CPT (Current Procedural Terminology) codes are five-digit numbers that describe every medical service or procedure. Your doctor, hospital, and insurance company use them to communicate exactly what was done. Every line on your medical bill has a CPT code, and knowing the code lets you look up what Medicare pays for that same service.

Why do providers charge so much more than Medicare pays?

Providers set their own "chargemaster" prices, which are essentially list prices. Medicare pays a fixed rate based on the resources each service actually requires (the RVU system for procedures, or the Clinical Lab Fee Schedule for lab tests). Commercial insurers typically pay 150% to 250% of Medicare rates. Uninsured patients are often billed the full chargemaster price, which can be 2x to 30x what Medicare pays.

Can I use Medicare rates to negotiate my bill?

Yes. Medicare rates are the closest thing to a "fair price" benchmark in U.S. healthcare. When negotiating, ask the provider what they accept from Medicare for the same CPT code. Most providers will accept 150% to 200% of Medicare for cash-pay patients, which is still far less than their chargemaster price. Many hospital financial assistance policies also use a multiple of Medicare as their discount floor.

How are Medicare rates calculated?

For most procedures, Medicare uses the Resource-Based Relative Value Scale (RBRVS). Each CPT code gets three RVU components: Work (physician time and skill), Practice Expense (overhead), and Malpractice. These are multiplied by geographic adjustment factors (GPCIs) and a conversion factor ($33.4009 in 2026). Lab tests (80000-89999 range) use a separate Clinical Laboratory Fee Schedule with flat national rates.

CPT 51798

Bladder Scan: Ultrasound Measurement of Post-Void Residual

CPT 51798 is a bladder scan that takes approximately 30 seconds using a portable ultrasound device placed on the lower abdomen. It measures how much urine remains in the bladder after urinating. Providers charge an average of $69.42 for this test, but Medicare pays only $12.69 (5.5x markup). This is one of the highest markups in outpatient medicine for a test performed by a medical assistant, not a physician.

Updated May 2026Source: CMS Physician Fee Schedule

CPT 51798 at a Glance

Average provider charge: $69.42
Medicare rate (office and facility): $12.69
Typical markup: 5.5x over Medicare
Test duration: ~30 seconds

Performed by: Medical assistant or nurse
Equipment: Portable bladder scanner
Common setting: Urology clinics
Beneficiaries (2023): 1,282,241

How the Medicare Rate Is Calculated

Medicare values every procedure using Relative Value Units (RVUs) across three components, then multiplies by a national conversion factor of $33.4009 (2026). Notice that 51798 has identical rates in office and facility settings because the practice expense RVU is the same in both:

Component	What It Covers	Office (Non-Facility)	Hospital (Facility)
Work RVU	Physician time, skill, and judgment	0.15	0.15
Practice Expense RVU	Rent, staff, equipment, supplies	0.17	0.17
Malpractice RVU	Professional liability insurance	0.02	0.02
Total RVU		0.34	0.34
x $33.4009	2026 conversion factor	$12.69	$12.69

The 5.5x markup in context: A bladder scan takes 30 seconds of a medical assistant's time using a $3,000 to $8,000 portable device. At $69 per scan and multiple scans per day, the revenue generated from this single test can easily exceed the cost of the equipment within a few weeks. Medicare values the service at $12.69, which arguably reflects its true resource cost more accurately.

Medicare Rate by State

Medicare adjusts the national rate by location using Geographic Practice Cost Indices (GPCIs). Because the base rate is so low ($12.69), the state variation in dollar terms is minimal (roughly $9.57 to $11.70).

Medicare Rate by State (2026)

Medicare adjusts payments by location using Geographic Practice Cost Indices (GPCIs). Select your state to see the adjusted rate.

Sample State Rates

State	Medicare Pays	Avg. Charge	Markup
Texas (Austin)	$10.44	$69.42	6.6x
California (Los Angeles)	$10.94	$69.42	6.3x
New York (Manhattan)	$11.00	$69.42	6.3x
Florida (Fort Lauderdale)	$10.54	$69.42	6.6x
Ohio	$9.96	$69.42	7.0x
Mississippi	$9.63	$69.42	7.2x
Arkansas	$9.57	$69.42	7.3x
Alaska	$11.70	$69.42	5.9x

Rates shown use 2026 GPCIs and the $33.4009 conversion factor. The average provider charge of $69.42 is the 2023 national average from CMS utilization data. Actual charges vary by provider.

What Insured Patients Actually Pay

A bladder scan is typically billed as part of a urology visit, so it adds to whatever you already owe for the office visit itself. Here is what the bladder scan alone costs patients:

Your Situation	What You Likely Pay	How It Works
Coinsurance plan (deductible met)	$6 to $14	20% of the negotiated rate ($30 to $70)
High-deductible plan (deductible NOT met)	$30 to $70	Full negotiated rate until deductible is met
Medicare Part B	$2.54	20% of the Medicare-approved amount ($12.69)
No insurance (self-pay)	$50 to $100	Full billed charge or cash-pay rate

The hidden cost of routine scanning: If your urologist performs a bladder scan at every visit (every 3 to 6 months), that is $140 to $280 per year in charges for a 30-second test. With a high-deductible plan, you could be paying $60 to $140 out of pocket annually for a scan that may not be changing your treatment plan. Ask whether the result would actually alter your care.

Common Billing Problems with 51798

Routine scanning without clinical indication

Some urology practices scan every patient at every visit as part of the "check-in" process, regardless of whether there is a clinical reason to measure post-void residual. If your bladder scan has been consistently normal (under 50 mL) for multiple visits and you have no new urinary symptoms, ask your urologist whether the scan is still necessary. You have the right to decline a test, and declining can save you $69 per visit.

Performed by MA, billed as physician service

The bladder scan is performed by a medical assistant using a handheld device. The physician typically never touches the scanner or interprets the result beyond glancing at the number. Yet the charge appears on the bill attributed to the physician. While this is technically compliant (the physician supervises the service), it is worth understanding that you are paying a physician-attributed fee for a task performed by support staff.

Duplicate billing with catheterization

If your post-void residual was measured by catheterization (inserting a catheter to drain remaining urine), that is a different code (51701). You should not see both 51798 (ultrasound PVR) and 51701 (catheter PVR) on the same date unless there was a clinical reason for both methods. If you see both, ask why.

Frequently Asked Questions

How much does a bladder scan (CPT 51798) cost?

Providers charge an average of $69.42 for a bladder scan. Medicare pays only $12.69 for this test, making the markup 5.5x. This is one of the highest markups in outpatient medicine for a test that takes approximately 30 seconds using a portable ultrasound device. Without insurance, expect to pay $50 to $100 depending on the practice.

Is a bladder scan necessary at every urology visit?

Not necessarily. While bladder scans are useful for diagnosing urinary retention (where urine is not emptying completely), some urology practices perform them routinely on every patient at every visit regardless of symptoms. If your previous scans have been consistently normal and you have no new urinary symptoms (difficulty urinating, feeling of incomplete emptying, frequent urination), ask your urologist whether the scan is clinically necessary or simply routine protocol.

Who performs the bladder scan?

A bladder scan is typically performed by a medical assistant or nurse, not a physician. A portable ultrasound device is placed on the lower abdomen over the bladder area, and the measurement displays automatically on screen. The entire process takes about 30 seconds. Despite being performed by support staff with no physician interpretation required, the charge is billed under the supervising physician.

Why is the markup on bladder scans so high?

The 5.5x markup ($69 charge vs. $12.69 Medicare rate) exists because the test is quick, easy to perform, and easy to justify as routine. Portable bladder scanners cost $3,000 to $8,000 and last for years. The test takes 30 seconds of a medical assistant's time. It can be performed on every patient at every visit with minimal pushback. This combination of low cost and high volume makes it highly profitable for urology practices.

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