Medical necessity denials: what evidence wins

The shape of a medical-necessity denial

Medical-necessity denials typically cite CARC code 50 (“Non-covered services because this is not deemed a medical necessity by the payer”) or sometimes 150 (“Payer deems the information submitted does not support this level of service”). The denial language is usually short: a sentence or two stating the insurer’s clinical reviewer concluded the service wasn’t necessary.

What the denial often won’t tell you: exactly which criteria weren’t met, which clinical information the reviewer didn’t have, and what would change their mind. Filling those gaps is the appeal.

Element 1 — The treating-provider letter

This is the single most important piece. A strong provider letter contains:

• Clinical history — relevant diagnoses, dates, prior treatments tried, and clinical outcomes.
• Why this specific service was indicated — not just “the patient needs it” but the clinical reasoning that connects the diagnosis to the treatment.
• Reference to guidelines — what professional society (AMA, ACOG, AAOS, APA, etc.) recommends for this situation.
• What would happen without the service — clinical consequences of denying treatment.
• Provider credentials — board certifications matter for credibility.

Most provider offices have templates for these letters. Our Provider Evidence Pack ($49) supplies a template, a checklist of records to request, and a fax cover sheet to streamline the request.

Element 2 — Peer-reviewed literature and guidelines

For higher-stakes appeals (especially anything that would normally cost over $5,000, or anything in oncology, mental health, or specialty drug categories), supporting the provider’s opinion with peer-reviewed evidence substantially strengthens the case:

• Treatment guidelines from professional societies (ASCO, NCCN, ADA, APA, etc.).
• Recent peer-reviewed studies showing the treatment’s effectiveness for your situation.
• FDA labeling, if it supports your specific indication.
• Cochrane reviews or systematic reviews when they exist.

You don’t need to cite ten studies. Two to four well-chosen, directly-applicable references usually outperforms a long bibliography of marginally-relevant ones.

Element 3 — Plan-language anchor

Cite your plan’s own medical-necessity definition and argue that your service meets it. Plan documents are usually specific:

“Medical necessity” or “medically necessary” means health care services that a physician, exercising prudent clinical judgment, would provide to a patient for the purpose of preventing, evaluating, diagnosing or treating an illness, injury, disease or its symptoms, and that are:
(a) in accordance with generally accepted standards of medical practice;
(b) clinically appropriate, in terms of type, frequency, extent, site and duration, and considered effective for the patient’s illness, injury or disease; and
(c) not primarily for the convenience of the patient or physician.

Quote the actual definition from your plan’s Summary of Benefits or Certificate of Coverage, then walk through each prong showing how the service meets it.

Putting it together

A strong medical-necessity appeal opens with a one-paragraph summary, walks through the plan’s medical-necessity definition prong-by-prong, attaches the provider letter and cited studies, and closes with a clear request for the specific relief sought (approval of the service, payment of the claim, or both).

How InsureDefense structures this appeal

We classify medical-necessity denials in triage and route them to our Premium tier ($499), which includes plan-language citations from our insurer corpus and 2–3 peer-reviewed citations. For time-sensitive medical-necessity denials (scheduled surgeries, urgent specialty drug continuation, ongoing inpatient care), our Urgent tier ($699) delivers the same package within 12 hours.

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