CPT code 86304: CA 125, quantitative tumor antigen2026 Medicare lab fee · Clinical Laboratory Fee Schedule
A quantitative immunoassay measures circulating CA 125, commonly to monitor ovarian cancer treatment or assess disease status alongside clinical findings.
Medicare pays $20.81 for 86304 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 86304 covers
This blood test measures CA 125, a tumor-associated antigen, using an immunoassay. It is commonly ordered for patients with epithelial ovarian cancer to follow treatment response or assess possible recurrence. Clinicians may also use the result when evaluating an adnexal mass, interpreted with the examination, imaging, and other clinical information. CA 125 alone does not establish a cancer diagnosis and is not a general screening test for people without symptoms or known risk.
Report 86304 for the quantitative CA 125 assay performed. Clinical laboratories commonly test serum; the result is a concentration, not a count of units to bill. Medicare pays the test only through the CLFS. The 2026 national CLFS amount is $20.81, unchanged from 2020 through 2026; one amount applies nationwide, without locality or office-versus-facility adjustment.
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 86304
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 86304. 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 86304 with status X (excluded by statute), so the test itself is paid only from the CLFS.
86304 on the lab fee schedule since 2020
86304 · 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.
86304 compared with similar tests
- 86305HE4 assayOvarian tumor marker$20.81
- 86305 measures HE4, not CA 125. Select the code for the antigen actually assayed; both may be performed in an adnexal mass evaluation.
- 86300Tumor markerCA 15-3 quantitative assay$20.81
- 86300 is the CA 15-3 assay, a different tumor marker. It does not represent a CA 125 measurement.
- 86301CA 19-9Quantitative tumor antigen$20.81
- 86301 measures CA 19-9 rather than CA 125. Choose according to the analyte tested.
86304 billing questions
When is 86304 appropriate?
Use it for a quantitative CA 125 assay, commonly to monitor known ovarian cancer or support evaluation of an adnexal mass. The result is interpreted with other clinical findings and is not a standalone diagnosis.
How does 86304 differ from 86305?
86304 measures CA 125; 86305 measures human epididymis protein 4 (HE4). They are distinct assays and may be ordered together in an ovarian mass evaluation.
How many units should be reported?
Report the assay performed, not separate units based on the measured CA 125 concentration. The concentration is part of the test result.
How does Medicare price this test?
Medicare pays one national CLFS amount for 86304 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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