CPT code 88263: Chromosome analysis, 45 cells for mosaicism2026 Medicare lab fee · Clinical Laboratory Fee Schedule
Banded chromosome analysis counts 45 cells to assess suspected mosaicism and is reported when this expanded cell count is used.
Medicare pays $150.29 for 88263 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
$150.29
In effect since Jan 1, 2026. The same amount in every state, payment locality and setting.
- Geographic adjustment
- None
- Office vs facility
- Same
- Since 2020
- 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 8 sections
What 88263 covers
Cytogenetics laboratories use 88263 for a banded chromosome analysis that counts 45 cells when evaluating genetic defects associated with suspected mosaicism. The analysis includes two karyotypes. Mosaicism means that different cells in one individual may have different chromosome patterns. A clinician may order this study when the clinical or laboratory picture raises concern for a chromosomal cell line present in only part of the sampled material.
Report 88263 for this 45-cell mosaicism analysis. Medicare pays it through the CLFS at one national amount in every state and locality, without an office-versus-facility payment difference. The 2026 national CLFS amount is $150.29, unchanged since 2020. The service is excluded from the physician fee schedule and paid only through the CLFS.
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 88263
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 88263. 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.
Excluded from the physician fee schedule
The physician fee schedule lists 88263 with status X (excluded by statute), so the test itself is paid only from the CLFS.
88263 on the lab fee schedule since 2020
88263 · CLFS 2026 Q4 (current)
$150.29
Unchanged since Jan 1, 2020
27 quarterly CLFS releases on file, first CLFS 2020 Q1. A code missing from a quarter wasn’t on that release.
88263 compared with similar tests
- 88262Chromosome analysis15–20 cells, two karyotypes$125.49
- 88262 describes a 15–20-cell chromosome analysis. Choose 88263 when the study counts 45 cells for mosaicism.
- 88264Chromosome analysis20-25 cells$144.61
- 88264 describes a 20–25-cell chromosome analysis; 88263 is the 45-cell study for mosaicism.
- 88285Chromosome countAdditional cells per study$26.91
- 88285 is for an additional chromosome count with a study. It is not the primary 45-cell mosaicism analysis represented by 88263.
88263 billing questions
When should 88263 be selected instead of another chromosome-analysis code?
Use 88263 when the chromosome analysis counts 45 cells for mosaicism. Other codes in the series describe different cell-count scopes or specimen contexts.
What does the 45-cell count indicate?
It identifies the cell count used for the mosaicism analysis. The service includes two karyotypes with banding.
Why does the study examine 45 cells?
The expanded cell count is used for evaluation of mosaicism, where a chromosome pattern may be present in only a subset of cells.
When are 88285 or 88289 reported with 88263?
88285 describes an additional chromosome count, and 88289 describes an additional chromosome study. They relate to additional work beyond the primary analysis when that work is performed.
Does Medicare pay 88263 under the physician fee schedule?
No. Medicare pays 88263 through the CLFS; the test is excluded from the physician fee schedule.
Does the CLFS amount vary by locality or place of service?
No. The code has one national CLFS amount across states and 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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