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Von Willebrand Disease (VWD)
Part 2: NHLBI Diagnosis Guidelines

Laboratory Recommendations



Expected Laboratory Values in VWD1

Slide 13

May 2011

This Figure from the NHLBI VWD Guidelines illustrates patterns of expected or prototypical laboratory test results in different types of VWD.

The column on the left identifies various VWD-related laboratory tests, including the 3 initial tests (circled). Persons with type 1 VWD have relatively concordant but variably reduced levels of VWF antigen and VWF ristocetin cofactor activity, and factor VIII may sometimes be reduced (usually, but not always to a lesser degree than VWF reduction).

Types 2A, 2B and 2M VWD are characterized by discordantly low VWF ristocetin cofactor activity relative to VWF antigen, and multimer analysis shows loss of high molecular weight multimers in Types 2A and 2B VWD (but no substantive reduction of high molecular weight multimers in type 2M VWD). RIPA (ristocetin-induced platelet aggregometry) using low dose ristocetin (LD-RIPA) is abnormal (present) in Type 2B VWD and platelet-type VWD, both of which often manifest thrombocytopenia, and which demonstrate loss of high molecular weight multimers. Type 2N VWD is characterized by substantially decreased factor VIII, relative to VWF antigen and VWF ristocetin cofactor activity (which are often normal unless a concomitant type 1 VWD gene is present). Supplemental reference laboratory testing can identify abnormally low VWF-factor VIII binding and/or causative VWF gene mutations. Type 3 VWD is characterized by the virtual absence of VWF, and factor VIII is secondarily decreased (to 1 to 9 IU/dL). Although the bleeding time (BT) and/or PFA-100 (platelet function analyzer) test results are often abnormal in patients with VWD, these tests lack sensitivity and specificity for VWD, and are not recommended for routine evaluation.

Expected Laboratory Values in VWD1

 


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