Moreover, interferences in the assay measuring ADAMTS13 can occur from a high concentration of von Willebrand factor (vWF), hyperlipidemia, hemolysis with plasma free Hb > 2 g/L, and hyperbilirubinemia, and cleavage by other proteases can even complicate identification of TTP [3]. This evidence concerns the gene VWF and thrombotic thrombocytopenic purpura.