Insurance appeal letter: a working template

Why structure matters more than tone

Appeal letters are read quickly. A grievance analyst or appeals nurse may handle ten to twenty cases a day, and they will skim for the specific information they need to make a decision. If your letter is well-structured, the reviewer finds the substance fast and weighs it. If it is a wall of emotional text, the reviewer extracts the claim number and the request and treats it as a generic complaint. Both are written by people who feel the same way — only one gets a careful read.

The template below works for every denial category covered in our appeal pillar guide. The skeleton stays the same; the contents shift based on denial type.

1. The header block (required)

Put this at the top of page one. It is the only thing that guarantees your letter reaches the right desk.

• Your full name exactly as on the policy
• Member ID from your insurance card
• Group number if your plan is employer-sponsored
• Claim number from the denial letter (also called the EOB number)
• Date of service for the denied claim
• Provider name and NPI if you have it
• Today’s date
• A subject line — e.g., “Re: Internal appeal of denial dated [date], claim #[number]”

2. Statement of facts (required)

Two to four sentences. What service was provided or requested, on what date, by which provider, and what the insurer did. Neutral and factual — no argument yet.

On [date] my treating physician, Dr. [name], ordered [service] for the treatment of [condition]. The claim was submitted to [insurer] on [date] and denied on [date], citing [denial reason and any CARC code]. This letter is a timely internal appeal of that denial.

3. Response to the denial reason (required)

This is the body of the letter. Address the specific reason the insurer gave — not denials in general. If the denial cited CARC code 50 for medical necessity, your response is about why the service is medically necessary. If the denial cited CARC code 197 for missing prior authorization, your response is about why the service did or should not require prior authorization, or about the circumstances under which it was provided. Address the reason the insurer actually gave; do not argue a different denial than the one you received.

Keep each paragraph focused. Lead with the conclusion, then the reasoning, then the supporting evidence. Reviewers value answers that arrive in the first sentence.

4. Plan-language citation (required)

Quote the part of your plan document — the Summary Plan Description, Certificate of Coverage, or Evidence of Coverage — that supports your position. Page or section reference is ideal. Plan language is the single highest-value evidence in an appeal because it is the contract that binds the insurer.

For a medical-necessity appeal, quote the plan’s definition of medical necessity and walk through how the service meets each prong. For a plan-exclusion appeal, quote the exclusion and argue why it does not apply to your service. For a prior-auth dispute, quote the prior-authorization requirements and argue compliance.

5. Request for relief (required)

One short paragraph stating exactly what you want the insurer to do. Be specific.

I respectfully request that [insurer] reverse the denial of claim #[number], approve coverage for [service], and process payment in accordance with the terms of my plan. I also request written notice of the appeal decision within the timeframes required by 29 CFR 2560.503-1 and that you preserve my right to external review if this internal appeal is not granted in full.

6. Signature block and attachment list (required)

Sign and date the letter. Beneath your signature, list every attachment by name so the reviewer (and you, later) can confirm nothing was lost.

• Copy of the denial letter / EOB
• Provider letter of support
• Relevant medical records
• Cited plan-language excerpts (highlighted)
• Peer-reviewed literature or guideline citations if any
• HIPAA authorization if someone is filing on your behalf

Optional sections worth considering

These are not required, but they help in specific situations:

• Urgency statement. If the standard timeline could jeopardize your health, ask for an expedited appeal under 29 CFR 2560.503-1(f) and explain why.
• Request for clinical criteria. Ask the insurer to provide the specific clinical guidelines or coverage policy used in the denial. You are generally entitled to this on request.
• Designated representative. If a family member, advocate, or appeal preparer is acting for you, include a signed authorization naming them.
• Reference to professional guidelines. For medical-necessity disputes, brief citations to ACR, NCCN, ADA, APA, AACE, or other society guidance carry weight.

What we do with this template

InsureDefense categorizes your denial, identifies the plan-language anchor that fits your situation, drafts the letter to this structure, and pulls the supporting citations that strengthen your specific case — whether that is a specialty drug appeal, an imaging dispute, or a medical-necessity argument. The skeleton above is the public version; the version we produce is filled in with the citations and evidence patterns that work for the category you fall into.

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