Subsequently, the ADAMTS13 assay results showed zero activities (0%) and markedly high level of ADAMTS13 inhibitor, 93.15 U/mL (negative < 12 U/mL; borderline 12–15 U/mL; positive > 15 U/mL) confirming the diagnosis of secondary TTP. This evidence concerns the gene ADAMTS13 and thrombotic thrombocytopenic purpura.