How to Appeal a Denied Health Insurance Claim: Internal Appeals, External Review and Medicare Levels?

A denial letter can feel final, especially when it arrives after a stressful procedure or a long illness. The jargon of “adverse benefit determinations,” “redeterminations” and “qualified independent contractors” doesn’t help. Yet a denial is rarely the end of the road, and a well-prepared appeal is often successful.

This is where a clear map helps. In this guide we’ll explain how appeals work across three systems: ACA and employer plans, Original Medicare and Medicare Advantage, and disability or income replacement coverage, which follows different rules. Our goal is to leave you knowing which deadlines matter, what evidence to gather and when to escalate.

Important: Deadlines, thresholds and procedures change, and individual plans vary. Always check the dates on your own denial letter or Medicare notice, and use this guide as a framework rather than legal advice.

Why Health Insurance Claims Get Denied (and Why It Isn’t Always the End)

Denials are often administrative rather than a judgment that you’re not entitled to care. Understanding the stated reason is the first step to answering it.

Common reasons for denial include:

• Medical necessity: the insurer decides the treatment isn’t appropriate for your condition.
• Prior authorization missing: approval was required before the service and wasn’t obtained.
• Out-of-network provider: the doctor or facility wasn’t in your plan’s network.
• Coding or billing errors: a wrong diagnosis or procedure code, or a missing modifier.
• Experimental or investigational treatment: the plan says the therapy isn’t proven.
• Coverage lapse or eligibility issues: the plan says you weren’t covered on the date of service.
• Service not covered: the plan says the benefit is excluded.

Myths Versus Facts About Denied Claims

Common Myth	The Reality
“A denial means my doctor was wrong.”	Denials often reflect paperwork or plan rules, not clinical error.
“Appeals rarely work, so it isn’t worth the effort.”	Many denials are overturned when the appeal includes the right documents and a supportive physician letter.
“I have to accept the insurer’s decision.”	You have legal rights to internal appeal and, for many plans, an independent external review.
“Only lawyers can win appeals.”	Many patients succeed on their own, though professional help is useful in complex cases.
“Medicare denials can’t be challenged.”	Medicare has a five-level appeals structure with clear rights at each stage.

First Steps After a Denial: Read, Request and Record

Before you write a single word of appeal, spend time on groundwork. It’s tempting to react quickly, but a calm, organised response is far more persuasive.

Step-by-Step: What to Do in the First Week

1. Read the denial letter or Explanation of Benefits (EOB) carefully. Note the claim number, date of service, reason code and appeal deadline.
2. Call the insurer and ask for the specific reason in plain language. Record the date, time, representative name and a reference number.
3. Request your full claim file and the clinical criteria used. You’re entitled to the documents the insurer relied on, free of charge.
4. Ask your provider’s billing office to check for coding errors. A simple correction and resubmission can resolve the matter without a formal appeal.
5. Gather your plan documents. The Summary of Benefits and Coverage and the full policy explain what’s covered.
6. Create a dated paper trail. Keep copies of every letter, email and portal message.

Clarity about the reason determines your strategy. A coding error calls for a corrected claim, while a medical necessity denial calls for clinical evidence and a physician letter.

Internal Appeals for ACA and Employer Health Plans

Most private health plans, including Marketplace plans and employer plans, must offer an internal appeal, which asks the insurer to take a second look. Under the Affordable Care Act, non-grandfathered plans must follow federal minimum standards. For a broader look at these protections, see our guide to ACA mandates, state-level protections and how to appeal denials.

Typical Internal Appeal Deadlines and Decision Times

Stage	Typical Timeframe
Time to file an internal appeal	Generally 180 days from the date you receive the denial
Urgent or expedited appeal decision	Within 72 hours where delay could seriously jeopardise health
Pre-service (before treatment) appeal decision	Generally within 30 days
Post-service (after treatment) appeal decision	Generally within 60 days

These are federal baseline rules. Your plan or state may offer shorter decision times, so check your own paperwork.

How to Build a Strong Internal Appeal

This is where many people either succeed or stall. The insurer is looking for a clear explanation that links the denial reason to evidence.

A strong appeal package usually contains:

• A short, factual cover letter that identifies the claim, quotes the denial reason and states exactly what you’re asking for.
• A letter of medical necessity from your treating physician explaining why the treatment is appropriate, what alternatives were tried and the risks of going without.
• Medical records and test results that support the diagnosis and treatment.
• Peer-reviewed studies or clinical guidelines where the denial cites “experimental” or “not medically necessary.”
• A copy of the denial letter and any relevant plan language.

Sample Opening Paragraph for an Appeal Letter

“I am writing to appeal the denial of claim number [number], dated [date], for [service]. The denial states that the service was not medically necessary. My treating physician, Dr. [name], has documented that [brief clinical reason], and I have enclosed supporting records and clinical guidelines. I respectfully request that this decision be overturned and the claim be paid in full.”

For a deeper look at structure and cost considerations, see our walkthrough on how to file an effective insurance appeal with a sample dispute letter, timeline expectations and cost considerations.

Expedited Appeals When Time Matters

If waiting could seriously harm your health, ask for an expedited (urgent) internal appeal. Your doctor’s statement that the situation is urgent usually carries real weight. In many cases you can request an expedited external review at the same time.

External Review: An Independent Second Opinion

If the insurer upholds its denial after the internal appeal, you may be entitled to an external review. This is where an independent reviewer, not employed by your insurer, examines the case and makes a decision that is generally binding on the insurer.

How External Review Works

• Who it’s for: most non-grandfathered individual and group plans, typically for denials involving medical necessity, appropriateness, level of care or experimental treatment.
• Deadline: generally four months after you receive the final internal denial.
• Decision time: usually within 45 days for standard cases, and as little as 72 hours for expedited cases.
• Cost: often free or capped at a small fee, depending on the state and plan.
• Who runs it: state-regulated plans use a state process, while self-funded employer plans typically use a federal process through independent review organisations.

State Process Versus Federal Process

Plan Type	Usual External Review Route
Fully insured individual or employer plan	State insurance department process
Self-funded employer plan (ERISA)	Federal external review process through an independent review organisation
Grandfathered plan	May not be required to offer the federal minimum standards, so check the plan documents
Medicare	Not applicable, as Medicare has its own appeals levels (explained below)

If you aren’t sure which process applies, ask your insurer or HR department whether your plan is “fully insured” or “self-funded.” This single question often clarifies who has oversight of your case.

When to Contact Your State Insurance Department

State regulators can explain your rights, accept complaints and sometimes intervene. Before escalating to litigation, our guide to questions to ask your state insurance commissioner’s office before filing a lawsuit over a denied claim can help you prepare.

Medicare Appeals: The Five Levels of Review

Medicare has its own appeals structure, which feels different from private insurance. The good news is that the steps are clearly defined and the early levels are free. If you’re still getting to grips with the basics, our explainer on Medicare Parts A, B, C and D and what each part covers and costs provides helpful background.

Original Medicare and Medicare Advantage share similar levels, but the starting point differs.

Original Medicare (Parts A and B): The Five Levels

Level	Who Reviews	Typical Deadline to Request	Typical Decision Time
1. Redetermination	The Medicare Administrative Contractor (MAC)	120 days from your Medicare Summary Notice	Up to 60 days
2. Reconsideration	Qualified Independent Contractor (QIC)	180 days from the redetermination notice	Up to 60 days
3. Administrative Law Judge (ALJ) hearing	Office of Medicare Hearings and Appeals	60 days from the reconsideration notice	Often several months, as backlogs vary
4. Medicare Appeals Council	Departmental Appeals Board	60 days from the ALJ decision	Generally up to 90 days
5. Federal district court	A federal judge	60 days from the Council decision	Varies

Levels 3 and 5 require a minimum amount in controversy, a dollar threshold that is adjusted each year. Check Medicare.gov for the current figures.

Medicare Advantage (Part C) Appeals

If you have a Medicare Advantage plan, your first appeal goes to the plan itself, not the MAC.

• Organisation determination: the plan’s initial decision to cover or deny a service.
• Reconsideration (Level 1): you generally have around 60 days (some recent rules extend this to 65) from the date on the notice to file. Standard pre-service decisions are due within 30 days, payment requests within 60 days and expedited requests within 72 hours.
• Automatic forwarding: if the plan upholds its denial, it must send your case to an Independent Review Entity (Level 2).
• Higher levels: ALJ, Medicare Appeals Council and federal court follow the same pattern as Original Medicare.

Part D Prescription Drug Appeals

Drug denials follow a slightly different path:

1. Coverage determination: you or your prescriber asks the plan for an exception, such as covering a non-formulary drug.
2. Redetermination: if denied, you generally have about 65 days to appeal. Standard decisions take up to 7 days and expedited decisions 72 hours.
3. Independent Review Entity: the next stage if the plan upholds the denial.
4. ALJ, Council and court: the same higher levels, subject to dollar thresholds.

A supporting statement from your prescriber explaining why other drugs on the formulary won’t work is often the single most important document. For help comparing coverage types before problems arise, see our overview of Medicare Parts A to D, Medigap and Advantage comparisons.

Fast-Track Appeals for Hospital Discharge and Skilled Nursing

If you’re told you’re being discharged from a hospital, or that skilled nursing, home health or rehabilitation services will end, you can request an immediate “fast-track” review from a Quality Improvement Organization (QIO).

• Act quickly: for hospital discharge, you generally need to call the QIO no later than noon of the day after you receive notice.
• Why it matters: during the review you generally aren’t responsible for the cost of continued stay beyond your normal cost-sharing.
• Where to find the number: it’s printed on your discharge notice (the Important Message from Medicare) and on Medicare.gov.

Is It a Coverage Denial or an Enrollment Problem?

Not every Medicare problem is a claim denial. Disputes about premium penalties follow different rules. If your issue concerns penalties, see our guide to Medicare Part B and Part D late enrollment penalties and whether you can appeal. Timing questions may also relate to the Medicare Initial Enrollment Period, key dates and how to avoid late penalties.

Disability and Income Replacement Insurance: A Different Appeals Landscape

Because this guide sits alongside disability and income replacement topics, it’s worth explaining where those claims differ. If your disability benefits are denied, the rules are not the same as for medical claims.

Employer-Sponsored Group Disability (ERISA)

• Appeal window: under federal regulations, you generally have 180 days to file an appeal after a denial.
• Insurer’s decision time: typically 45 days, with a possible extension of another 45 days in special circumstances.
• One mandatory internal appeal: you usually must exhaust it before going to court.
• The record is critical: in many ERISA cases, a court reviews only the evidence you submitted during the appeal. This is why everything you want considered must be included before the appeal closes.

Individual Disability Policies

Privately bought policies are generally governed by state contract law rather than ERISA. Procedures, deadlines and remedies vary, so review your policy and consult a licensed attorney familiar with disability claims.

Social Security Disability Insurance (SSDI)

SSDI uses its own four-step sequence: reconsideration, hearing before an Administrative Law Judge, Appeals Council review and federal court. The usual deadline at each step is 60 days from receiving the decision.

Strong Evidence in Disability Appeals

• Detailed physician statements describing functional limitations, not just diagnoses.
• Consistent medical records that show ongoing treatment.
• Vocational evidence about why you can’t perform your own or any occupation.
• Personal statements from you and, where appropriate, family or colleagues.

Other kinds of insurance have their own procedures, so it’s useful to understand the differences. For example, our guide to appealing workers’ compensation insurance decisions successfully shows how a different system handles work-related injuries.

Which Appeal Route Applies to You? A Quick Comparison

Your Coverage	First Step	Independent Review	Final Option
ACA Marketplace or employer plan	Internal appeal with insurer	External review (state or federal)	Regulator complaint, possible litigation
Original Medicare	Redetermination by MAC	QIC reconsideration	ALJ, Council, federal court
Medicare Advantage	Plan reconsideration	Independent Review Entity	ALJ, Council, federal court
Medicare Part D	Plan redetermination	Independent Review Entity	ALJ, Council, federal court
Group disability (ERISA)	Internal appeal	Usually none	Federal court
SSDI	Reconsideration	ALJ hearing	Appeals Council, federal court

Practical Examples: How Appeals Succeed

Examples help show how the process works in practice. The following are illustrative scenarios, not guarantees.

Example 1: Prior Authorisation Dispute

A 58-year-old patient is denied coverage for an MRI because prior authorisation wasn’t obtained. The doctor’s office realises the request was submitted but never logged. They supply the submission confirmation and a letter explaining the clinical urgency. The insurer reverses the denial at the internal appeal stage.

Example 2: Medicare Advantage Rehabilitation Denial

A Medicare Advantage member is told her stay in a rehabilitation facility will end. She calls the QIO, her physician documents ongoing therapy needs and the decision is reversed. She has avoided a costly gap in care.

Example 3: Experimental Treatment Under ACA

A patient’s cancer therapy is classed as “experimental.” Internal appeal fails, but at external review the independent reviewer finds that published clinical guidelines support the treatment and orders coverage.

Common Mistakes That Weaken an Appeal

• Missing the deadline. This is the most avoidable error, so note it in your calendar the day the letter arrives.
• Sending a vague letter. Failing to address the specific denial reason gives the reviewer little to work with.
• Leaving out your doctor. A physician letter often outweighs pages of personal explanation.
• Not keeping copies. Without records, you can’t prove what was sent or when.
• Giving up after one refusal. The first denial is just the first stage.
• Assuming a phone call counts. Always follow up in writing.

When to Seek Extra Help

You don’t have to handle everything alone, and several free or low-cost resources exist.

• State Health Insurance Assistance Programs (SHIPs): free, local Medicare counselling.
• Your state insurance department: can explain rights, accept complaints and sometimes intervene.
• Medicare Rights Center and patient advocacy groups: offer guidance on Medicare appeals.
• Hospital patient advocates and billing departments: often experienced with insurer disputes.
• Employee benefits administrators: can help with employer plan appeals.
• Licensed attorneys: particularly useful for high-value claims, ERISA disability appeals and potential