[The diagnostic characteristics of von Willebrand's disease].

70 patients from 48 families were examined. Of them, 59 (84%) patients had type I Willebrand's disease (WD), 9 (13%) type II, 2 (3%) type III WD. Hemostasis was assessed by functional tests: APTT, FVIII activity, bleeding time, ristocetin-cofactor activity of plasma Willebrand factor (WF). The WF levels in plasma and platelets were measured on a Reader-210 Microwell system by enzyme immunoassay with 380 F2 monoclonal antibodies to human WF. The functional parameters in 65 patients in remission were within normal range in half the patients. The only objective diagnostic criterion of the patients inclusion into WB group was the level of WF in plasma, especially when patients with type I WD were examined. The level of WF was always low in patients of this group even in the presence of normal values of functional tests. The severity of WD course and definition of laboratory signs of the disease depended mainly on the involvement of platelet WF in pathological process. In patients with a decrease of both plasma and platelet WF the course of the diseases was most serious and laboratory data most shifted from normal.