Von Willebrand-Related Test Abnormalities

Differential Diagnosis

Low value for von Willebrand factor (vWF) and/or ristocetin cofactor (RCoF) or values in the low end of these normal ranges with a history of mild bleeding affecting males and females in the family suggest von Willebrand disease (vWD).

vWD could be type 1, 2A, 2B, 2M, 2N, or 3.

A person with blood type O who does not have vWD, since persons with blood type O have a mean vWF of only about 75% of normal.

Suggested Additional Lab Testing

RCoF, vWF, and factor VIII level (factor VIII level often decreases along with the other 2).

• In type 1 vWD, RCoF and vWF are suppressed approximately equally and mildly abnormal.

• In type 2, vWF is typically greater than or equal to 15% greater than RCoF, and the values for both are in the 20% range or lower.

• In type 3, both of these values approximate 0.

Fibrinogen is an important measurement, because it is an acute phase reactant.

• Fibrinogen elevation suggests that RCoF and vWF levels do not represent the patient's true baseline values and that a repeat test at a later time is necessary.

Obtain blood type: mean value for vWF varies with blood type.

VWF multimer analysis by agarose gel electrophoresis and Western blotting is useful when there is a high likelihood of non-type 1 vWD.

Desmopressin (DDAVP) stimulation test (except if the patient has type 2B or platelet type vWD) may be useful to determine if DDAVP can be used clinically to treat vWD.

• In the test, samples for RCoF and vWF are taken before DDAVP administration and then again 60 minutes after completion of a 30-minute infusion of DDAVP.