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Test Code LAB14969 CHROMOGENIC FACTOR VIII

Important Note

This chromogenic substrate assay (CSA) is useful for measuring a patient's endogenous factor VIII activity.  It is not impacted by the bi-specific monoclonal antibody therapy emicizumab (Hemlibra). 

This assay is NOT recommended for patients on Altuviiio/(antihemophilic factor (recombinant), Fc-VWF-XTEN fusion protein-ehtl).  Altuviiio will cause FVIII levels to be overestimated in this chromogenic assay.  Instead, order the Factor VIII assay (silica one-stage clotting assay (OSA) for patients on Altuviiio.

Recommendations suggest using both the OSA (factor VIII) and CSA (chromogenic factor VIII) methods for the initial diagnostic investigation of Hemophilia A or where there is a clinical suspicion of Hemophilia A and yet the clotting test is normal (e.g. helpful to diagnose "Discrepant Hemophilia A").

Must be drawn at the ACC if the specimen cannot be run or processed and frozen within 2 hours of collection.

Additional Codes

Orderable Codes:

Epic Code Atlas Code Mayo Access ID Order LOINC
LAB14969 LAB14969 FAH5939 49865-9

Result Component(s):

Reporting Name Epic Code Atlas Code Mayo Access ID Result LOINC
Chromogenic Factor VIII 12301012044 CHROM8R FAH5940 49865-9

Specimen Information

Container Specimen Temperature Collect Vol Submit Vol Min Vol Stability
*Blue Top Tube Plasma Frozen To fill line 1 mL 0.5 mL 6 months
3.5 mL Blue Top Whole Blood Ambient To fill line To fill line To fill line 2 hours
2 mL Blue Top Whole Blood Ambient To fill line To fill line To fill line 2 hours

*Preferred specimen type

Refer to Coagulation Specimen Handling before collecting. Submit 2 × 0.5 mL frozen plasma aliquots for this test. Draw blood in light blue top tube(s). Spin down, remove plasma, spin plasma again, and place citrate platelet-poor plasma in required number of plastic vials (Glass vials cannot be accepted.)  Freeze specimen at less than or equal to minus 40° C, if possible. Send specimen frozen on dry ice. Each coagulation assay  requested should have its own vial.

Test Schedule / Analytical Time / Test Priority

Monday – Friday / 1 day / NOT available STAT

Method

Chromogenic Substrate Assay

Instrumentation

ACL TOP

Reference Range

≥ 18 years:  43.2 – 159.3%

CPT(s)

Description CPT Code
Chromogenic Assay Coagulation Test          85130

 

Section

Coagulation

Performing Location

University of Vermont Medical Center

Is the UVMMC lab NY State Certified to perform this testing?  Yes/No

Yes