Scope note: This guide primarily covers ACA-compliant individual and employer health plans. Medicare, Medicaid, self-funded employer (ERISA) plans, short-term plans, and certain grandfathered plans may use different appeal procedures. Always follow the deadline and instructions stated in your denial notice and plan documents.
2026 federal external-review notice: As of July 1, 2026, the HHS-administered Federal External Review Process is temporarily unavailable for certain plans that rely on that process in Alabama, Florida, Georgia, Texas, Wisconsin, and specified U.S. territories. This does not necessarily mean no review option exists. Follow the instructions in your final denial notice and check current HealthCare.gov guidance to determine whether a state process or another independent review route applies.
A denied health insurance claim is not always the final answer, and the first thing you should do is usually not write a long appeal letter. First, find out whether the claim was truly denied or simply rejected because of a coding or paperwork error, which the provider can often fix and resubmit. At the same time, record the appeal deadline in your letter, because fixing a billing problem does not always pause the clock.
If your insurer denied a claim, you generally have the right to appeal. Most cases begin with an internal appeal to the insurer and, for eligible denials, proceed to an external review by an independent organization whose decision is binding on the insurer. In urgent situations, an expedited external review may be requested before the internal process is complete. An appeal does not guarantee coverage, but it gives you a formal opportunity to answer the insurer’s stated reason and submit evidence that may not have been considered initially.
Do these three things today:
- Record the appeal deadline printed in your denial letter.
- Call the insurer and provider to confirm the exact denial reason.
- Ask the billing office to place the account on hold while you sort it out.
Why appealing is worth it
Appeals can succeed when the original denial involved missing documentation, coding errors, or a prior-authorization technicality rather than a genuine coverage dispute. Filing an appeal gives you the chance to submit missing evidence and challenge the stated reason. The process takes documentation and follow-up, but the potential benefit can be substantial when the denial rests on a fixable problem.
Confirm whether the claim was denied or never properly submitted
This quick check can save you from filing an appeal you never needed. Make sure the claim was actually denied and not simply rejected for a clerical reason at intake. A claim may be rejected at intake because of an incorrect member ID, a mismatched diagnosis code, or missing information, all of which the provider’s billing office can often fix and resubmit without a formal appeal. Call both your insurer and your provider to confirm the claim’s status, because a resubmission is faster than an appeal when the issue is a paperwork error.