title: Clinical measurement of von Willebrand factor by fluorescence correlation spectroscopy.
abstract: BACKGROUND
  Identification of von Willebrand factor (vWF) abnormalities in a variety of conditions is hampered by the limitations of currently available diagnostic tests. Although direct multimer visualization by immunoelectrophoresis is a commonly used method, it is impractical as a routine clinical test. In this study, we used a biophysical analysis tool, fluorescence correlation spectroscopy (FCS), to measure vWF distributions. The goals were to develop a method that is quicker and simpler than vWF gel electrophoresis and to evaluate the potential of FCS as a clinical diagnostic technique.
  
  
  METHODS
  We analyzed plasma from 12 patients with type 1 von Willebrand disease (vWD), 14 patients with type 2 vWD, and 10 healthy controls using a fluctuation-based immunoassay approach.
  
  
  RESULTS
  FCS enabled identification and proper classification of type 1 and type 2 vWD, producing quantitative results that correspond to qualitative gel multimer patterns. FCS required minimal sample preparation and only a 5-min analysis time.
  
  
  CONCLUSIONS
  This study represents the first implementation of FCS for clinical diagnostics directly on human plasma. The technique shows potential for further vWF studies and as a generally applicable laboratory test method.
authors.affiliation: Department of Biomedical Engineering, Yale University and Yale School of Medicine, New Haven, CT, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Torres
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Genzen
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Levene
mesh_terms: D016022:Case-Control Studies; D006801:Humans; D007118:Immunoassay; D013050:Spectrometry, Fluorescence; D056725:von Willebrand Disease, Type 1 / Q000097:blood / Q000175:diagnosis*; D056728:von Willebrand Disease, Type 2 / Q000097:blood / Q000175:diagnosis*; D014841:von Willebrand Factor / Q000032:analysis*
chemical_list: D014841:von Willebrand Factor