Your Medical Bill Is Probably Wrong
It sounds like an exaggeration, but it isn’t. Multiple studies — from the Medical Billing Advocates of America to internal hospital audits — have found that up to 80 percent of medical bills contain at least one error. The average overcharge ranges from a few hundred dollars to several thousand, and high-cost hospital stays routinely contain five-figure errors.
The problem isn’t that hospitals are intentionally defrauding patients. The problem is that medical billing is extraordinarily complex, the codes change constantly, and the people entering charges often work under pressure with minimal oversight. The result is a system where mistakes are the rule, not the exception — and the burden of catching them falls almost entirely on the patient.
Here are nine of the most common errors to look for, with real dollar examples of what they can cost you.
1. Duplicate Charges
The simplest and most common error. The same procedure, supply, or medication is billed twice on the same date of service.
Example: A patient is billed twice for a single CT scan during an ER visit — once by the radiology department and once by the ER charge entry system. Cost of the error: $1,800.
Scan your itemized bill for any line item that appears more than once with the same date. Duplicate charges are easy to dispute because they’re obvious; billing departments almost always remove them when challenged.
2. Upcoding
Upcoding happens when a provider bills for a more complex (and more expensive) service than what was actually performed. The Current Procedural Terminology (CPT) coding system has tiered codes for office visits, procedures, and consultations, and the difference between tiers can be hundreds of dollars.
Example: A 15-minute follow-up visit should be billed as CPT 99213 ($90–$120). Instead, it’s billed as CPT 99215 (a 40-minute high-complexity visit, $200–$280). Cost of the error: $160 per visit. Over a year of monthly visits, that’s nearly $2,000.
Compare the procedure codes on your bill against your medical records and your memory of the appointment. If you spent 10 minutes with the provider but the bill shows a 40-minute visit code, that’s upcoding.
3. Unbundling
Some procedures are designed to be billed together as a single bundled code. Unbundling is when a provider bills each component separately, inflating the total.
Example: A surgical procedure that includes pre-op labs, anesthesia setup, and post-op recovery is supposed to be billed as one bundled code. Instead, each component is billed individually. Cost of the error: $2,400 on a routine outpatient surgery.
Unbundling is harder to spot without billing expertise, but a clear signal is when you see many small charges for components of a single procedure (especially in surgery, OB, or imaging).
4. Phantom Charges
Charges for services, supplies, or medications you never actually received. These are most common after hospital stays, where the billing is automated and high-volume.
Example: A patient is billed for a daily physical therapy session on a day they were never seen by PT — the order existed but the session was canceled. Cost of the error: $350 per missed session. Across a one-week stay with three missed sessions, that’s over $1,000.
The defense against phantom charges is your own memory and your medical records. Request your discharge summary and nursing notes, and cross-reference them with the itemized bill.
5. Balance Billing Violations
Under the No Surprises Act, you cannot be balance billed for emergency services or for out-of-network providers at in-network facilities. If you’re seeing a charge that represents the gap between what your insurance paid and the provider’s full rate, you may have grounds to dispute the entire amount.
Example: A patient has surgery at an in-network hospital but the anesthesiologist is out of network. The anesthesiologist sends a balance bill for $3,200. Under the No Surprises Act, the patient owes only their in-network cost share — the rest is the providers’ problem to negotiate. Cost of the error: $3,200.
The No Surprises Act took effect January 1, 2022. If you’ve been balance billed since then in a covered scenario, the charge is almost certainly disputable.
6. Incorrect Patient Information
Mistakes in your name, date of birth, insurance ID number, or policy details cause claims to be denied or processed incorrectly. The result is often that the full charge is passed to you instead of being billed to your insurance.
Example: A typo in the insurance member ID causes a $4,800 imaging bill to be denied. The hospital bills the patient directly, and the patient pays — not realizing that resubmitting with the correct ID would have shifted nearly the entire amount back to the insurance company. Cost of the error: $4,800.
Always verify that your demographic and insurance information was captured correctly. A quick call to the billing department to confirm can save thousands.
7. Inflated Supply and Pharmacy Charges
Hospital supplies and medications are often marked up extraordinarily — a $50 saline bag, a $30 acetaminophen tablet, a $1,200 “surgical kit” that’s a few sterile gauze pads.
Example: A patient is charged $1,800 for a “post-operative supply kit.” On inspection of the itemized list, the kit consists of items that cost roughly $40 retail. Cost of the markup: $1,760.
These charges aren’t technically errors, but they’re often negotiable. Ask for a fair-market adjustment, citing the actual market price for the supplies in question.
8. Charges for Preventive Services
Under the Affordable Care Act, insurance plans must cover preventive services without any cost sharing — no copay, no coinsurance, no deductible. This includes annual physicals, mammograms, colonoscopy screenings, vaccinations, well-child visits, and many others.
Example: A patient is billed $620 for an annual wellness visit. Under the ACA, this should have been fully covered. The bill is the result of either a coding error (the visit was coded as diagnostic instead of preventive) or an improper application of the deductible. Cost of the error: $620.
If you’re being billed for any visit that you booked as preventive, ask the provider to recode it and resubmit to insurance.
9. Charges After Insurance Adjustments
Sometimes a bill is sent before your insurance has finished processing the claim, or after they’ve processed it but the hospital’s system hasn’t updated to reflect the adjustment. You can end up paying the full charge when your actual responsibility is the much smaller in-network rate.
Example: A bill arrives showing a $7,200 charge with no insurance adjustment applied. The patient’s actual responsibility, after the in-network discount and insurance payment, should be $480. Cost of the error if paid as billed: $6,720.
Before paying any bill, check your Explanation of Benefits (EOB) from your insurance company. If the bill doesn’t match what the EOB shows you owe, the bill is wrong.
What to Do When You Find an Error
The basic process is the same regardless of which error you’re looking at:
- Don’t pay anything yet. Once you pay, you lose leverage.
- Request a fully itemized bill if you don’t already have one. Federal law gives you the right to this.
- Compare the itemized bill against your EOB and your medical records.
- Send a written dispute letter identifying the specific line items, the codes, the amounts, and the reasons for dispute.
- Follow up by phone after a week, citing your written dispute.
- Escalate if needed — to a supervisor, to the patient advocacy department, or to your state insurance commissioner.
How AskBenji Helps
Manually auditing a medical bill takes hours and requires you to look up CPT codes, Medicare reimbursement rates, and applicable federal regulations. AskBenji does this work automatically. Upload your itemized bill at askbenji.co/billing, and within minutes you’ll receive a line-by-line audit, flagged errors with dollar amounts, a dispute letter written in your voice, and a phone script you can use to negotiate.
The service is free, privacy-first, and ephemeral — your documents are automatically deleted after 24 hours and no PHI is stored. You don’t need to create an account, and you don’t need to be technical. You just need an itemized bill and a few minutes.
Most medical bills contain errors. The patients who check are the ones who don’t overpay.