Medical bill doesn't match your EOB? What to check and who to call

Why the two documents disagree

Your insurer's explanation of benefits (EOB) says you owe $85. The bill from the hospital says $410. Which one is right?

Often neither is wrong, just out of step. CMS, the federal agency that runs Medicare, says your bill should not be higher than the patient balance on your EOB. When it is, there is usually a reason you can find. These are the most common ones.

1. The bill was sent before the claim was processed. Some providers mail a statement as soon as the claim goes out. The insurer's payment and adjustments haven't been applied yet, so the bill shows the full charge.

2. You're comparing different claims. One visit can create several claims: the facility, the doctor, the lab, the imaging reader. Each gets its own EOB. Make sure the dates of service and provider names match.

3. The provider didn't apply the plan discount. For an in-network provider, the difference between the charge and the allowed amount is normally written off. If the bill still includes that difference, ask why.

4. A payment you made isn't reflected. CMS notes that the EOB does not show what you already paid, such as a copay at check-in. The bill may or may not include it.

5. The provider billed you for something the plan denied. If the EOB shows a denial, the provider may pass the full amount to you. That is a different problem: you may need to appeal the denial, not just question the bill.

6. The provider is out of network. An out-of-network provider may bill you the difference between its charge and the plan's allowed amount, called balance billing. In some situations federal law limits this. More on that below.

7. Simple errors. Wrong patient, wrong date, duplicate lines, a service you didn't get. CMS lists double billing as a common error, especially when several providers are involved.

Line them up side by side

Lay the bill and the EOB next to each other and match these fields:

• patient name and member ID;

• provider name;

• date of service;

• service description or code;

• total charge;

• amount the plan paid;

• amount you owe.

Here is a synthetic example.

Sample bill · Northgate Regional Hospital (synthetic)

Date of service 05/14 · Outpatient imaging · Total charges $1,420.00 · Insurance payment $0.00 · Balance due $1,420.00

Sample EOB · Northgate Health Plan (synthetic)

Date of service 05/14 · Northgate Regional Hospital · Billed $1,420.00 · Allowed $610.00 · Plan paid $488.00 · Patient responsibility $122.00 (coinsurance)

The bill shows no insurance payment and no adjustment, so it was probably printed before the claim was processed. If the next statement still shows $1,420 after the EOB date, call the hospital's billing office, give them the claim number from the EOB and ask them to apply the insurer's payment and contractual adjustment.

A step-by-step plan

1. Don't pay the higher amount yet

CMS advises paying only once you have a bill, and checking that the amount matches your EOB. If a due date is close, call the billing office, tell them you are checking the bill against your EOB and ask them to note the account. Ask whether that pauses collection activity, and write down the answer.

2. Ask the provider for a detailed bill

A summary statement may show one total. A detailed or itemized bill lists each charge. CMS's checklist for spotting errors starts with this step.

3. Call the billing office first

Have the claim number, the EOB date and the patient balance ready. Ask:

• "Has the insurer's payment from [date] been posted to this account?"

• "Why is the balance higher than the patient responsibility on my EOB?"

• "Was the contractual adjustment applied?"

• "Can you send a corrected statement?"

4. Call the insurer if the provider says the EOB is wrong

Sometimes the provider says the claim was processed incorrectly, or that it was resubmitted. Ask the insurer whether there is a newer EOB, whether the claim was reprocessed, and whether the provider is in network for your plan.

5. Put it in writing

If calls don't fix it, send a short letter or portal message to the billing office. Include the account number, the claim number, the date of service, the amount on the EOB and the amount on the bill, and ask for a corrected bill. Keep a copy.

6. Get outside help

CMS points to state Consumer Assistance Programs and patient advocates for help with billing problems. For problems that may fall under the No Surprises Act, you can contact the No Surprises Help Desk at 1-800-985-3059.

When federal surprise billing rules may apply

If the higher bill is from an out-of-network provider, check whether the care falls under the No Surprises Act. CMS says most people with private coverage are protected from surprise out-of-network bills for emergency care, for certain care at in-network hospitals and surgery centers, and for air ambulance services. In those cases, you generally shouldn't be charged more than your in-network cost sharing. CMS says you can submit a complaint if you got an out-of-network bill in one of those situations. The protections have limits; CMS lists ground ambulance and some plan types as not covered.

A short letter you can adapt

Re: Account [number], date of service [date]

My insurer's explanation of benefits for claim [number], dated [date], shows a patient responsibility of $[amount]. Your statement dated [date] shows a balance of $[amount]. Please review the account, apply the insurer's payment and any contractual adjustment, and send a corrected itemized statement. Please let me know in writing if you believe the EOB is incorrect.

Have your bill and EOB compared line by line

EasyToDecode, launching soon, will read your bill and your EOB, quote the lines that matter from each, and flag where the numbers don't match. It will also draft the questions to send to the billing office or insurer, so you can start the conversation with the facts in front of you. See how it works or join the waitlist.