Getting a claim denied feels like a dead end — but it's not. Insurance companies deny claims knowing that most patients won't appeal. The ones who do win 40–60% of the time. Here's how to be one of them.
Why Insurers Deny Claims
Common denial reasons include:
- Not medically necessary — the insurer doesn't agree the procedure was needed
- Prior authorization not obtained — the provider forgot to get pre-approval
- Out-of-network provider — you saw a doctor not in your plan's network
- Coding error — wrong CPT or diagnosis code on the claim
- Duplicate claim — the same service billed twice
- Plan exclusion — the service isn't covered under your plan
The denial reason matters because it determines your appeal strategy. Always start by reading the denial letter carefully.
Step 1: Get the Full Picture
Request your complete Explanation of Benefits (EOB) and the insurer's specific reason for denial. Under the ACA, insurers must provide a written explanation. Also request a copy of your plan's Summary of Benefits and Coverage — you'll need it to reference what's covered.
Step 2: File an Internal Appeal
Every insurer has an internal appeal process. You typically have 180 days from the denial date to file (check your EOB for your plan's deadline). Your appeal letter should include:
- Your name, policy number, and claim number
- Date of service and the service that was denied
- Why you believe the denial was wrong (cite your plan documents)
- Supporting documentation: doctor's letter of medical necessity, clinical guidelines, peer-reviewed studies
Our Insurance Fighter tool generates a customized appeal letter based on your specific denial reason and EOB.
Step 3: Get Your Doctor Involved
A letter of medical necessity from your physician is the most powerful piece of appeal evidence. Ask your doctor to write a letter explaining:
- Your diagnosis and why the treatment was medically necessary
- What would happen without the treatment
- References to clinical guidelines supporting the treatment
Insurers are far less likely to uphold a denial when a physician has documented medical necessity in writing.
Step 4: Request an External Review
If your internal appeal is denied, you have the right to an independent external review — a requirement under the ACA for most health plans. An independent organization reviews your case with no financial stake in the outcome.
External reviews overturn insurer decisions about 40% of the time. File within 4 months of your internal appeal denial. Your insurer must provide information on how to request external review in their denial letter.
Step 5: Escalate Further If Needed
Additional options if external review fails:
- State Insurance Commissioner — file a complaint; regulators sometimes pressure insurers to reconsider
- Employer's HR department — if you have employer-sponsored insurance, HR can often intervene
- Consumer assistance programs — many states have free programs to help patients navigate appeals
- Attorney — for large claims, a consumer rights attorney working on contingency may be worth consulting
Emergency and Urgent Care Denials
A special note: under the No Surprises Act (effective 2022), insurers cannot deny coverage for emergency care based on whether the provider was in-network. If your emergency visit was denied because the ER was out-of-network, that denial may be illegal.
Key Takeaways
- Always appeal — 40–60% of appeals succeed
- Get a medical necessity letter from your doctor
- Use the external review process if internal appeal fails
- Know your deadlines — most are 60–180 days from denial
Use our Insurance Fighter tool to analyze your EOB, identify the strongest appeal arguments, and generate your appeal letter for free.