Billing Essentials
The 10 Most Common Medical Billing Errors
Most medical bills contain at least one error. These are the ten mistakes that show up most often - and how to catch each one.
Updated August 18, 2026 · 8 min read
Quick answer
The most common medical billing errors are duplicate charges, upcoding, unbundling, phantom services, incorrect patient information, wrong dates of service, balance billing violations, quantity errors, missing insurance adjustments, and denied claims billed to the patient by mistake.
Errors That Inflate Your Bill
These mistakes directly increase what you are asked to pay.
- Duplicate charges - the same service billed twice, sometimes under different descriptions.
- Upcoding - billing a more complex, pricier code than the service performed.
- Unbundling - splitting one bundled procedure into multiple separate charges.
- Phantom services - charges for tests, medications, or supplies you never received.
- Quantity errors - billing for ten units of something when two were used.
Errors That Misidentify You
Clerical mistakes can attach someone else's charges to your account.
- Wrong patient information - another patient's services merged into your record.
- Wrong date of service - care attributed to a visit that did not happen.
- Missing insurance information - the claim processed as if you were uninsured.
Errors That Break the Rules
Some errors violate billing protections outright.
- Balance billing violations - out-of-network providers charging beyond legal limits.
- Denied claims passed through - insurers deny, then providers bill you without reprocessing.
How To Catch Them
Request an itemized bill, lay it beside your EOB, and check each service line for duplicates, unfamiliar items, and amounts exceeding your plan-approved rates. Every error you find becomes leverage for a dispute.
What the research says
Roughly half of employer health plans audited contain billing errors, and most go undiscovered.
Frequently asked questions
How common are medical billing errors?
Studies repeatedly find errors in a majority of reviewed bills, ranging from minor clerical issues to significant overcharges.
What if I find multiple errors on one bill?
Dispute them all in one written letter, listing each error specifically. Corrected bills often shrink dramatically.
Not sure where your bill stands?
Upload your medical bill and insurance EOB. Clearwell compares them, finds likely billing errors, and gives you a plain-language action plan — in minutes.
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