Stratmann et al. compared the AcuStar® ADAMTS13 activity assay and Technozym® ADAMTS13 activity ELISA on 24 paired citrated plasma samples; these were derived from ten consecutively recruited patients (n = 8, acquired TTP; n = 1, atypical haemolytic uremic syndrome; n = 1, normal control), of which nine test samples were collected from acute TTP patients and 13 samples were collected from TTP patients in clinical remission [19]. This evidence concerns the gene ADAMTS13 and thrombotic thrombocytopenic purpura.