Factor VIII Activity
| Profile or Test Panel |
Intrinsic Factor Evaluation Profile
Bleeding Diathesis with a Normal APTT/PT Profile
Factor VIII Inhibitor Profile
VWD Profile
If the APTT is prolonged and the factor VIII is normal, this panel reflexes to an APTT Reflexive Evaluation Profile.
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| Method | Clottable |
| Test Information | 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 Range 54-152%, effective 3/1/12 |
| Sample Requirements | Whole Blood: 3.2% Sodium Citrated (blue top) OR Frozen Plasma |
| Requested Volume | 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. |
| Sample Information | 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. |
| Shipping Information | Whole Blood: Send at ambient temperature (18-25C) and must be received within the lab in less than or equal to 3 hours after collection. Frozen Plasma: send on dry iceSend samples to:Bloodworks Northwest Attn: Hemostasis Laboratory 921 Terry Ave Seattle, WA 98104 For additional information, please see Ordering Information |
| Requisition Form | RFT- Hemostasis Reference Laboratory |
| Transaction Code | 3210-13 |
| CPT Codes | 85240 |
| Test Schedule | Monday – Friday |
| Turn around Time (analytic time) | 3 business days; available STAT (5 business days when ordered with VWD panel) |
| Report/ Results | Fax number required to receive report |