Appeal: experimental or investigational
Asks your plan to reverse an experimental or investigational denial, to explain its clinical reasoning for your diagnosis, and to answer the evidence your doctor relies on.
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- A template, not legal advice
This one is for a specific kind of coverage
It is written for the coverage tagged above. If you have a different kind (for example Medicare or Medicaid instead of a job-based or individual plan), it may cite the wrong rules. Check what kind of coverage you have and use the letter written for it.
When to use this, and what it is not
When to use this. Use this when your plan says a treatment, test or drug is experimental or investigational. Ask your doctor to name the evidence that supports the treatment for you before you fill this in.
This is a template, not legal advice. Read it, change anything that is not true for you, and send it only when you are satisfied. Your notice and your plan document control.
Fill in the letter
Your letter
[Your name] [Your address]
13 November 2026
[Name and address of the plan's appeals department]
Re: Appeal: experimental or investigational Plan: [Name of the health plan] Member ID: [Member ID] Claim or reference number: [Claim or reference number]
To the reviewer:
I am appealing the decision dated [Date on the denial notice] on claim [Claim or reference number], which denied [The care or drug that was denied] ([Doctor, hospital or pharmacy]) on the ground that it is experimental or investigational. I ask you to reverse that decision and approve and pay for this care under [Name of the health plan], member ID [Member ID].
My diagnosis is [Your diagnosis]. I have already tried: [What you have already tried] My treating doctor, [Your treating doctor's name and specialty], recommends this treatment for me.
The plan relied on this wording: [The plan's wording on experimental or investigational care] The plan's reason was: [The reason the plan gave] My doctor relies on the following evidence for using this treatment in my situation: [The studies, guidelines or approvals your doctor relies on]
I ask the plan to identify the specific plan provision and the clinical rule, guideline or policy it relied on. I also ask it to explain the scientific or clinical reasons it concluded that this treatment is experimental for my diagnosis, to say how it applied those reasons to my medical circumstances, and to answer the evidence listed above.
Under the federal claims and appeals rules, including Title 29 of the Code of Federal Regulations (CFR), sections 2560.503-1 and 2590.715-2719 (for individual coverage, 45 CFR 147.136), I am entitled to a full and fair review. I ask that someone who was not involved in the first decision, and who is not that person's subordinate, decide this appeal and give no deference to the first decision. Because the denial rests on a medical judgment, I also ask that you consult a health care professional with training and experience in the field of my condition who was not consulted on the first decision. Please consider every record and comment I send, including anything that was not before the first reviewer.
Please send me your decision in writing within the time the rules allow. If you uphold the denial, I will ask for external review by an independent organization, which can review decisions about whether a treatment is experimental, and may complain to the agency that regulates my plan.
Enclosures: 1. Copy of the denial letter 2. Relevant pages of my medical records 3. Letter from my treating doctor naming the evidence 4. Copies of the studies or guidelines my doctor cites
Sincerely, [Your name]
Before you send it
Send it to the appeals address printed on your denial notice, by a method that proves delivery, such as certified mail with a return receipt or the plan's online portal with a saved confirmation page. Keep a complete copy of the letter and everything you enclose, and write down the date and the method you used.
What to enclose
- Copy of the denial letter
- Relevant pages of my medical records
- Letter from my treating doctor naming the evidence
- Copies of the studies or guidelines my doctor cites
What happens next
- Your plan must decide within 30 days after it receives your appeal if the care has not happened yet, or within 60 days if you have already had it. If your plan has two appeal levels, each level gets half that time. Check the date on your notice, which controls.
- Ask your doctor to send the plan a letter that names the guidelines or studies supporting this treatment for your diagnosis. Naming the specific guidelines or studies gives the reviewer something specific to answer. The plan must give the scientific or clinical reasoning for an experimental denial, or say it is available free on request.
- If the plan says no again or does not answer in time, ask for external review. It covers denials that turn on whether a treatment is experimental or investigational. For most job-based and individual plans you have at least four months after you receive the final denial to ask. Check the date on your notice, which controls.
- You can also complain to the agency that oversees your plan. A complaint does not stop your appeal deadline, so file the appeal first.
- If you are writing for someone else, tick "I am writing for someone else". The plan may require its own authorization form. See the letter "Name someone to act for you".
The rule behind this
Sources
Denial reasons this answers
- Denial reason
Experimental or investigational
The plan says the treatment is unproven or still being tested. That is a medical question, so the appeal rests on evidence. Independent external review is open if your plan is not grandfathered, short-term, fixed indemnity or a sharing ministry.