Medical bills can look like they're written in a foreign language. Learn how to decode every line item, understand your EOB, and spot costly errors before you pay.
Why Understanding Your Medical Bill Matters
The average American receives at least one medical bill they don't fully understand each year. More alarmingly, studies suggest that up to 80% of medical bills contain errors. If you can't read your bill, you can't catch mistakes—and those mistakes cost money.
This guide will teach you to read medical bills like a pro.
The Two Documents You'll Receive
After receiving medical care, you'll typically get two important documents:
1. Explanation of Benefits (EOB)
Your EOB comes from your insurance company (not the doctor). It's not a bill—it's a summary of how your claim was processed.
Key EOB sections:- Services Provided: What was done
- Amount Billed: What the provider charged
- Allowed Amount: What your insurance agreed to pay
- What Insurance Paid: Their portion
- What You Owe: Your responsibility
2. The Actual Bill
Your bill comes from the provider (hospital, doctor, lab). This is what you're expected to pay.
Always compare your bill to your EOB. They should match. If they don't, something is wrong.Decoding Common Medical Billing Codes
CPT Codes (Current Procedural Terminology)
These 5-digit codes describe the procedure or service performed:
| Code | Description |
|---|---|
| 99213 | Office visit, established patient, 20-29 mins |
| 99214 | Office visit, established patient, 30-39 mins |
| 99215 | Office visit, established patient, 40-54 mins |
| 99283 | ER visit, moderate severity |
| 99285 | ER visit, high severity |
| 36415 | Blood draw |
| 80053 | Comprehensive metabolic panel |
ICD-10 Codes (Diagnosis Codes)
These codes describe your diagnosis and justify why services were needed.
Revenue Codes
Used by hospitals to categorize departments (pharmacy, radiology, etc.).
Line Items You'll See on Hospital Bills
Room and Board
- Room charges: Per-night cost for your bed
- ICU charges: Intensive care (much higher)
- Observation vs. Admission: Big difference in how insurance pays
Pharmacy Charges
- Each medication listed separately
- Often marked up significantly
- Check against retail prices
Lab Services
- Blood tests, cultures, etc.
- Multiple codes for one blood draw
- Can vary wildly in price
Radiology/Imaging
- X-rays, CT scans, MRIs
- Technical fee (taking the image)
- Professional fee (reading it)
Supplies
- Everything from bandages to surgical mesh
- Often extremely marked up
- Can request itemization
Red Flags: Common Billing Errors
Duplicate Charges
Same service appearing twice. Common with:- Multi-day stays
- Complex procedures
- Lab work
Unbundling
Services that should be billed together are separated to charge more. Example: A blood panel should be one charge, not 12 separate tests.Upcoding
Being charged for a more expensive service than you received. Example: Charged for a complex office visit (99215) when you had a routine one (99213).Incorrect Patient Information
Wrong name, ID number, or dates can cause:- Claim denials
- Coverage issues
- Billing to wrong person
Never Events
Hospitals shouldn't bill for:- Hospital-acquired infections
- Wrong-site surgery
- Objects left in body
How to Dispute a Bill
Step 1: Request an Itemized Bill
Call billing and specifically ask for a line-by-line itemized statement, not just a summary.Step 2: Compare to EOB
Every charge should have a corresponding EOB entry. Mismatches = problems.Step 3: Research Prices
Use resources like:- Healthcare Bluebook
- FAIR Health Consumer
- Medicare fee schedule
Step 4: File a Formal Dispute
Put it in writing with:- Specific charges you're disputing
- Reason for dispute
- Supporting documentation
Step 5: Escalate if Needed
- Hospital patient advocate
- Insurance appeals process
- State insurance commissioner
Understanding Insurance Terms
| Term | What It Means |
|---|---|
| Deductible | What you pay before insurance kicks in |
| Copay | Fixed amount per visit |
| Coinsurance | Percentage you pay after deductible |
| Out-of-pocket max | Most you'll pay in a year |
| Allowed amount | Max insurance will pay for service |
| Balance billing | Provider billing you the difference |
Quick Reference: Reading Your EOB
Steps to review your EOB:Get Help Understanding Your Bill
Still confused? You're not alone. Medical billing is intentionally complex, and everyone needs help sometimes.
Use our free Bill Explainer → Upload any medical bill and get a plain-English breakdown of exactly what each charge means.---
This guide is for educational purposes. For specific billing disputes, consider consulting with a medical billing advocate or healthcare attorney.