SCREENING FOR VON-WILLEBRAND-DISEASE WITH A NEW ANALYZER USING HIGH-SHEAR STRESS - A STUDY OF 60 CASES

We have evaluated the performance of a new analyzer using high shear s tress, the PFA-100 (Platelet Function Analyzer, Dade International, Ma ssy, France), for screening of patients with von Willebrand disease (v WD). Whole citrated blood is aspirated through a capillary to the cent ral aperture of a membrane coated with collagen and with a platelet ag onist (either epinephrine or adenosine diphosphate [ADP]). The time re quired to obtain occlusion of the aperture by a platelet plug is defin ed as the closure time (CT). We studied 60 patients with different typ es of vWD and 96 normal subjects. Fourteen subjects with hemophilia an d 15 patients with a platelet disorder were also analyzed. When omitti ng results from two patients with type 2N, the 58 other patients with type 1, type 2A, type 2B, type 3, or acquired vWD all exhibited an abn ormal occlusion with collagen-ADP (sensitivity, 100%) and 56 of 58 had an abnormal CT with collagen-epinephrine (sensitivity, 96.5%). Only t wo patients with mild type 1 were not detected with collagen-epinephri ne. In comparison, the bleeding time (BT) was normal in 20 patients: 1 7 with type 1, two with type 2A, and one with acquired vWD (sensitivit y, 65.5%). The specificity of the PFA-100 was over 95% with both types of cartridges. Thus, the analyzer Is well adapted to routine testing, as it has the advantages of simplicity and ease of execution, and dem onstrates a high sensitivity, clearly superior to that of BT, for the screening of patients with vWD. (C) 1998 by The American Society of He matology.