CPT code 85670: Thrombin time, fibrinogen screening2026 Medicare lab fee · Clinical Laboratory Fee Schedule
Measures how quickly plasma clots after thrombin is added, helping evaluate fibrinogen-related abnormalities or an unexplained prolonged clotting time.
Medicare pays $5.77 for 85670 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
$5.77
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 85670 covers
The thrombin time assay adds thrombin to plasma and measures the time to clot. It assesses the final step of clot formation, in which fibrinogen is converted to fibrin. Laboratories typically perform it on citrated plasma as part of an evaluation of a prolonged clotting time, suspected fibrinogen abnormality, or possible anticoagulant effect. Hospital and independent laboratories report the result to the ordering clinician, often alongside other coagulation studies.
Report 85670 for the plasma thrombin time screening assay; it is distinct from a thrombin time titer. Medicare pays it only through the CLFS. The 2026 national CLFS amount is $5.77, unchanged each year from 2020 through 2026. The same amount applies across states and localities, without geographic adjustment or an office-versus-facility difference. The test is excluded from the physician fee schedule, so payment is through the CLFS rather than a separate physician-fee-schedule payment.
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 85670
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 85670. 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 85670 with status X (excluded by statute), so the test itself is paid only from the CLFS.
85670 on the lab fee schedule since 2020
85670 · CLFS 2026 Q4 (current)
$5.77
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.
85670 compared with similar tests
- 85675Thrombin timeTiter for fibrinogen screening$6.85
- 85670 reports the plasma thrombin time screening assay; 85675 is the distinct thrombin time titer test.
- 85635Reptilase testFibrin-forming step$9.85
- 85635 measures clotting with reptilase, a different reagent. It may help distinguish causes of an abnormal thrombin time.
- 85610Prothrombin timeRoutine coagulation test$4.29
- 85610 measures prothrombin time, not the thrombin-driven conversion of fibrinogen to fibrin assessed by 85670.
- 85730Partial thromboplastin timePTT, plasma or whole blood$6.01
- 85730 is the partial thromboplastin time assay; it evaluates a different coagulation test endpoint from thrombin time.
85670 billing questions
When is 85670 chosen instead of a prothrombin time?
Use 85670 for a thrombin-initiated plasma clotting assay that evaluates the fibrinogen-to-fibrin step. Prothrombin time (85610) evaluates a different part of the coagulation pathway.
How does 85670 differ from the thrombin time titer?
85670 is the plasma thrombin time screening test. Code 85675 identifies a thrombin time titer, a distinct assay rather than another unit of the screening test.
How does a reptilase test relate to 85670?
Reptilase time (85635) uses a different clotting reagent and may be used in evaluating an abnormal thrombin time.
Is 85670 commonly reported with other coagulation tests?
It may be ordered alongside prothrombin time (85610) or partial thromboplastin time (85730) during a coagulation evaluation. Each code represents a different assay.
How does Medicare pay for 85670?
Medicare pays 85670 through the CLFS at one national amount that applies across localities and settings. The test has no separate physician-fee-schedule payment.
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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