CPT code 85384: Fibrinogen test, functional activity2026 Medicare lab fee · Clinical Laboratory Fee Schedule
Measures functional fibrinogen in plasma to evaluate low fibrinogen or impaired clot formation in bleeding and coagulation disorders.
Medicare pays $9.72 for 85384 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
$9.72
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 85384 covers
This test measures fibrinogen’s functional contribution to clot formation. It is commonly ordered when evaluating bleeding, suspected disseminated intravascular coagulation, liver disease, or another condition that may reduce fibrinogen or impair coagulation. The test is generally performed on citrated plasma in a hospital, reference, or independent clinical laboratory and may be part of a broader coagulation evaluation.
Report 85384 for the fibrinogen activity assay performed. Medicare pays it through the CLFS, with one national amount applying in every locality and no office-versus-facility difference. The 2026 national CLFS amount is $9.72, unchanged from 2020 through 2026. The code is paid only through the CLFS, not 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 85384
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 85384. 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 85384 with status X (excluded by statute), so the test itself is paid only from the CLFS.
85384 on the lab fee schedule since 2020
85384 · CLFS 2026 Q4 (current)
$9.72
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.
85384 compared with similar tests
- 85385Fibrinogen antigenAntigen, not activity$14.46
- 85384 assesses fibrinogen function in clot formation; 85385 measures fibrinogen antigen.
- 85379D-dimerQuantitative assay$10.18
- 85379 measures fibrin degradation products quantitatively. It does not measure fibrinogen activity.
- 85380D-dimerQualitative or semiquantitative$10.18
- 85380 is the D-dimer test, used to detect a fibrin breakdown marker; 85384 evaluates fibrinogen’s clot-forming function.
85384 billing questions
When should 85384 be used instead of 85385?
Use 85384 for functional fibrinogen activity. Code 85385 measures fibrinogen antigen, which assesses the amount of the protein rather than its clot-forming function.
Does 85384 measure fibrinogen degradation products?
No. It measures fibrinogen activity. Codes such as 85379 or 85380 are used for fibrin degradation products or D-dimer testing, respectively.
Does the numerical fibrinogen result change the code?
No. Code 85384 identifies measurement of fibrinogen activity; the reported result does not change the code selection.
Is a physician interpretation separately payable with 85384?
The test is paid only through the CLFS. The physician fee schedule lists no separate payment for this code.
Does Medicare payment vary by locality or place of service?
No. Medicare applies one national CLFS amount in every locality, with no office-versus-facility 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
Fee sheets · Coming soon
Put 85384 and the rest of your codes on one sheet
Your codes at your locality, with payer contracts beside Medicare.
Join the waitlist