Factor VIII Activity (One Stage)
|A one-stage intrinsic system clotting assay is used to measure circulating factor VIII levels. Clotting times of dilutions of patient plasma are compared to dilutions of a plasma pool from normal donors, when added to deficient plasma. Levels are reduced by hereditary (Hemophilia A) or acquired factor VIII deficiency, factor VIII inhibitors, von Willebrand disease, or disseminated intravascular coagulation (DIC). Levels may also be reduced in female carriers of Hemophilia A. Since factor VIII is an acute phase reactant, levels are elevated by stress, inflammation, surgery, exercise, pregnancy, or estrogen therapy.
|Additional Test Information
|Normal ranges are included on testing report and can be made available upon request.
|Whole Blood: 3.2% sodium citrated (blue top) OR
|Two 5 ml 3.2% sodium citrated (blue top) tubes as whole blood OR
Frozen plasma in 4 X 1mL aliquots in plastic tubes
|Minimum Volume or Pediatric Volume
|Frozen Plasma: at least 0.5ml in 2 plastic tubes.
|Whole blood is preferred for testing, but if it is not possible to send whole blood tubes TO ARRIVE HERE WITHIN 2 HOURS of collection, then send frozen plasma. To prepare plasma centrifuge blue top tubes at 1500g for 15 minutes and remove the plasma and centrifuge a second time at 1500g for an additional 15 minutes. Aliquot approximately 1 ml of plasma into 4 plastic tubes, and freeze.
|Whole Blood: Send at ambient temperature (18-25°C) and must be received within the lab in less than or equal to 2 hours after collection.
Frozen Plasma: Send on dry ice.
Send samples to:
For additional information, please see Ordering Information
|RFT- Hemostasis Reference Laboratory
|Monday – Friday
|Turn around Time (analytic time)
|3 Business Days
|Fax number required to receive report