How to appeal a medical necessity denial
A “not medically necessary” denial is one of the most common — and one of the most appealable. It is the insurer’s opinion under its coverage rules, not the last word. Here is how to push back with evidence.
What a medical necessity denial actually means
When an insurer says a service was “not medically necessary,” it means the service didn’t meet the plan’s clinical criteria for coverage — not that the care was worthless or that your doctor erred. Insurers apply internal medical policies and criteria sets to decide what they’ll pay for. Those policies can be stricter than your physician’s judgment, which is exactly why the appeal exists.
Because this is a clinical disagreement, you win it with clinical evidence — not emotion. Your job is to show that the care meets accepted standards for your diagnosis.
How to build your argument
- Get a letter of medical necessity from your treating physician explaining your diagnosis, what was tried before, and why this care is needed.
- Cite recognized clinical guidelines (specialty society guidelines, standard treatment protocols) that support the care.
- Show your history — prior treatments, tests, and why less intensive options were inadequate.
- Request the insurer’s own criteria for this service, then map your records to each requirement.
- Quote the denial and answer its specific reason point by point.
You can ask your insurer for the specific medical-necessity criteria or clinical policy it used. Once you see the exact standard, it’s much easier to demonstrate that your care meets it.
Evidence checklist
- Denial letter and EOB with the reason/codes
- Physician letter of medical necessity
- Relevant medical records, imaging, and test results
- Clinical guidelines that support the treatment
- Documentation of prior, less-intensive treatments tried
If the internal appeal is denied
Don’t stop. Medical-necessity disputes are exactly what external review exists for — an independent clinician outside your insurer takes a fresh look, and the decision is binding. Mind your appeal deadline and follow the full process in our step-by-step guide.
Frequently asked questions
What does "not medically necessary" mean?
It means the insurer decided the service was not needed to diagnose or treat your condition under its coverage rules — not that your doctor was wrong. You can appeal and ask the insurer to reconsider against the clinical evidence.
How do I prove medical necessity?
Use your treating physician’s letter of medical necessity, your medical records, recognized clinical guidelines, and evidence of treatments you already tried. Tie each piece to the specific reason the insurer gave.
Can I see the criteria the insurer used?
Often yes. You can request the specific medical-necessity criteria or clinical policy the insurer applied to your claim, then show how your case meets it.
Find out free if it's worth fighting
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IntelClaim is a self-help tool — not legal, medical, or insurance advice — and does not guarantee any particular outcome. Information on this site is general and may not reflect the rules of your specific plan or state. Always read your own denial letter, plan documents, and the deadlines that apply to you, and consider professional advice for your situation. No PHI is collected on this marketing site.