Factor VIII Activity, Clotting

Last Modified: 9/22/2021 2:46:21 PM

Medical Necessity Documentation:  
Client Notes:  
Patient Preparation:  
Specimen Requirements:

 1.0 mL Frozen Plasma from a Blue Top Tube - 3.2% Na Citrate in a Plastic Vial

Collection Instructions: Centrifuge light blue-top tube for 15 minutes at approximately 1500 g within 60 minutes of collection. Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet buffy layer and place into a plastic vial. Centrifuge a second time and transfer platelet-poor plasma into a new plastic vial. Plasma must be free of platelets (<10,000/mcL).
Minimum Volume: 0.5 mL platelet poor plasma
Transport & Storage: Temperature/Stability: Unacceptable Ambient
Unacceptable Refrigerated
30 days Frozen -20°C

Freeze immediately and ship on dry ice.

Note: Storage of whole blood at refrigerated temperatures prior to processing may lead to cryoprecipitate formation and falsely low Factor VIII and von Willebrand Factor studies.
Reference Range: 50% - 180% of normal
Critical Ranges:  
Test Comments: For patients receiving Hemilbra (aka emicizumab), the Factor VIII activity clotting method is not recommended. Hemilbra will cause falsely elevated Factor VIII activity values. A chromogenic Factor VIII Activity method is recommended.
Methodology: Clotting Detection
Clinical Significance: The most common form of hemophilia, Hemophilia A, is caused by a deficiency of Factor VIII. Hemophilia A is an X-linked disorder affecting between 1 in 5000 to 10000 males. Measurement of Factor VIII activity levels is used to classify Hemophilia A (mild, moderate or severe) and to assess response to treatment.
Custom Panel: No


Turn Around Time: 3 to 5 days
Days Performed: Monday, Tuesday, Wednesday, Thursday, Friday
Sites Performed: Quest - Chantilly
PHL Test Code: FACT8
EPIC Test Code: LAB306
Send Out Test Code: 347
Alternate Test Names: Anti-Hemophilia; Factor 8; Factor VIII Assay; Factor VIII Functional; Hemophilia A; Procoagulant Factor 8
Included Tests:  
CPT Coding: 85240

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