What to include in an insurance appeal letter

The nine parts, in order

1. Your identifying information at the top: member ID, claim number, the date of the denial, and the specific service involved. Immediately after that, a one-line statement that this is a formal appeal, citing the specific procedure it's filed under, your plan's own appeal process, the federal regulation 29 CFR 2560.503-1 for ERISA plans, or your state's insurance code. This tells the reader exactly what kind of document they're holding before they read another word.
2. A single paragraph stating what you're asking for. Not the full argument yet, just the ask: reverse the denial and approve the specific service or medication in question. Reviewers read hundreds of these. Make the ask impossible to miss.
3. The denial's stated reason, quoted back verbatim from the letter you received. Don't paraphrase it. Quoting it precisely shows you're responding to what they actually said, not to an assumption, and it locks the reviewer into addressing the same reason on the way back.
4. A point-by-point rebuttal, mapped directly to the plan's own coverage criteria document for the denied service. This is the section that actually wins or loses the appeal. Request the criteria document in writing before you start drafting (see the procedural demands below), then go through it element by element, showing where your medical record satisfies each requirement.
5. A clinical narrative from your treating physician, in their own words, covering the diagnosis with the relevant codes, the treatments already tried and why they failed or weren't tolerated, why this specific treatment is needed now, and what happens if it isn't approved. This section carries the most weight in the entire letter, and every clinical claim in it has to come directly from the physician. Nothing here gets invented or extrapolated on their behalf.
6. Supporting evidence: relevant specialty-society clinical guidelines plus somewhere between two and five peer-reviewed citations that back the treatment for your specific diagnosis. This isn't about burying the reviewer in paper. A handful of well-chosen citations that directly support your physician's rationale does more than a long bibliography.
7. Your procedural demands: a written request for the complete claim file, the specific internal criteria or guideline the insurer relied on, and the identity and specialty of whoever reviewed the claim. All three are your right, free of charge, and asking for them puts the insurer on notice that you're watching how the process is run, not just what the outcome is.
8. A recital of your deadline: state the date by which the insurer must respond, based on your plan's procedures or the applicable regulation. If your situation is urgent, meaning the standard timeline would seriously jeopardize your life, health, or ability to regain maximum function, request expedited review here and note that your physician supports that request.
9. A copy line at the bottom: cc your state's Department of Insurance or Consumer Assistance Program. This isn't a formal requirement, but it's a real signal. Insurers behave differently when they know a regulator has visibility into the file.

Why the order matters

Reviewers read the ask and the quoted denial reason first, so those need to be unambiguous even to someone skimming. The rebuttal and physician letter carry the actual argument, so they come next while attention is highest. The procedural demands and deadline recital go near the end because they function as a signal about how the case will be handled if this appeal doesn't succeed, not as the core argument. Putting them last doesn't mean they're less important. It means they land as the closing statement of intent.

What never belongs in the letter

Every clinical assertion, diagnosis detail, treatment history, and medical rationale has to come from the treating physician directly. Nothing gets invented, softened, or extrapolated to make the case sound stronger, even when it would help. An appeal letter with one fabricated or exaggerated clinical detail can undermine an otherwise strong case if it's caught, and it should never be caught because it should never be there. If you're working with an advocate or representative, you should review and authorize the final letter before it's submitted. It's your case and your name on it.

If you're missing pieces

It's common to start drafting before you have everything. If you don't yet have the plan's internal criteria document, send the procedural-rights request first and hold the rebuttal section until it arrives rather than guessing at what the plan requires. If your physician's letter isn't ready, don't submit without it if you can avoid it. The clinical narrative is usually the difference between a denial that gets reversed and one that doesn't. For the full appeal timeline and which deadlines apply to your plan type, see our step-by-step appeal guide.