CPT code 80175: Lamotrigine level, quantitative drug assay2026 Medicare lab fee · Clinical Laboratory Fee Schedule
Reports quantitative measurement of lamotrigine, commonly used to assess antiseizure medication exposure and guide treatment monitoring.
Medicare pays $13.25 for 80175 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
$13.25
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 7 sections
What 80175 covers
This assay quantifies lamotrigine in a patient specimen. It is used in therapeutic drug monitoring for patients treated with lamotrigine, including epilepsy care when a clinician needs to assess medication exposure, investigate suspected toxicity or inadequate response, or evaluate adherence or dose needs. A clinical laboratory performs the assay and reports the measured level to the ordering clinician. The result informs clinical management but does not itself set a dose.
Report 80175 for a quantitative lamotrigine measurement, not an assay of another medication. Medicare pays the test through the CLFS at one national amount across states and localities, with no geographic or office-versus-facility adjustment. The 2026 national CLFS amount is $13.25, unchanged since 2020. The code is excluded from the physician fee schedule and is 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 80175
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 80175. 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 80175 with status X (excluded by statute), so the test itself is paid only from the CLFS.
80175 on the lab fee schedule since 2020
80175 · CLFS 2026 Q4 (current)
$13.25
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.
80175 compared with similar tests
- 80177Levetiracetam levelQuantitative concentration$13.25
- 80177 reports levetiracetam measurement. Use 80175 when the analyte being measured is lamotrigine.
- 80183Oxcarbazepine levelQuantitative concentration assay$13.25
- 80183 reports oxcarbazepine measurement. The medication measured, rather than the shared antiseizure monitoring purpose, determines the code.
- 80185Phenytoin levelTotal drug concentration$13.25
- 80185 measures total phenytoin; it is not the code for a lamotrigine level.
80175 billing questions
When should 80175 be selected instead of another antiseizure drug assay?
Use 80175 when the laboratory measures lamotrigine. Select the assay code that matches the different medication being measured, such as levetiracetam or oxcarbazepine.
Does the result measure lamotrigine quantitatively?
Yes. The service reports a quantitative lamotrigine level, not a general drug screen or a result for another medication.
Can a physician bill modifier 26 with 80175?
No. Medicare pays 80175 only through the CLFS; the code is excluded from the physician fee schedule.
How does Medicare price 80175?
Medicare uses one national CLFS amount for the code across states and 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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