Approach to VWD initial diagnosis

Diagnosis of VWD includes both clinical and laboratory features. The evaluation first determines whether VWD is present (as illustrated here) and then determines the subtype, which has implications for management (refer to separate algorithm in UpToDate). Screening may be performed by the primary clinician or hematologist. Secondary testing is generally done by the consulting hematologist or clinician with expertise in diagnosing VWD.

VWD: von Willebrand disease; VWF: von Willebrand factor; ELISA: enzyme-linked immunosorbent assay; GPIb: glycoprotein Ib; HMW: high molecular weight.
* "VWF Levels" includes VWF antigen (VWF:Ag) and/or VWF activity (VWF:Act). Concordant reductions in VWF:Ag and VWF:Act suggest type 1 VWD, or, if both are undetectable or extremely low, type 3 VWD; discordant reductions (VWF:Act lower than VWF:Ag) suggest type 2A, type 2B, or type 2M VWD.
¶ Factor VIII activity can be low in VWD because VWF is a carrier for factor VIII. Factor VIII activity is typically low-normal or moderately decreased in type 1, 2A, 2B, and 2M VWD. Factor VIII activity can be low in type 2N and type 3; in these cases, it is important to distinguish between VWD and mild hemophilia A using VWF levels, and, for type 2N, using additional testing listed in the box above.
Δ Individuals with 30 to 50% VWF levels require repeat testing, especially after recovery from an acute stress or after estrogen exposure (estrogen-containing contraceptives or pregnancy). Diagnosis of VWD in individuals with VWF levels of 30 to 50% is based on the bleeding history.
◊ A VWF:Ag to factor VIII activity ratio >3 is expected; if this does not occur, initial VWD screening should be repeated.

Graphic 131037 Version 2.0

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Approach to VWD initial diagnosis