How to check a medical bill against your EOB before you pay

An Explanation of Benefits (EOB) is not a bill. It is your insurer's record of how a claim was processed: what the provider charged, what the plan allowed, what the plan paid, and what it says you owe. The provider's bill should agree with it. Often it doesn't, and when it doesn't, the difference is rarely in your favor.

Before you pay any medical bill, put it next to the EOB for the same visit and run five checks.

Match the visit. Confirm that the patient, the provider and the date of service are the same on both documents. A bill with no matching EOB usually means the claim is still being processed. Paying now means paying before your insurer has applied its negotiated rate.

Compare what you owe. Find the patient responsibility on the EOB, sometimes labeled "what you owe" or "your share." The amount due on the bill should not be higher. If it is, ask the provider to explain the difference before you pay anything.

Look for the contractual adjustment. In-network providers agree to accept the plan's allowed amount. The gap between what they billed and what the plan allowed should appear on the bill as an adjustment, not as a balance for you to pay.

Check for payments already made. Copays collected at check-in, deposits and earlier payments should all be credited on the bill. A bill that ignores them is asking you to pay twice.

Check the EOB itself. Billed should equal allowed, plus the network discount, plus anything not covered. Allowed should equal what the plan paid plus your share. If the EOB's own columns don't add up, ask your insurer for a corrected EOB before you deal with the bill.

If something doesn't match, call the provider's billing office with both documents in front of you. Note the date and the name of the person you spoke with, and ask for a corrected statement in writing. Many errors are resolved at this stage, once someone points to the specific line.

General information, not legal, medical or financial advice. Every plan is different, so check the details against your own plan documents.