the Medical Necessity Appeal Letter Template – $29
✔ Instant download
✔ Customizable for your case
✔ Written by an insurance attorney
✔ Designed specifically for medical necessity denials
Not Ready to Buy Yet? Start With the Free Appeal Guide
If you want to understand the appeal process before submitting your appeal, download the FREE Health Insurance Appeal Guide.
It explains:
How insurance appeals work
What insurers look for
Common mistakes that cause denials
When external review may apply
📘 Download the FREE Health Insurance Appeal Guide
Medical necessity denials are common—but many are reversible.
The key is understanding how insurers think and responding with a clear, structured appeal that forces proper review.
If your claim was denied, time matters—and so does how you appeal.
👉 Use the attorney-written Medical Necessity Appeal Letter Template and submit your appeal with confidence.
