CPT code 88189: Flow cytometry, 16 or more markers2026 Medicare rate & RVUs in Guam
Reports the professional interpretation of a flow cytometry study using 16 or more markers, commonly for immunophenotyping blood, marrow, tissue, or fluid specimens.
Medicare pays $81.10 for 88189 in the office in Guam (Hawaii, Guam, HI). 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.
Your location
On this page 9 sections
What 88189 covers
A pathologist or other qualified physician interprets flow cytometry findings from a study using 16 or more markers and prepares the interpretive report. These studies commonly support evaluation of suspected hematologic malignancies, such as leukemia or lymphoma, using specimens such as peripheral blood, bone marrow, lymph node tissue, or body fluids. The interpretation assesses the marker findings as a whole rather than billing for the laboratory work that processes and analyzes the specimen.
Select this level according to the number of markers in the study: 88189 is for 16 or more, while 88187 and 88188 cover lower marker ranges. The record should support the marker count and include the signed interpretation and report. This is a professional-component-only code; separate code or codes cover the technical portion. The technical services may include 88184 for the first marker and 88185 for additional markers, as appropriate.
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.
88189 in Hawaii, Guam, HI
| Payment locality | Office | Facility |
|---|---|---|
| Hawaii, Guam, HI | $81.10 | $81.10 |
How the 88189 rate is calculated
Each of 88189’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 · 88189
RVUs × geographic indexes × conversion factor
Work1.66
1.66 RVUs× 1.000 GPCI
Practice expense0.64
0.64 RVUs× 1.000 GPCI
Malpractice0.07
0.07 RVUs× 1.000 GPCI
Adjusted RVUs
2.3700
Conversion factor
$33.4009
Medicare rate
$79.16
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 88189
The CMS indicators that decide how 88189 is paid alongside other services.
CMS payment indicators · 88189
Flow cytometry, 16 or more markers
| 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 | 2 | Professional component only. |
88189 compared with similar codes
Compare codes · National
5 codes, side by side
How to choose
- 88187Flow cytometry2–8 marker interpretation
- Both report professional interpretation of flow cytometry; choose 88187 for the lower marker range and 88189 for 16 or more markers.
- 88188Flow cytometry9–15 markers
- 88188 applies to 9 through 15 markers. Use 88189 when the study reaches 16 markers or more.
- 88184Flow cytometryFirst marker, technical component
- 88184 represents technical work for the first marker, not the physician's interpretation and report represented by 88189.
- 88185Flow cytometry add-onTechnical work, each additional marker
- 88185 represents technical work for additional markers. It does not replace the professional interpretation code when that work is performed.
88189 billing questions
When should 88189 be selected instead of 88188?
Use 88189 when the flow cytometry study includes 16 or more markers. Code 88188 is for the lower range of 9 through 15 markers.
Does 88189 include the laboratory's technical work?
No. It represents the professional interpretation and report; separate code or codes cover the technical portion.
Which codes may represent the technical portion?
Code 88184 covers the technical work for the first marker, and 88185 covers additional markers, as appropriate to the study.
What documentation supports reporting 88189?
Keep the flow cytometry report, the marker count supporting the 16-or-more level, and the signed professional interpretation.
Should modifier 26 be appended to 88189?
No. 88189 is already a professional-component-only code.
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
Fee sheets · Coming soon
Put 88189 and the rest of your codes on one sheet
Your codes at your locality, with payer contracts beside Medicare.
Join the waitlist