A complete, plain-English guide to understanding why claims get denied, knowing your legal rights, and filing appeals that actually get approved.
An insurance denial (also called a "claim denial" or "adverse benefit determination") means your health insurance company has refused to pay for a service, procedure, or medication. Understanding why your claim was denied is the first step to overturning it.
Your insurer says the service needed pre-approval that wasn't obtained, or the pre-approval request was denied. This is the most common denial type and one of the most successfully appealed.
The insurer claims the treatment isn't "medically necessary." Often the reviewing doctor has never examined you. Your treating doctor's letter of medical necessity is your strongest weapon here.
The provider isn't in your plan's network. Under the No Surprises Act (2022), you may be protected from balance billing for emergency services and certain non-emergency situations.
The insurer labels the treatment "experimental." If your doctor can provide peer-reviewed studies and clinical guidelines supporting the treatment, this denial can often be overturned.
Denials are a business decision, not always a medical one. Insurers know that most people won't appeal. Common reasons include:
By law, your insurer must tell you why the claim was denied, what clinical criteria they used, and how to appeal. Read your denial letter carefully — it contains the exact information you need to fight back.
You have powerful legal protections at both the federal and state level. Insurance companies are required to follow these rules — and most patients don't know they exist.
Requires all non-grandfathered plans to offer an internal appeal process and an independent external review. Your insurer must respond to your internal appeal within 30 days (72 hours for urgent cases). If they deny your internal appeal, you have the right to an external review by an independent third party.
If you get insurance through your employer, ERISA governs your plan. You have the right to a full and fair review of any denied claim. The insurer must provide the specific reason for denial, the plan provision it's based on, and any additional information needed to perfect your appeal. You get 180 days to file your appeal.
Most states have their own external review laws that may provide additional protections beyond federal requirements. Many states require reviews to be completed within 45 days. Some states allow external review for any denial, not just medical necessity disputes. Check your state's Department of Insurance website.
Protects you from surprise balance billing for emergency services, air ambulance from out-of-network providers, and non-emergency services from out-of-network providers at in-network facilities. If you receive a surprise bill that violates this law, you can dispute it through the federal independent dispute resolution (IDR) process.
Don't wait. Mark these deadlines on your calendar the day you receive your denial.
Appealing a denial follows a clear path. Each stage gives you a new opportunity to present your case. Don't give up after the first "no" — that's exactly what they expect.
Your denial letter (called an Explanation of Benefits or EOB) contains critical information. Look for:
Pro tip: Call the number on your denial letter and ask for a copy of the complete claim file, including any medical director notes and the clinical criteria used. You are legally entitled to this under ERISA and the ACA.
This is your formal request to the insurance company to reconsider. Here's what to include:
Send everything via certified mail with return receipt so you have proof of delivery. Keep copies of everything you submit. Also send by fax if your plan accepts fax submissions — belt and suspenders.
Your insurer must respond within 30 days for post-service claims or 15 days for pre-service claims. For urgent cases, they must respond within 72 hours.
If your internal appeal is denied, you have the right to an external review by an Independent Review Organization (IRO). This reviewer is not employed by your insurer.
Why external reviews matter:
How to request: Your internal appeal denial letter must include instructions. You can also contact your state's Department of Insurance for their external review process.
Submit the same documentation as your internal appeal, plus your internal appeal denial letter. Add any new evidence or studies that have become available.
You can file a complaint with your State Department of Insurance at any point during the process. This is especially powerful because:
How to file: Search for "[your state] Department of Insurance complaint" to find your state's online complaint form. Most are free and can be submitted online.
Additionally, you can contact the Centers for Medicare & Medicaid Services (CMS) at 1-800-633-4227 if you believe your rights under the ACA have been violated.
If external review and state complaints don't resolve your issue, you have legal options:
Many healthcare attorneys offer free consultations. Contact your state bar association for referrals to health insurance attorneys.
Most people don't appeal because they think it's pointless. The data tells a very different story. Insurance companies count on you giving up. Don't.
of all appeals are successful. Nearly half of denied claims that go through the appeals process get overturned. Some studies show success rates as high as 60%.
of denied claims are ever appealed. Out of 200+ million denied claims per year, fewer than 1 in 500 are formally appealed. The system counts on your silence.
of external reviews overturn denials. When an independent reviewer looks at the case, they often side with the patient. External review is binding on the insurer.
average surprise medical bill. Many of these are negotiable or should never have been billed to you in the first place. Don't pay without questioning it first.
Every appeal you file costs the insurance company time and money to process. Even if your first appeal is denied, each step up the chain gets your case reviewed by a new set of eyes. The people who fight back get results — that's a fact, not a slogan.
Ready-to-use templates for the most common denial types. Click to expand, customize the highlighted fields with your information, and send. Every template includes the key legal phrases that strengthen your case.
Battle-tested strategies from patient advocates and healthcare attorneys. These tips can make the difference between a denied appeal and an approved one.
You're legally entitled to your complete claim file, including the medical director's notes, clinical criteria used, and any internal communications. Call and request it in writing. This shows you what you're fighting against.
Certain phrases carry legal weight. Use them in your communications:
I am exercising my right to appeal adverse benefit determination full and fair review medically necessary as determined by my treating physician independent external review
Ask your doctor to include references to peer-reviewed studies and clinical practice guidelines from recognized medical societies (NCCN, AMA, AHA, etc.) that support the recommended treatment. PubMed.gov is a free resource for finding studies.
Phone calls are fast, but they leave no paper trail. Always follow up every phone call with a written summary sent to the insurer: "Per our conversation on [date] with [name], you confirmed that [details]." This creates a record.
Mark every deadline on your calendar the moment you receive a denial or correspondence. Set reminders 2 weeks before each deadline. Missing a deadline can forfeit your appeal rights entirely. When in doubt, file early.
If the phone agent can't help, ask for a supervisor. If the first appeal fails, file for external review. File a state insurance complaint simultaneously with your appeal — this signals you're serious. CC your state legislator on correspondence for high-dollar claims.
Free resources: Patient Advocate Foundation (1-800-532-5274), your state's Consumer Assistance Program, and State Health Insurance Assistance Program (SHIP) for Medicare beneficiaries. Your employer's HR department may also intervene on your behalf.
Keep a log of every interaction: date, time, person's name, what was discussed. Save every letter, EOB, and email. Take screenshots of online portal messages — insurers have been known to remove or modify records. Your documentation is your armor.
Insurance companies process thousands of appeals. The cases that succeed are the ones that are well-documented, clearly argued, and backed by medical evidence. You don't need a law degree — you need patience, organization, and the right template. You've got this.
Start with the templates above. If you want help along the way, join the MyHealthVoice waitlist for access to more courses, community support, and tools when we launch.