CPT code 38900: Sentinel node mapping, intraoperative identification2026 Medicare rate & RVUs in Missouri
Report intraoperative sentinel lymph node mapping when the surgeon identifies sentinel nodes during cancer surgery, commonly for breast cancer or melanoma.
Medicare pays $138.41–$142.90 for 38900 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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On this page 9 sections
What 38900 covers
This add-on describes the surgeon’s intraoperative identification of sentinel lymph node(s), the first node or nodes expected to receive lymphatic drainage from a tumor site. It is commonly used during breast cancer or melanoma surgery. The surgeon may inject nonradioactive dye and identify the draining node(s) for removal; the node excision itself is represented by the applicable primary procedure code.
Report 38900 only with a primary procedure, such as an open sentinel node biopsy, and document the tumor site, mapping or identification performed, and the associated operation. The code includes injection of nonradioactive dye when performed, so that injection is not separately represented by 38900. CMS treats this as an add-on paid within the primary procedure’s global period. For a bilateral procedure reported with modifier 50, CMS pays 150% of the code’s applicable payment.
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 38900 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
$138.41 to $142.90
| Payment locality | Office | Facility |
|---|---|---|
| Metropolitan Kansas City, MO | $141.84 | $121.14 |
| Metropolitan St. Louis, MO | $142.90 | $121.91 |
| Rest of Missouri | $138.41 | $119.41 |
How the 38900 rate is calculated
Each of 38900’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 · 38900
RVUs × geographic indexes × conversion factor
Work2.44
2.44 RVUs× 1.000 GPCI
Practice expense1.31
1.31 RVUs× 1.000 GPCI
Malpractice0.59
0.59 RVUs× 1.000 GPCI
Adjusted RVUs
4.3400
Conversion factor
$33.4009
Medicare rate
$144.96
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 38900
The CMS indicators that decide how 38900 is paid alongside other services.
CMS payment indicators · 38900
Sentinel node mapping, intraoperative identification
| Rule | CMS value | What it means |
|---|---|---|
| Global period | ZZZ | Add-on code: falls within the primary procedure’s global period. |
| Multiple procedures | 0 | No multiple-procedure reduction. |
| Bilateral (modifier 50) | 1 | Bilateral with modifier 50 pays 150% of the fee schedule amount. |
| Assistant at surgery (80/81/82/AS) | 2 | Paid. |
| Co-surgeons (62) | 1 | Permitted with supporting documentation. |
| Team surgery (66) | 0 | Not permitted. |
| Professional/technical | 0 | Physician service: no professional/technical split. |
What modifiers do to the payment
Modifier 50 · payment effect
With and without the modifier
38900 without 50 · national office
$144.96
Sentinel node mapping, intraoperative identification
38900-50 · Bilateral: 150%
$217.44
Both sides on one line with modifier 50 are paid at 150% of the fee schedule amount (subject to multiple-procedure rules with other procedures).
38900 compared with similar codes
Compare codes · National
4 codes, side by side
How to choose
- 38525Axillary node biopsyOpen, deep axillary nodes
- 38525 reports open biopsy or excision of deep axillary node(s). Use 38900 for intraoperative mapping and identification, with the appropriate primary procedure.
- 38500Lymph node biopsyOpen, superficial node
- 38500 reports open biopsy or excision of superficial lymph node(s); it does not describe the mapping service represented by 38900.
- 38792Sentinel node injectionRadioactive tracer
- 38792 describes injection of radioactive tracer for sentinel node identification. Code 38900 describes intraoperative identification and includes nonradioactive dye injection when performed.
38900 billing questions
Is 38900 reported for each sentinel node removed?
Report it for the intraoperative mapping service, not once for every node identified or excised. The node removal is reported with the applicable primary procedure.
Can 38900 be billed by itself?
No. It is an add-on code and must be reported with a primary procedure, such as an open lymph node biopsy.
Is injection of blue dye separately reported with 38900?
The code includes injection of nonradioactive dye when performed. Document the mapping and dye use in the operative report.
How does 38900 differ from 38792?
38900 describes intraoperative identification of sentinel node(s). Code 38792 describes injection of radioactive tracer for sentinel node identification.
How is bilateral mapping reported?
When the procedure is bilateral and reported with modifier 50, CMS pays 150% of the applicable payment for 38900.
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
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