When an insurance company denies a claim, it feels like a final verdict. The letter arrives with cold, bureaucratic language stating that a service was "not medically necessary" or "not a covered benefit." However, a denial is often just the beginning of a negotiation. In the Medicare Advantage world alone, government data shows that 75% of denials are overturned upon appeal . The problem is that most people don't know how to fight back. This section provides the tactical steps to challenge a denial and win.

Why Claims Get Denied: The Usual Suspects

To fight a denial, you first have to understand why it happened. The "denial code" on your EOB or the explanation in your denial letter will usually point to one of these reasons:

Lack of Prior Authorization: Many services, especially surgeries and expensive scans, require the doctor to get "permission" from the insurance company before the service happens. In 2026, 99% of Medicare Advantage enrollees are subject to prior authorization for at least some services . If your doctor forgot to file this, the claim will be denied.
Medical Necessity: The insurance company’s doctors (who have never met you) decide that the treatment your doctor prescribed isn't actually needed for your condition.
Step Therapy: Common in prescription drug plans (Part D), this requires you to try a "Step 1" (cheaper, generic) drug before they will pay for a "Step 2" (expensive, brand-name) drug .
Experimental/Investigational: The insurer claims the treatment is too new or not backed by enough evidence.
Coding Errors: A simple typo in the CPT code can make a routine procedure look like an uncovered cosmetic one.

The Step-by-Step Appeal Process

If you receive a denial for a service you and your doctor believe is necessary, follow this playbook:

1. Call for Clarification

Before filing a formal appeal, call your insurance company. Ask the representative to explain the denial in plain English. Sometimes, it’s a simple fix—like a missing medical record—that can be resolved over the phone without a formal process . Always ask for a reference number for the call .

2. Enlist Your Doctor

Your doctor is your greatest ally. They have the medical expertise to argue why a treatment is necessary. Ask them to write a "Letter of Medical Necessity" that specifically addresses the insurer's reason for denial. If the insurer says the treatment is "experimental," your doctor can provide peer-reviewed studies to prove otherwise.

3. Use AI Tools to Level the Playing Field

Writing a formal appeal letter is a major hurdle for many patients. New AI-powered tools are emerging to help.

Claimable: This service uses AI to generate personalized appeal letters in under 30 minutes, supplementing your story with peer-reviewed evidence and legal citations . They charge a flat fee (around $40) regardless of the outcome.
Fight Health Insurance: A free alternative that uses a chatbot to help you draft an appeal letter based on your denial notice .
General AI (ChatGPT/Gemini): While not specifically trained for medical appeals, these can help you structure a professional letter if you provide them with the details of your denial. Note: Always have a human review AI-generated letters for accuracy .

4. File the Formal Appeal

Follow the instructions in your denial letter exactly. There are usually two levels of appeal:

Internal Appeal: You ask the insurance company to reconsider its own decision.
External Review: If the internal appeal fails, you can take the case to an independent third party. This is a powerful right granted by the Affordable Care Act. The insurance company must follow the third party's decision.

Negotiating When You Still Owe Money

Sometimes, the appeal fails, or you are responsible for a large bill due to a high deductible. You still have options to reduce the burden:

Ask for a "Cash Discount": Hospitals often have a "chargemaster" price (high) and a "cash price" (lower). If you can pay upfront, ask for a discount. AnnMarie McIlwain suggests proposing 20% off the balance for an immediate cash payment .
Apply for Charity Care: Nonprofit hospitals are required by law to have financial assistance programs. These are often based on income (e.g., if you make less than 400% of the Federal Poverty Level). Some programs offer retroactive aid, wiping out bills you've already received .
Set up a Payment Plan: Most hospitals will allow you to pay a bill over 12 to 24 months with zero interest. This is always better than putting a medical bill on a high-interest credit card .
Hire a Patient Advocate: If the bill is massive (e.g., $10,000+), it may be worth hiring a professional. Organizations like the Patient Advocate Foundation offer free help for those with chronic conditions, while private advocates may charge a flat fee or a percentage of what they save you .

Special Case: Workers' Compensation

If your injury happened at work, the rules change entirely. Workers' compensation is a state-mandated program where the employer pays 100% of the premiums . If you accept workers' comp benefits, you generally waive the right to sue your employer, but in exchange, you should have zero out-of-pocket costs for medical care related to that injury . If you receive a bill for a workplace injury, do not pay it. Contact your state's Workers' Compensation Board to resolve the dispute .

The Power of Persistence

The secret to winning an insurance battle is often just staying on the line. Keep a "Medical Paperwork Journal." Write down the date of every call, the name of every person you spoke to, and the reference number for the conversation . It is much harder for an insurance company to deny a claim when you can say, "On October 12th, Sarah told me this would be covered under reference number 12345."

Checklist for Fighting a Denial

Task	Completed?
Read the denial letter and identified the "Denial Code"	[ ]
Called the insurer to ask for a plain-English explanation	[ ]
Confirmed with the doctor's office that the CPT codes were correct	[ ]
Requested a "Letter of Medical Necessity" from the physician	[ ]
Checked if the service requires "Prior Authorization"	[ ]
Drafted an appeal letter (using AI tools if needed)	[ ]
Submitted the appeal within the 180-day window	[ ]
Followed up 14 days after submission to ensure receipt	[ ]

By mastering the EOB and the appeal process, you move from being a victim of the healthcare system to being an empowered consumer. Insurance companies count on you being too tired to fight. When you show up with an itemized bill, a CPT code, and a reference number, you change the dynamic of the conversation. You are not just asking for help; you are demanding the coverage you have already paid for.