An automated von Willebrand factor (VWF) assay called HemosIL VWF is shown to be effective for the screening of type 1 von Willebrand disease (VWD), a bleeding disorder similar to hemophilia.

The HemosIL VWF assay had a sensitivity of 94.7% and specificity of 80.0% for the detection of type 1 VWD, according to a study published in the International Journal of General Medicine.

HemosIL VWF and the current standard VWD diagnostic assay—the von Willebrand factor ristocetin cofactor (VWF:RCo) activity functional assay—were shown to be highly correlated, with a correlation coefficient of 0.874. In addition, the area under the receiver operator characteristic (ROC) curve was larger for HemosIL compared to VWF:RCo (0.928 vs 0.863, P =.0138).

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“Our results demonstrate that the HemosIL VWF activity assay was an effective method for type 1 VWD screening and diagnosis,” the study’s authors said. “With its advantages of greater speed and automated performance, these results suggest that the HemosIL VWF activity assay was reliable and precise in the clinical setting.”

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The authors mentioned that the VWF:RCo assay is labor-intensive, time-consuming, and can sometimes have variable results between clinical laboratories due to differences in the experience of laboratory technicians. The HemosIL VWF assay is automated, which makes it faster, less labor dependent, and possibly more accurate, according to the article.

In the study, a total of 38 patients with type 1 VWD and 70 participants without VWD were recruited. Platelet poor plasma samples were obtained using 9 parts of freshly drawn venous blood for all participants and were subsequently used during analysis.

The HemosIL VWF assay is fully automated with VWF:RCo and utilizes latex particles coated with a monoclonal anti-VWF antibody that targets the glycoprotein Ib receptor binding portion of the VWF molecule. The latex molecules agglutinate, causing increased turbidity of the samples that can be measured automatically with a coagulation analyzer.


Lai S-W, Chang C-Y, Cheng S-N, Hu S-H, Lai C-Y, Chen Y-C. A comparative evaluation of an automated functional assay for Von Willebrand factor activity in type 1 Von Willebrand disease. Int J Gen Med. 2021;14:5167-5174. doi:10.2147/IJGM.S321605