TABLE 1.

Acquired von Willebrand disease testing

	Initial	9 d later	24 wk later
Platelet count (per µL)	2 533 000	1 655 000	663 000
VWF antigen (%)	98%	70%	114%
VWF ristocetin cofactor (%)	36%	35%	70%
Factor VIII activity (%)	217%	154%	180%
High MW multimers (%)	9%	15%	18%
Intermediate MW multimers (%)	51%	52%	55%
Low MW multimers (%)	40%	33%	27%
VWF GPIbM activity (IU/dL) Reference 60‐184 IU/dL	NT	58	102%

Changes in VW testing over time, as platelet count decreased with increased hydroxyurea therapy.

Abbreviation: NT, not tested.