A denial for a rare disease claim feels devastating. But it's not the end. Health plans must give you a clear reason and a way to appeal. Rare diseases don't fit standard guidelines, so denials happen—lack of protocols, high costs, misclassification. The appeals process is your structured path to challenge it. Your odds go up when you're strategic, thorough, and use every legal right under ERISA and the ACA.
Step 1: Understand Why the Claim Was Denied
Before you appeal, get the exact reason. The insurer must send a formal denial letter (required by ERISA for employer plans, state law for individual plans). That letter should include:
- The specific reason(s)—like “not medically necessary,” “experimental/investigational,” “out-of-network,” or “not a covered benefit”
- The plan provision or exclusion cited
- The appeals process and deadlines
- Instructions for how to submit additional info
For rare diseases, the most common denial reasons are “experimental/investigational” or “lack of medical necessity.” Why? FDA-approved treatments may not exist, or plan guidelines were written for common conditions. Your appeal must address those points.
Step 2: Gather Critical Supporting Evidence
Your appeal is only as strong as the evidence you provide. A generic doctor's letter isn't enough. Collect these:
- Detailed letter from your treating specialist explaining why the denied treatment is medically necessary for your case. Include peer-reviewed studies, case reports, or clinical trial data.
- Medical records showing disease progression, failed alternative treatments, and symptoms.
- Published literature on the treatment's efficacy for your condition—even small studies or case series.
- Support from patient advocacy organizations (like NORD, EveryLife Foundation)—they often provide letters of medical necessity or research summaries.
- A second opinion from a rare disease specialist at an academic medical center (many have dedicated clinics).
If the denial says “lack of medical necessity” or “experimental,” submit a formal “Medical Necessity Appeal” with a clinical rationale from an expert. Plans sometimes require a peer-to-peer review—a direct talk between your doctor and their medical director. That can overturn denials in real time.
Step 3: Follow the Formal Internal Appeals Process
Every health plan has multi-level internal appeals. You must exhaust these before external review. Here's how:
- File the first-level appeal within the deadline (typically 180 days for employer plans under ERISA). Write a formal letter referencing the claim number, denial reason, and your evidence. Send it certified mail or via the online portal with a receipt.
- If denied, file a second-level internal appeal—some plans offer this for high-cost or rare disease claims. You can request an expedited appeal if delay could seriously harm your health.
- Request a peer-to-peer review before or during the appeal. This is often the most effective step for rare disease claims because your specialist can discuss your unique case directly with the plan's physician, bypassing an algorithm or non-specialist.
Keep a detailed log of every phone call, email, and letter. Note names, dates, and what was discussed. Always meet every deadline—missing one can forfeit your appeal rights.
Step 4: If Internal Appeals Are Denied, Seek External Review
If the internal process fails, you have the right to an independent external review. Under the ACA, most non-grandfathered plans must allow this. The external decision is binding. Steps:
- File a request with the plan or state insurance department (the denial letter explains how). Usually 60 days from the final internal denial.
- Submit your case with all evidence—medical records, specialist letters, research.
- The external reviewer uses independent medical experts who evaluate against standard evidence, not just the plan's guidelines.
For rare diseases, external reviewers are more likely to consider off-label or novel treatments if backed by credible evidence. Some states also have their own external review programs for fully insured plans—check with your state's insurance commissioner.
Step 5: Elevate to Legal and Regulatory Options
If external review fails, you still have options:
- File a complaint with the Employee Benefits Security Administration (EBSA) if your plan is ERISA-governed. They investigate fiduciary violations.
- Hire an attorney specializing in ERISA, health insurance, or rare disease litigation. Many offer free consultations. They can argue the denial is arbitrary or the plan breached its duty.
- Leverage patient assistance programs from pharma companies, non-profits, or disease foundations—they may cover treatment costs or provide legal aid.
- Consider a class action if the denial pattern affects many patients—longer-term.
Key Tips for Employees and Employers
Both sides can reduce friction for rare disease claims:
- Employers: Review your plan's medical necessity criteria for rare diseases during annual enrollment. Consider a “rare disease rider” or work with a TPA experienced in rare conditions. Some self-funded employers include orphan drug provisions to avoid automatic denials.
- Employees: Document everything from day one—medications, visits, denial letters. Get a “plan of care” from your specialist stating the treatment and why it's essential. If enrolled in a health-to-wealth system like WellthCare that rewards prevention, note that early documentation can support later appeals. WellthCare's AI-drafted, clinician-reviewed plans of care create a documented, clinically-supported record that strengthens any appeal you may need.
Why Persistence Pays Off
Most rare disease denials get overturned. Studies show 40-60% of internal appeals succeed with strong clinical evidence. Treat the appeals process not as a formality but as a rigorous, evidence-based negotiation. Understand the system, build a robust case, use every legal lever available. For employers, a more transparent benefits ecosystem that rewards prevention and reduces waste can prevent these denials altogether.