CPT code 80299: Drug assay, unlisted therapeutic drug2026 Medicare lab fee · Clinical Laboratory Fee Schedule
Reports laboratory measurement of a therapeutic drug when no more specific assay code describes the quantitative test performed.
Medicare pays $18.64 for 80299 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
$18.64
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 80299 covers
80299 reports laboratory quantitation of a therapeutic drug when no more specific assay code describes the test. Therapeutic drug measurements may be ordered during treatment to evaluate drug concentration in relation to therapy, including when a clinician is assessing treatment or dose. The code is not tied to a named medication; topiramate, vancomycin, infliximab, and lacosamide each have drug-specific assay codes. Laboratories perform and report the quantitative assay, and the ordering clinician uses the result in managing medication therapy.
Report 80299 when no drug-specific assay code identifies the therapeutic drug measured. Medicare pays the test only through the CLFS. CMS sets one national amount that applies across states and localities, with no geographic adjustment or office-versus-facility difference. The 2026 national CLFS amount is $18.64, unchanged from 2020 through 2026. The test is excluded from the physician fee schedule.
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 80299
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 80299. 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 80299 with status X (excluded by statute), so the test itself is paid only from the CLFS.
80299 on the lab fee schedule since 2020
80299 · CLFS 2026 Q4 (current)
$18.64
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.
80299 compared with similar tests
- 80201Topiramate levelTopiramate-specific assay$11.92
- 80201 is the specific assay code for topiramate. Use 80299 for a therapeutic drug without a more specific assay code.
- 80202Vancomycin levelAntibiotic concentration$13.54
- 80202 is the specific assay code for vancomycin. Use 80299 for a therapeutic drug without a more specific assay code.
- 80230Infliximab assayDrug measurement$38.57
- 80230 identifies infliximab testing. Use 80299 when the therapeutic drug measured does not have a more specific assay code.
80299 billing questions
When should a biller use 80299 instead of a drug-specific assay code?
Use 80299 when the laboratory quantifies a therapeutic drug for which no more specific assay code describes the test. Use the named assay code when one describes the drug measured.
Which nearby drugs have specific assay codes?
Topiramate, vancomycin, infliximab, and lacosamide have drug-specific assay codes. Use the code for the named drug rather than 80299 when that is the test performed.
How does Medicare pay for 80299?
Medicare pays the test only through the CLFS, using one national amount across states and localities with no office-versus-facility difference.
What should documentation identify for 80299?
Documentation should identify the therapeutic drug measured and the quantitative assay performed, supporting use of 80299 rather than a drug-specific assay code.
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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