"Not medically necessary" is the most common reason insurers deny claims — and one of the most commonly overturned on appeal. Your doctor ordered it for a reason. Here's how to prove it.
Appeal My Medical Necessity Denial →Takes 3 minutes · No login required · Cite clinical guidelines
Understanding the denial is the first step to overturning it.
When an insurer says a treatment is "not medically necessary," they mean it doesn't meet their internal utilization review criteria — proprietary guidelines like InterQual or Milliman Care Guidelines. These criteria are often stricter than what the medical community considers standard of care. The reviewer may be a nurse or a physician in a completely different specialty than your condition.
Your treating physician ordered the treatment based on their clinical judgment after examining you, reviewing your history, and considering evidence-based medicine. Medical necessity from a clinical perspective means the service is required to diagnose or treat your condition and is consistent with generally accepted standards of care. Your doctor's opinion carries significant weight in appeals.
Federal and state laws often define medical necessity more broadly than insurers do. Under the ACA, essential health benefits must be covered when medically necessary. Many states define medical necessity as treatment that is "consistent with generally accepted standards of medical practice" — not the insurer's proprietary guidelines. This gap between legal standards and insurer criteria is where successful appeals live.
Insurers use medical necessity denials because they are subjective and hard for consumers to challenge without medical knowledge. The reviewer may lack access to your full medical records, apply criteria meant for a different condition, or simply disagree with your doctor. Many denials are made by algorithms or nurses following flowcharts — not by physicians who specialize in your condition.
These treatments are frequently denied — and frequently overturned on appeal.
Your appeal is only as strong as the evidence behind it. Here's what to gather.
Call your insurer and ask for the specific clinical guidelines, criteria, or policy they used to deny your claim. You have a legal right to this information. Ask for it in writing. Knowing their criteria tells you exactly what evidence you need to counter.
Ask your treating physician to write a detailed letter explaining why the treatment is medically necessary for your specific condition. The letter should reference your diagnosis, treatment history, failed alternatives, and why the recommended treatment is the appropriate standard of care.
Find published studies supporting the treatment for your condition. PubMed, medical society guidelines, and systematic reviews carry the most weight. Even a few well-chosen citations showing the treatment is evidence-based can shift an appeal in your favor.
Gather relevant office notes, test results, imaging reports, and treatment history. Denials often happen because the reviewer didn't have your full picture. A complete record showing the severity of your condition and failed alternatives is powerful evidence.
If your primary doctor's opinion isn't enough, a second opinion from a specialist in the relevant field — especially one who is board-certified — adds significant credibility to your appeal.
One phone call between your doctor and the insurer's reviewer can overturn a denial. Here's how it works.
A peer-to-peer review is a direct conversation between your treating physician and the insurance company's medical director or reviewing physician. It's an opportunity for your doctor to explain their clinical reasoning, provide additional context, and advocate for your treatment. Many states require insurers to offer this before finalizing a denial.
Call the number on your denial letter and ask to schedule a peer-to-peer review. In many cases, your doctor's office can initiate this directly. Time is critical — most insurers require the peer-to-peer to happen within 5-10 business days of the denial. Ask your doctor's office to prioritize scheduling it.
Prepare your doctor by sharing the specific denial criteria the insurer used. Your doctor should address each criterion directly, explain why alternatives won't work for your case, and reference clinical guidelines or studies. The most successful peer-to-peer calls are those where the doctor comes prepared with targeted rebuttals to the insurer's specific objections.
If the insurer still denies after peer-to-peer, you haven't lost — you've created a record. Document what was discussed and proceed with a formal written appeal. If the internal appeal is denied, you have the right to an external review by an independent physician under the ACA. External reviews overturn roughly 40-50% of medical necessity denials.
ClaimBack generates these strategies automatically, but here's what makes a medical necessity appeal letter effective.
Don't write a generic letter. Obtain the insurer's clinical criteria and refute each point. If they said you haven't tried conservative treatment, document the treatments you've already failed. If they said the condition isn't severe enough, provide objective measurements.
A letter from your treating physician carries more weight than anything you can write yourself. It should explain your diagnosis, prognosis without treatment, why this specific treatment is needed, and why alternatives are insufficient or have already failed.
Reference guidelines from recognized medical organizations (AMA, specialty societies). If a major medical association recommends the treatment for your condition, that directly contradicts the "not medically necessary" finding.
If you've already tried cheaper or less invasive treatments that the insurer might prefer, document each one — when you tried it, how long, and why it failed. Step therapy failures are powerful evidence for medical necessity.
Review your plan's Summary of Benefits and Coverage (SBC) and Evidence of Coverage (EOC). If the treatment falls within covered benefits and meets the plan's own definition of medical necessity, cite those documents directly in your appeal.
"Not medically necessary" means your insurance company's utilization review team determined that the treatment, procedure, or service your doctor ordered does not meet their internal clinical criteria for coverage. This does not mean your doctor was wrong — it means the insurer's reviewer (often a nurse or doctor who never examined you) disagrees based on their guidelines. These guidelines are often more restrictive than accepted medical standards of care.
Start by requesting the specific clinical criteria your insurer used to deny the claim. Then gather supporting documentation from your treating physician, including a letter of medical necessity explaining why the treatment is required for your condition. Submit an internal appeal with this evidence. If denied again, request an external review — federal law (ACA) guarantees your right to an independent external review for medical necessity denials.
A peer-to-peer review is a phone call between your treating physician and the insurance company's medical director. During this call, your doctor can explain the clinical rationale for the treatment directly. Many denials are overturned at the peer-to-peer stage because the insurer's reviewer gains context they didn't have from the paperwork alone. Ask your doctor's office to schedule this as soon as you receive a denial.
Common conditions denied for medical necessity include mental health and substance abuse treatment, physical therapy and rehabilitation, advanced imaging (MRI, CT scans), surgeries deemed "elective" by insurers (like spinal surgery or joint replacement), cancer treatments, specialty medications, and durable medical equipment. Many of these denials are overturned on appeal when proper clinical documentation is provided.
Your doctor ordered this treatment for a reason. ClaimBack builds your appeal letter with clinical citations, legal references, and the specific language that gets denials overturned.
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ClaimBack provides AI-assisted document drafting. We are not a law firm and do not provide legal advice.