Your Health Insurance Claim Was Denied: Here's Exactly How to Appeal and Win

Getting a claim denial letter is frustrating and intimidating - but it's far more common than most people realize. Studies show that roughly 17-20% of in-network claims are initially denied. The shocking part: fewer than 1% of denied claims are appealed, despite the fact that appeals succeed over 50% of the time for internal appeals and even higher for external reviews. The system counts on you giving up. Don't.

Common Reasons for Claim Denials

Not medically necessary. The insurer's reviewer determined the service wasn't needed based on their clinical guidelines. This is the most common denial reason and often the most winnable on appeal - your doctor can provide documentation supporting medical necessity.

Prior authorization not obtained. The service required pre-approval that wasn't obtained before treatment. This is harder to overturn but not impossible, especially if the service was urgent or your doctor can document why prior authorization wasn't practical.

Out-of-network provider. You received care from a provider not in your plan's network. If you didn't choose to go out-of-network (emergency care, or you were referred by an in-network doctor), the No Surprises Act may protect you from the bill.

Coding errors. The provider submitted the wrong diagnosis or procedure code. This is the easiest denial to fix - contact your provider's billing department and ask them to review and resubmit with corrected codes.

Benefit exclusion. The service isn't covered under your plan's terms. This is the hardest to appeal unless you can demonstrate the service falls under a covered category or is medically necessary as an alternative to a covered service.

Step 1: Understand the Denial

Read the denial letter carefully. It must include the specific reason for denial, the plan provision or clinical guideline used to make the decision, your right to appeal and the deadline, and instructions for requesting your complete claim file. If any of this is missing, the denial may be procedurally invalid. Call the number on the denial letter and ask for a clear explanation if the written reason is vague.

Step 2: Internal Appeal

You have the right to an internal appeal - a review of the denial by someone at the insurance company who wasn't involved in the original decision. The deadline is typically 180 days from the denial. Submit a written appeal letter including your policy number, claim number, and date of service, a clear statement of why you believe the denial is wrong, a letter from your doctor explaining medical necessity, relevant medical records, test results, and clinical documentation, and any clinical guidelines or peer-reviewed research supporting the treatment.

Your doctor is your most powerful ally in this process. A detailed letter of medical necessity from your treating physician - explaining why the service was needed, what alternatives were considered, and why the insurer's reasoning is incorrect - significantly increases appeal success rates.

Step 3: External Review

If the internal appeal is denied, you have the right to an external review by an independent third party not affiliated with your insurer. This reviewer examines the medical evidence and makes a binding decision. External review success rates are higher than internal appeals - over 40% of external reviews overturn the denial. The external review process is free to you, and the insurer must comply with the decision.

Tips for a Successful Appeal

Act quickly. Don't let the appeal deadline pass. Start gathering documentation as soon as you receive a denial.

Be specific and organized. Reference the exact plan provision the insurer cited, and explain specifically why their interpretation is wrong or doesn't apply to your situation. Attach all supporting documents in a logical order with a cover letter summarizing your argument.

Get your doctor involved early. Ask your doctor to write a letter of medical necessity the same week you receive the denial. Doctors' offices handle these regularly and know what insurers look for.

Keep records of everything. Document every phone call (date, time, representative name, what was discussed), save copies of all correspondence, and send appeal letters via certified mail or confirmed electronic submission.