The interaction of VWF and GP1b alpha. The GP1b receptor on the surface of platelets allows the platelet to bind to VWF, which is exposed upon damage to vasculature. The VWF A1 domain (yellow) interacts with the extracellular domain of GP1ba (blue).

Current guidelines agree that Type 2 VWD should be diagnosed when there is a significant discrepancy between VWF functional assays (e.g. VWF:RCo, VWF:CB, VWF:Gp1bR, Gp1bM or FVIII:C) compared to plasma VWF:Ag levels.

The Gp Ib functions as a receptor for von Willebrand factor (VWF). The complete receptor complex includes noncovalent association of the alpha and beta subunits with platelet glycoprotein IX and platelet glycoprotein V to form the glycoprotein Ib-IX-V complex .

In addition to assessment of von Willebrand factor (VWF) antigen (VWF:Ag), the first-line laboratory investigation of possible von Willebrand disease (VWD) often includes an assay to measure GPIb (glycoprotein Ib) binding activity of VWF.

VWF GPIbM Activity is a ristocetin-independent activity assay and is an alternative to VWF Ristocetin Cofactor Activity with superior precision and sensitivity. USA test status: This is a laboratory developed test (LDT).

Order in conjunction with von Willebrand Factor Antigen and Factor VIII, Activity as part of initial workup for suspected von Willebrand disease (VWD). Also useful for monitoring treatment in patients with VWD.

Feb 20, 2023 · Unfolded vWF multimers form long bundles that anchor to subendothelial collagen and expose binding sites for nearby platelets. The A1 domain of vWF interacts with platelet GP1b receptors to initiate platelet aggregation and activation, which leads to …

Nov 20, 2009 · The initial adhesion of platelets to sites of vascular injury in large part involves binding of the VWF A1 domain to the platelet glycoprotein receptor GPIb alpha. This VWF A1-GPIb alpha interaction, along with deficiency of the ADAMTS13 plasma metalloprotease, is thought to be required for the pathogenesis of TTP.

This test is used for quantitative determination of the von Willebrand factor-GPIb activity and can be used as an aid in the evaluation of patients with suspected or confirmed von Willebrand factor disorders.

VA ECMO patients have severely impaired platelet function, which improved but did not normalize with VWF concentrate. The data suggest that GP1bα receptor loss of dysfunction also contributes to impaired platelet adhesion and aggregation during ECMO.