How to Appeal a Health Insurance Denial: The Complete Playbook

Extract three things from the denial letter: the exact denial reason and code, the plan provision cited, and your appeal deadline (at least 180 days from notice under ACA rules). Calendar the deadline immediately, and a self-imposed target 60 days earlier.

Send two requests the same week: to the insurer, for the complete claim file — the criteria applied, reviewer credentials, and documents relied on (free on request for ERISA plans); to your provider, for the medical records and an appointment to discuss a letter of medical necessity.

The physician letter is your centerpiece for any clinical denial: diagnosis, treatment history and failures, why the requested care is indicated under accepted standards, and — critically — a point-by-point response to the insurer's stated criteria. Pair it with the specific records that back each sentence.

For administrative denials (coding, prior-auth process, network status), the record is different: corrected claims, provider statements about whose obligation authorization was, network-search documentation, ER timestamps. Match the record to the denial type — an appeal that answers the actual reason beats a generic protest every time.

Format it as a business letter: patient identifiers and claim number up top; paragraph one states the denial being appealed and invokes your appeal rights; then 3–5 headed arguments, each tying evidence to plan language or law; then the remedy — approve the claim, or authorize the care — and a request for expedited handling if your health can't wait the standard timeline.

Cite as you go: the plan provision by section number, ACA Section 2719 (appeal and external review rights), 29 CFR 2560.503-1 for ERISA full-and-fair review, and the clinical guidelines your physician relies on. Mark anything you can't verify for follow-up rather than guessing.

If the internal appeal fails, denials involving medical judgment qualify for external review by an Independent Review Organization — request it within four months of the final internal denial. The IRO's decision binds the insurer. Send the entire record: your appeal, the physician letter, records, and the insurer's responses.

In parallel, complaints to your state insurance regulator are free and force a response; for ERISA plans, exhausting appeals preserves the right to sue, where the administrative record you built is the evidence. Urgent cases: request expedited review at every stage — 72-hour decisions are required where standard timelines would jeopardize health.