title: Von Willebrand Disease Lab Diagnosis.
abstract: The hemorrhagic diseases are characterized by bleeding which can vary considerably according to their severity. The von Willebrand disease (VWD) is the most frequent hereditary hemorrhagic disease and the prevalence of clinically significant disease is probably closer to 1:1000, being an extremely heterogeneous and complex disorder that is related to the deficiency in concentration, structure or function of von Willebrand factor (VWF). The VWD is divided into type 1, with partial deficiency of the VWF, type 2, with qualitative defects in the molecule with four subdivisions, and type 3, with very low or undetectable levels of plasma and platelet VWF and ristocetin cofactor activity. The laboratory diagnosis of VWD is complex. Specific tests that assess the functionality and concentrations of the VWF and FVIII are needed. The routine tests are the bleeding time, the activated partial thromboplastin time and the platelet count, however, singly, they may not suggest the diagnosis of VWD, requiring further specific tests, such as VWF function evaluation through its ristocetin cofactor assay (VWF:RCo), VWF protein concentration immunoassay (VWF:Ag), the factor VIII coagulation assay (
  C), VWF binding to immobilized collagen (VWF:CB), ristocetin-induced platelet aggregation (RIPA), VWF multimers patterns, factor VIII binding of immobilized VWF (VWF:FVIIIB), among others. From the moment the diagnosis is confirmed, the appropriate treatment for each patient is sought, with the purpose of increasing plasma concentrations of the deficient protein, both in bleeding episodes, as for invasive procedures. Although diagnosis facilitates treatment other approach in the present scenario is prenatal diagnosis which, is the need of the hour.
authors.affiliation: Undergraduated in Pharmacy by the Higher Education Center Campos Gerais (CESCAGE), Ponta Grossa, PR Brazil.
authors.forename: Francine Charan
authors.initials: FC
authors.lastname: de Faria
authors.affiliation: Department of Clinical Analysis, Federal University of Parana, Curitiba, PR Brazil.
authors.forename: Railson
authors.initials: R
authors.lastname: Henneberg
authors.affiliation: Department of Clinical Analysis, Federal University of Parana, Curitiba, PR Brazil.
authors.forename: Aguinaldo José
authors.initials: AJ
authors.lastname: do Nascimento
authors.affiliation: Health and Biosciences School, Pontifical Catholic University of Parana, Curitiba, PR Brazil.
authors.forename: Karen Sumire
authors.initials: KS
authors.lastname: Kubo
authors.affiliation: Health and Biosciences School, Pontifical Catholic University of Parana, Curitiba, PR Brazil.
authors.forename: Henrique Ravanhol
authors.initials: HR
authors.lastname: Frigeri
authors.affiliation: Department of Clinical Analysis, Federal University of Parana, Curitiba, PR Brazil.
authors.forename: Paulo Henrique
authors.initials: PH
authors.lastname: da Silva
keywords: Platelet aggregation; Platelet count; Ristocetin cofactor; Von Willebrand disease; Von Willebrand factor