Denied for "Not Medically Necessary" — How to Appeal

Every plan defines medical necessity in its Evidence of Coverage — typically care that is appropriate for the diagnosis, consistent with accepted standards of practice, and not primarily for convenience. The denial letter must tell you which criteria the reviewer applied. Request the specific guideline (and the reviewer's credentials) in writing; ERISA-governed plans must provide the documents relied on, free, on request.

Once you can read the actual criteria, appeals stop being abstract. Either your clinical facts satisfy the listed criteria — and the appeal shows it line by line — or the criteria themselves are narrower than the plan's own definition of medical necessity, which is itself a winning argument.

The core exhibit is a letter of medical necessity from your treating physician that maps your diagnosis and history onto the insurer's criteria: what was tried and failed, why this treatment is indicated now, what the clinical guidelines and peer-reviewed literature say, and what the consequences of non-treatment are. Ask your physician to reference the specific criteria the insurer cited.

Attach the records that support each claim in the letter — imaging, labs, prior treatment notes. An appeal that quotes the plan's definition, cites ACA Section 2719 appeal rights, and walks the criteria with record citations reads like the file of someone who will go to external review. Insurers settle those.

File the internal appeal within your deadline (at least 180 days under ACA rules). If the denial is upheld, medical-judgment denials qualify for external review by an Independent Review Organization — independent clinicians whose decision binds the insurer. Consumers win a substantial share of external reviews of medical-necessity denials; figures around 40% are commonly reported.

If your condition makes waiting dangerous, request expedited handling at both stages — decisions can be required in as little as 72 hours.