Decoding Your Medical Bill: Understanding CPT Codes and Charges

That confusing medical bill covered in cryptic codes and baffling charges? You're not alone. Medical billing errors are shockingly common—and they almost always favor the provider. Here's how to read your bill, understand the codes, and catch mistakes.

Anatomy of a Medical Bill

A typical medical bill or Explanation of Benefits (EOB) includes several key sections:

1. Provider Information

The name and address of the healthcare provider or facility. Verify this matches where you actually received care.

2. Date of Service

When the service was provided. Check that this matches your actual appointment or hospital stay dates.

3. Procedure Codes (CPT/HCPCS)

These 5-character codes describe exactly what was done. Understanding these is key to spotting errors.

4. Diagnosis Codes (ICD-10)

These codes indicate why the service was provided—your diagnosis. They usually start with a letter followed by numbers (e.g., J06.9 = Upper respiratory infection).

5. Charges and Payments

• Billed Amount: What the provider charged
• Allowed Amount: What your insurance agrees to pay
• Insurance Paid: What your insurance actually paid
• Adjustments: The "discount" from being in-network
• Patient Responsibility: What you owe

Understanding Procedure Codes

CPT Codes (Current Procedural Terminology)

CPT codes are 5-digit numeric codes maintained by the American Medical Association. They describe medical, surgical, and diagnostic services.

HCPCS Codes (Healthcare Common Procedure Coding System)

HCPCS codes start with a letter (A-V) followed by 4 digits. They cover items not in CPT, like ambulance services, durable medical equipment, and certain medications.

• A codes: Transportation, supplies, miscellaneous
• E codes: Durable medical equipment (wheelchairs, CPAP)
• J codes: Drugs administered by providers
• L codes: Orthotics and prosthetics

Common Billing Errors to Watch For

1. Upcoding

Billing for a more expensive service than what was provided. For example, billing a 30-minute visit (99214) when you only spent 15 minutes with the doctor (99213).

2. Unbundling

Billing separately for services that should be billed together as a package. This artificially inflates the total cost.

3. Duplicate Billing

Being charged twice for the same service. This can happen when a hospital and a doctor both bill for the same thing, or when a procedure is accidentally entered twice.

4. Services Not Rendered

Being charged for services you never received. This might be a data entry error or fraud.

5. Incorrect Patient Information

Errors in your name, date of birth, or insurance information can cause claims to be denied or applied to the wrong person.

6. Wrong Diagnosis Code

An incorrect ICD-10 code can cause insurance denials or result in higher costs for you. It can also affect your medical record.

7. Balance Billing Violations

Under the No Surprises Act (2022), you generally can't be balance billed for emergency services or by out-of-network providers at in-network facilities. If you see unexpected out-of-network charges, this may be illegal.

How to Challenge a Medical Bill

Step 1: Request an Itemized Bill

Always request a fully itemized bill—not just a summary statement. You have a legal right to see exactly what you're being charged for.

Step 2: Get Your Medical Records

Request the medical records for the visit in question. These should document what actually happened, how long you were there, and what procedures were performed.

Step 3: Compare and Research

Compare the itemized bill to your medical records and your own notes. Research any codes you don't understand using resources like:

• AAPC CPT Code Lookup (free basic lookup)
• Your insurance company's website (often has code descriptions)
• CMS HCPCS Codes (free)

Step 4: Contact the Billing Department

Call the provider's billing department with specific questions:

• "Can you explain what CPT code 99214 represents?"
• "I was only with the doctor for 10 minutes—why is this billed as a 30-minute visit?"
• "I see two charges for surgical supplies. Can you confirm these aren't duplicates?"

Step 5: File a Formal Dispute

If the billing department doesn't resolve the issue, file a formal written dispute. Include:

• Your name, date of birth, and account number
• Specific charges you're disputing
• Why you believe they're incorrect
• Supporting documentation (medical records, notes)
• Request for written response within 30 days

Step 6: Involve Your Insurance

Your insurance company has a financial interest in catching billing errors. Call your insurer's member services and ask them to review the claim.

Step 7: Seek Outside Help

If you can't resolve it yourself, consider:

• Medical billing advocates: Professionals who dispute bills on your behalf (usually work for a percentage of savings)
• State insurance commissioner: For disputes involving insurance
• State attorney general: For potential fraud
• Patient advocacy organizations: Many offer free guidance

Protecting Yourself

The Bottom Line

Medical billing is complex by design, but you have the right—and the ability—to understand and challenge your bills. Always request itemized bills, compare them to your records, and don't be afraid to ask questions. A few hours of review could save you hundreds or thousands of dollars.