An Explanation of Benefits (EOB) arrives after a scan, surgery, doctor visit, or prescription, and one word immediately stands out: “Denied.”
A health insurance denial can feel like a final decision—and an immediate financial emergency. But a denied medical claim is not always the end of the road. A denial may result from missing information, a billing error, a coverage rule, prior authorization requirements, or a disagreement about medical necessity.
In many cases, patients have the right to appeal the decision. The key is understanding why the insurance claim was denied and what to do next.
Why Do Health Insurance Companies Deny Claims?
Health insurance companies deny claims for many reasons. Some are administrative and may be corrected without a formal appeal.
Common reasons include:
- Incorrect billing or medical codes
- Missing medical records or documentation
- Inactive coverage on the date of service
- Out-of-network providers or facilities
- Services excluded from the health plan
- Prior authorization was required but not obtained
- Medical necessity was not established
- The plan requires step therapy before approving a medication
- Benefit or utilization limits were reached
- The insurer considers a treatment experimental or investigational
A denial does not necessarily mean your doctor recommended unnecessary care. It may simply mean the insurer did not receive the information required to approve or pay the claim.
The Centers for Medicare & Medicaid Services (CMS) explains that consumers generally have appeal rights when a health plan refuses to pay for covered medical care.
Start With Your Explanation of Benefits
Before paying a medical bill, read your Explanation of Benefits (EOB) carefully.
An EOB is not necessarily a bill. It explains how your insurance company processed the claim, including the amount billed, the amount the insurer allowed, what it paid, and what may be your responsibility.
Look for:
- Date of service
- Provider or facility
- Claim number
- Denial reason
- Amount denied
- Patient responsibility
- Appeal instructions
- Appeal deadline
If the denial reason is unclear, call the number on your insurance card and ask the insurer to explain the specific reason for the decision.
You can also ask which coverage provision, policy, or clinical criteria were used.
Check Whether the Denial Can Be Fixed
Not every denied claim requires an appeal.
For example, a provider may have submitted the wrong billing code or incorrect insurance information. In that situation, the provider’s billing department may be able to correct and resubmit the claim.
Ask your provider:
- Was the claim submitted correctly?
- Was prior authorization required?
- Was authorization obtained?
- Were the necessary medical records submitted?
- Can the claim be corrected and resubmitted?
- Has the insurer requested additional information?
Fixing an administrative error can sometimes be faster than filing a formal appeal.
How to Appeal a Health Insurance Denial
If the denial involves medical necessity, coverage, prior authorization, or another substantive issue, you may be able to file an internal appeal.
HealthCare.gov says insurers must explain why a claim was denied and provide information about how to appeal. For many plans subject to federal rules, consumers generally have 180 days from receiving a denial notice to request an internal appeal, although plan-specific rules can vary.
A strong appeal should directly address the reason for the denial.
Include:
- Your insurance and claim information
- A copy of the denial notice or EOB
- The service, medication, or treatment that was denied
- Medical records and test results
- Relevant treatment history
- A letter of medical necessity when appropriate
- Documentation explaining why alternative treatments may not be appropriate
For example, if a medication was denied because of step therapy, your doctor may need to document previous medications that failed, caused problems, or were clinically inappropriate.
The more directly your documentation addresses the insurer’s stated reason for denial, the stronger the appeal may be.
What If the Denial Is Urgent?
If waiting for a standard appeal could seriously jeopardize your health or ability to regain function, ask whether you qualify for an expedited appeal.
Federal guidance allows faster appeal procedures for certain urgent situations. HealthCare.gov says an urgent appeal can be handled much faster than a standard appeal, and in qualifying cases an expedited external review may also be available.
Tell both the insurer and your healthcare provider that the situation is medically urgent and ask what expedited process applies to your plan.
What Happens If the Appeal Is Denied?
If the insurer upholds its decision after an internal appeal, you may have the option of requesting an external review.
An external review is conducted by an independent reviewer rather than the insurance company. It can apply to certain disputes involving medical necessity, appropriateness of care, experimental or investigational treatment, and other eligible coverage decisions.
Under the federal external review process, HealthCare.gov says consumers generally have four months after receiving the final denial to request an external review, although state and plan rules can differ.
Your final denial notice should explain whether you qualify and how to request the review.
Don’t Ignore the Medical Bill
A denied claim and an incorrect medical bill are two separate issues.
If a bill looks wrong, ask the provider for an itemized statement and compare it with your EOB. Check the dates, services, insurance information, and amounts.
You should also confirm whether the providers and facilities involved were in network. Federal protections limit many surprise out-of-network bills in certain circumstances, although exceptions apply.
If you are dealing with significant healthcare costs, you may also want to read our guide to the complex world of healthcare finance in the U.S..
Keep Records of Your Appeal
Keep copies of your denial notice, appeal, medical records, letters, and every communication with the insurer and provider.
Write down:
- Date of each call
- Representative’s name
- Reference number
- Documents submitted
- Submission date
- Expected response date
Good records can make a complicated insurance dispute much easier to manage.
What to Do When Your Health Insurance Denies a Claim
A health insurance denial can be frustrating, but “denied” does not always mean “final.”
Start with these steps:
- Read your EOB or denial letter.
- Identify the exact reason for the denial.
- Check for billing or administrative errors.
- Ask your provider whether the claim can be corrected.
- Check your appeal deadline.
- Gather supporting medical documentation.
- File an internal appeal when appropriate.
- Ask about an expedited appeal if the situation is urgent.
- If necessary, check whether you qualify for external review.
- Keep copies of everything.
You may also find our articles on Medicare Advantage vs. Medigap and digital health benefits offered by insurers useful for understanding other parts of the U.S. health insurance system.
The most important question after a denial is not simply, “Why was this denied?” It is: “What information or documentation would be needed to change this decision?”
This article is for general educational purposes and is not medical, legal, or insurance advice. Appeal rights, deadlines, and procedures vary by plan, state, and type of coverage. Review your insurance documents and denial notice for the rules that apply to your specific situation.