How to appeal a denied insurance claim

Denials fall into categories, and the category determines the strategy. Administrative denials are the largest group: a wrong or outdated procedure code, a diagnosis code that does not support the procedure billed, missing information, a duplicate submission, or a claim filed after the plan's filing deadline. These are the easiest to overturn because nothing substantive is in dispute.

Eligibility denials say the plan did not cover you on that date, or that the service is excluded by the policy. Sometimes this is simply wrong — coverage that had started, a dependent recorded incorrectly, a plan change that had not propagated — and sometimes it is an exclusion you did not know about.

Network denials say the provider was out of network. These are worth scrutinising, because provider directories are frequently inaccurate, hospital-based clinicians such as anaesthetists and radiologists are often out of network at in-network facilities, and federal protections now restrict surprise billing in several of those situations.

Prior authorisation denials say approval was required before the service and was not obtained. If it genuinely was not obtained, appeal on the basis that the care was medically necessary and, in urgent cases, that obtaining authorisation first was not practicable.

Medical necessity denials are the substantive category. The insurer accepts you are covered but says this service, at this intensity, for this condition, is not warranted under its criteria. These are the hardest and the most worth fighting, because they turn on clinical judgement and the appeal is where your clinician's judgement finally gets read.

Experimental or investigational denials say the treatment is not established. These are frequently overturned at external review, because independent reviewers apply the evidence base rather than the insurer's internal list, and lists lag published evidence.

Before appealing, call the provider's billing office as well as the insurer. A significant share of denials are resolved by the provider simply resubmitting with a corrected code, which takes days rather than the weeks an appeal takes. Ask specifically whether the denial is a coding issue they can rebill.

Ask the insurer for the specific plan language and clinical criteria relied on. You are generally entitled to the documents used to decide your claim, and requesting them serves two purposes: it tells you what you must rebut, and it establishes that the criteria were actually applied.

Find the explanation of benefits and the denial letter, and distinguish them. An explanation of benefits is not a bill and is not always a denial; it shows what was billed, what the plan paid and what it attributes to you. The denial letter is the document that states a decision and triggers appeal rights.

Locate the stated reason and the denial code. Insurers use standardised reason and remark codes, and the code is more precise than the plain-language summary. If the letter does not explain it in terms you can act on, call and ask them to explain the specific code in writing.

Locate the appeal deadline and write it in your calendar immediately, with a reminder two weeks before. This is the most consequential line in the letter. Deadlines are measured from the date of the denial notice and are enforced; missing one can end your rights regardless of the merits.

Check whether an expedited appeal is available. Where a delay would seriously jeopardise your health or your ability to regain function, plans must offer an expedited process running in days rather than weeks, and it can run alongside a request for external review in urgent cases.

Gather your evidence: the denial letter, the explanation of benefits, itemised bills, the relevant medical records, the referral or authorisation if there was one, and your plan's summary of benefits and coverage. Request the full plan document if the summary does not settle the question.

Get a letter of medical necessity from the treating clinician. This is the single highest-value item in a medical necessity appeal. It should state the diagnosis, what was tried before and why it failed or was inappropriate, the clinical reasoning for this specific treatment, and the expected consequence of not receiving it — with references to guidelines where they exist.

Start a log: date, who you spoke to, their reference number, what was said, what they agreed to send. Insurers work from their own call records and a specific date-and-reference log is what turns 'someone told me it was approved' into something actionable.

Never rely on a phone call alone. Confirm every material conversation in writing, send appeals by a method that produces proof of delivery, and keep copies of everything you send.

File the internal appeal in writing, following the plan's stated process and within its deadline. Keep the letter short and structured: who you are and the claim number, what was denied, the reason given, why that reason is wrong, what you are enclosing, and what outcome you want.

Rebut the stated reason directly rather than arguing generally. If the denial says the service was not medically necessary under a named criterion, address that criterion. If it says prior authorisation was missing, address whether it was obtained, whether it was required, or why it could not be obtained in time. An appeal that does not engage with the actual reason usually produces the same decision again.

Attach the letter of medical necessity and the supporting records. Do not assume the reviewer has your file — send what supports your case, indexed, with the key passages marked.

Note that you may appoint an authorised representative, which can be a family member, an advocate or the treating clinician's office. Provider billing departments deal with this daily and will frequently pursue an appeal on your behalf if asked, because they want the claim paid too.

Plans must decide internal appeals within set timescales that differ for services not yet received, services already received, and urgent cases. If the deadline passes without a decision, that failure can itself entitle you to move to external review.

If the internal appeal fails, request external review. This is the stage with genuine independence: the case goes to an independent review organisation whose clinicians do not work for the insurer, and the decision binds the insurer. Depending on your state and plan type the review is run by the state insurance department or through a federal process.

External review deadlines are separate and typically run from the final internal denial. Do not let the disappointment of losing the internal appeal absorb the window for the external one — this is the commonest way people lose a case they would have won.

For self-funded employer plans, which cover a very large share of workers, the regulator is the federal Department of Labor rather than your state insurance department, and the external review route runs federally. Ask your HR or benefits department whether the plan is self-funded or fully insured, because it determines who to escalate to.

If the external review upholds the denial, remaining options are narrower: a complaint to your state insurance department or the federal regulator, negotiation with the provider on the bill itself, financial assistance or charity care policies at non-profit hospitals, and in some circumstances litigation. Ask the hospital's financial assistance office regardless of the appeal outcome, because eligibility is often broader than people assume.

Medicare has its own appeals structure with multiple escalating levels, beginning with a redetermination and rising through reconsideration, a hearing before an administrative law judge at the Office of Medicare Hearings and Appeals, the Medicare Appeals Council and finally federal court. Each level has its own deadline and its own form.

Which route applies depends on which part of Medicare is involved. Appeals under Original Medicare differ from appeals within a Medicare Advantage plan, and prescription drug coverage under Part D has its own process including coverage determinations and exceptions requests.

There are specific fast-track rights worth knowing. If you are told that hospital care or skilled nursing, home health or hospice services are ending and you disagree, there is an immediate review process that can be triggered before discharge, and the notice you are given explains how. These are time-critical and measured in a day or two.

Medicaid appeals are run by states within federal rules, and the central right is the fair hearing — an administrative hearing before an official who did not make the original decision. Where benefits are being reduced or terminated, requesting a hearing within a short window can keep them in place while the appeal is decided, which is one of the most valuable procedural rights in the whole system.

Marketplace coverage appeals are two different things and people conflate them. Appealing a denied medical claim goes to your insurer and then to external review. Appealing a marketplace eligibility decision — about whether you can enrol, what subsidy you qualify for, or a special enrolment period — goes to the marketplace itself under a separate process with its own form and deadline.

Employer plan appeals depend on whether the plan is fully insured or self-funded, as above. Self-funded plans are governed by federal benefits law, which sets out claim and appeal procedures and the right to receive the documents used to decide your claim.

In all of these systems, ask for the decision and the reason in writing every time. Administrative appeals turn on the record, and a reason given verbally that is never documented cannot be rebutted at the next level.

Property and casualty insurance has no federal internal-appeal-then-external-review structure. It is regulated at state level by insurance departments, and the escalation path runs through the insurer's complaint process and then to that department.

Start by getting the denial in writing with the specific policy provision relied on. Insurers must generally explain which exclusion or condition they are applying, and 'not covered' without a citation is not a usable answer. Read the policy language yourself — exclusions are narrower than summaries suggest, and the distinction between, say, sudden water discharge and gradual seepage decides many claims.

Understand the common denial reasons: an excluded peril such as flood or earth movement, wear and tear or lack of maintenance rather than sudden damage, late notification, insufficient documentation, disputed valuation, or a policy condition you did not meet such as failing to protect the property from further damage.

Where the dispute is about the amount rather than whether it is covered, most property policies contain an appraisal clause. Each side appoints an appraiser, the two select an umpire, and the resulting decision resolves the valuation. It is faster and cheaper than litigation and is under-used because policyholders do not know it exists.

You can hire your own help. A public adjuster works for you rather than the insurer, for a percentage of the settlement, and is generally worth considering on large or complex property losses. Check they are licensed in your state and be cautious of anyone soliciting immediately after a disaster.

Document everything from the moment of loss: photographs before any cleanup, an itemised inventory, receipts, contractor estimates, and a written record of every conversation. Claims are frequently lost on evidence rather than on coverage, and evidence is only available at the beginning.

Escalate to the state insurance department if the insurer will not engage. Departments take consumer complaints, require the insurer to respond, and monitor patterns of unfair claims handling. Every state has one and the National Association of Insurance Commissioners maintains the directory.

Know the honest limit. If the loss is genuinely excluded — flood damage under a standard homeowners policy is the classic example — no amount of appealing changes it, and the useful action is to understand the gap and buy the separate cover before the next event rather than to keep fighting this one.