CPT code 80163: Digoxin assay, free concentration2026 Medicare lab fee · Clinical Laboratory Fee Schedule
Measures unbound digoxin when a clinician needs a free concentration, including assessment after digoxin immune Fab treatment rather than a total level.
Medicare pays $13.28 for 80163 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
$13.28
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 80163 covers
This laboratory test measures the unbound fraction of digoxin, distinct from the total digoxin concentration. A clinician may request the free concentration when that specific result is needed, including assessment after digoxin immune Fab treatment, because Fab-bound drug can affect interpretation of a total level. A clinical laboratory performs and reports the assay for patients being evaluated or monitored for digoxin exposure.
Report 80163 for an assay of free digoxin; use 80162 when the requested test is total digoxin. Medicare pays the test under the CLFS, with one national amount applying in every locality and no office-versus-facility adjustment. The 2026 national CLFS amount is $13.28, unchanged since 2020. The test 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 80163
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 80163. 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 80163 with status X (excluded by statute), so the test itself is paid only from the CLFS.
80163 on the lab fee schedule since 2020
80163 · CLFS 2026 Q4 (current)
$13.28
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.
80163 compared with similar tests
- 80162Digoxin assayTotal concentration$13.28
- 80162 measures total digoxin. Report 80163 when the test performed measures the free, unbound concentration.
- 80157Carbamazepine levelUnbound carbamazepine$13.25
- 80157 measures free carbamazepine, not digoxin. Select the code for the drug actually assayed.
- 80165Valproic acidFree level$13.54
- 80165 measures free dipropylacetic acid, not digoxin. Select the code that matches the analyte.
80163 billing questions
When should the free digoxin assay be reported instead of the total assay?
Use this code when the laboratory measures unbound digoxin. Code 80162 is for the total digoxin concentration.
Can this assay be useful after digoxin immune Fab treatment?
Yes. A free digoxin concentration can help assess unbound drug after Fab treatment, when a total digoxin result may be difficult to interpret.
Does this code represent a free digoxin result or a separately reported interpretation?
It represents the laboratory assay for free digoxin. Medicare pays for the test through the CLFS; the code is excluded from the physician fee schedule.
Is this test paid under the physician fee schedule or the CLFS?
Medicare pays this test only through the CLFS.
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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