Ristocetinum for analysis of von Willebrand factor: Do we actually need it?

Abstract

Ristocetinum – cofactor analysis (R:Co) is the main method for estimation of von Willebrand factor activity at diagnostic
of Willebrand diseases (WD). Nevertheless, this analysis is distinct with bad reproducibility and low sensibility at low rates of
FWV and it is considerably time-consuming. In this paper, Lawrie and coauthor have evaluated the productivity of new immuno-turbidimetric analysis to define activity of FWV (INNOVANCE® VWF Ac., Siemens Healthcare Diagnostics, Marburg,
Germany). In this analysis ristocetinum and thrombocytes are not use and changed with fragment of recombinant glycoprotein of thrombocytes lb (GPlb) with affectedly impregnate mutations ameliorative fixation FWV and GPlp.
There were use 50 standard control samples, blood samples of 80 WD patients and 50 with erythrocatalysis, icterus and
hiperlipoidemia evidences which were compared with data of classic FWV:RCo test, rest on thrombocytes. Results correlation of FWV:RCo was satisfactory as well as calculated quotient of FWV:Ac and FWV:RCo to FWV:Aг. Nonetheless, detection limit of FWV:Ac was lower than FWV:RCo (3cl/lg and 5cl/lg) properly.
Authors reason that new analysis is sure and more sensitive than FWV:RCo at low concentration of FWV. Analysis is
simple and less difficult for carrying out at unspecialized laboratories.