How common are hospital billing errors?

Studies report error rates of 49–80% depending on methodology. The American Medical Association estimated that 49% of Medicare claims it audited contained errors. A 2023 report by PatientRightsAdvocate.org found significant pricing irregularities in a majority of hospital bills reviewed.

What are the most common hospital billing errors?

The most common errors are: duplicate charges (same service billed twice), upcoding (billing a more expensive procedure than was performed), unbundling (splitting a bundled procedure into multiple separate charges), incorrect patient information causing claims to be rejected, and charges for services that were never provided.

How much money do billing errors cost patients?

The average overpayment per billing error varies widely, but a 2022 study estimated that billing errors cost US patients $30 billion annually. Individual errors can range from small ($20–50 duplicate charge) to catastrophic ($10,000+ upcoded surgery).

How do I find errors in my hospital bill?

Request an itemized bill (you have a legal right to one), then check each CPT code against the Medicare rate. Look for duplicate dates with the same CPT code, procedure codes that seem more complex than your treatment, and line items you don't recognize. BillKarma can automate this check.

What Percentage of Hospital Bills Have Errors?

Depending on the study, 49–80% of hospital bills contain at least one error. The American Medical Association found errors in 49% of Medicare claims in a large audit. Independent patient advocates routinely find that the majority of complex hospital bills have at least one overcharge.

Why billing errors are so common

Hospital billing is extraordinarily complex. A single inpatient stay can generate hundreds of line items coded by medical coders who may not have direct clinical knowledge of what happened. Add to this:

Pressure to maximize revenue in a fee-for-service system
Lack of standardized billing software across systems
High coder turnover and workload
No automatic patient verification of line items before billing

The most common error types

1. Duplicate charges

The same service billed twice — often because it was ordered by two different departments or entered by two different coders. Look for the same CPT code appearing twice on the same date.

2. Upcoding

Billing a more complex (and more expensive) version of a procedure than was actually performed. For example, billing CPT 99285 (high-complexity ER visit) when the actual care was a 99283 (moderate complexity). Upcoding is the most costly error type.

3. Unbundling

Splitting a procedure that should be billed as a single code into multiple component codes that together cost more. CMS publishes NCCI edits (National Correct Coding Initiative) that prohibit specific code combinations.

4. Phantom charges

Charges for services, supplies, or medications that were never actually provided. These can be hard to spot without a detailed medical record comparison.

5. Incorrect modifiers

Modifier codes attached to CPT codes can dramatically change the reimbursement amount. Wrong or missing modifiers can inflate charges significantly.

How to check your bill

Get the itemized bill — not the summary statement. Request it in writing if needed.
Match CPT codes to Medicare rates — use BillKarma or CMS.gov.
Scan for duplicates — same CPT code, same date, same amount.
Check quantities — a quantity of 3+ on a single procedure is a red flag.
Compare to your medical records — every billed service should appear in your records.

Bottom line: Assume your bill has an error until you've verified it. Nearly half of all hospital bills contain at least one — and the average overcharge can run into hundreds or thousands of dollars.