Factor VIII Activity Assay  Email this article           Printer friendly page

Primary Name Factor VIII Assay
Synonym Factor VIII functional assay
Synonym Factor VIII activity assay
Contraction FVIII
Contraction FVIII:C
UAB Procedure Number 2500480
CPT Code 85240
Specimen Collect one (1) blue-stopper tube (3.2% sodium citrate), filled to specified volume. Do not underfill or overfill.

Specimen Management Note time of collection and time of last treatment if applicable. Centrifuge blue-stopper tube within one (1) hour of collection, separate plasma and test or quick-freeze at -70°C.
Specimen Accepted Daily including weekends
Test Performed Monday-Friday.
Available Stat? Pathologist approval required.
Description Congenital factor VIII deficiency, termed hemophilia A, is inherited as a sex-linked recessive and is seen in 1 in 5000 males. Factor VIII deficiency is also seen in some cases of von Willebrand disease.

Rare inhibitors (autoantibodies) cause acquired factor VIII deficiency, usually in adults. Factor VIII deficiency is associated with mild to severe bleeding.

Chronic elevated factor VIII confers a 2- to 3-fold risk of venous thrombosis. Because factor VIII is an acute phase reactant, a single elevated result may not alone indicate a risk of thrombosis.

Reference Interval 50-186%
Critical Value None
Follow-up Test *If von Willebrand disease is suspected, the ristocetin cofactor (vWF activity) and von Willebrand factor antigen assays are recommended. *If an anti-VIII inhibitor is suspected, an inhibitor titer (Bethesda titer) is recommended
Associated With Bleeding disorders
Associated With Venous thrombosis
Associated With Von Willebrand disease
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