How to Check Your Medical Bill for Errors: 7-Point Checklist

Medical billing advocates report that up to 80% of hospital bills contain errors. Even conservative estimates put the rate at 30–40%. With nearly 70,000 diagnosis codes and over 71,000 procedure codes in the medical billing system, mistakes are inevitable.

The problem? Most people never check. A survey by Gitnux found that 32% of patients pay a bill immediately just to avoid the confusion, even if they suspect it might be wrong. And 72% don't know how to dispute a billing error.

This 7-point checklist gives you a simple, repeatable process for reviewing any medical bill before you pay a cent.

Before You Start: Get the Right Documents

You need two things to audit a medical bill:

1. The bill itself — the statement from your healthcare provider asking for payment
2. Your Explanation of Benefits (EOB) — the statement from your insurance company showing how the claim was processed

Never pay a bill before the EOB arrives. If a provider sends you a bill before your insurance has processed the claim, call them and ask them to wait. You need the EOB to verify that the bill is correct.

The 7-Point Medical Bill Audit Checklist

1. Does the Bill Match the EOB?

Compare the "patient responsibility" amount on your EOB to the amount on the provider's bill. They should match. If the bill is higher than what the EOB says you owe, the provider is overcharging you.

For in-network providers, the allowed amount on the EOB is the maximum the provider can charge. They are contractually required to write off the difference between their list price and the negotiated rate.

2. Are There Duplicate Charges?

This is the single most common billing error. Look for the same service, same date, same CPT code appearing twice. This happens more often than you'd think — especially after hospital stays, where billing departments process hundreds of charges per patient.

Check for subtle duplicates too: sometimes the same service is billed under slightly different descriptions or codes but is essentially the same charge.

3. Were You Billed for Services You Didn't Receive?

These are sometimes called "phantom charges." Common examples:

• Operating room time that exceeds what you were actually in surgery
• Supplies that were opened but not used on you
• A room upgrade you didn't request
• Tests that were ordered but never performed

If you see anything you don't recognize, call the billing department and ask them to explain each charge. You have the right to an itemized bill — always request one.

4. Is the Billing Code Correct?

Upcoding is when a provider bills for a more expensive procedure than what was actually performed. For example:

• A 15-minute office visit coded as a "comprehensive exam"
• A standard X-ray coded as a more complex imaging study
• A generic medication billed at the brand-name price

You don't need to be a coding expert to catch this. If the description on the bill doesn't match what actually happened during your visit, ask the provider to review and correct the code.

5. Is the Provider In-Network?

Check whether the provider listed on the bill is in your insurance plan's network. If they are in-network, they cannot balance bill you — meaning they can't charge you the difference between their list price and the insurance-negotiated rate.

If you received care at an in-network facility but one of the providers (like an anesthesiologist or radiologist) was out of network, the No Surprises Act likely protects you from the excess charges.

6. Is the Amount Above the "Allowed Amount"?

Your EOB shows the allowed amount — what your insurance considers the reasonable cost for each service. If the provider's bill exceeds the allowed amount for in-network services, something is wrong.

For out-of-network services where the No Surprises Act doesn't apply, you may be responsible for the difference. But even then, you can negotiate. Providers will often accept the allowed amount or somewhere in between if you call and negotiate directly.

7. Did You Receive a Surprise Bill?

A surprise bill is an unexpected charge from an out-of-network provider, typically one you didn't choose. Common scenarios:

• Emergency room care at any hospital
• An out-of-network specialist at an in-network hospital (you didn't pick them)
• Air ambulance services

The No Surprises Act (2022) makes most surprise bills illegal. If you receive one, you should only owe your normal in-network cost-sharing amount (copay, coinsurance, or deductible). If the bill is higher, dispute it.

What to Do When You Find an Error

Step 1: Request an Itemized Bill

Call the provider's billing department and say: "I'd like a fully itemized bill showing every charge, service code, and date of service." You have the right to this. Many initial bills only show a lump sum — the itemized version is where errors become visible.

Step 2: Call the Billing Department

Use this script:

"I'm reviewing my bill for [date of service] and I've found what appears to be an error. Specifically, [describe the issue — duplicate charge, wrong code, service not received, etc.]. Can you review this and correct it? My account number is [X]."

Write down the name of the person you speak with, the date, and what they say. If they agree to correct it, ask for a corrected bill in writing.

Step 3: Escalate If Necessary

If the billing department won't correct a clear error:

• Ask for a supervisor — billing reps can't always override charges
• File a formal dispute in writing — send a letter describing the error and requesting correction. Send it certified mail so you have proof of delivery.
• Contact your state's Department of Insurance — if the provider refuses to correct a billing error, your state regulator can investigate
• Mention your state's consumer protection statute — the sentence "I'd like to request a review of this charge under [your state]'s consumer protection statute" gets attention

Can You Negotiate a Medical Bill?

Yes. Even if the bill is technically correct, you can almost always negotiate. Providers would rather get partial payment than send you to collections. Common negotiation strategies:

• Ask for the cash price — many providers offer a discount (often 20–40%) if you pay in full without going through insurance
• Request a payment plan — most providers will set up interest-free monthly payments
• Ask about financial assistance — nonprofit hospitals are legally required to have charity care programs
• Reference fair pricing — look up the fair price for your procedure on FAIR Health Consumer and use that as your negotiation benchmark

The Bottom Line

Never pay a medical bill without checking it first. Five minutes with this checklist could save you hundreds or thousands of dollars. The billing system is complex, mistakes are common, and the only person who's going to catch those mistakes is you.

Want help? BenefitGuard can read your medical bills and EOBs and flag potential errors automatically — no billing expertise required.