Health Insurance Claim Denied? Your Next Steps

By the Editorial Team. Reviewed and updated on August 19, 2026.

This article is educational and independent. It is not medical, legal, insurance, or financial advice. Coverage rules, appeal rights, and billing protections vary by plan, by state, and by individual circumstance. Confirm details with your plan documents, your state insurance department, or the official sources named in this article.

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A health insurance claim denied notice rarely announces itself. It arrives as an Explanation of Benefits (EOB) with a strange code in one column and a zero in the “plan paid” column, or as a letter that says an MRI was “not medically necessary,” a lab was out-of-network, a specialty drug is not on the formulary, or your physical therapy visits have been “exhausted.” The language is formal, the deadline is buried, and the amount you supposedly owe is very real.

Here is the part the letter does not say plainly. A denial is the beginning of a process, not the end of one. Federal law gives most people with private coverage the right to a full internal appeal, and after that, review by an independent physician outside the insurance company. Plans reverse a meaningful share of their own denials when someone actually appeals with documentation. Most people never do.

This article walks the whole sequence in order: reading the denial letter and the EOB, telling a billing error from a true coverage decision, the internal appeal and the 72-hour expedited track, external review by an independent review organization, why the type of plan you have changes your options, and where free help exists. No one can promise your appeal will succeed. What can be said honestly is that an appeal built on records and plan language is a different thing entirely from a phone call that says “but my doctor ordered it.”

What a Health Insurance Claim Denied Notice Must Contain

The formal term for a denial is an adverse benefit determination. It covers a refusal to pay a claim, a refusal to authorize a service in advance, a reduction in something already approved (like cutting physical therapy from 20 visits to 8), and a termination of coverage for care in progress. Using that phrase in your correspondence signals that you know the rulebook exists.

Under federal claims rules, the notice has to give you specific things. Not as a favor. As a requirement.

The specific reason for the denial, stated in understandable language, including the denial code and what it means.
A reference to the exact plan provision the decision rests on.
A description of any additional information that would perfect the claim, and why it is needed.
An explanation of the plan’s appeal process and its deadlines, including your external review rights.
If the decision used an internal guideline or clinical criterion, a copy of it, or a statement that you can get a copy free on request.
For medical necessity denials, the clinical reasoning applied to your case, free on request.

Those last two items are the quiet superpower of the whole process. You are entitled to see the actual criteria used to decide your MRI or infusion drug was not necessary. Almost nobody asks. Ask, in writing, within the first week.

The U.S. Department of Labor explains these requirements for employer plans in its consumer guide, Filing a Claim for Your Health Benefits.

Two people comparing an explanation of benefits with medical bills before filing an appeal

Reading the EOB: Codes, Columns, and the Clock

The Explanation of Benefits is not a bill, even though it looks like one. It is the plan’s accounting of a claim: what the provider charged, the plan’s allowed amount, what the plan paid, and what it says you owe. When a claim is denied, the EOB is often where you learn it first, as a remark code such as CO-50 (“not deemed a medical necessity”) or PR-204 (“not covered under the patient’s current plan”) with a short definition in the footnotes.

Four things to locate on the EOB and the letter before you do anything else:

The denial code and its plain-language reason. This tells you which of the five categories below you are dealing with, and the fix is different for each.
The date of the notice. Your appeal deadline runs from this date, not from the day you opened the envelope. Write it at the top of a fresh page.
The appeal instructions. Where to send the appeal, whether a form is required, and the stated deadline. For most private plans the internal appeal window is at least 180 days.
The claim number and member ID. Every call and every letter should carry both.

One more distinction: a provider bill is a third document, generated by the clinic or hospital, not the plan. If the numbers on the bill and the EOB disagree, believe neither until you have called both offices.

The Five Denial Categories and the First Move for Each

Nearly every health insurance claim denied in the United States falls into one of five buckets. Identifying yours is the single most useful thing you can do in the first hour, because the evidence that fixes one category does nothing for another.

Denial category	What it usually means	Your first move
Not medically necessary	The documentation sent with the claim did not match the plan’s written criteria for that test, drug, or service	Request the plan’s criteria in writing, then ask the ordering physician for a letter of medical necessity that answers each criterion with dated chart evidence
Not a covered benefit / off formulary	The plan document excludes the service, or the drug is not on the plan’s covered list	Read the actual exclusion language in the Evidence of Coverage. For drugs, ask about a formulary exception (covered below)
Out-of-network	The provider or facility has no contract with the plan	Check whether the plan has out-of-network benefits, whether the provider was in-network on the date of service, and whether surprise-billing protections apply
Missing information / no prior authorization	Paperwork never arrived, arrived incomplete, or an authorization step was skipped, often by the provider’s office	Call the provider’s billing office. This is frequently fixable by resubmission or a retro-authorization request, not a formal appeal
Coding or billing error	Wrong procedure code, wrong diagnosis code, wrong provider identifier, duplicate claim	Ask the provider to submit a corrected claim. This is not an appeal at all

Two of those five rows are administrative, and they matter more than people expect. Which brings us to the step that saves the most time in the entire process.

Billing Error or True Denial? Make One Phone Call First

Before you write a single appeal paragraph, call the provider’s billing office and ask one question: “My plan denied this claim with code X. Was this claim submitted correctly, and can it be corrected and resubmitted?”

A large share of “denials” are mechanical. A knee MRI billed with a shoulder diagnosis code. A claim filed under the wrong provider number after a practice merged. In those cases the fix is a corrected claim from the provider, it usually costs you nothing, and a formal appeal would actually be the slower path.

Signs you are looking at a fixable error rather than a coverage decision:

The denial reason mentions “invalid,” “incomplete,” “duplicate,” or “information requested from provider.”
The same service was paid without trouble on earlier dates.
The provider’s office is surprised to hear about the denial.
The EOB shows a diagnosis or procedure description that does not match what actually happened.

If the billing office confirms the claim went out clean and the plan simply refused it, you have a true adverse benefit determination, and the appeal path below is your route. Either way, log the call: date, name, reference number, what was said.

The Internal Appeal, Step by Step

The internal appeal is the plan reviewing its own decision, with fresh eyes and whatever new evidence you supply. Deadlines below are federal minimum standards for most private coverage; your plan may allow more time, never less. HealthCare.gov describes the process in plain terms on its internal appeals page.

Day 0. The denial notice is dated. Note the 180-day internal appeal deadline on a calendar you actually look at.
Days 1-7. Send a short written request for the file: the criteria or guideline used, the reviewing clinician’s specialty, and a complete copy of everything the plan relied on. Free of charge for group health plans.
Days 1-7, in parallel. Make the billing-office call above and rule out a coding fix.
Days 7-45. Build the package: a letter of medical necessity from the ordering physician that answers the plan’s criteria point by point, with dates; relevant chart notes and test results; a history of what was tried first (decisive for PT cutoffs and step-therapy drug denials); and a paragraph quoting the plan language you believe covers the service.
Well before day 180. File the appeal in a way that produces proof of delivery. Keep an exact copy of the package.
Decision. Plans generally must decide pre-service appeals within 30 days and post-service appeals within 60 days. Urgent appeals are decided within 72 hours.

A letter that says “this MRI is necessary in my professional judgment” is easy to set aside. A letter that says “your criterion requires six weeks of documented conservative therapy before advanced imaging; the chart shows physical therapy from March 2 through April 20 with worsening findings” forces the reviewer to engage with the criteria the plan itself wrote. The difference between those two letters is most of the game.

If the service required approval in advance and the denial happened at that stage instead of after care, the mechanics are slightly different; we cover that whole pipeline separately in our guide to how prior authorization decisions get made.

The 72-hour expedited track

If waiting the standard 30 days would seriously jeopardize your health or your ability to regain maximum function, or the denial involves care currently underway, ask for an expedited appeal, which you can request by phone. The plan must decide urgent internal appeals within 72 hours, and in urgent situations expedited external review can run at the same time. Your physician’s statement that the situation is urgent generally controls whether the fast track applies.

Drug denials: the formulary exception, briefly

When a specialty drug is denied because it is off formulary or fenced behind step therapy, the purpose-built shortcut is a formulary exception request: your prescriber submits a statement, with clinical support, that the covered alternatives would be less effective or harmful for you. Plans generally must answer standard exception requests within 72 hours and expedited ones within 24. A refused exception is itself an adverse benefit determination, and the full appeal ladder applies to it.

External Review: A Decision the Plan Cannot Overrule

If the internal appeal fails, most people with private coverage can take the dispute outside the company entirely. An independent review organization (IRO) — physicians with no financial relationship to the plan — re-examines medical judgment questions like medical necessity and experimental-treatment determinations. You generally have 4 months from the final internal denial to request it, it costs nothing or close to nothing, and the result binds the plan: if the IRO says the MRI was necessary, the plan must cover it.

	Internal appeal	External review
Who decides	The plan itself, using a reviewer not involved in the original denial	An independent review organization with no financial stake
Deadline to request	At least 180 days from the denial notice	Generally 4 months from the final internal denial
Decision time	72 hours urgent, 30 days pre-service, 60 days post-service	Generally 45 days standard, about 72 hours expedited
Best suited for	Every denial; required first step in most cases	Medical judgment disputes: necessity, level of care, experimental determinations
Is the result binding?	No; you can escalate	Yes; the plan must comply if the denial is overturned

Some states run their own external review programs and some plans use a federal process; the request instructions in your final denial letter tell you which applies. The Centers for Medicare & Medicaid Services explains both routes on its appeals and external review page, and HealthCare.gov covers the consumer side at its external review page.

People stop too early. An upheld internal appeal feels final. It is not. Independent reviewers overturn a meaningful share of the denials that reach them — not most, and never predictably, but enough that skipping external review on a large bill leaves real money on the table.

ERISA or Not: One Question That Changes Your Complaint Options

If your coverage comes through a private employer, find out whether the plan is self-funded (the employer pays claims from its own money, with an insurance company only administering) or fully insured (a policy regulated by your state). Ask HR, or look for the statement of ERISA — the Employee Retirement Income Security Act — rights near the back of the Summary Plan Description.

Why it matters: state insurance regulators generally have no authority over self-funded ERISA plans, so a state complaint goes nowhere; the U.S. Department of Labor is the right regulator instead. And if an ERISA dispute ever reaches court, the judge usually reviews only the record built during the internal appeal — the strongest argument for putting every piece of evidence into the appeal itself. Marketplace plans, individual policies, Medicaid, Medicare, and most government and church employee plans sit outside ERISA and follow their own review paths. If your dispute is actually about long-term disability income rather than a medical bill, that is a different process with its own traps, covered in this guide to disability benefit appeals under ERISA.

The State Insurance Department, and When to Use It

For fully insured and individual-market coverage, your state Department of Insurance takes consumer complaints at no cost, and a complaint usually forces the insurer to respond in writing within weeks. It is most useful when the plan has broken its own procedures — blown deadlines, ignored document requests, lost appeals. A complaint does not replace the appeal and does not pause your deadlines; run both tracks. The National Association of Insurance Commissioners keeps a directory of every state’s department at naic.org.

A note on out-of-network denials specifically: if the bill came from emergency care, or from an out-of-network clinician working inside an in-network facility, the No Surprises Act (NSA) may prohibit the balance billing you are being asked to pay, turning the dispute from an appeal into a billing-protection question. The rules are specific enough that we covered them separately in our plain-English piece on the federal surprise-billing protections.

A Worked Example (Illustrative Composite, Not a Real Person)

The following is a fictional composite built to show the sequence. It does not describe any real individual, plan, insurer, or provider, and it is not a prediction of any outcome.

Dana, 47, has coverage through her employer. Her physician orders a lumbar MRI after ten weeks of worsening back and leg pain. The plan denies the prior authorization: “not medically necessary; conservative therapy requirements not met.” The imaging center cancels the appointment.

Day 1. Dana requests, in writing, the imaging criteria the plan applied and the reviewer’s specialty. She also confirms with her doctor’s office that the authorization request was submitted with chart notes — it was, but the notes covered only the most recent visit.

Day 6. The criteria arrive. They require six weeks of documented conservative treatment and a neurological finding. Dana realizes the plan never saw her physical therapy records, because the PT practice is separate from her physician’s office.

Day 18. The appeal goes out with proof of delivery: a one-page cover letter listing the enclosures, a physician letter addressing each criterion by number, ten weeks of PT notes showing declining function scores, and the exam note documenting a positive straight-leg-raise test.

Day 39. The plan overturns its denial at the internal appeal stage and authorizes the MRI. In this illustration, the original file was simply incomplete — the most common story behind “not medically necessary.” Had the denial been upheld, Dana’s next move was external review, with 4 months to request it.

The unglamorous lesson: the appeal that worked contained no argument at all. It contained records the plan had never seen, organized against the plan’s own checklist.

Your Denial-to-Appeal Checklist

Print this or copy it into a note. Add dates as you go.

[ ] Find the date on the denial notice. Calculate the 180-day internal appeal deadline and write both down.
[ ] Identify the denial code and match it to one of the five categories above.
[ ] Call the provider’s billing office and rule out a coding or submission error.
[ ] Request in writing: the criteria used, the reviewer’s specialty, and the complete claim file.
[ ] Pull your Evidence of Coverage or Summary Plan Description and read the provision the denial cites.
[ ] Find out whether the plan is self-funded (ERISA) or fully insured (state-regulated).
[ ] Ask the ordering physician for a letter of medical necessity keyed to the plan’s criteria.
[ ] Gather records from every relevant provider, not just the one who ordered the service.
[ ] Decide whether the situation qualifies as urgent; if so, request expedited handling by phone and in writing.
[ ] Assemble the package behind a one-page cover letter; send with delivery tracking; keep an exact copy.
[ ] Calendar the plan’s decision deadline: 72 hours urgent, 30 days pre-service, 60 days post-service.
[ ] If upheld, request external review within 4 months of the final internal denial.
[ ] Log every phone call: date, name, reference number, substance. After important calls, send a short email summarizing what you were told.

Where to Get Free, Unbiased Help

None of these charge for their services, and none of them are selling anything.

State Consumer Assistance Programs (CAPs). In states that run one, staff help consumers file appeals and understand denial letters directly. HealthCare.gov lists them under its consumer help resources.
Your state Department of Insurance, for complaints about fully insured and individual-market plans, and often for running the external review program itself.
The Employee Benefits Security Administration (EBSA) at the U.S. Department of Labor, for employer-plan questions. Benefits advisors answer calls at 1-866-444-3272; start at dol.gov/agencies/ebsa.
Hospital financial counselors, for the bill side of a denial. If it leaves you with a hospital bill you cannot pay, read our companion piece on how hospital financial assistance works before agreeing to any payment plan.
Medicare and Medicaid help lines. Both programs run their own appeal systems with their own notices and deadlines. Medicare beneficiaries can get free counseling from their State Health Insurance Assistance Program, and Medicaid enrollees have a right to a state fair hearing.

One adjacent situation: if the denial arrives while you are between jobs and paying for continued employer coverage out of pocket, the premium math changes what is worth appealing. Our explainer on what COBRA continuation coverage really costs covers that scenario.

Frequently Asked Questions

How long do I have to appeal a denied health insurance claim?

For most private plans, at least 180 days from the date of the adverse benefit determination for the internal appeal, then generally 4 months from the final internal denial to request external review. Plan documents may allow more time; Medicare and Medicaid run on their own timelines.

Is a health insurance claim denied on the EOB the same as getting a bill?

No. The EOB is the plan’s statement of how it processed the claim; the bill comes from the provider. A denial on the EOB often produces a bill later, but the two documents can disagree, and a pending appeal can change what you ultimately owe.

What does “not medically necessary” actually mean?

It means the documentation the plan received did not satisfy its written clinical criteria for that service — not that a doctor reviewed your life and disagreed with yours. The criteria are available to you free on request, and the most effective appeals respond to them line by line.

Should I pay the bill while I appeal?

Paying does not waive your appeal rights, and appealing does not erase the provider’s bill. Many people ask the billing office to hold the account while the appeal is pending; offices frequently agree. Get any hold in writing and watch that the account does not go to collections in the meantime.

Can my doctor file the appeal for me?

Yes, with your written authorization, and physician offices handle prior-authorization appeals routinely. You remain the claimant and the deadline remains yours, so confirm in writing that the office actually filed.

What is an independent review organization?

An outside body of clinicians, with no financial relationship to your plan, that decides external reviews. Its reviewers must generally include physicians in the relevant specialty, and its decision binds the plan.

Do appeals actually get denials overturned?

A meaningful share of internal appeals succeed, particularly when new records arrive with the appeal, and independent reviewers overturn a further share at external review. No source can honestly tell you the odds for your claim, and no outcome is ever guaranteed.

My physical therapy was approved, then cut off mid-course. Is that a denial?

Yes. A reduction or termination of an already-approved course of treatment is an adverse benefit determination made through utilization review, and it carries the same appeal rights. When ongoing care is terminated, plans generally must give advance notice, and expedited handling often applies.

The denial says the lab was out-of-network, but I went to an in-network facility. Now what?

This pattern — in-network visit, out-of-network ancillary provider you never chose — is exactly what federal surprise-billing rules address for emergency care and for out-of-network providers at in-network facilities. Check whether the No Surprises Act applies before treating it as an ordinary out-of-network denial, because if it applies, you generally owe only in-network cost sharing.

What happens if the plan misses its own appeal deadline?

Under federal rules, a plan’s failure to follow its claims procedures can let you treat the internal process as exhausted and move straight to external review or, for employer plans, to court. Keep precise records of every date if this happens.

Does a denied claim affect my credit?

The denial itself does not. An unpaid provider bill that follows one can eventually reach collections, though paid medical collections no longer appear on credit reports and unpaid medical debts under $500 are excluded by the major bureaus.

Final Thoughts

Do two things today. Call the provider’s billing office and ask whether the claim can be corrected and resubmitted. Then send the plan a written request for the criteria behind the decision and the complete claim file. Those two steps cost you an hour, and they sort nearly every health insurance claim denied into its true category: a paperwork error someone else can fix, or a coverage decision you now have the documents to challenge properly. After that, the calendar is your ally. You have months for the internal appeal and months again for external review. Use the time to build a file, not to talk yourself out of filing.

This article is for general informational purposes only and does not constitute medical, legal, insurance, or financial advice. It is not an evaluation of any individual claim or bill. Health coverage rules, appeal rights, billing protections, and assistance programs vary by plan, by state, and by individual circumstance, and they change over time. This site is independently operated. It is not an insurance company, broker, or advisor, a healthcare provider, a law firm, a government agency, or an advocacy organization, and it does not represent anyone. Reading this article creates no professional relationship of any kind. Always confirm current requirements with your plan documents, a licensed professional in your state, or the official government sources cited above before making any decision.

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