Comparison of a new chemiluminescent immunoassay for von Willebrand factor activity with the ristocetin cofactor-induced platelet agglutination method

Abstract

Measuring von Willebrand factor (VWF) activity is essential for the diagnosis of von Willebrand disease (VWD). The VWF activity is usually assessed based on measurement of the ristocetin cofactor (VWF:RCo). However, that test is technically challenging and has high intra- and inter-assay variabilities. A new automated chemiluminescent immunoassay VWF activity has recently become commercially available (HemosIL AcuStar von Willebrand Factor Ristocetin Cofactor Activity). The main objective of this study was to evaluate this new method and to compare it with the VWF:RCo assay as the reference method. We studied 91 samples, 18 healthy volunteers samples and 73 samples from patients (VWF:RCo level <50 IU dL(-1) ): 29 type 1 VWD, 13 type 2A, 5 type 2B, 5 type 2M, 3 type 2N, 5 type 3, 4 type 3 under treatment, 5 type 3 carriers and 4 samples with other pathologies. The HemosIL AcuStar VWF:RCo assay was 96% sensitive and 100% specific for detecting VWF abnormalities. The good analytical performance, and the sensitivity and specificity of HemosIL AcuStar VWF:RCo to detect VWF deficiency renders it a suitable method for VWD screening.

An international collaborative study to compare different von Willebrand factor glycoprotein Ib binding activity assays: the COMPASS‐VWF study

“…As expected, and also reported by others, all of the new assays (i.e. VWF:GPIbR by the HemosIL latex agglutination assay and the HemosIL AcuStar assay , the VWF:GPIbM Siemens assay and the VWF:Ab assay ) performed well and yielded results close to the old reference standard VWF:RCo. Although statistically significant and consistent in all participating laboratories, the slightly steeper regression lines for the VWF:Ab and VWF:GPIbM were clinically insignificant.…”

The diagnosis and management of von Willebrand disease: a United Kingdom Haemophilia Centre Doctors Organization guideline approved by the British Committee for Standards in Haematology

“…Other approaches to automation have used a monoclonal antibody to link recombinant GPIb to latex beads (Lawrie, et al 2011, Lawrie, et al 2013) or magnetic particles (Cabrera, et al 2013). The use of a recombinant GPIb with gain-of-function mutations can remove the requirement for ristocetin (Flood, et al 2011, Lawrie, et al 2013).…”

Rapid discrimination of the phenotypic variants of von Willebrand disease

“…These assays have used chemiluminescense and turbidimetric detection. [37][38][39][40] This current VWF multiplex activity assay takes advantage of incorporating the VWF:GPIbM assay 13 and in this study was exclusively used to reflect VWF binding activity to GPIb in LDA and ROC analysis. Furthermore, in type 2B subjects, the VWF:GPIbM/VWF:Ag is significantly enhanced, 13 which confers benefit of this by discriminating type 2B VWD from all other variant VWD.…”