A denial is when your insurer refuses to pay for a service, in whole or in part. A denial is not the final word — you have the legal right to challenge it, and a meaningful share of appeals succeed.
A denialWhen your insurer refuses to pay a claim. You usually have the right to appeal. is when your insurer refuses to pay for a service, in whole or in part. A denial is not the final word — you have the legal right to challenge it, and a meaningful share of appealsA formal request asking your insurer to reconsider a denied claim. Many denials are overturned. succeed.
Why claims get denied
Common reasons include: the service wasn’t considered medically necessary by the insurer, a required prior authorizationYour insurer's approval before it will cover certain care, tests, or medicines. Without it, the claim can be denied. wasn’t obtained, the providerAnyone licensed to give you medical care — a physician, nurse practitioner, or physician assistant. Clinics use "provider" as a catch-all for whoever is caring for you. was out-of-networkProviders without a contract with your plan. Your costs are usually higher, and some plans do not cover them at all., a coding or paperwork error, or the plan simply doesn’t cover that service. Your denial letter (or EOBA summary from your insurer showing what was billed, what the plan paid, and what you may owe. It is not a bill.) must state the reason and explain how to appeal.
Your two levels of appeal
Federal rules give most plans a standard appeals process:
- Internal appeal. You formally ask the insurer to reconsider. You can submit additional information — often a letter from your doctor explaining medical necessity is the single most powerful piece.
- External review. If the internal appeal fails, you can ask an independent third party (not the insurer) to review the decision. For many denials, the external reviewer’s decision is binding on the insurer.
(Source: HealthCare.gov — Appealing a Health Plan Decision.)
Deadlines matter
Appeals have time limits — often 180 days from the denial for an internal appeal, with faster timelines available for urgent situations where waiting could seriously harm your health. Act promptly and keep copies of everything.
A simple action plan
- Read the denial reason carefully. It tells you what to fix.
- Call your insurer to confirm the appeal steps and deadline.
- Gather support — your medical records and a letter of medical necessity from your provider.
- File the internal appeal in writing. Keep dated copies.
- Escalate to external review if needed.
Why this matters to you
Many people pay denied bills they never owed, simply because they didn’t know they could appeal. Denials are sometimes errors, and the appeal process exists specifically to correct them. Persistence pays.
For self-funded employer plans (see the Insurance & Costs page), appeal rights are often governed by ERISA, the federal law for employer benefit plans; the U.S. Department of Labor explains those rights. General appeal guidance is at HealthCare.gov and CMS.gov.