Factor VIII Activity, Clotting

Overview

  • EPIC Code:
  • LAB306
  • Soft Test Code:
  • FACT8
  • Send Out Test Code:
  • 347
Alternate Names
  • Anti-Hemophilia
  • Factor 8
  • Factor VIII Assay
  • Factor VIII Functional
  • Hemophilia A
  • Procoagulant Factor 8
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.


Specimen Collection & Preparation

Specimen Requirements

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


Transport And Storage

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.


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


Neonatal Volume

Clinical Interpretation

Reference Range:

50% - 180% of normal


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:
  • Clot 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.


Production Schedule

Sites Performed
  • Quest - Chantilly
Days Performed
Monday
Tuesday
Wednesday
Thursday
Friday
Departments
  • Sendouts - Clinical
Turn Around Time

3 to 5 days


Coding & Compliance

CDM

01453628


CPT Coding

85240