CPT code 80198: Theophylline level, drug concentration assay2026 Medicare lab fee · Clinical Laboratory Fee Schedule
Measures theophylline concentration in a blood specimen to support medication monitoring, evaluation of suspected adverse effects, or assessment of an unexpected treatment response.
Medicare pays $14.14 for 80198 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
$14.14
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 80198 covers
This assay measures theophylline concentration in a blood specimen, typically serum. Clinicians may order it for patients taking theophylline for asthma or chronic obstructive pulmonary disease to guide dose adjustments, evaluate a suspected adverse effect, or investigate an unexpected response. Drug interactions and changes in health can alter the concentration, so the result helps the treating clinician assess the medication level alongside clinical findings. Hospital and independent laboratories commonly perform and report the assay for outpatient or inpatient care.
Report this assay when the laboratory measures theophylline concentration, rather than as a general drug screen. Medicare pays it under the CLFS; the 2026 national amount is $14.14, unchanged from 2020 through 2026. The same amount applies across states and localities, with no office-versus-facility difference. Medicare pays the test only from 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 80198
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 80198. 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 80198 with status X (excluded by statute), so the test itself is paid only from the CLFS.
80198 on the lab fee schedule since 2020
80198 · CLFS 2026 Q4 (current)
$14.14
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.
80198 compared with similar tests
- 80184Phenobarbital levelQuantitative drug assay$15.30
- Select 80184 for a phenobarbital level. Select 80198 when the laboratory measures theophylline.
- 80185Phenytoin levelTotal drug concentration$13.25
- 80185 is for total phenytoin concentration; it is not the assay for theophylline.
- 80186Phenytoin levelUnbound concentration$13.76
- 80186 measures free phenytoin, whereas 80198 measures theophylline.
80198 billing questions
When should this code be selected instead of another drug assay?
Use it when the laboratory measures theophylline concentration. Select a different drug-assay code when the test measures another medication, such as phenobarbital or phenytoin.
Is this a general drug screen?
No. It identifies a theophylline level, rather than screening a specimen for multiple drugs or drug classes.
What specimen is typically tested?
The assay is typically performed on serum from a blood specimen.
How should the assay be reported?
Report this code when the laboratory measures theophylline concentration. It describes a drug-level assay, not a medication dose or a multi-drug panel.
How does Medicare pay for this test?
Medicare pays the test under the CLFS at one national amount across localities and settings. It is paid only from 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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