Collagen Binding Assay

vWF Collagen Binding Activity

13 days

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Test Includes:
Collagen-binding ratio, vWF antigen, vWF collagen-binding activity

Causes for Rejection:
Lipemia; icteric specimen; hemolysis; clotted specimen; specimen contaminated with heparin (i.e., drawn with blood gases)

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This test is used to screen for the presence of type II von Willebrand disease in plasma.

Plasma

2 mL

Blue top (sodium citrate) 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.

Collection Instructions
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 unless the sample is collected using a winged (butterfly) collection system. With a winged blood collection set, a discard tube should be drawn first to account for the dead space of the tubing and prevent under-filling of the evacuated tube. 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 alternative 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.