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Coagulation

Coagulation laboratory tests

von Willebrand disease testing - general


Reviewer: Jeremy Parsons, M.D. (see Reviewers page)
Revised: 11 February 2013, last major update November 2012
Copyright: (c) 2002-2013, PathologyOutlines.com, Inc.

General
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● Often need to repeat tests because von Willebrand factor and factor VIII are elevated during acute phase reactions, pregnancy, estrogen use and in newborns - can measure fibrinogen (acute phase reactant) to determine if acute phase condition exists
Tests: von Willebrand factor antigen assay, von Willebrand factor activity (ristocetin cofactor activity), factor VIII levels, fibrinogen (or other acute phase reaction marker) or multimer analysis

Interpretation (Thromb Haemost 1994;71:520):
● All results normal (considering ABO blood type) - unlikely to have vWD if no acute phase reaction, pregnancy, estrogen use or newborn
● All results normal but elevated fibrinogen / factor VIII - acute phase reaction may mask abnormalities; repeat when fibrinogen and factor VIII levels are normal
● Reduced antigen, activity and factor VIII - likely type 1 vWD
● Severely reduced (< 10%) or undetectable antigen, activity and factor VIII - likely type 3 vWD
● Activity reduced more than antigen and factor VIII - possibly type 2 vWD; perform multimer analysis and low dose ristocetin cofactor
     ● Normal multimer analysis - likely type 2M vWD
     ● Missing high molecular weight multimers - likely type 2A vWD
     ● Missing high and intermediate molecular weight multimers - likely type 2B or platelet type vWD
     ● Increased low dose ristocetin aggregation - likely type 2B or platelet type vWD
     ● Normal or decreased low dose ristocetin aggregation - not type 2B or platelet type vWD
     ● Reduced factor VIII (5-40%), normal activity and activity - possibly type 2N vWD or in males, mild hemophilia A; also possibly factor VIII degradation due to processing delay

End of Coagulation > Coagulation laboratory tests > von Willebrand disease testing - general


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