CPT code 85612: Viper venom time, undiluted assay2026 Medicare lab fee · Clinical Laboratory Fee Schedule
An undiluted Russell viper venom clotting assay assesses factor X and is reported when this specific coagulation test is performed.
Medicare pays $17.49 for 85612 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
$17.49
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 85612 covers
Code 85612 identifies an undiluted Russell viper venom time, a clotting-factor X assessment performed with venom reagent. It is distinct from the diluted Russell viper venom assay and the routine prothrombin time. The undiluted and diluted assays may be used together in a specialized lupus anticoagulant evaluation; report the assay condition actually performed. Clinical laboratories perform and report this coagulation test.
Report 85612 when the undiluted assay is performed; use 85613 for the diluted assay. Medicare pays this test through the CLFS at one national amount in every state and locality, with no geographic or office/facility adjustment. The 2026 national CLFS amount is $17.49, unchanged since 2020. The test is excluded from the physician fee schedule 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 85612
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 85612. 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 85612 with status X (excluded by statute), so the test itself is paid only from the CLFS.
85612 on the lab fee schedule since 2020
85612 · CLFS 2026 Q4 (current)
$17.49
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.
85612 compared with similar tests
- 85613Viper venom testDiluted clotting assay$9.58
- 85613 is for the diluted Russell viper venom assay; 85612 is for the undiluted assay.
- 85610Prothrombin timeRoutine coagulation test$4.29
- 85610 is the routine prothrombin time. Code 85612 identifies the undiluted Russell viper venom time.
- 85670Thrombin timeFibrinogen screening$5.77
- 85670 is a thrombin time test. Code 85612 identifies the undiluted Russell viper venom time.
85612 billing questions
How does 85612 differ from 85613?
85612 is the undiluted Russell viper venom assay. Use 85613 for the diluted assay.
Is 85612 the same as a routine prothrombin time?
No. Code 85610 reports a routine prothrombin time; 85612 identifies an undiluted Russell viper venom time.
Can 85612 be part of a lupus anticoagulant workup?
The undiluted assay may be used alongside 85613 in a specialized lupus anticoagulant evaluation. Report the assay actually performed.
Is modifier 26 used for 85612?
No. 85612 is paid only through the CLFS and is excluded from the physician fee schedule.
How does Medicare pay for 85612?
Medicare pays one national CLFS amount per code, without locality or office-versus-facility adjustment. The test is excluded from the physician fee schedule.
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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