title: Comparison of von Willebrand factor (VWF) activity levels determined by HemosIL AcuStar assay and HemosIL LIA assay with ristocetin cofactor assay by aggregometry.
abstract: BACKGROUND
  Diagnosis of von Willebrand disease (VWD) requires quantitative as well as qualitative determination of von Willebrand factor (VWF) levels. For functional assessment of VWF, ristocetin cofactor assay by aggregometry is considered to be the gold standard. However, need for technical expertise, labour intensiveness, difficult standardization and high intra- and inter- assay variabilities are some of the limitations of this methodology. Various assays for determination of VWF adhesive function using different methodologies have been developed in recent years.
  
  
  OBJECTIVE
  To evaluate the HemosIL AcuStar chemiluminescence assay (VWF:RCo[Acu]) and the HemosIL latex immunoassay (VWF:act) as diagnostic tests for VWD and identification of type 2 VWD in comparison with the ristocetin cofactor assay performed by aggregometry (VWF:RCo[Agg]).
  
  
  METHODS
  Results from 96 samples analysed by VWF:RCo[Acu] and 128 samples by VWF:act were compared with VWF:RCo[Agg]. Sixty of these samples (25 normal, 17 type 1 and 18 type 2) were analysed by all three assays.
  
  
  RESULTS
  VWF:RCo[Acu] showed excellent agreement with VWF:RCo[Agg], and readily identified all type 2 VWD samples tested. VWF:act showed reasonable agreement with VWF:RCo[Agg] for most patients, but had a slightly lower sensitivity for detection of type 2 VWD.
  
  
  CONCLUSIONS
  VWF:RCo[Acu] assay has the potential to replace VWF:RCo[Agg] for the diagnosis of VWD.
authors.affiliation: Haematology Division, SA Pathology, Adelaide, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Sagheer
authors.affiliation: Haematology Division, SA Pathology, Adelaide, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Rodgers
authors.affiliation: Haematology Division, SA Pathology, Adelaide, Australia.
authors.forename: O
authors.initials: O
authors.lastname: Yacoub
authors.affiliation: Haematology Department, The Alfred, Prahan, Australia.
authors.forename: R
authors.initials: R
authors.lastname: Dauer
authors.affiliation: Haematology Division, SA Pathology, Adelaide, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Mcrae
authors.affiliation: Haematology Division, SA Pathology, Adelaide, Australia.
authors.forename: E
authors.initials: E
authors.lastname: Duncan
mesh_terms: D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008163:Luminescent Measurements / Q000379:methods*; D008863:Microspheres; D010949:Plasma / Q000737:chemistry*; D012015:Reference Standards; D015203:Reproducibility of Results; D012310:Ristocetin / Q000032:analysis*; D012680:Sensitivity and Specificity; D014842:von Willebrand Diseases / Q000175:diagnosis*; D014841:von Willebrand Factor / Q000032:analysis*
chemical_list: D014841:von Willebrand Factor; D012310:Ristocetin
keywords: AcuStar; HemosIL LIA assay; chemiluminescence; ristocetin cofactor; von Willebrand disease; von Willebrand factor