CPT code 84305: IGF-1 test, somatomedin C2026 Medicare lab fee · Clinical Laboratory Fee Schedule
Measures somatomedin C, or IGF-1, to support evaluation of growth disorders and suspected growth hormone excess or deficiency.
Medicare pays $21.26 for 84305 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
$21.26
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 84305 covers
This blood test measures somatomedin C, commonly called insulin-like growth factor 1 (IGF-1), a growth factor produced largely in response to growth hormone. Clinicians use it when evaluating children with unusually slow or accelerated growth and adults with suspected growth hormone excess or deficiency. Because IGF-1 levels are more stable than episodic growth hormone secretion, the result can support assessment of the growth hormone axis. Endocrinologists and other clinicians order the test, and clinical laboratories commonly perform it on serum.
Report 84305 when the laboratory measures somatomedin; a growth hormone assay measures a different analyte. Medicare pays this test only under the Clinical Laboratory Fee Schedule (CLFS). The 2026 national CLFS amount is $21.26, unchanged since 2020. The same amount applies across localities, with no office or facility payment difference. 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 84305
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 84305. 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 84305 with status X (excluded by statute), so the test itself is paid only from the CLFS.
84305 on the lab fee schedule since 2020
84305 · CLFS 2026 Q4 (current)
$21.26
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.
84305 compared with similar tests
84305 billing questions
When should I report 84305 instead of a growth hormone assay?
Report 84305 when the laboratory measures somatomedin C (IGF-1). A growth hormone assay measures growth hormone itself, so the choice depends on which analyte was tested.
Is 84305 the same test as somatostatin?
No. Somatomedin C is IGF-1; somatostatin is a different analyte reported with 84307.
What specimen is commonly used for 84305?
Clinical laboratories commonly perform the assay on serum.
Does Medicare pay a different amount by locality or setting?
No. Medicare uses one national CLFS amount across localities, with no office or 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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