Your EOB says the claim was denied — what to do first

This page is for people who opened an Explanation of Benefits and saw the word "denied." It explains what the notice means, how internal and external appeals work, and the deadlines to know.

The word "denied" on an Explanation of Benefits (EOB) sounds like a verdict. It is not one. CMS says an EOB is a notice from your health plan. It shows the costs of your care. It is not the bill your provider sends you for payment.

Before paying anything, compare the EOB with the bill from your provider. Do not assume you owe the full amount. A denial at this stage is just the start of a process. Federal rules give you the right to run that process.

When an insurer refuses a claim, it must tell you why in writing. That written reason shapes your whole plan.

Some denials are simple mistakes. Maybe it was the wrong code, a missing referral, a name mismatch, or the wrong date on a bill. Your provider's billing office may be able to fix these with the plan. Ask them. Ask your clinic's billing staff to check the reason code first.

Other denials go deeper. The plan may say the service was not needed, was not covered, or needed approval it never got first. Those need a real appeal.

An internal appeal is your request. You are asking the insurance company to fully and fairly review its own choice. HealthCare.gov lists three steps. First, you or your provider file a claim. Next, the insurer denies it in writing and gives reasons. Then you formally push back on that denial with more proof.

To file, you can:

• Fill out any forms your insurer wants. Or write a letter with your name, claim number, and insurance ID number.
• Send in proof. A letter from your doctor and your medical records both work well.
• Call your state's Consumer Assistance Program if you want help filing.

You have 180 days — about six months — from the day you get the denial notice. Do not let that clock run out while you wait for a provider to fix things on their own.

Two different clocks run here, and they are easy to mix up.

The first is for the original claim decision. HealthCare.gov says the plan must tell you within 15 days if you are seeking prior authorization for a treatment. It is 30 days for medical services already received, and 72 hours for urgent care cases.

The second is for the appeal itself. The plan must decide within 30 days if the appeal is for a service you have not received yet. It has 60 days if the appeal is for a service you have already received.

If waiting the normal time could hurt your health, ask for a faster decision. A final answer on an expedited appeal must come within 4 business days after your request is received.

For someone in active cancer treatment, this matters a lot. If a denial is holding up planned treatment, say so clearly. Ask for the fast track. Do not just file quietly and wait.

You still have options. HealthCare.gov says you can take the appeal to an outside reviewer. This means the insurance company no longer has the final word on your claim. Send your written request within four months of the notice that your claim was denied. The reviewer either upholds your insurer's decision or decides in your favor, and your insurer must accept that decision. You will find the contact details on your EOB or the denial notice.

Keep one folder — paper or digital. Put the EOB, the denial letter, every document you send, and a log of your calls in it. Write down names and dates for each call. Ask your cancer care team's billing staff for help early. Many cancer centers have a person whose whole job is this kind of work.

Keep your treatment talk apart from your billing talk. A denial is about payment, not care. What treatment you should get is a question for your doctors. Still, it is worth asking them if anything about your plan changes while the appeal is pending.

Checked 2026-10-02: HealthCare.gov pages on internal appeals and external review. The CMS definition of an EOB was not re-opened.