CPT code 0337U: Plasma Cell Assay, peripheral Blood2026 Medicare lab fee · Clinical Laboratory Fee Schedule
A proprietary peripheral-blood assay selects, identifies, characterizes, and counts circulating plasma cells to evaluate abnormalities associated with plasma cell disorders and myeloma.
Medicare pays $2,435.00 for 0337U under the 2026 Clinical Laboratory Fee Schedule: one national amount, the same in every state and setting.
Medicare lab fee · CLFS 2026 Q4
National CLFS amount
$2,435.00
In effect since Jan 1, 2026. The same amount in every state, payment locality and setting.
- Geographic adjustment
- None
- Office vs facility
- Same
- Since 2024
- Unchanged
- CMS updates
- Quarterly
Medicare pays the lesser of the lab’s charge and this amount. Patients usually owe no Part B deductible or coinsurance for covered clinical lab tests.
On this page 7 sections
What 0337U covers
0337U identifies a proprietary laboratory analysis of circulating plasma cells in peripheral blood. The assay uses immunologic selection and evaluates differential expression of CD138, CD38, CD19, and CD45 to identify, morphologically characterize, and enumerate the cells. It evaluates plasma cells for abnormalities associated with plasma cell disorders and myeloma. A laboratory performs and reports this specific assay.
Medicare pays 0337U only under the Clinical Laboratory Fee Schedule (CLFS). One national amount applies across all states and localities, without geographic adjustment or an office-versus-facility difference. The CLFS pays one amount per code. The 2026 national CLFS amount is $2,435.00, unchanged from 2024 and 2025. The code has no physician fee schedule payment.
This summary was written with AI assistance from CMS Clinical Laboratory Fee Schedule data. Amounts on this page come directly from CMS files.
How Medicare pays 0337U
Clinical lab tests aren’t priced like physician services. They’re paid from their own fee schedule, with its own rules. See the whole lab fee schedule.
One national amount
CMS sets a single Clinical Laboratory Fee Schedule amount for 0337U. There’s no geographic (GPCI) adjustment, so it pays the same in every state and payment locality.
No office or facility rate
Lab tests aren’t built from relative value units, so there’s no office and facility split: the place of service doesn’t change the CLFS amount.
Updated every quarter
CMS republishes the CLFS each quarter. New tests, often proprietary laboratory analyses (PLA codes), join during the year; existing amounts are updated each January.
Not on the physician fee schedule
The physician fee schedule doesn’t list 0337U: Medicare pays the test only from the CLFS.
0337U on the lab fee schedule since 2022
0337U · CLFS 2026 Q4 (current)
$2,435.00
Unchanged since Jan 1, 2024
Every change on file
- Jan 1, 2024 · CLFS 2024 Q1MAC-priced → $2,435.00
17 quarterly CLFS releases on file, first CLFS 2022 Q4. A code missing from a quarter wasn’t on that release.
0337U compared with similar tests
- 88184Flow cytometryFirst marker, technical component$69.49–$116.43
- 88184 reports the technical service for the first marker in a flow cytometry study. 0337U identifies a specific assay for selecting, characterizing, and enumerating circulating plasma cells.
- 88185Flow cytometry add-onTechnical work, each additional marker$19.80–$33.23
- 88185 reports an additional marker in a flow cytometry study. 0337U identifies the specific peripheral-blood plasma-cell assay, which evaluates differential expression of four named markers.
- 88189Flow cytometry16 or more markers$75.01–$107.22
- 88189 is a flow cytometry interpretation code. 0337U identifies a specific assay for selecting, characterizing, and enumerating circulating plasma cells.
0337U billing questions
What specimen does 0337U evaluate?
It evaluates circulating plasma cells in peripheral blood.
Which markers are evaluated?
The assay evaluates differential expression of CD138, CD38, CD19, and CD45 to identify, characterize, and enumerate plasma cells.
How does 0337U differ from flow cytometry codes 88184 and 88185?
0337U identifies a specific proprietary assay for circulating plasma cells in peripheral blood. Codes 88184 and 88185 describe flow cytometry marker services.
How does Medicare pay 0337U?
Medicare pays it under the CLFS at one national amount across localities, with no office-versus-facility difference.
Where this amount comes from
FeeBase reads lab amounts directly from the CMS Clinical Laboratory Fee Schedule file for the quarter: one row per code, with its payment indicator and national amount. Contractor-priced tests are labeled, never given a made-up amount. Amounts are Medicare payment limits, not a patient’s bill or a commercial rate.
CMS CLFS 2026 Q4 · effective Oct 1, 2026 through the day before Jan 1, 2027
Show the CMS file line behind this amount
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