Factor VIII Antigen

FVIII Quantitation (Nonfunctional)

11 days

Enzyme-linked immunosorbent assay (ELISA)

Special Instructions:
If the patient's hematocrit exceeds 55%, the volume of citrate in the collection tube must be adjusted. Refer to Coagulation Collection Procedures for directions.

Causes for Rejection
Ideally, the patient should not be on anticoagulant therapy. Avoid warfarin (Coumadin®) therapy for two weeks prior to the test and heparin, direct Xa and thrombin inhibitor therapies for about three days prior to testing.

Accredited Laboratory Partner

Contact Technical Support

The test is used for the measurement of the amount of factor VIII protein (not activity) of factor VIII to identify individuals that are cross-reacting material (CRM)-positive.

Plasma

1 mL

Blue stopper 3.2% sodium citrate plasma evacuated tube

No special preparation is required for this test. You may eat, drink, and take your medications as normal, unless instructed otherwise by your healthcare provider. Do not draw from an arm with a heparin lock or heparinized catheter.

Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate. Evacuated collection tubes must be filled to completion to ensure a proper blood to anticoagulant ratio. The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. A discard tube is not required prior to collection of coagulation samples. When noncitrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes. Any tube containing an alternate anticoagulant should be collected after the blue-top tube. Gel-barrier tubes and serum tubes with clot initiators should also be collected after the citrate tubes. Centrifuge and carefully remove the plasma using a plastic transfer pipette, being careful not to disturb the cells. Transfer the plasma into a Labcorp PP transpak frozen purple tube with screw cap (Labcorp No. 49482). Freeze immediately and maintain frozen until tested. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.