Quick answer: start by reading the denial notice and your explanation of benefits to find the exact reason. Fix simple errors through the provider. If the plan still says no, file a written internal appeal within 180 days of the denial notice, with a letter, the claim details and supporting records such as a letter from your doctor. The plan must decide within 30 days for care you have not received yet and 60 days for care you already got, or within 72 hours for urgent care. If the denial stands, you can usually ask for an independent external review within four months, and the plan must follow that reviewer’s decision.
Health plans and insurance companies deny claims more often than many people realize, and most claim denials are never challenged. KFF, the health policy research group, analyzed federal data for plans sold on HealthCare.gov and found that insurers denied 20% of in-network claims in 2023. Consumers appealed fewer than 1% of those denied claims.
Appeals are not always successful, but the process is free, the deadlines are generous and the law gives you rights at every step. This guide covers how to read a denial, how to file an internal appeal, when to go to external review and where to find free help. For the basics of how plans work, start with our health insurance guide covering costs, plan types and enrollment.
Deadlines and rules here come from HealthCare.gov, the U.S. Department of Labor’s guide to filing health claims, Medicare.gov and CMS, and KFF’s analysis of federal claims data, checked October 2026. Your plan documents and state law may give you more time or extra rights. This is general information, not legal or medical advice.
Why Health Insurance Claims Get Denied
A claim is a request for payment, usually sent by your doctor, hospital or pharmacy. A denial can be full or partial. The Department of Labor makes the point clearly: paying anything less than 100% of a claim counts as a denial in part, which means partial payments also carry appeal rights.
HealthCare.gov lists common reasons a plan may deny coverage:
- The benefit is not offered under your plan.
- The care came from a provider or facility outside the plan’s network.
- The plan decided the service was not medically necessary.
- The plan considers the treatment experimental or investigational.
- You were no longer enrolled or eligible.
- The plan is cancelling coverage back to the start date because it says your application was false or incomplete.
What the data shows about reasons
The KFF analysis of 2023 HealthCare.gov data found that insurers most often listed “other” as the reason for in-network denials (34%), followed by administrative reasons (21%), excluded services (14%) and lack of prior authorization or referral (9%). Only 6% were based on lack of medical necessity. KFF cautions that the public data on reasons is limited, but the pattern is useful: many denials are about paperwork, not medicine, and paperwork problems are often the easiest to fix.
Pre-service vs post-service denials
Federal rules sort claims into three types, and the type controls your deadlines:
- Pre-service claims: requests for approval before care, such as prior authorization.
- Urgent care claims: pre-service claims where waiting the normal time could seriously harm your health.
- Post-service claims: claims for care you already received. The Department of Labor says most group health claims fall into this group.
Step 1: Read the Denial Notice and Your EOB
Your plan must tell you about a denial in writing. HealthCare.gov says insurers must notify you within 15 days for prior authorization requests, within 30 days for services already received and within 72 hours for urgent cases.
For job-based plans, the Department of Labor lists what a denial notice must include:
- The specific reason for the denial.
- The plan provision the decision relied on.
- Any extra information needed and why.
- A description of the plan’s appeal procedures.
- For medical necessity or experimental-treatment denials, an explanation of the clinical judgment or a statement that one is free on request.
- Your right to go to court after the appeal process.
Plans that are not grandfathered under the Affordable Care Act must also give details of the claim, the denial code and its meaning, and information about internal and external appeals and consumer assistance. On request, they must provide the diagnosis and treatment codes and what they mean.
Read the denial alongside your explanation of benefits, which shows how the claim was processed and which remark codes apply.
Decoding the denial letter and medical codes
A denial letter often uses short codes instead of plain words. Claims are built on medical coding: procedure codes (CPT or HCPCS) describe what was done, and diagnosis codes (ICD-10-CM) describe why. A mismatch between the two is a common reason a claim is rejected, for example when a diagnosis code does not support the test that was billed. Plans that are not grandfathered must include the denial code and its meaning, and on request the diagnosis and treatment codes, so ask for them if the letter leaves them out.
When you have the codes, read them with your doctor’s billing office. If they find a coding error, the fix is usually a corrected claim from the provider, which can be faster than a formal internal appeal process.
Ask for the claim file
You have a right to the documents behind the decision. The Department of Labor says job-based plans must provide copies of documents, records and other information relevant to your claim free of charge on request, and you can ask for the identity of any medical expert the plan consulted. Request these in writing early; they often reveal exactly what the reviewer saw, or did not see.
Check Your Insurance Policy Before You Appeal
Your strongest evidence is often the plan’s own wording. Your insurance policy, and the shorter documents built from it, set out what the health plan covers, what it excludes and which rules apply, such as referrals or prior authorization.
Which plan documents to pull
- Summary of Benefits and Coverage (SBC): a standard short summary that most health plans must provide under the Affordable Care Act, useful for quick checks of covered services and cost sharing.
- Evidence of Coverage or certificate of coverage: the full insurance policy terms for an individual or fully insured plan, including definitions and exclusions.
- Summary Plan Description (SPD): the main document for most job-based ERISA plans, including the claims and appeal procedures.
- Drug formulary and medical policies: lists and clinical rules the insurance provider uses for prescriptions and specific treatments.
What to look for
Find the exact section the denial letter cites, then read the definitions behind it. Terms such as “medically necessary,” “experimental” or “emergency” are usually defined in the policy, and the definition matters more than the everyday meaning. If the plan’s wording supports coverage, quote it in your appeal with the page or section number.
Step 2: Fix Simple Problems First
Before starting a formal appeal, check whether the denial is a fixable error. Call the provider’s billing office and the plan’s member services line with the claim number ready.
Common fixable problems:
- A wrong code, date of service or patient name.
- Missing referral or prior authorization that the provider can submit or correct.
- A request for “other insurance” information, which you can answer by phone or online.
- A provider listed as out of network by mistake.
- A duplicate claim flagged when the first one was never paid.
Medicare.gov gives the same advice for Original Medicare: if an item or service is denied, call the provider’s office to make sure it submitted the correct information, because the office may be able to resubmit.
Keep a call log
HealthCare.gov recommends keeping notes and dates from every phone conversation with your insurer or doctor about the appeal, including the day, time, name and title of the person you spoke with and what was said. Those notes become evidence if the case moves forward.
Step 3: File an Internal Appeal
If the plan stands by its decision, the next step is an internal appeal, which asks the plan to take a full and fair second look.
Deadlines to file
HealthCare.gov says you must file an internal appeal within 180 days (six months) of receiving notice that your claim was denied. The Department of Labor says job-based plans must give you at least 180 days, and some plans give more, so check your Summary Plan Description.
How to file
According to HealthCare.gov, you can complete your insurer’s appeal forms or write to the insurer with your name, claim number and health insurance ID number, and add any information you want considered, such as a letter from your doctor. Your state’s Consumer Assistance Program can also file an appeal for you. The Department of Labor adds that plans generally cannot charge you to file claims or appeals.
Who decides
For job-based plans, the Department of Labor says the appeal must be reviewed by someone new who looks at all the information and consults qualified medical professionals when medical judgment is involved. That reviewer cannot be the person who made the original decision or that person’s subordinate.
How long the plan has
| Situation | Internal appeal deadline for the plan |
|---|---|
| Urgent care | As soon as possible, no more than 72 hours |
| Care not yet received (pre-service) | No more than 30 days |
| Care already received (post-service) | No more than 60 days |
These limits come from HealthCare.gov and the Department of Labor. If a plan uses two levels of internal appeal, the Department of Labor says each level generally gets half the time.
What to Include in a Strong Appeal
An appeal is most persuasive when it answers the plan’s stated reason directly. A general complaint that the denial is unfair rarely changes anything.
Your appeal packet
- A short cover letter with your name, member ID, claim number, date of service, provider and the decision you are appealing.
- The reason you disagree, tied to the plan’s reason. If the plan says the service is not covered, quote the part of your plan documents that says it is.
- A letter of medical necessity from your doctor for clinical denials. It should explain your diagnosis, what was tried before and why this service was needed.
- Medical records that support the doctor’s letter.
- Plan documents: the relevant pages of your Summary of Benefits and Coverage, Evidence of Coverage or Summary Plan Description.
- Copies of the denial notice and EOB.
- Proof of anything the plan said was missing, such as an approved referral.
- An authorized representative form if someone else, such as your doctor, is filing for you.
Practical tips
- Send copies, never originals. HealthCare.gov advises keeping your original documents.
- Use a method that shows delivery, such as certified mail or an upload confirmation in the insurer’s portal.
- Note the date the appeal was received; the plan’s clock starts then.
- Keep the tone factual. The reviewer is checking your evidence against the plan’s rules.
Clinical guidelines can help
For medical necessity denials, ask the plan which clinical criteria it used. Job-based plans must describe the rules or protocols relied on, or offer them free on request. Your doctor can then explain how your case meets those criteria or why a different published guideline applies.
Urgent Appeals
If waiting could seriously jeopardize your life, health or ability to regain maximum function, you can ask for an expedited appeal. HealthCare.gov says that in urgent situations you can request an external review even before finishing the plan’s internal appeals, and you can file the internal appeal and the external review at the same time.
For job-based plans, the Department of Labor says that if a physician with knowledge of your condition tells the plan a pre-service claim is urgent, the plan must treat it as urgent. A call from your doctor’s office to the plan, followed by the written request, is often the fastest route.
Ongoing treatment
If a plan reduces or ends a course of treatment it had already approved, ask about continued coverage while the appeal is pending. Federal rules for job-based plans give extra protection in this situation, and your denial notice should explain the process.
Step 4: Ask for an External Review
If the internal appeal fails, most people can take the case to an independent reviewer outside the insurance company.
Which denials qualify
HealthCare.gov lists three types of denials that can go to external review:
- Any denial that involves medical judgment where you or your provider disagree with the plan.
- Any denial based on a decision that treatment is experimental or investigational.
- Cancellation of coverage based on a claim that you gave false or incomplete information when you applied.
Denials based only on eligibility or on a plain exclusion in the contract may not qualify, which is one reason it helps to understand the plan’s stated reason early.
Deadlines and decisions
- To file: a written request within four months after you receive the final denial, according to HealthCare.gov.
- Standard decision: as soon as possible, no later than 45 days after the request is received.
- Expedited decision: as soon as possible, no later than 72 hours.
The insurer is required by law to accept the external reviewer’s decision.
Who runs it and what it costs
Depending on your state and plan, the review may be run by your state, by an independent review organization the plan contracts with, or by the HHS-administered federal process. HealthCare.gov says the federal process is free, and any charge under other processes cannot be more than $25 per review. Your plan’s final denial must tell you how to request external review.
How rarely people use it
KFF found that HealthCare.gov enrollees filed about 5,000 external appeals in 2023, around 3% of upheld internal appeals among insurers reporting the data. Its survey work also found that many people do not know external review exists, which suggests the option is underused.
Emergency Care Denials and the No Surprises Act
Emergency claims have extra federal protections, so a denial of emergency care deserves a close look. HealthCare.gov explains that insurers cannot require prior approval before you get emergency room services from a provider or hospital outside your plan’s network, and cannot charge higher copayments or coinsurance for out-of-network emergency care.
Under the No Surprises Act, CMS says most plans must also:
- Cover most emergency services as if they were in-network, with your cost sharing counted toward your in-network deductible and out-of-pocket maximum.
- Use the “prudent layperson” standard, which asks whether an average person with ordinary health knowledge would reasonably have believed the situation was an emergency.
- Judge that question on your presenting symptoms, not only the final diagnosis code, and do this before denying the claim.
If an emergency claim was denied because the final diagnosis turned out to be minor, say so in your appeal and describe the symptoms that sent you to the emergency room. For non-emergency treatment, normal network rules and prior authorization still apply, although the No Surprises Act also limits surprise bills from certain out-of-network providers at in-network hospitals and surgery centers. The No Surprises Help Desk at 1-800-985-3059 can answer questions about these bills.
Medicare, Medicaid and Other Plan Types
Different coverage has different appeal paths.
Original Medicare
Original Medicare has five levels of appeal. The first is a redetermination by the Medicare Administrative Contractor, which CMS says you must request within 120 days of receiving the initial determination, such as the Medicare Summary Notice. The last page of the MSN explains how to file. Later levels include reconsideration by a Qualified Independent Contractor, a hearing with the Office of Medicare Hearings and Appeals, review by the Medicare Appeals Council and federal court. Our Medicare guide explains how Original Medicare and private Medicare plans differ.
Medicare Advantage and Part D
Medicare Advantage plans are run by private insurers under Medicare rules, and Medicare.gov describes five levels of appeal. A coverage decision is called an organization determination. If the plan says no, you, your representative or your doctor can ask the plan for a reconsideration within 65 days of the date on the denial notice. The plan generally has 30 days to decide a pre-service appeal and 60 days for a payment appeal, or 72 hours for a fast appeal when waiting could seriously harm your health. If the plan upholds its denial, it must automatically send the case to an Independent Review Entity, so you do not have to file that second level yourself. Later levels include a hearing with the Office of Medicare Hearings and Appeals, which for 2026 requires at least $200 in dispute. Part D drug plans have a similar but separate process, and the plan’s Evidence of Coverage lists the details.
Medicaid and CHIP
Medicaid and CHIP appeals follow state procedures, which typically include the right to a fair hearing. The denial notice from your state agency or managed care plan explains the steps and deadlines.
Job-based plans
Most private employer plans are ERISA plans, governed by the Employee Retirement Income Security Act, and follow the federal claims rules described above. Plans sponsored by governments and most religious bodies are exceptions, according to the Department of Labor. If your plan is self-funded, the Department of Labor’s Employee Benefits Security Administration can help at 1-866-444-3272.
More on ERISA plans
With ERISA plans, it helps to know whether the plan is fully insured (the employer buys a policy from an insurance company) or self-funded (the employer pays claims and hires an insurer only to administer them). Your Summary Plan Description should say which. Fully insured plans are also overseen by your state insurance department, while self-funded plans are regulated mainly at the federal level. ERISA also gives you the right to sue in federal court after you finish the plan’s appeals, which is why a complete appeal record matters.
Plan type affects denials
How a plan is built shapes which denials are likely. HMOs and EPOs, for example, rarely pay for non-emergency care outside the network, and many require referrals. Our comparison of HMO vs PPO vs EPO vs POS plans explains the trade-offs.
Keep Paying Your Insurance Premium While You Appeal
A denied claim and a cancelled policy are two different things. When an insurance company denies a claim for medical services or medical care, your coverage normally stays in force, and so does your monthly insurance premium. Keeping that premium current protects the appeal itself, because a plan can only be asked to pay for care received while you were covered.
Why the premium still matters
If you stop paying your insurance premium in protest, the insurer can end the policy for non-payment, which is a separate problem from the denial. HealthCare.gov explains that people with a Marketplace plan who use the premium tax credit, and who have already paid at least one full month’s premium in the benefit year, usually get a 3-month grace period. If all owed premiums are not paid by the end of it, coverage can end back to the last day of the first month you missed. Under federal Marketplace rules, the insurer must pay claims for the first month of that grace period but may hold claims from the second and third months. If you do not get the premium tax credit, your state Department of Insurance sets the grace period rules.
If the insurer cancels coverage instead of denying a claim
Sometimes the problem is bigger than one claim: the health insurance provider says you gave false or incomplete information when you applied and cancels the policy back to its start date. That retroactive cancellation is called a rescission. HealthCare.gov notes that under the Affordable Care Act, rescission is illegal except in cases of fraud or intentional misrepresentation of material fact, and CMS lists rescission as a decision you can appeal through the same internal appeal and external review process. A cancellation for unpaid insurance premiums is treated differently and is not a rescission.
Looking at coverage options while you wait
An appeal can take weeks. If the denial shows that your current insurance policy is a poor fit, for example because a key doctor is out of network or a drug you take every month is excluded, note it for the next enrollment window. Comparing coverage options at open enrollment, or after a qualifying life event, can lower future costs, but do not drop your current coverage until the new plan is in place and the appeal is finished. Changing plans does not cancel your right to appeal claims from the months you were covered.
Who Can Help: Insurance Companies, Agents and Advocates
Different people can help at different points, and knowing who does what saves phone calls.
| Who | How they can help | What they cannot do |
|---|---|---|
| Your insurance company’s member services | Explain the denial, confirm what is missing, send forms and the claim file | Decide your appeal on the call |
| Your provider’s billing office | Correct coding errors, resubmit claims, send records and a letter of medical necessity | Change the plan’s rules |
| An insurance agent or broker who sold you the plan | Help you find plan documents and contacts, and explain plan terms | Overrule the insurer’s decision |
| Your employer’s benefits or HR team | Confirm whether the plan is self-funded and get the Summary Plan Description | See your medical details without permission |
| State Consumer Assistance Program or insurance department | File or guide an appeal, take complaints | Represent every plan type |
If an insurance agent helped you enroll, they are a useful first call for documents and contacts, but the appeal itself still goes to the insurance company or plan in writing.
Where to Get Free Help
You do not have to handle an appeal alone. Several free sources of help exist:
- State Consumer Assistance Programs. HealthCare.gov notes that your state’s program can file an appeal for you and help with external review.
- Your state department of insurance. It oversees fully insured plans and can take complaints.
- The Department of Labor’s EBSA. Benefits advisors help people with job-based plans, at 1-866-444-3272.
- The No Surprises Help Desk. CMS runs it at 1-800-985-3059 for surprise billing problems.
- Your doctor’s office. Many practices have staff who handle prior authorizations and appeals every day.
- Hospital patient advocates and financial counselors. They can explain bills and the hospital’s financial assistance options while an appeal is under way.
If the final decision is still a denial, the Department of Labor notes that people in job-based plans may want legal advice about their right to challenge the decision in court, which usually requires finishing the plan’s appeal process first.
Who regulates your health plan
Insurance regulation in the U.S. is split. State Departments of Insurance regulate fully insured policies sold in that state, including most individual and small-group plans, and they take complaints about how an insurance company handled a claim. Self-funded job-based plans fall under federal ERISA rules enforced by the Department of Labor’s EBSA, which is why your employer’s benefits team should confirm which type you have before you pick where to complain. Medicare and Medicaid have their own appeal systems, covered above.
Frequently Asked Questions
How long do I have to appeal a denied health insurance claim?
HealthCare.gov says you must file an internal appeal within 180 days of receiving the denial notice. Job-based plans must allow at least 180 days, and some allow more. External review requests are generally due within four months of the final denial.
How long does a health insurance appeal take?
Internal appeals must be decided within 30 days for care you have not received, 60 days for care already received and 72 hours for urgent care. Standard external reviews must be decided within 45 days, and expedited ones within 72 hours.
Does it cost money to appeal?
Plans generally cannot charge you to file claims or appeals. External review through the HHS-administered process is free, and other external review processes cannot charge more than $25.
Can my doctor file the appeal for me?
Yes. You can name your doctor or another person as an authorized representative. For urgent care claims in job-based plans, the treating physician can act for you without a form.
What are my chances of winning an appeal?
There is no single success rate. KFF found that HealthCare.gov insurers upheld 56% of internal appeals in 2023, which means the rest were not upheld. Strong appeals answer the plan’s specific reason with records and a doctor’s letter.
What if my insurer denies the appeal?
Ask for an external review if the denial involved medical judgment, experimental treatment or a cancellation of coverage. The plan’s final denial notice must explain how.
Can I appeal a denial for emergency room care?
Yes. Insurers cannot require prior approval for emergency room services, and under the No Surprises Act most plans must judge emergency claims by your symptoms using the prudent layperson standard, not only the final diagnosis. Include a description of your symptoms in the appeal.
How do I appeal a Medicare Advantage denial?
Ask your plan for a reconsideration within 65 days of the date on the denial notice, following the instructions in the notice. If the plan upholds its decision, it automatically sends your case to an Independent Review Entity.
What should a denial letter include?
It should give the specific reason, the plan rule it relied on, what extra information is needed and how to appeal. Non-grandfathered plans must also give the denial code and its meaning and, on request, the diagnosis and treatment codes.
Should I keep paying my insurance premium during an appeal?
Yes. A claim denial does not cancel your policy, and falling behind on your insurance premium can end coverage for non-payment. If you use the premium tax credit on a Marketplace plan, HealthCare.gov describes a 3-month grace period, but claims in the second and third months can be held.
Can I appeal if my insurance company cancels my coverage?
Yes, if it is a rescission, meaning a cancellation back to the start date because the insurer says your application was wrong. Rescission is only allowed for fraud or intentional misrepresentation of material fact, and it can go through internal appeal and external review. Use the review form or written request your insurer provides, and keep copies.
Sources
- HealthCare.gov, Internal appeals and External review.
- U.S. Department of Labor, Employee Benefits Security Administration, Filing a Claim for Your Health Benefits.
- KFF, Claims Denials and Appeals in ACA Marketplace Plans in 2023 (updated March 2026).
- CMS, First Level of Appeal: Redetermination by a Medicare Contractor.
- Medicare.gov, Medicare Summary Notice (MSN).
- HealthCare.gov, Getting emergency care; CMS, Key Responsibilities for Group Health Plans and Health Insurance Issuers Under the No Surprises Act; Medicare.gov, Appeals in Medicare health plans.
- HealthCare.gov, Premium payments, grace periods and losing coverage and Rescission (glossary); 45 CFR 156.270 (grace period for APTC enrollees); CMS, Internal Claims and Appeals and the External Review Process (rescission as an appealable decision).
