This guide is educational only. It is not legal, medical, billing, insurance, or financial advice.
Insurance Denied Help
Medical Necessity Denial: What It Means and What to Do
By PapaShield Team
Last updated: July 2026
Checked for clarity, sourcing, and safe wording. See our editorial standards.
Quick Answer
If your insurer says a service was not medically necessary, it means the plan did not approve the request under its rules as submitted. This does not prove the care was unnecessary; it means you should review the denial reason, ask what information is missing, and consider whether your provider can supply supporting documentation. You may be able to appeal, ask about peer-to-peer review, or request external review if your situation qualifies.
Draft an Appeal
Use a draft to organize the denial reason, supporting documents, and request for review.
If this is your situation, start here
- “The denial reason is unclear”: Ask the insurer what rule or guideline was used.
- “The insurer wants more information”: Ask your provider what records may support the request.
- “My provider disagrees with the denial”: Ask whether they can write a supporting letter.
- “My appeal was denied”: Ask whether external review may be available.
What does "not medically necessary" mean?
A medical necessity denial is a plan or insurer decision made under the plan's rules, based on how the request was submitted. It does not mean your provider was wrong, and it does not mean the decision is final.
The denial notice should explain the reason and your appeal options. If the reason is unclear, ask your insurer for the plan rule, guideline, or criteria used to make the decision.
What this means for you
“Not medically necessary” is a plan decision made under plan rules, not a personal judgment about you or your care. Asking what rule was used is often the fastest way to understand what the appeal needs to address.
Why might a claim be denied as not medically necessary?
The insurer needs more clinical information
The notice may say the insurer needs more clinical details before it can decide. Ask your provider if they can supply additional notes or documentation.
The plan says another treatment should be tried first
Some plans require trying a different treatment before approving the requested service. The notice should explain whether this applies and what the plan's rules require.
The request does not match the plan's criteria
The notice may say the request does not meet the plan's medical review criteria. Ask your insurer what criteria were used and whether you can request a copy.
The request was submitted without enough documentation
The notice may say the original request was missing information. Ask your provider's office if they can supply additional records or notes.
Prior authorization was missing or denied
If prior authorization was required and was missing or denied, the notice should explain what was needed. Ask your insurer and provider about next steps.
The service is considered experimental or investigational by the plan
The notice may say the plan classifies the service as experimental or investigational. Ask your insurer what that classification means and write down whether it can be reviewed.
Does a different rule apply to mental health or substance use denials?
If your denial involves mental health or substance use disorder care, the Mental Health Parity and Addiction Equity Act (MHPAEA) generally requires plans to apply medical necessity criteria to those benefits that are comparable to the criteria used for medical and surgical benefits. Plans generally cannot make it harder to get a mental health or substance use claim approved than a comparable medical claim.
CMS guidance says plans must make the criteria used for a mental health or substance use disorder medical necessity determination available to a current or potential participant, beneficiary, or contracting provider upon request. Asking for this in writing gives you something concrete to compare against the denial reason.
Simple way to ask
Try saying: “This denial is for mental health or substance use disorder care. Can you send me the specific medical necessity criteria used, and confirm that comparable criteria are applied to medical and surgical benefits under this plan?”
What should I do first?
- 1Read the denial notice carefully.
- 2Identify the exact medical necessity reason.
- 3Ask for the plan guideline or rule used.
- 4Ask your provider what documentation may help.
- 5Check the appeal deadline.
- 6Gather supporting documents.
- 7Keep copies of everything.
If the denial reason is unclear, call the number on the letter and ask what rule they used, then write down the answer.
Simple way to ask
Try saying: “The denial says the service was not medically necessary. Can you tell me what rule or guideline was used and what documentation may help with an appeal?”
How can my provider support a medical necessity appeal?
Your provider may be able to:
- Write a letter or provide notes.
- Explain diagnosis, symptoms, treatment history, or why the service was requested.
- Address failed alternatives, step therapy, or urgency if relevant.
- Participate in peer-to-peer review, if available.
What is a provider letter?
A provider letter is written by your provider to explain why the service was requested. It should be specific to the denial reason and does not guarantee approval.
What is peer-to-peer review?
Peer-to-peer review is a conversation between your provider and a plan reviewer that may help clarify the request. Ask your provider and insurer whether it is available for your situation.
How do I appeal a medical necessity denial?
- 1Use the denial reason as the focus.
- 2Gather only relevant supporting documents.
- 3Ask your provider for support if appropriate.
- 4Write a clear appeal request.
- 5Attach the documents required by your plan.
- 6Submit using the required method.
- 7Ask for the decision in writing.
What documents should I gather?
DocumentWhy it may helpWhere to find it
Medical necessity denial letter
Explains the reason for denial and appeal instructions.
Mailed or emailed by your insurer.
Explanation of Benefits
Shows how the claim was processed.
Your insurer's website or member portal.
Provider letter or notes
May help explain why the service was requested.
Ask your provider's office directly.
Relevant medical records or visit notes (if your provider recommends them)
May support the medical necessity appeal.
Your provider's medical records department.
Treatment history
May show what has already been tried, if relevant.
Your provider's records or your own notes.
Records of tried alternatives or step therapy (if relevant)
Documents treatments already tried, if step therapy applies.
Your provider's office.
Test results or clinical notes (if relevant)
May support the clinical basis for the request.
Your provider's medical records department.
Prior authorization notice (if relevant)
Shows what was requested or approved before the service.
Your insurer or provider's office.
Plan document or summary plan description
Explains what your plan covers and the rules used.
Your insurer or employer benefits portal.
Call notes or written messages
Documents what you were told and when.
Your own records. Keep a simple log.
Medical necessity denial letter
Why it may help
Explains the reason for denial and appeal instructions.
Where to find it
Mailed or emailed by your insurer.
Explanation of Benefits
Why it may help
Shows how the claim was processed.
Where to find it
Your insurer's website or member portal.
Provider letter or notes
Why it may help
May help explain why the service was requested.
Where to find it
Ask your provider's office directly.
Relevant medical records or visit notes (if your provider recommends them)
Why it may help
May support the medical necessity appeal.
Where to find it
Your provider's medical records department.
Treatment history
Why it may help
May show what has already been tried, if relevant.
Where to find it
Your provider's records or your own notes.
Records of tried alternatives or step therapy (if relevant)
Why it may help
Documents treatments already tried, if step therapy applies.
Where to find it
Your provider's office.
Test results or clinical notes (if relevant)
Why it may help
May support the clinical basis for the request.
Where to find it
Your provider's medical records department.
Prior authorization notice (if relevant)
Why it may help
Shows what was requested or approved before the service.
Where to find it
Your insurer or provider's office.
Plan document or summary plan description
Why it may help
Explains what your plan covers and the rules used.
Where to find it
Your insurer or employer benefits portal.
Call notes or written messages
Why it may help
Documents what you were told and when.
Where to find it
Your own records. Keep a simple log.
Only include information needed for the appeal. Ask your provider or insurer what documents are required.
Can external review help with medical necessity denials?
External review may apply for some denials involving medical necessity, but it is not automatic. Internal appeal may need to happen first, unless urgent-situation rules apply.
HealthCare.gov says external review is an independent third-party review, and the plan must accept the external reviewer's decision.
What mistakes should I avoid?
Watch out for these common mistakes
- Missing the appeal deadline
- Arguing without addressing the denial reason
- Sending too much unrelated information
- Not asking for the plan guideline or rule used
- Not asking your provider what documentation may help
- Assuming the first denial is final
- Not keeping copies
When should I use PapaShield tools?
Use tools when:
- You need a draft appeal structure.
- You need to organize provider questions.
- Prior authorization was involved.
- You want a checklist of documents and next steps.
Sources
- HealthCare.gov - Internal appeals
- HealthCare.gov - External review
- HealthCare.gov - How to appeal an insurance company decision
- U.S. Department of Labor - Filing a Claim for Your Health Benefits
- U.S. Department of Labor - Filing a Claim for Your Health or Disability Benefits
- CMS - Appealing Health Plan Decisions
- CMS - Action Plan: Health insurance plan denied a claim
- CMS - The Mental Health Parity and Addiction Equity Act of 2008 (MHPAEA)
Frequently asked questions
What does not medically necessary mean?
It means the health plan did not approve the service under its rules as submitted. It does not mean your provider was wrong or that the decision is final.
Can I appeal a medical necessity denial?
In many situations, yes. Check your denial notice for appeal instructions, timing, and what documents are required.
Should my doctor write a letter?
A provider letter may help when it explains the request in relation to the denial reason. Ask your provider what information they can provide.
Can external review apply to medical necessity denials?
It may apply in some situations, especially after an internal appeal or in urgent cases. Check your notice and ask your insurer how external review works for your plan.
What if my doctor disagrees with the insurer's decision?
That disagreement is often useful for an appeal. Ask your provider whether they can submit a letter explaining why the requested care meets accepted medical standards, since insurers generally want that clinical reasoning in writing, not just a verbal disagreement.
How is this different from a prior authorization denial?
A prior authorization denial means the plan did not approve a request before treatment happened. A medical necessity denial specifically means the plan's clinical criteria were not met, and can happen before or after treatment. See our prior authorization guide for that side of it.
Can PapaShield tell me if my care is medically necessary?
No. PapaShield does not make medical decisions. It can help you organize questions, documents, and a draft appeal to review.
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Ready to prepare your appeal?
Start by focusing on the denial reason, then gather the documents your plan or provider says may help.