How to dispute a medical bill that doesn't look right

Medical billing is a maze of codes, network rules, and discounts negotiated separately by every insurer. The bills are wrong more often than they're right.

Start with an itemized bill

Don't dispute from the summary you got in the mail. Call the provider and ask for an itemized bill — by law in most states they have to send one. It lists every service with a CPT or HCPCS code and a charge. That's what you actually review.

What to look for

• Duplicate charges — the same code billed twice for one visit.
• Services you didn't receive — common after surgery; review every line.
• Codes that don't match what happened. Mismatched diagnosis codes can trigger a denial that should have been a covered service.
• Out-of-network charges from in-network facilities. The No Surprises Act covers many of these — you don't have to pay the balance.
• Charges for items bundled into a procedure (e.g., supplies billed separately when they should be included).

Get your EOB and compare

Log into your insurer's portal and pull the Explanation of Benefits for the same date of service. The EOB shows what the insurer paid, the negotiated rate, and what you owe. If the bill from the provider doesn't match the EOB, the provider is wrong.

Make the call(s)

Call the provider's billing department first with your itemized bill and EOB. Be specific: 'Line 4, code 99213, is duplicated.' If they push back, escalate to a supervisor. If the issue is on the insurer's side, call them — and ask the rep to call the provider with you on the line (a three-way call). It speeds things up dramatically.