CPT code 80204: Methotrexate assay, drug concentration2026 Medicare lab fee · Clinical Laboratory Fee Schedule
Measures methotrexate for monitoring drug levels during high-dose treatment, including cancer therapy, to support assessment of clearance and treatment management.
Medicare pays $38.57 for 80204 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
$38.57
In effect since Jan 1, 2026. The same amount in every state, payment locality and setting.
- Geographic adjustment
- None
- Office vs facility
- Same
- Since 2021
- 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 80204 covers
Methotrexate assay reports measurement of methotrexate, commonly ordered during high-dose methotrexate therapy, including oncology treatment, to follow drug levels and assess clearance. Treating clinicians use serial results to support management of therapy and potential toxicity. Hospitals and independent laboratories perform and report this laboratory test for clinicians managing patients receiving methotrexate.
Report 80204 for measurement of methotrexate rather than the general quantitative drug assay code 80299 or a drug-specific assay for another medication. Medicare pays the test only under the CLFS, with one national amount per code applying across localities and no office-versus-facility difference. The 2026 national amount is $38.57, unchanged from 2021 through 2026. The physician fee schedule excludes the test; payment is 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 80204
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 80204. 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 80204 with status X (excluded by statute), so the test itself is paid only from the CLFS.
80204 on the lab fee schedule since 2021
80204 · CLFS 2026 Q4 (current)
$38.57
Unchanged since Jan 1, 2021
24 quarterly CLFS releases on file, first CLFS 2021 Q1. A code missing from a quarter wasn’t on that release.
80204 compared with similar tests
- 80299Drug assayUnlisted therapeutic drug$18.64
- 80204 identifies methotrexate specifically. Code 80299 is a general quantitative drug assay code.
- 80202Vancomycin levelAntibiotic concentration$13.54
- 80202 is the drug-specific assay for vancomycin; 80204 is for methotrexate.
- 80203Zonisamide levelQuantitative drug assay$13.25
- 80203 is the drug-specific assay for zonisamide; 80204 is for methotrexate.
80204 billing questions
When is this assay typically ordered?
It is commonly used to monitor methotrexate levels during high-dose treatment, particularly in cancer care. Results help the treating team assess drug levels and clearance during therapy.
How does 80204 differ from 80299?
Use 80204 for a methotrexate assay. Code 80299 is a general quantitative drug assay code.
Which code applies to a vancomycin assay?
Code 80202 identifies the vancomycin assay; 80204 is for methotrexate.
What does 80204 identify?
It identifies measurement of methotrexate, not an assay for another medication.
How does Medicare pay for 80204?
Medicare pays it through the CLFS using one national amount across localities, with no office-versus-facility payment 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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