Performance Evaluation of INNOVANCE^® VWF Ac Assay employing recombinant glycoprotein Ib mutant

Abstract

The measurement of von Willebrand factor (VWF) activity and antigen (Ag) are required to diagnose von Willebrand disease (VWD). In Japan, ristocetin cofactor activity of VWF (VWF:RCo) has been used in a clinical setting. INNOVANCE^® VWF Ac Assay is based on latex immunoagglutination and measures VWF:GPIbM activity, which employ recombinant glycoprotein Ib carrying two gain-of-function mutation. However, it has not been introduced in Japan yet. Here, we evaluated the performance of INNOVANCE^® VWF Ac Assay in CS-5100 autoanalyzer. The results showed that within-run and between-day precision were the CVs of <3% and <2%, respectively. We observed a good dilution linearity and a superior limit of detection compared with VWF:RCo. The VWF:GPIbM assay was not affected by interference substances such as bilirubin, hemolytic hemoglobin and chyle, and also by unfractionated heparin (<10 IU/mL). The correlations of VWF:GPIbM versus VWF:RCo or VWF:Ag were excellent in normal plasma. In plasma from patients with VWD, VWF:GPIbM activity was also correlated with VWF:RCo. Taken together, INNOVANCE^® VWF Ac Assay showed a remarkable performance and it would be expected the future introduction in Japan.