How to Check Your Medical Bill for Errors

Executive Summary: Up to 80% of hospital bills contain errors. To check yours: (1) Request itemized bill with CPT/HCPCS codes, not a summary. (2) Compare each charge to Medicare rates. Hospital charges at 400%+ of Medicare benchmark warrant investigation. (3) Check for common errors: duplicate codes (same CPT on same date), NCCI bundling violations (billing components separately that should be packaged), pharmacy markups (hospital drug costs at 500%+ acquisition cost), and services never rendered. (4) Use automated bill checkers that cross-reference 3.3 million CMS coding rules. (5) Dispute in writing with specific CPT codes and dates. Most hospitals correct documented errors within 30-45 days.

You get a bill for $4,200. Is that right? Too high? Full of errors?

You have no way to know.

The hospital’s prices are hidden. Your insurer’s rates are confidential. The codes on your bill might as well be another language. And the billing department’s answer to every question is the same: “That’s what the system says.”

This guide shows you exactly how to check your medical bill for errors—what to look for, what the codes mean, and when you have grounds to dispute.

Step 1: Get an itemized bill with codes

Your first bill is usually a summary. It shows a total but not what you’re being charged for. Before you can check for errors, you need the details.

Call the billing department and request:

• An itemized bill with CPT/HCPCS codes
• Revenue codes (if hospital/facility)
• The date of service for each line item
• Quantity and unit price for each charge

What these codes look like:

• CPT codes: 5 digits (e.g., 99213, 99283, 71046)
• HCPCS codes: Letter + 4 digits (e.g., J1885, G2211)
• Revenue codes: 4 digits starting with 0 (e.g., 0450, 0636)

If the billing department resists, cite your right to an itemized statement. Under the No Surprises Act and most state laws, you’re entitled to a detailed breakdown.

Step 2: Compare each charge to Medicare rates

Medicare publishes what it pays for every medical procedure. While your insurance may pay more or less, Medicare rates give you a benchmark for what’s reasonable.

How to interpret the comparison:

A charge at 300% of Medicare isn’t automatically wrong. But a charge at 800% of Medicare deserves a closer look.

Check your codes against Medicare rates →

Step 3: Look for these common billing errors

Duplicate charges

The same procedure billed twice. This happens when:

• Multiple departments enter the same service
• A corrected claim gets submitted alongside the original
• Lab work or imaging is billed by both the ordering physician and the facility

What to look for: Same CPT code appearing multiple times on the same date of service.

Unbundling (billing separately for bundled services)

Some procedures include other services by definition. Billing them separately is called “unbundling” and violates CMS rules.

Example: A knee arthroscopy (29881) includes certain cartilage work (29877, 29876). If all three codes appear on your bill, you may be overcharged.

CMS publishes 3.3 million code pairs that shouldn’t be billed together. These are called NCCI (National Correct Coding Initiative) edits.

Check your bill for NCCI violations →

Upcoding

Being billed for a more expensive version of a service than you received.

Common examples:

• ER visit level 5 (99285) when documentation supports level 3 (99283)
• Complex office visit (99215) for a routine follow-up
• Extended procedure time when the actual time was shorter

How to spot it: Compare the procedure description to what actually happened during your visit. If you were in the ER for 20 minutes with a minor issue, a level 5 charge is questionable.

Quantity limit violations

CMS sets maximum units per day for many procedures. These are called MUE (Medically Unlikely Edits).

Example: CPT code 99458 (chronic care management) has a limit of 3 units per day. If your bill shows 5 units, that’s a violation.

Services not rendered

Charges for things that didn’t happen:

• Medications you refused or never received
• Tests that were ordered but cancelled
• Procedures that were discussed but not performed

Check your discharge summary against the itemized bill. Every charge should correspond to documented care.

Step 4: Understand what you can and can’t dispute

You have strong grounds when:

• Coding errors exist: Duplicate charges, unbundled services, wrong codes
• Charges don’t match services: You’re billed for something that didn’t happen
• Balance billing violations: In-network provider charges more than the allowed amount
• No Surprises Act applies: Emergency care or out-of-network provider at in-network facility

Negotiation is harder when:

• Insurance already processed the claim: The provider is bound by contracted rates
• Charges match your EOB: Your “patient responsibility” amount is typically non-negotiable
• The bill is accurate: High prices aren’t the same as billing errors

Key distinction: A bill can be expensive and still be correct. Focus your disputes on actual errors, not just high prices.

Step 5: What to do when you find an error

For coding errors (duplicates, unbundling, upcoding):

1. Document the specific error with code numbers and amounts
2. Call the billing department and reference the specific CPT codes
3. Ask them to review and resubmit the claim
4. Request written confirmation of any adjustments
5. If denied, request the denial in writing and escalate to your insurance

For potential overcharges:

1. Ask for the hospital’s financial assistance policy
2. Request a cash-pay discount if you’re uninsured
3. Ask if a payment plan is available
4. Consider contacting a patient advocate

For No Surprises Act violations:

1. File a complaint with CMS at cms.gov/nosurprises
2. Contact your state insurance commissioner
3. Request the Independent Dispute Resolution process

What Medicare data can and can’t tell you

Using Medicare as a benchmark gives you context, not certainty.

Medicare data tells you:

• What the government pays for each procedure
• Whether two codes should be billed together
• Maximum units allowed per day
• Relative value of different services

Medicare data doesn’t tell you:

• Your insurer’s negotiated rate (that’s confidential)
• Exactly what you should owe (depends on your plan)
• Whether you’ll win a dispute (outcomes vary)

When we flag an NCCI violation, that’s a definitive error based on published CMS rules. When we show you’re at 400% of Medicare, that’s context you didn’t have before. Both are useful. Neither guarantees a specific outcome.

Check your bill now

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Additional resources

• CMS Medical Bill Rights — No Surprises Act protections
• Dollar For — Free help applying for hospital financial assistance
• Patient Advocate Foundation — Case management for billing disputes

OrbDoc builds tools to help patients understand medical bills and clinicians document accurately. Learn more about our clinical documentation platform →