Anti‐ADAMTS13 autoantibodies in immune‐mediated thrombotic thrombocytopenic purpura do not hamper ELISA‐based quantification of ADAMTS13 antigen

Background The biological diagnosis of immune-mediated thrombotic thrombocytopenic purpura (iTTP) is based on determination of ADAMTS13 activity (<10%) and anti-ADAMTS13 autoantibodies. ADAMTS13 antigen levels are not routinely measured in iTTP patients, but studies have shown that antigen levels are a valuable prognostic factor. Objectives To (a) report the validation of our in-house developed ADAMTS13 antigen enzyme-linked immunosorbent assay...