How are specimens collected for a von Willebrand factor ristocetin cofactor (vWF:RCo) assay?

Updated: Feb 12, 2020
  • Author: Vadim Kostousov, MD; Chief Editor: Eric B Staros, MD  more...
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Collection and panel details are as follows:

  • Specimen - Citrated plasma

  • Collection - Tube with sodium citrate 3.2% citrate, blue top

  • Centrifugation - 2000-2500 g for 15 minutes or similar regime to produce platelet poor plasma

  • Storage - As long as 6 hours at 18-25ºC or plasma sample should be frozen; specimen stable for 1 month at -20ºC (Whole blood after collection should not be stored at refrigerator temperature [2-4ºC] due to cold-induced binding of vWF to platelets and selective loss of vWF:RCo activity in plasma. [3] )

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