Insurance Denied Your Claim? How to Fight Back and Win

Understanding why your claim was denied is the first step to overturning it. The denial letter (called an Explanation of Benefits or EOB) must include a reason code. Common denial reasons include:

• —Prior authorization not obtained: The insurer required pre-approval for the service, and it wasn't obtained before treatment. This is one of the most common denials — and one of the most successfully appealed, especially for emergency care where prior auth was impossible.
• —Out-of-network provider: You received care from a provider not in your plan's network. The No Surprises Act now provides significant protections for many of these situations.
• —Not medically necessary: The insurer's review determined the service wasn't required. This is a medical judgment call that can be challenged with supporting documentation from your doctor.
• —Coding errors: The provider used incorrect billing codes. This is an administrative error that's easily correctable.
• —Timely filing deadline missed: The provider didn't submit the claim within the insurer's required timeframe. This is the provider's error, not yours — and you should not be held responsible for it.
• —Duplicate claim: The insurer believes the claim was already submitted and processed.

Read your denial letter carefully. The specific reason determines your appeal strategy.

Federal law (the ACA) ² guarantees your right to appeal any claim denial through the insurer's internal appeals process. Here's how it works:

• —Step 1: Request the full claim file. Call your insurer and ask for the complete file, including the clinical reviewer's notes and the specific policy language they relied on to deny your claim. You have a legal right to this information.
• —Step 2: Get your doctor involved. Ask your treating physician to write a letter of medical necessity explaining why the service was required. This is the single most powerful piece of evidence in a medical necessity denial appeal.
• —Step 3: Write your appeal letter. Address the specific denial reason. Include your doctor's letter, relevant medical records, and any clinical guidelines or peer-reviewed studies that support the treatment. Reference your plan's specific coverage language.
• —Step 4: Submit within the deadline. Most plans require internal appeals within 180 days of the denial. Submit via certified mail or the insurer's online portal, and keep copies of everything.
• —Step 5: Expedited appeal for urgent cases. If the denial involves ongoing treatment, an upcoming procedure, or a life-threatening condition, request an expedited appeal. Insurers must respond to expedited appeals within 72 hours.

The insurer must respond to standard internal appeals within 30 days for pre-service denials and 60 days for post-service denials.

If the internal appeal fails, you have the right to an external review — an independent evaluation by a third-party reviewer who is not employed by your insurer ². This is a critical safeguard because the external reviewer has no financial incentive to uphold the denial.

How external review works:

• —You request external review through your insurer or your state's insurance department (the process varies by state)
• —An independent, certified reviewer examines your case, including all medical records, the insurer's denial rationale, and your appeal documentation
• —The reviewer makes a binding decision — if they overturn the denial, the insurer must pay the claim
• —Most external reviews are completed within 45 days (or 72 hours for expedited cases)

External review is free to you. The insurer bears the cost. You have nothing to lose by requesting it.

External review is particularly effective for medical necessity denials because the independent reviewer is a medical professional evaluating whether the treatment was appropriate — not a cost-containment decision-maker employed by the insurer.

The No Surprises Act ³, which took effect in January 2022, provides significant new protections against unexpected medical bills from insurance denials related to out-of-network care.

Key protections:

• —Emergency services: You cannot be balance-billed for emergency care at any facility, regardless of network status. If your insurer denies a claim for emergency care because the provider was out-of-network, this is a direct violation of the No Surprises Act.
• —Non-emergency care at in-network facilities: If you receive care at an in-network hospital but are treated by an out-of-network provider (such as an anesthesiologist or radiologist you didn't choose), you're protected from balance billing.
• —Air ambulance services: Out-of-network air ambulance providers cannot balance-bill you.

If you receive a bill that you believe violates the No Surprises Act:

• —Contact your insurer and reference the No Surprises Act by name. Many denials related to out-of-network emergency care are resolved at this stage.
• —File a complaint with the Centers for Medicare and Medicaid Services (CMS) No Surprises Help Desk or your state's insurance commissioner.
• —Request independent dispute resolution (IDR): Under the No Surprises Act, payment disputes between providers and insurers go through a federal arbitration process — you should not be caught in the middle.

If internal appeals, external review, and No Surprises Act protections haven't resolved your situation, you have additional escalation paths.

State Insurance Commissioner:

Every state has an insurance regulatory agency (often called the Department of Insurance) that oversees health insurers operating in the state ⁴. Filing a complaint with your state's insurance commissioner can:

• —Trigger a formal investigation of your denied claim
• —Force the insurer to provide a detailed explanation of the denial
• —Result in the insurer overturning the denial to avoid regulatory action
• —Contribute to pattern-and-practice investigations if other consumers have filed similar complaints

File your complaint through your state's insurance department website. Include your denial letter, appeal documentation, and a timeline of events.

Employer HR Escalation (for employer-sponsored plans):

If your insurance is through your employer, your HR department has leverage you don't. Employers are the insurer's actual customer — they pay the premiums and can threaten to switch carriers. Steps:

• —Contact your HR benefits team and explain the denied claim
• —Ask them to intervene directly with the insurer's account representative
• —Request that HR escalate the issue to the insurer's employer relations team
• —Large employers often have dedicated representatives at the insurance company who can override standard denial processes

While your appeal is pending, you need to prevent the hospital bill from escalating to collections. Here's how:

• —Notify the hospital. Call the billing department and inform them that you are appealing the insurance denial. Ask them to place your account on hold pending the appeal outcome. Most hospitals will comply.
• —Get it in writing. Request written confirmation that the account is on hold and that no collection actions will be taken while the appeal is in process.
• —Do not pay the disputed amount. Paying the bill while appealing signals acceptance of the charges and makes recovery more difficult if the appeal succeeds.
• —Keep the hospital updated. If the appeal takes longer than expected, call the billing department periodically to confirm the hold is still in place.
• —Document everything. Keep copies of all appeal submissions, denial letters, hold confirmations, and phone call notes with dates and names. This documentation protects you if the hospital sends the bill to collections despite the pending appeal.

If the hospital refuses to hold the account, send a written letter referencing the pending appeal and stating that you are actively disputing the charges. This creates a paper trail that protects you under the Fair Debt Collection Practices Act if the bill reaches collections.