CPT code 86300: Tumor marker, CA 15-3 quantitative assay2026 Medicare lab fee · Clinical Laboratory Fee Schedule
Quantitative CA 15-3 testing measures a breast cancer-associated tumor marker, most often to follow disease activity or treatment response in patients with breast cancer.
Medicare pays $20.81 for 86300 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
$20.81
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 86300 covers
This quantitative immunoassay measures CA 15-3, also identified with CA 27.29, in serum. It is commonly ordered in oncology care to monitor marker trends in patients with breast cancer, particularly advanced disease, alongside clinical assessment and imaging. It is not a stand-alone screening or diagnostic test. Clinical laboratories perform the assay, and the ordering clinician interprets results in context.
Report 86300 for quantitative CA 15-3 testing; use a different marker-specific code when testing CA 19-9 or CA 125. Medicare pays the test only under the CLFS. The 2026 national CLFS amount is $20.81, unchanged since 2020. One amount applies in every state and locality, without geographic adjustment or an office-versus-facility difference. The service is excluded from the physician fee schedule by statute.
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 86300
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 86300. 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 86300 with status X (excluded by statute), so the test itself is paid only from the CLFS.
86300 on the lab fee schedule since 2020
86300 · CLFS 2026 Q4 (current)
$20.81
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.
86300 compared with similar tests
- 86301CA 19-9Quantitative tumor antigen$20.81
- Select 86301 for quantitative CA 19-9 testing, not CA 15-3. The codes identify different tumor markers.
- 86304CA 125Quantitative tumor antigen$20.81
- Select 86304 for quantitative CA 125 testing. It measures a different marker from CA 15-3.
- 86316Tumor markerQuantitative, each antigen$20.81
- Use 86316 for immunoassay testing of another tumor antigen rather than the specifically identified CA 15-3 marker.
86300 billing questions
When should this code be selected instead of another tumor-marker code?
Use it for quantitative CA 15-3 testing, including the CA 27.29 assay associated with this code. Codes 86301 and 86304 represent CA 19-9 and CA 125 testing, respectively.
Is CA 15-3 used to screen for or diagnose breast cancer?
It is commonly used to monitor marker trends in patients with breast cancer, particularly advanced disease. Results are interpreted with clinical findings and imaging rather than used alone to screen for or diagnose cancer.
What specimen is typically tested?
The assay is generally performed on serum from a blood specimen.
How does Medicare pay for this assay?
Medicare pays it only under the CLFS, using one national amount across localities and care settings. It is excluded from the physician fee schedule by statute.
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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