The first thing a hospital sends is usually a summary: a few lines, a large total, a due date. It is not detailed enough to check, and it is not meant to be. What you want is the itemised bill, and you can simply ask for it.
The three documents
Three different pieces of paper get confused with each other constantly:
- The summary bill — what the hospital wants from you, with no detail.
- The itemised bill — every charge, with its billing code, quantity and price. This is the document to work from.
- The explanation of benefits (EOB) — from your insurer, not the hospital. It shows what was billed, what the negotiated rate was, what the insurer paid and what they say you owe. It is not a bill, and it says so, but it is the number to reconcile against.
If the hospital's figure and the EOB's "patient responsibility" figure disagree, that gap is the first thing to ask about.
The codes
Charges are recorded in code, and the codes are public:
- CPT / HCPCS codes describe individual procedures and services — a specific scan, a specific test.
- MS-DRG covers a whole inpatient stay, grouped by diagnosis. It is why an inpatient bill often has one enormous line rather than many small ones.
- Revenue codes say which department a charge came from.
- ICD-10 codes are diagnoses, not services — they explain why, not what.
You can look any of them up. If a code on your bill describes something more complex than what happened to you, that is worth a phone call — upcoding is a real and common billing error.
What to check
- Dates. Charges dated to days you were not there, or a room charge for the discharge day.
- Duplicates. The same test billed twice, or a procedure billed alongside a bundle that already includes it.
- Quantities. A decimal-place error on a supply line is easy to make and expensive to ignore.
- Things that never happened. Medications you refused, a specialist who never appeared.
- Network status of every named provider, not just the hospital.
Then ask
Call the billing department with the itemised bill in front of you and ask about specific lines by code and date. Vague complaints get vague answers; a line-by-line query gets a person who has to look it up. Put anything important in writing afterwards, and do not let the account go to collections while a query is open — say explicitly that the bill is disputed.