Step 1: Request and review the itemized bill
You have the right to a complete itemized bill listing every charge individually with its CPT procedure code, service description, and cost. Call the billing department or submit a written request. Give them 7-10 business days to respond. Once you have the itemized bill, review it against your Explanation of Benefits (EOB) from your insurer — your EOB shows what was billed to insurance and how it was processed. You're looking for charges on your patient bill that don't appear in the EOB (suggesting they were billed to you twice), charges that appear incorrectly coded, and charges for services you don't recall receiving.
What to look for in the itemized bill
Check each line for: service date (does it match when you were actually there?), provider name (is this a physician you actually saw?), CPT code (does it match the description of care you received?), and quantity (was a supply item billed multiple times when it was used once?). Red flags include charges ending in unusual amounts (suggesting manual adjustments), procedure codes that seem inconsistent with your condition, and items described as "miscellaneous" or "other supplies" without specific descriptions.
Step 2: Identify the type of error and the responsible party
Before you dispute, determine: Is this a billing error by the provider, or a claim processing error by your insurer? A billing error (wrong code, duplicate charge, phantom supply) needs to be addressed with the provider's billing department. A claim processing error (insurer paid the wrong amount, miscalculated your deductible, applied incorrect network status) needs to be addressed with your insurer. Sometimes it's both — the provider submitted a wrong code and the insurer processed it incorrectly. Handle each separately with the appropriate party.
Step 3: Write a formal dispute letter
Your dispute letter should include: your name, account number, and date of service; a specific identification of each disputed charge by line item number, CPT code, and description; a clear explanation of why each charge is incorrect; the documentation you're attaching; and a request for a corrected bill within 30 days. Send via certified mail with return receipt. Example language: "I am disputing line item 47 on my statement dated [date], account number [number], billing CPT 99285 for $1,200 for my emergency room visit on [date]. According to my medical records, which I have reviewed, the level of service performed corresponds to CPT 99283 or 99284 based on the documented complexity. I am requesting that you review the supporting documentation and issue a corrected statement."
Step 4: Follow up and document every interaction
Keep a dispute log: date of each call, name of the person you spoke with, their direct number, what they said, and any reference or case number they provide. Follow up in writing after every phone call — send an email or letter summarizing what was agreed. Billing departments handle high volumes of disputes; documented follow-up prevents your dispute from falling through the cracks. If the billing department says they'll correct the error, ask for a written confirmation and corrected statement within a specific timeframe.
Step 5: Escalate if the billing department refuses to correct a clear error
If a provider refuses to correct what appears to be an obvious billing error or overcharge, you have several escalation options. File a complaint with your state insurance commissioner — they regulate insurance billing practices and can investigate. File a complaint with your state attorney general's consumer protection office — medical billing fraud is within their jurisdiction. For Medicare billing errors, file a complaint with the Centers for Medicare & Medicaid Services (CMS). For errors involving the No Surprises Act (out-of-network billing at in-network facilities), file with the federal No Surprises Help Desk at 1-800-985-3059.
When to involve a medical bill advocate
Consider hiring a professional medical billing advocate — a specialist who reviews bills and disputes errors on your behalf for a fee or percentage of savings — when: the total disputed amount is over $5,000, the bill is from a complex inpatient stay or surgery, you've been unsuccessful in resolving the dispute yourself after 60 days, the billing involves complex coding issues you can't interpret, or the account is heading toward collections and you need expert intervention. The Alliance of Claims Assistance Professionals (ACAP) and Medical Billing Advocates of America (MBAA) have directories of certified advocates.