CPT code 88377: ISH analysis, computer-assisted, per specimen2026 Medicare rate & RVUs in Michigan
Reports computer-assisted quantitative or semiquantitative morphometric analysis of in situ hybridization findings for a probe in a tissue specimen.
Medicare pays $354.96–$373.23 for 88377 in the office in Michigan, from Rest of Michigan to Detroit, MI. 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 88377 covers
This service uses computer-assisted image analysis to quantify or semiquantify in situ hybridization findings for a probe in a tissue specimen. A pathologist typically reviews the stained tissue and image-analysis results in a pathology laboratory, such as when evaluating tumor cells for a molecular marker. The analysis supplements the underlying ISH test by providing a measured assessment of the probe signal rather than a visual interpretation alone.
Report the service when the specimen undergoes the specified morphometric analysis, and identify the specimen, probe, method, and analyzed findings in the pathology record. The code is reported per specimen; the probe and analysis performed should be clear enough to support the reported service. CMS recognizes professional and technical components: modifier 26 represents interpretation, modifier TC represents equipment and staff, and reporting without either modifier represents the global service.
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 88377 pays more and less in Michigan
| Payment locality | Office | Facility |
|---|---|---|
| Detroit, MI | $373.23 | Unavailable |
| Rest of Michigan | $354.96 | Unavailable |
How the 88377 rate is calculated
Each of 88377’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 · 88377
RVUs × geographic indexes × conversion factor
Work1.37
1.37 RVUs× 1.000 GPCI
Practice expense10.09
10.09 RVUs× 1.000 GPCI
Malpractice0.04
0.04 RVUs× 1.000 GPCI
Adjusted RVUs
11.5000
Conversion factor
$33.4009
Medicare rate
$384.11
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 88377
The CMS indicators that decide how 88377 is paid alongside other services.
CMS payment indicators · 88377
ISH analysis, computer-assisted, per specimen
| 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 | 1 | Diagnostic test with separate professional (26) and technical (TC) components. |
What modifiers do to the payment
Modifier 26 · payment effect
With and without the modifier
88377 without 26 · national office
$384.11
ISH analysis, computer-assisted, per specimen
88377-26 · Professional component
$60.79
Pays only the interpretation and report.
88377 compared with similar codes
Compare codes · National
4 codes, side by side
How to choose
- 88367ISH analysisAutomated morphometric analysis
- 88377 describes quantitative or semiquantitative morphometric analysis of ISH findings per specimen. Consider 88367 when the service is computer-assisted ISH but is not the morphometric analysis described here.
- 88361Tumor immunohistochemistryComputer-assisted analysis
- 88361 is computer-assisted morphometric analysis of tumor immunohistochemistry. This code is for morphometric analysis of in situ hybridization findings.
- 88369ISH morphometryQuantitative or semiquantitative
- Both codes concern morphometric ISH analysis. Compare the code descriptors and documented method to determine which service was performed.
88377 billing questions
When is this code preferable to a general ISH service?
Use it when the service includes computer-assisted quantitative or semiquantitative morphometric analysis of ISH findings. A routine ISH service without that morphometric analysis is a different service.
What should the pathology record identify?
Document the specimen and probe, the computer-assisted morphometric method, and the analysis results. The record should support that the reported work was performed for that specimen.
How do modifiers 26 and TC affect reporting?
Modifier 26 reports the professional interpretation, and modifier TC reports the technical service involving equipment and staff. Without either modifier, the claim represents the global service.
Is the service reported per probe or per specimen?
The code descriptor identifies analysis for each probe and specifies reporting per specimen. Keep the probe and specimen details distinct in the documentation.
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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