What Is an Appeal Letter
An appeal letter is a written request you submit to your insurance company asking them to reconsider a claim denial. It includes medical evidence, clinical rationale, and documentation explaining why the denied service meets your plan's coverage criteria and was medically necessary.
You typically file an appeal letter after receiving a denial on your Explanation of Benefits (EOB). The letter becomes your primary tool to dispute denials related to medical necessity, lack of prior authorization, or claim processing errors. Most insurers require the appeal within 30 to 180 days of the denial date, depending on your state's regulations and plan type.
The Appeal Process and Timeline
Insurance appeals operate in two stages in most states. An Internal Appeal goes to your insurer's review department, which must respond within 30 days for standard appeals or 72 hours for urgent cases (when treatment is time-sensitive). If the internal appeal fails, you can file an External Appeal with your state's Department of Insurance, which employs an independent medical reviewer who has no financial stake in the denial.
Your appeal letter is the centerpiece of the internal stage. Without a well-constructed letter supported by clinical documentation, your case relies entirely on the insurer's original denial reasoning.
What Your Appeal Letter Must Include
- Claim details: Date of service, claim number, provider name, and specific procedure or service code
- Denial reason: The exact reason listed on your EOB (for example, "not medically necessary" or "requires prior authorization")
- Medical evidence: Clinical notes from your doctor, peer-reviewed studies, treatment guidelines (like those from NCCN or ASCO), or letters from your treating physician explaining why the treatment was appropriate
- Plan language reference: Quotes from your insurance plan documents showing the service should be covered under stated conditions
- Your statement: A brief explanation of your medical situation and why the denied service was necessary
Common Denials and Appeal Strategies
Medical necessity denials are the most frequent. If your insurer claims a treatment isn't medically necessary, your doctor's letter explaining the clinical indication is critical. Reference diagnostic test results, symptom severity, or failed prior treatments that justify the procedure.
Prior authorization denials occur when your provider didn't obtain approval before treatment. If this happened due to provider error rather than your choice, include documentation showing the provider should have requested it. Some states have "emergency care" exemptions that waive prior authorization requirements.
Claim processing errors like incorrect coding require less clinical evidence. Simply submit the correct claim coding with a brief letter requesting correction.
Common Questions
- Can I appeal after the deadline? Some states allow late appeals if you have "good cause," such as provider error or illness preventing timely filing. Contact your state's Department of Insurance to confirm your state's policy.
- Should I hire someone to write my appeal? Patient advocates or medical billing specialists charge $200 to $500 per appeal but increase approval rates. Many nonprofits offer free appeal assistance based on income.
- What if internal and external appeals both fail? You can sue in court or file a complaint with your state's Department of Insurance. Some plans also allow an independent medical review if state law permits it.