ADAMTS13 and thrombotic thrombocytopenic purpura: These large vWF multimers may be seen in serum from patients with TTP due to decreased levels of ADAMTS-13, which causes an increased platelet adhesion along with those vWF multimers, leading to severe thrombocytopenia and microangiopathic hemolytic anemia associated with side effects in vital organs [2-4].