CPT code 0667U: FGF21 assay, quantitative serum or plasma2026 Medicare lab fee · Clinical Laboratory Fee Schedule
0667U reports quantitative serum or plasma FGF21 by ELISA for determining an inborn error of metabolism associated with primary mitochondrial disease.
Medicare has no national amount for 0667U: it’s on the 2026 Clinical Laboratory Fee Schedule as contractor-priced, so each Medicare Administrative Contractor sets the payment.
Medicare lab fee · CLFS 2026 Q4
Contractor-priced (CLFS indicator L)
Set by your MAC
CMS lists 0667U on the Clinical Laboratory Fee Schedule without a national amount: each Medicare Administrative Contractor prices it for its jurisdiction.
- National amount
- None
- Priced by
- Each MAC
- Fee schedule
- Clinical lab
- CMS updates
- Quarterly
The contractor that processes the claim sets the amount for its jurisdiction. Patients usually owe no Part B deductible or coinsurance for covered clinical lab tests.
On this page 7 sections
What 0667U covers
0667U identifies a proprietary laboratory analysis that measures fibroblast growth factor 21 (FGF21) concentration by enzyme-linked immunosorbent assay (ELISA). The specimen is serum or plasma, and the reported result is quantitative. The analysis determines an inborn error of metabolism in the context of primary mitochondrial disease. This describes the specific FGF21 assay rather than general quantitative immunoassay testing.
Report 0667U for this analysis and its quantitative result. Medicare pays the code under the Clinical Laboratory Fee Schedule (CLFS). The code is locally priced, with each Medicare Administrative Contractor setting the payment, and it was added to the CLFS effective October 1, 2026. The code has no physician fee schedule payment row 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 0667U
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.
Priced by each contractor
0667U carries CLFS indicator L: CMS publishes no national amount, and each Medicare Administrative Contractor sets the payment for its jurisdiction. Ask your MAC for its current amount.
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.
Not on the physician fee schedule
The physician fee schedule doesn’t list 0667U: Medicare pays the test only from the CLFS.
0667U compared with similar tests
- 83520Quantitative immunoassayNot otherwise specified$17.27
- 83520 is a general quantitative immunoassay code. 0667U identifies the specific quantitative FGF21 ELISA analysis.
- 83516ImmunoassayMultiple-step, qualitative or semiquantitative$11.53
- 83516 describes a qualitative or semiquantitative immunoassay; 0667U represents a quantitative FGF21 result.
0667U billing questions
What specimen does 0667U use?
The assay measures FGF21 in serum or plasma.
When is 0667U used instead of 83520?
0667U identifies the specified quantitative FGF21 ELISA analysis. CPT 83520 is a general quantitative immunoassay code; distinguish the codes by the service performed.
Does 0667U report a quantitative or qualitative result?
0667U represents a quantitative FGF21 result.
How does Medicare pay 0667U?
Medicare pays it under the CLFS using local pricing set by each Medicare Administrative Contractor.
Is 0667U paid under the physician fee schedule?
No. The code is paid 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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