Insurance didn't pay my medical bill: what to do next

You opened a medical bill, and it says your insurance didn't pay. It may say "denied" or "not covered," or it may just ask for the full amount. Before you pay, find out why.

Many unpaid claims come down to paperwork the provider can fix. Others need an appeal. This guide shows you how to tell the difference. It's part of our guide on how to appeal an insurance denial.

You'll need your bill and your explanation of benefits (EOB) for the same visit. Your EOB is your insurer's record of the claim. It's not a bill.

Why didn't my insurance pay?

A claim is the provider's request for payment from your plan. It can go unpaid for a few reasons:

• The claim was never sent, or it went to the wrong plan.
• Your plan is still processing it.
• The claim had a paperwork error, like a wrong member ID or a missing code.
• Your plan says the service isn't covered.
• Your plan says the care wasn't medically necessary.
• The care needed approval ahead of time, called prior authorization, and it wasn't on file.

Paperwork problems are common. A 2026 KFF analysis of HealthCare.gov plans found that 25% of in-network claim denials in 2024 were for administrative reasons. Those include missing information, duplicate claims, and claims sent too late.

What to do when insurance didn't pay

1. Don't pay yet. Call the billing office. Say you're checking a denied claim, and ask them to hold your account so it doesn't go to collections.
2. Find the claim. Log in to your insurer's website or app, or call the member services number on your insurance card. Look for the same date of service.
3. Read the reason. Your EOB should show a denial code or a note. The table below matches common codes to the fix.
4. Ask the provider to fix paperwork errors. If the problem is on the claim itself, the provider can correct it and send it again. You usually don't need to appeal.
5. Appeal decisions you disagree with. If your plan says the care isn't covered or wasn't needed, file an internal appeal with your plan.
6. Keep notes. Write down each call's date, the person's name, and any reference number.

If no claim was filed

If you can't find a claim, the provider may not have your insurance details. Give the billing office your plan information and ask them to bill your insurer. Our letter asking the provider to bill your insurance first puts the request in writing.

If you have Original Medicare, the law requires your provider to file the claim. Medicare claims must be filed within 12 months of the date of service.

If the claim is still processing

Claims can take a few weeks. For most employer plans and plans you buy yourself, your plan has 30 days to decide a claim for care you already got. It can add up to 15 more days if it tells you why. Ask the provider to hold your bill until the claim is done.

What does the denial code mean?

Your EOB may show a number from a standard list of claim adjustment reason codes. It often has 2 letters in front, like CO-16 or PR-96. Some insurers use their own codes instead, and the EOB explains them. Our guide to denial codes explained covers more of them.

If you have 2 health plans, code 22 is a sign the plans disagree about who pays first. Our guide to coordination of benefits explains how that order works.

Which denials can the provider fix?

Codes 16, 31, and 22 aren't decisions about your care. They're paperwork problems. The provider can usually fix the claim and send it again, with no appeal from you.

A missed filing deadline, code 29, works a bit differently. Filing deadlines are usually part of the provider's contract with your plan. When an in-network provider misses one, the code often starts with CO, for "contractual obligation." Under standard billing rules, CO amounts are generally the provider's write-off and aren't billed to the patient.

So if an in-network provider missed the deadline, it often can't bill you for that amount. Check that your EOB shows $0 for you. Then ask the billing office to take the charge off your bill.

Which denials need an appeal?

Some denials are your plan's decision about coverage. For those, you'll need to appeal.

• Not covered (codes 96 and 204). Read what your plan documents say about the service. If they clearly exclude it, an appeal may not change that. If you think the service fits a covered benefit, appeal and quote the plan language.
• Not medically necessary (code 50). This is a judgment call, so an appeal is worth it. Ask your doctor for a letter that explains why you needed the care.
• No prior authorization (code 197). First ask the provider whether they requested approval. Our guide on prior authorization denied covers what to do next.

You usually have 180 days from the denial notice to file an internal appeal. If your plan still says no, you may be able to ask for an outside review. Our guide to external review for health insurance explains which comes when.

Say Maya's son had an urgent care visit and a strep test on March 9, 2026. In April, the in-network clinic sent a bill for $310 marked "insurance denied." Here's her first EOB.

Service	Amount billed	Code	You may owe
Urgent care visit	$250	CO-16	$0
Strep test	$60	CO-16	$0
Total	$310		$0

The EOB note said the member ID didn't match. Maya called the clinic. They had her old ID from last year's card. They fixed it and sent the claim again. Here's the new EOB.

Service	Amount billed	Allowed amount	Plan paid	You may owe
Urgent care visit	$250	$160	$110	$50 copay
Strep test	$60	$30	$30	$0
Total	$310	$190	$140	$50

The in-network discount took off $120, and her plan paid $140. That left $50, her copay. The clinic's new bill asked for $50 instead of $310.

Before you pay any corrected bill, compare it with your EOB one more time. Our guide to comparing an EOB vs. a medical bill shows how to check each number.

When to get help

You can fix many denials with 1 or 2 calls. It's worth getting help when:

• The provider and your insurer each say the other one needs to act.
• The bill is already in collections, or you're getting collection calls.
• You're appealing a denial for costly or ongoing care.
• You're handling bills for someone else and you're short on time.

Your insurer's member services team can explain a denial. For employer plans, the Department of Labor's Employee Benefits Security Administration answers questions at 1-866-444-3272. Your state insurance department or your state's consumer assistance program may also help you appeal.

If you have Medicare, call 1-800-MEDICARE (1-800-633-4227), or get free counseling from your State Health Insurance Assistance Program. A medical bill advocate can also make the calls for you.