CPT code 88331: Frozen section, first block, one specimen2026 Medicare rate & RVUs in Illinois
Reports a pathologist’s intraoperative microscopic assessment of frozen tissue from a specimen, providing a rapid diagnosis to guide the surgeon’s immediate decisions.
Medicare pays $92.76–$99.79 for 88331 in the office in Illinois, from Rest of Illinois to Suburban Chicago, IL. 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 88331 covers
A pathologist examines frozen tissue during surgery and communicates a rapid microscopic interpretation to the surgeon, often to assess a margin or clarify the nature of tissue before the operation proceeds. The service is performed in connection with an operation, with pathology staff preparing the frozen tissue and slides and the pathologist providing the interpretation. The assessment is for one specimen’s first tissue block.
Report this code for the first frozen-section block; report each additional block for that specimen with 88332. Documentation should identify the specimen and block, describe the intraoperative examination, and record the interpretation communicated to the surgical team. CMS recognizes separately priced professional and technical components: modifier 26 identifies the interpretation, modifier TC identifies the equipment and staff work, and an unmodified claim 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 88331 pays more and less in Illinois
The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.
4 payment localities
$92.76 to $99.79
| Payment locality | Office | Facility |
|---|---|---|
| Chicago, IL | $99.05 | Unavailable |
| East St. Louis, IL | $93.62 | Unavailable |
| Rest of Illinois | $92.76 | Unavailable |
| Suburban Chicago, IL | $99.79 | Unavailable |
How the 88331 rate is calculated
Each of 88331’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 · 88331
RVUs × geographic indexes × conversion factor
Work1.16
1.16 RVUs× 1.000 GPCI
Practice expense1.72
1.72 RVUs× 1.000 GPCI
Malpractice0.03
0.03 RVUs× 1.000 GPCI
Adjusted RVUs
2.9100
Conversion factor
$33.4009
Medicare rate
$97.20
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 88331
The CMS indicators that decide how 88331 is paid alongside other services.
CMS payment indicators · 88331
Frozen section, first block, one 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
88331 without 26 · national office
$97.20
Frozen section, first block, one specimen
88331-26 · Professional component
$57.78
Pays only the interpretation and report.
88331 compared with similar codes
Compare codes · National
5 codes, side by side
How to choose
- 88329Pathology consultGross examination only
- 88329 applies to an intraoperative consultation based on gross examination. Choose 88331 when the pathologist microscopically examines frozen tissue.
- 88332Frozen sectionEach additional tissue block
- 88331 represents the first frozen-section block for a specimen. Use 88332 for each additional block, not as a substitute for the first-block service.
- 88333Surgical cytologyInitial specimen
- 88333 covers intraoperative cytologic examination, such as a touch preparation or squash preparation. 88331 is for microscopic examination of frozen tissue.
- 88305Tissue pathology examLevel IV specimen
- 88305 is a definitive surgical pathology examination selected by specimen and service. 88331 is the rapid intraoperative frozen-section consultation.
88331 billing questions
When is 88331 chosen instead of 88329?
Use 88331 when the intraoperative consultation includes microscopic examination of frozen tissue. Code 88329 is for an intraoperative pathology consultation based on gross examination.
How are additional frozen-section blocks reported?
Report 88331 for the first block for a specimen and 88332 for each additional block. The record should support the blocks actually examined.
Can 88331 be billed with modifier 26 or TC?
Yes. Modifier 26 represents the pathologist’s interpretation, while TC represents the technical work, including equipment and staff. Without either modifier, the claim represents the global service.
How does 88331 differ from 88333?
88331 reports microscopic examination of frozen tissue. Code 88333 is for an intraoperative cytologic examination, such as a touch preparation or squash preparation.
Can a definitive surgical pathology examination also be reported?
A definitive examination of the specimen may follow the intraoperative frozen-section assessment. Select the surgical pathology code, such as 88305, based on the specimen and the work performed for that examination.
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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