CPT code 20501: Sinus tract injection2026 Medicare rate & RVUs in Missouri
Injection of contrast into a draining sinus tract to define its course for diagnosis, commonly as part of a fistulogram or sinogram.
Medicare pays $120.57–$130.40 for 20501 in the office in Missouri, from Rest Of Missouri to Metropolitan St. Louis. 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.
On this page 9 sections
What 20501 covers
The clinician introduces contrast into an existing sinus tract to outline its path and show where it leads. This is used in evaluating a draining tract, such as one that persists after surgery or infection. A surgeon or other clinician familiar with the tract may perform the injection in an office, procedure room, or facility; radiology staff may provide the associated imaging service. The injection helps distinguish the tract’s course and connections from what can be established by examination alone.
Report 20501 for the diagnostic injection, not for therapeutic instillation into the tract. Documentation should identify the tract, the diagnostic purpose, and the injection performed; report the radiologic examination separately when it is performed and documented. The code has a 0-day global period, so same-day preoperative and postoperative care is included. When multiple procedures are performed in the same session, the highest-valued procedure is paid in full and others are subject to the standard 50% reduction. Modifier 50 is inappropriate. Medicare does not pay an assistant at surgery; co-surgeons and team surgery are not permitted.
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 20501 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
$120.57 to $130.40
| Payment locality | Office | Facility |
|---|---|---|
| Metropolitan Kansas City | $128.93 | $30.76 |
| Metropolitan St. Louis | $130.40 | $30.88 |
| Rest Of Missouri | $120.57 | $30.45 |
How the 20501 rate is calculated
Each of 20501’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 · 20501
RVUs × geographic indexes × conversion factor
Work0.74
0.74 RVUs× 1.000 GPCI
Practice expense3.25
3.25 RVUs× 1.000 GPCI
Malpractice0.07
0.07 RVUs× 1.000 GPCI
Adjusted RVUs
4.0600
Conversion factor
$33.4009
Medicare rate
$135.61
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 20501
The CMS indicators that decide how 20501 is paid alongside other services.
CMS payment indicators · 20501
Sinus tract injection
| Rule | CMS value | What it means |
|---|---|---|
| Global period | 000 | Same-day global: pre- and post-op care on the day of the procedure is included. |
| Multiple procedures | 2 | Standard reduction: highest-valued procedure at 100%, others at 50%. |
| Bilateral (modifier 50) | 0 | The 150% bilateral adjustment doesn’t apply. |
| Assistant at surgery (80/81/82/AS) | 1 | Not paid (statutory restriction). |
| Co-surgeons (62) | 0 | Not permitted. |
| Team surgery (66) | 0 | Not permitted. |
| Professional/technical | 0 | Physician service: no professional/technical split. |
What modifiers do to the payment
Modifier 51 · payment effect
With and without the modifier
20501 without 51 · national office
$135.61
Sinus tract injection
20501-51 · Second procedure: 50%
$67.81
When this isn’t the highest-valued procedure in the session, Medicare pays 50% of its fee schedule amount (the highest is paid at 100%).
20501 compared with similar codes
Compare codes · National
4 codes, side by side
How to choose
- 20500Sinus tract injection
- 20501 is the diagnostic injection used to outline a sinus tract. 20500 describes therapeutic injection into the tract.
- 76080Fistula imaging
- 76080 represents the radiologic examination of the sinus tract; 20501 represents the injection that helps produce the study.
- 49424Cavity contrast study
- 49424 concerns contrast evaluation through an existing percutaneous drainage catheter. Use 20501 for diagnostic injection into a sinus tract.
20501 billing questions
When should 20501 be chosen instead of 20500?
Use 20501 when contrast is injected to map a sinus tract for diagnosis. Use 20500 when material is injected therapeutically into the tract.
Can the imaging service be reported separately?
Yes. When a radiologic examination of the tract is performed and documented, the imaging service may be reported separately, such as with 76080.
Does 20501 have a global period?
It has a 0-day global period. Same-day preoperative and postoperative care is included.
Should modifier 50 be appended for two tracts?
No. CMS identifies bilateral adjustment as inappropriate for this code. Do not use modifier 50 to represent bilateral anatomy.
How are multiple procedures in the same session paid?
The highest-valued procedure is paid in full, and the other procedures are subject to the standard multiple procedure reduction, with payment at 50%.
Can an assistant surgeon or co-surgeon be reported?
Medicare does not pay an assistant at surgery for this code. Co-surgeons and team surgery are not permitted.
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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