How to File a Health Insurance Claim

How Health Insurance Claims Work

The health insurance claims process involves several steps between receiving medical care and getting your bill resolved. When you visit an in-network provider, they typically handle everything: after your visit, the provider's billing department submits an electronic claim to your insurance company with diagnosis codes (ICD-10), procedure codes (CPT), and charges. The insurance company processes the claim by applying your deductible, copay, and coinsurance based on your plan's benefits. They pay their portion directly to the provider and send you an Explanation of Benefits (EOB) showing what was billed, what the plan paid, and what you owe. The provider then bills you for any remaining patient responsibility. For out-of-network providers, you may need to pay the full amount upfront and submit a claim yourself for reimbursement, or the provider may submit the claim but you are responsible for the balance after insurance pays. The entire process typically takes 2–8 weeks depending on the complexity of the claim and whether it requires manual review. Claims can be denied for various reasons, in which case you have appeal rights.

What Is an Explanation of Benefits (EOB)?

An Explanation of Benefits (EOB) is a document your insurance company sends after processing a claim. It is not a bill — it explains how the claim was handled and what you may owe. Every EOB includes: patient information (name, claim number, date of service), provider information (doctor or facility name), amount billed (what the provider charged), allowed amount (the negotiated rate the insurer has agreed to pay — this is almost always less than the billed amount), amount not covered (charges the plan does not cover, such as non-covered services or amounts above the allowed rate for out-of-network), amount applied to deductible (how much of the allowed amount counts toward your deductible), plan paid (what the insurance paid the provider), and patient responsibility (what you owe — deductible, copay, coinsurance, or non-covered charges). Read your EOB carefully and compare it to the provider's bill. If the provider bills you for more than the EOB shows as your responsibility, contact both the provider and your insurance company. EOBs are typically available through your insurer's online portal within 2–4 weeks of claim submission.

How to File a Claim

In most cases, you do not need to file a claim yourself — your in-network provider submits claims electronically on your behalf. However, you may need to file a claim manually in certain situations: if you received care from an out-of-network provider who does not submit claims for you, if you received emergency care out of network and need to be reimbursed at in-network rates, or if you are covered by a private indemnity plan that requires you to submit claims. To file a claim manually, follow these steps. First, obtain a claim form from your insurance company's website (usually called a CMS-1500 form for professional services or UB-04 for facility services). Complete the form with your policy information, the provider's information, dates of service, diagnosis and procedure codes, and the amount charged. Attach an itemized bill from the provider showing the services provided, diagnosis codes, procedure codes, and charges. Include any supporting documentation like medical records or referral letters if required. Submit the claim by mail or through the insurer's online portal within the required timeframe (typically 90–365 days from service, depending on your plan). Keep copies of everything you submit and follow up within 30 days if you have not received an EOB.

Common Reasons Claims Are Denied

Health insurance claims are denied for many reasons, and understanding why helps you avoid and resolve denials. The most common reasons include: out-of-network provider — you received care from a provider who is not in your plan's network, and your plan does not cover out-of-network services (or covers them at a lower rate). Pre-existing condition exclusion — only applicable to non-ACA-compliant plans (short-term, fixed indemnity). ACA-compliant plans cannot deny claims based on pre-existing conditions. Service not covered — the treatment or procedure is excluded from your plan's benefits (cosmetic surgery, experimental treatments, certain elective procedures). Lack of prior authorization — you received a service that requires pre-approval from your insurance company, and you did not obtain it. Medical necessity denial — the insurer determined the service was not medically necessary based on their clinical guidelines. Coding errors — the provider used incorrect diagnosis or procedure codes, causing the claim to be rejected. Duplicate claim — the same service was already billed and paid. Timely filing limit expired — the claim was submitted after the deadline specified in your plan. When you receive a denial, the EOB or denial letter will include a specific reason code and instructions for appeal.

How to Appeal a Denied Claim

If your health insurance claim is denied, you have the right to appeal the decision. The appeals process has several levels. Internal appeal (Level 1): submit a written appeal to your insurance company within the timeframe specified in the denial letter (typically 180 days). Include your policy number, claim number, the specific reason you disagree with the denial, and supporting documentation (medical records, letters from your provider, relevant plan language). The insurer must respond within 30 days (expedited: 72 hours for urgent care). If the internal appeal is denied, you can request a second-level internal appeal. If that is denied, you can request an external review (Level 2) by an independent third party. The ACA guarantees all Marketplace plans and most employer plans access to external review — the independent reviewer's decision is binding on the insurance company. In some states, you can also contact your state insurance department or state ombudsman for assistance. If the claim involves urgent care, you can request an expedited appeal. Keep detailed records of all communications, including dates, names, and reference numbers. Many internal appeals are successful — studies show that 40–60% of denials are overturned on appeal.

Timelines for Filing and Appealing

Health insurance claims and appeals are subject to strict deadlines. For filing a claim: in-network providers generally must submit claims within 90 days to 1 year, depending on your plan. If you are filing a claim yourself (for out-of-network services), your plan's deadline is typically 90–365 days from the date of service. Check your plan's Summary of Benefits for the specific timely filing limit. For internal appeals: you generally have 180 days from receiving the denial notice to file an internal appeal. The insurer must process standard appeals within 30 days (15 days for pre-service claims) and expedited appeals within 72 hours for urgent care. For external review: you have up to 60 days from the date of the internal appeal denial to request an external review. The external reviewer must make a decision within 45 days for standard review or 72 hours for expedited. If you miss any deadlines, you lose your appeal rights — so act promptly. Mark the deadlines on your calendar as soon as you receive a denial. If you are having difficulty, contact your state's insurance consumer assistance program (available in most states) or the federal Centers for Medicare & Medicaid Services (CMS) for help.

Getting Help with Claims

Several resources are available if you need help with health insurance claims and appeals. Your insurer's customer service department should be your first contact — they can explain the denial reason and what documentation you need. Your provider's billing office can help by submitting corrected claims or providing medical records for appeals. State insurance departments regulate insurance companies and can investigate complaints, though they cannot overturn medical necessity denials (external review does that). State consumer assistance programs (CAPs) provide free help with appeals and complaints — many states have these programs funded by the ACA. Legal aid organizations may help with appeals involving significant medical bills, especially for low-income individuals. Patient advocacy organizations (like the Patient Advocate Foundation or the National Patient Advocate Foundation) offer free or low-cost assistance with claims and appeals. Employee benefits departments can help if you have employer-sponsored coverage. If your claim involves a large amount and you have been denied at both internal and external review levels, you may need to consult a healthcare attorney specializing in insurance law. Many attorneys offer free initial consultations and take cases on a contingency basis.

Common Claims Mistakes

People often make mistakes in the claims process that cost them money or delay payment. The most common is assuming the provider filed the claim correctly — always follow up to confirm the claim was submitted, and check your EOB to ensure it reflects the services you received. Another frequent error is ignoring denials or Explanation of Benefits — if you do not respond to a denial within the appeal window, you lose your rights. Not keeping copies of everything makes it difficult to appeal effectively. Failing to check if prior authorization was required leads to preventable denials. Paying the billed amount without waiting for the EOB — you may overpay if the insurance company's allowed amount is less than the billed amount. Submitting incomplete claim forms (missing codes, dates, or supporting documentation) causes processing delays. Missing appeal deadlines is the most costly mistake — you have limited time to act. Not understanding the difference between an EOB and a bill — paying a bill before your insurance processes the claim can result in overpayment and difficult reimbursement. Finally, not checking whether your provider is in-network before receiving care is the root cause of many denials and surprise bills.

FAQs

How long does a health insurance claim take to process?

Most electronic claims from in-network providers are processed within 2–4 weeks. Paper claims filed manually can take 4–8 weeks. If additional information is needed or the claim requires medical review, it may take 30–45 days. You should receive an EOB within this timeframe.

What should I do if my claim is denied?

Read the denial letter carefully to understand the reason. File an internal appeal with your insurance company within 180 days, including supporting documentation from your provider. If the internal appeal is denied, request an external review by an independent third party.

Can I file a health insurance claim for a past visit?

Yes, as long as you are within the plan's timely filing limit (typically 90–365 days from the date of service). After that deadline, the claim will be automatically denied. Submit the claim form with an itemized bill and any required documentation as soon as possible.

What is the difference between an EOB and a bill?

An EOB (Explanation of Benefits) is from your insurance company showing how a claim was processed — what was covered, what was paid, and what you may owe. A bill is from the provider requesting payment. Always wait for the EOB before paying a bill to ensure the amounts match.

Do I need to file a claim for in-network providers?

No. In-network providers submit claims electronically on your behalf as part of their agreement with the insurance company. You only need to file a claim yourself if you receive care from an out-of-network provider who does not submit claims for you.