he Explanation of Benefits is not a bill. It is a notice. Most people file it. A lot of people should read it, because one field — "patient responsibility" — is where billing errors hide. Six fields on this document actually matter. The rest is noise.
I.
The six fields that matter
- Date of service — match to your calendar. If the date is wrong, the claim is wrong.
- Provider / CPT code — the five-digit code that identifies the procedure. Look it up; confirm it matches what you received.
- Billed — what the provider charged. This is the chargemaster rate and is almost always inflated.
- Allowed — what your insurance agreed the procedure is worth. Contract rate.
- Paid — what insurance sent to the provider.
- Patient responsibility — your copay, coinsurance, or deductible hit. This is the number you're liable for.
The math that should always check out: Allowed - Paid = Patient responsibility (minus any non-covered amount). If patient responsibility is higher than Allowed - Paid, there's a coding or benefit error.
II.
Cross-check against the itemized bill
Request an itemized bill from the provider (they're required to provide one). Line-by-line, confirm each service on the bill matches a line on the EOB. Any service on the bill that isn't on the EOB is either a mistake or wasn't submitted to insurance — call and ask.