High Resolution Multimer Analysis and the PFA-100 Platelet Function Analyser Can Detect Von Willebrand Disease Type 2A Without a Pathological Ratio of Ristocetin Cofactor Activity and Von Willebrand Antigen Level

摘要: BACKGROUND The biological variability of von Willebrand factor and the in assays can make diagnosis subclassification disease (VWD) difficult. We describe a case series four patients with typical history VWD prolonged closure time platelet function analyser (PFA-100) but initially normal ratio ristocetin cofactor activity (VWF:RCo) to antigen levels (VWF:Ag) for whom further diagnostics verified type 2A. METHODS For initial we measured VWF:Ag, VWF:RCo, aggregation induced by ADP, collagen, PFA-100 test, count. used VWF multimer analysis collagen binding capacity extended diagnostics. were carried out as part extensive laboratory screening exclude other haemostatic defects. RESULTS Multimer revealed absence ultralarge multimers all 4 patients. Ristocetin-induced was consistently diminished three hereditary 2A not patient essential thrombocythaemia. After repeat testing, VWF:RCo (VWF:CB) could be identified However, cases would have been missed if had performed only once. CONCLUSIONS A single measurement VWF:RCo/VWF:Ag does VWD. is suitable screening. To ensure that no are missed, functional testing aggregation, VWF:CB necessary.