To appeal an insurance denial, read the denial letter to find the exact reason the insurer gave, gather documents that directly contradict that reason, and file a written internal appeal before your deadline runs out. For health plans governed by the ACA or ERISA, you have 180 days from the date you receive the denial; for auto and homeowners claims, the window is set by your policy and state law and can be as short as 60 days. Roughly four in ten appeals succeed, but fewer than one in 500 denied health claims ever gets appealed. The process rewards people who follow through.
Start With the Denial Letter
Every appeal begins with the reason the insurer put in writing. Denial letters use specific language that maps to specific counterarguments, so the stated reason matters more than the denial itself. For health insurance, federal rules require the notice to include the specific reasons for the denial, any internal guidelines or clinical criteria the insurer relied on, a description of what additional information could improve the claim, and instructions for internal appeal and external review.1HHS.gov. Internal Claims and Appeals and the External Review Process Overview State laws impose similar rules on auto and homeowners denials, though the level of detail varies. If a denial notice arrives without reasoning or without appeal instructions, document that gap in writing. It strengthens your position later.
The most common denial reasons and how they change your approach:
- Lack of medical necessity. The insurer’s reviewer concluded the treatment wasn’t required. Your treating physician usually has a more complete picture, and this is one of the most winnable denials.
- Missing prior authorization. A service that needed pre-approval was performed without it. Sometimes the provider’s office can help fix this retroactively.
- Out-of-network provider. If you had no reasonable in-network option or were treated in an emergency, you may have grounds to appeal.
- Policy exclusion. Read the exclusion language carefully. Adjusters sometimes apply exclusions too broadly.
- Coding or billing errors. A wrong diagnosis or procedure code can trigger an automatic denial. These are often the easiest to overturn because the fix is clerical.
- Insufficient documentation. Resubmitting with complete records often resolves the issue.
- Wear and tear on property or auto claims. The insurer classified the damage as gradual deterioration rather than a covered event. An independent assessment can contradict that.
Know Your Deadline
Deadlines are strict and unforgiving, so mark yours on a calendar the day the denial arrives. For health insurance under the ACA or ERISA, you get 180 days from the date you receive the denial to file an internal appeal.2HealthCare.gov. Appealing a Health Plan Decision Internal Appeals Auto and homeowners policies set their own timelines, and 60 days is not unusual. Missing the deadline almost always kills your right to appeal. Some plans and regulators recognize good cause extensions for extraordinary circumstances like hospitalization, but those are exceptions, not a safety net.
If waiting even 30 days would seriously jeopardize your life, health, or ability to regain maximum function, you’re entitled to an expedited appeal. Under federal rules, insurers must decide expedited internal appeals within 72 hours of receiving the request.3eCFR. 45 CFR 147.136 Internal Claims and Appeals and External Review Processes Your attending physician’s determination that the situation qualifies as urgent care controls, and the insurer must defer to that judgment. You can file by phone or fax without waiting for paperwork.
Build the Appeal Package
A strong appeal isn’t a letter explaining why you think the insurer is wrong. It’s a package of documents that systematically addresses every reason the insurer gave for denying the claim. Work through each stated reason and gather evidence that undermines it.
For health insurance, the core documents are medical records, a letter from your physician explaining why the treatment was necessary, and any clinical guidelines or peer-reviewed studies supporting the treatment. If the denial rested on a coding error, ask your provider for a corrected claim with the accurate codes. For auto or homeowners claims, gather independent repair estimates, photographs of the damage, and if the insurer’s adjuster undervalued the loss, a report from a licensed independent appraiser. In every case, include a copy of your policy with the relevant coverage sections highlighted.
Write a clear appeal letter that walks through each denial reason and points to the specific document that answers it. Stick to facts, policy language, and evidence. Some insurers provide standardized appeal forms, but a well-organized letter with numbered attachments is usually more effective. Send everything by certified mail or another method that gives you proof of delivery and a timestamp.
What Happens During the Internal Review
Once you file, the insurer assigns your appeal to a different reviewer than the one who made the original decision. For health insurance, federal law sets hard deadlines: 30 days for services you haven’t received yet (pre-service claims) and 60 days for services already provided (post-service claims).2HealthCare.gov. Appealing a Health Plan Decision Internal Appeals For disability benefits under ERISA, the plan has 45 days to issue a decision, with a possible 45-day extension if special circumstances require more time.4eCFR. 29 CFR 2560.503-1 Claims Procedure For property and auto claims, state laws and policy terms control, but 30 to 90 days is typical.
During review, the insurer re-examines the claim against policy language, your evidence, and any new documentation. A medical necessity denial can flip if your physician’s letter and clinical guidelines make a compelling case. An auto claim denied under a wear and tear exclusion can be overturned if your independent appraiser shows a covered event caused the damage. If the insurer asks for clarification or more records, respond quickly. Delays at this stage can stall your appeal past decision deadlines.
For health-related claims, ask about a peer-to-peer review, where your treating physician speaks directly with the insurer’s medical reviewer. A conversation between two doctors can resolve clinical disagreements that paperwork alone cannot.
A Note on ERISA Plans
If your health or disability coverage comes through an employer, it’s almost certainly governed by ERISA, and that changes the rules. You generally must exhaust all internal appeals before you can file a lawsuit. Skip the internal appeal and go straight to court, and a judge will likely send you back to start over. ERISA gives you at least 180 days to file an internal appeal after receiving a denial.4eCFR. 29 CFR 2560.503-1 Claims Procedure The administrative record you build during the appeal is often the only evidence a court will consider later, so treat the internal appeal as your one real chance to put in the facts.
External Review for Health Claims
If the internal appeal doesn’t reverse the denial, health insurance policyholders have a powerful next step: external review by an independent third party. You must request it within four months of receiving the final internal appeal denial.5HealthCare.gov. External Review The review is conducted by an independent review organization with no ties to your insurer, and the result is binding. Federal regulations require the plan to provide benefits pursuant to the external review decision without delay, even if the insurer plans to seek judicial review.3eCFR. 45 CFR 147.136 Internal Claims and Appeals and External Review Processes
A standard external review decision must come within 45 days of your request. An expedited external review, for situations where delay would seriously jeopardize your health, must be completed within 72 hours.5HealthCare.gov. External Review The reviewer is a licensed healthcare professional evaluating whether the treatment meets accepted standards of care. Filing costs are minimal or nothing in most states.
For property and auto insurance, external options depend on state law. Some states offer binding arbitration or appraisal. Others provide mediation through the state insurance department. Check with your state’s department of insurance if your internal appeal fails on one of these claims.
The Appraisal Clause for Property and Auto Valuation Disputes
Property and auto policies usually contain an appraisal clause that works differently from the appeal process. It’s not about whether the claim is covered. It’s about how much the covered loss is worth. If you and the insurer agree the damage is covered but disagree on the dollar amount, either side can invoke the clause by making a written demand.
The process works like a mini-arbitration. Each side hires its own independent appraiser. The two appraisers then select an umpire, a neutral third party who breaks ties. If they can’t agree on an umpire, either party can ask a court to appoint one. Each appraiser evaluates the damage and sets a value. If the two agree, that number is final. If they disagree, the umpire steps in, and any two of the three reaching agreement produces a binding award. Each side pays for its own appraiser, and both sides split the umpire’s costs equally. This route is usually faster and cheaper than a lawsuit, though it won’t help if the insurer denied the claim outright.
When to Bring in a Lawyer or State Regulator
Not every denied claim needs an attorney, but some situations are hard to handle alone: apparent bad faith by the insurer, a large sum at stake, ambiguous policy language, or a failed internal appeal and external review.
Bad faith is more than a disagreement about coverage. It means the insurer unreasonably denied a valid claim, failed to investigate properly, ignored evidence, or dragged out the process without justification. Most states allow policyholders to recover not just the original claim amount but also additional damages when bad faith is proven, which can include compensation for emotional distress, attorney fees, and in egregious cases, punitive damages. Availability and scope vary by state.
Many insurance attorneys offer free initial consultations and work on contingency, collecting a fee only if you win. Ask what percentage the attorney takes, whether you’re responsible for costs if you lose, and how many insurance denial cases they’ve handled. You can also file a complaint with your state’s department of insurance, which may investigate independently and sometimes resolve the issue without litigation.
Follow Through After You File
Filing the appeal is the beginning, not the end. Insurers handle thousands of claims, and quiet files get deprioritized. Call or email at regular intervals to confirm your appeal is progressing and that all documents were received. Keep a log of every interaction: the date, the name of the person you spoke with, what was said, and any reference numbers. That record becomes evidence if the insurer mishandles your case or misses its own deadlines.
If your appeal is approved, get written confirmation and review any settlement terms before accepting. If you’re offered partial payment, make sure accepting it doesn’t waive your right to dispute the rest. Read the release language. Some settlement checks come with conditions printed on the back that limit your future options.
If the appeal is denied again, request the detailed written explanation you’re entitled to and weigh what’s left: submitting additional evidence for reconsideration, filing for external review if you haven’t already, invoking an appraisal clause on a valuation dispute, filing a complaint with your state insurance department, or consulting an attorney. Insurers count on most people giving up after the first denial. Most people do.