CPT code 83525: Insulin assay, total insulin2026 Medicare lab fee · Clinical Laboratory Fee Schedule
Measures total insulin for evaluation of unexplained hypoglycemia, suspected excess insulin, or other concerns involving insulin secretion and glucose regulation.
Medicare pays $11.43 for 83525 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
$11.43
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 83525 covers
Total insulin testing measures insulin and is used in evaluating unexplained hypoglycemia or suspected excess insulin. Clinicians may also order it to assess insulin secretion. Results are interpreted alongside glucose and other clinical findings. Code 83525 identifies a total-insulin measurement, while 83527 identifies free-insulin testing. Clinical laboratories perform and report the assay, commonly in outpatient testing.
Report 83525 for the total-insulin assay performed. Medicare pays the test only through the CLFS; the 2026 national amount is $11.43, unchanged since 2020. The same national amount applies in every locality, with no office-versus-facility payment difference. The physician fee schedule excludes the test by statute. Separately performed glucose or C-peptide assays are reported under their own codes when also ordered and performed.
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 83525
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 83525. 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 83525 with status X (excluded by statute), so the test itself is paid only from the CLFS.
83525 on the lab fee schedule since 2020
83525 · CLFS 2026 Q4 (current)
$11.43
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.
83525 compared with similar tests
- 83527Insulin assayFree fraction$12.95
- Choose 83525 for total insulin and 83527 for free insulin. The distinction is the insulin fraction measured.
- 84681C-peptideEndogenous insulin marker$20.81
- 84681 reports a C-peptide assay, not an insulin measurement. It may be performed alongside 83525 as a distinct test.
- 82947Blood glucoseQuantitative, not reagent strip$3.93
- 82947 reports a glucose assay. It measures blood glucose rather than insulin and is coded separately when performed.
83525 billing questions
How does 83525 differ from 83527?
83525 identifies total-insulin testing, while 83527 identifies free-insulin testing.
Is 83525 the code for a glucose test?
No. It reports total insulin. A glucose assay is reported separately, such as with 82947 when that assay is performed.
Can a C-peptide assay be reported with 83525?
Yes, when both assays are performed. C-peptide is a separate measurement reported with 84681.
What should the record support?
Document the clinical reason for testing and that the assay measured total insulin. Results are commonly considered alongside glucose and other clinical findings.
How does Medicare pay for 83525?
Medicare pays 83525 through the CLFS only, at one national amount across localities. The physician fee schedule excludes the test by statute.
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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