CPT code 51798: Bladder scan, post-void residual or bladder capacity2026 Medicare rate & RVUs in Missouri
A non-imaging ultrasound bladder scan measures post-void residual urine or assesses bladder capacity when a documented volume measurement is needed.
Medicare pays $11.02–$12.12 for 51798 in the office in Missouri, from Rest of Missouri to Metropolitan St. Louis, MO. Which amount applies depends on the service address.
Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.
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What 51798 covers
This service uses a non-imaging ultrasound scanner placed on the lower abdomen to estimate urine volume in the bladder. It is commonly performed just after a patient voids to measure post-void residual urine. A full-bladder measurement may be used when bladder capacity is being assessed; a pre-void reading alone does not establish capacity. Medical assistants, nurses, and technicians perform scans in urology, gynecology, primary care, and skilled nursing settings. Common reasons include suspected urinary retention, benign prostatic hyperplasia, incontinence, neurogenic bladder, and postoperative voiding complaints.
Report the scan when the record supports the clinical reason and documents the measured volume and whether the reading was obtained before or after voiding. CMS classifies 51798 as a technical-component-only code: its payment accounts for the scanning resources, while a separate code covers interpretation when separately reportable. Do not split 51798 with modifiers 26 or TC. An ultrasound examination that produces diagnostic images is a different service from this non-imaging volume measurement.
This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.
Where 51798 pays more and less in Missouri
The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.
3 payment localities
$11.02 to $12.12
| Payment locality | Office | Facility |
|---|---|---|
| Metropolitan Kansas City, MO | $11.94 | Unavailable |
| Metropolitan St. Louis, MO | $12.12 | Unavailable |
| Rest of Missouri | $11.02 | Unavailable |
How the 51798 rate is calculated
Each of 51798’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.
How the rate is built · 51798
RVUs × geographic indexes × conversion factor
Work0.00
0.00 RVUs× 1.000 GPCI
Practice expense0.36
0.36 RVUs× 1.000 GPCI
Malpractice0.02
0.02 RVUs× 1.000 GPCI
Adjusted RVUs
0.3800
Conversion factor
$33.4009
Medicare rate
$12.69
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 51798
The CMS indicators that decide how 51798 is paid alongside other services.
CMS payment indicators · 51798
Bladder scan, post-void residual or bladder capacity
| Rule | CMS value | What it means |
|---|---|---|
| Global period | XXX | The global surgery concept doesn’t apply. |
| Multiple procedures | 0 | No multiple-procedure reduction. |
| Bilateral (modifier 50) | 0 | The 150% bilateral adjustment doesn’t apply. |
| Assistant at surgery (80/81/82/AS) | 0 | Not paid without supporting documentation. |
| Co-surgeons (62) | 0 | Not permitted. |
| Team surgery (66) | 0 | Not permitted. |
| Professional/technical | 3 | Technical component only. |
51798 compared with similar codes
Compare codes · National
4 codes, side by side
How to choose
- 76857Pelvic ultrasoundLimited or follow-up
- 76857 is a limited imaging pelvic ultrasound with images and an interpretation. 51798 is a non-imaging bladder volume measurement.
- 51701Bladder catheterizationIn-and-out catheter
- 51701 is a catheter insertion that can drain the bladder and measure residual urine directly. 51798 estimates bladder volume without a catheter.
- 51725CystometrogramSimple filling-phase study
- 51725 measures bladder pressure during filling through simple cystometry and can assess capacity. 51798 estimates urine volume externally without measuring bladder pressure.
51798 billing questions
Can this be billed when a diagnostic ultrasound examination produces images?
51798 describes a non-imaging volume measurement. When the service instead includes diagnostic images and an interpretation, select the appropriate imaging ultrasound code, such as 76857 for a limited pelvic examination.
Can modifier 26 or TC be appended?
No. CMS classifies 51798 as technical-component-only rather than a code split into professional and technical portions. A separate code covers interpretation when it is separately reportable.
Can a bladder scan be reported with an office visit on the same day?
A medically necessary E/M visit may be reported with a distinct, medically necessary bladder volume measurement when the record supports both services.
Can straight catheterization and a bladder scan both be billed for residual urine?
If catheterization alone is used to measure residual urine, do not also report a scan. A scan followed by separately necessary catheterization to drain retained urine may support reporting both documented services.
What documentation supports the bladder scan?
Record the measured volume, whether the reading was obtained before or after voiding, and the reason for testing, such as suspected retention or incomplete emptying.
How is a bladder scan reported with a uroflow study?
A patient may void into a uroflowmeter and then have a bladder scan for residual urine. Report both when each distinct measurement is medically necessary and documented.
Where these rates come from
FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.
CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027
Show the CMS file lines behind this rate
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