Insurance Claim Denied? Here's Exactly What to Do (2026)

Your insurance company denied your claim. It feels like a dead end—but it’s not. 39% of denied claims that are appealed are overturned. Insurers count on the fact that most patients won’t fight back. Here is exactly what to do, step by step.

1. Most common denial reasons

Before you appeal, understand why the claim was denied—the denial letter is legally required to state the specific reason and the clinical criteria used. Here are the most common denial categories and what they mean for your appeal strategy:

Before drafting an appeal, call your insurer’s member services and ask for the specific clinical criteria used to deny the claim (e.g., InterQual Level of Care criteria). You have the right to this information. Knowing exactly which criterion your case didn’t meet helps you target your appeal precisely.

2. Your right to internal appeal under the ACA

The Affordable Care Act guarantees you the right to appeal any adverse benefit determination. Key rules:

• 180 days to file: You have at least 180 days from the date of the denial notice to submit an internal appeal. Many plans give longer—check your Summary Plan Description.
• Decision timeline: The insurer must decide your appeal within 60 days for non-urgent claims, 30 days for pre-service (before you receive care), and 72 hours for urgent/concurrent care.
• New reviewers required: The internal appeal cannot be reviewed by the same person who made the initial denial decision.
• New information welcome: Submit additional medical records, doctor letters, and clinical guidelines that were not part of the original claim.
• Written decision required: The insurer must provide a written decision explaining the specific reasons and clinical basis for upholding or reversing the denial.
• Simultaneous external review: For urgent care, you can request external review at the same time as your internal appeal (you don’t need to wait for internal appeal exhaustion).

3. External independent review

If your internal appeal is denied (or if 60 days pass without a decision), you can request external review by an Independent Review Organization (IRO):

1. Who can request: You (or your authorized representative, such as your doctor or a patient advocate).
2. Eligibility: Most denied claims of $100 or more are eligible. Coverage denials and rescissions (cancellations) are covered. Benefit amount disputes (how much the plan pays) may not qualify.
3. Process: The insurer must provide you with contact information for the IRO. You submit your case materials. The IRO is an accredited, independent organization with no financial relationship to your insurer.
4. Timeline: The IRO must decide within 45 days for standard requests, 72 hours for urgent/expedited requests.
5. Binding decision: The IRO’s decision is final and binding on the insurer. If the IRO reverses the denial, the insurer must pay the claim. You are not bound by the decision—you can still pursue legal action if the external review upholds the denial.
6. No cost to you: External review is free for the consumer (the insurer pays the IRO fees).

Success rates matter: External reviews overturn insurer denials at a meaningful rate—particularly for medical necessity denials where the IRO can weigh clinical evidence without the insurer’s financial interest in the outcome.

4. How to write an effective appeal

A strong appeal has four components:

1. Letter of medical necessity from your doctor. This is the single most important document. Your doctor should write a detailed letter explaining:
   • Your specific diagnosis and its severity
   • Why this specific treatment is the most appropriate option
   • What alternatives were tried or considered and why they are inadequate
   • The expected outcome and risk of not receiving the treatment
   • How the treatment meets the insurer’s clinical criteria (if you obtained those criteria)
2. Clinical guidelines and peer-reviewed literature. Cite guidelines from medical specialty societies (e.g., American College of Cardiology, American Cancer Society, Endocrine Society) and peer-reviewed studies showing the treatment is the standard of care. If the insurer used InterQual criteria, cite the same criteria and show how your case meets them.
3. Your appeal letter. Keep it factual and organized. State: (a) what was denied; (b) why the denial is incorrect; (c) what evidence you’re providing; (d) the decision you are requesting. Avoid emotional language—insurers respond to clinical and legal arguments.
4. Supporting records. Include relevant medical records, prior treatment history, lab results, imaging reports, and any prior authorization correspondence.

Peer-to-peer review: Before or during the internal appeal, your doctor can request a peer-to-peer review—a direct conversation with the insurer’s medical reviewer. Many denials are overturned at this stage when a physician speaks directly to another physician. Ask your doctor to request this immediately upon denial.

5. ERISA plans: employer insurance appeals

If your health insurance comes through your employer and is self-funded (the employer pays claims directly using an administrator like Cigna or Aetna as a third-party processor), your plan is governed by ERISA rather than state insurance law:

• ERISA plans must follow federal internal appeal and external review requirements
• State insurance commissioner complaints generally cannot force action on ERISA plan decisions
• The Department of Labor Employee Benefits Security Administration (EBSA) handles ERISA complaints at dol.gov/agencies/ebsa
• If external review fails, ERISA allows you to sue the plan in federal court for benefits wrongfully denied
• ERISA litigation uses an “arbitrary and capricious” standard of review in most cases—courts defer to the plan unless the denial was unreasonable or contrary to clinical evidence
• An ERISA attorney can often take these cases on contingency for significant claims

6. Free help from Consumer Assistance Programs

You don’t have to navigate this alone. Free resources include:

• State Consumer Assistance Programs (CAPs): ACA-required programs that provide free help with insurance complaints and appeals. Find yours at healthcare.gov/appeal-insurance-company/get-help.
• Patient advocacy organizations: Disease-specific nonprofits (cancer, rare disease, chronic illness) often have staff who help patients appeal denials for specific treatments.
• Hospital patient advocates and social workers: If the claim involves a hospital stay, the hospital’s financial counselors or social workers can help navigate appeals—it’s in the hospital’s interest for your claim to be paid.
• Legal aid societies: For low-income patients, local legal aid organizations may provide free legal representation in insurance disputes.
• BillKarma: BillKarma can automatically generate appeal letters based on your specific denial reason, EOB, and medical records.

7. State insurance commissioner complaints

Filing a complaint with your state’s insurance commissioner serves two purposes: it creates an official record of the dispute and can trigger an investigation that pressures the insurer to resolve the claim. Find your state commissioner at naic.org/consumer_home.htm.

When a state complaint is most effective:

• The insurer failed to follow required timelines for decisions
• The denial letter didn’t include the required clinical rationale
• The insurer refused to provide the clinical criteria used to deny the claim
• You received a balance bill that appears to violate state surprise billing laws

Remember: state insurance commissioners have jurisdiction over fully insured plans (individual, small group, marketplace). They generally cannot regulate self-funded ERISA employer plans.

Frequently asked questions

Sources

• HealthCare.gov: How to Appeal a Health Insurance Decision
• KFF: Claims and Appeals: An Overview of ACA-Required Protections (2024)
• U.S. Department of Labor: ERISA Claims and Appeals Procedures
• CMS: External Review of Health Plan Decisions
• NAIC: Consumer Insurance Resources by State