Patients with levels of ADAMTS13 ≥ 10% and no antibody against ADAMTS13, are unlikely to respond to such therapies, and should be assessed for other causes of anemia and thrombocytopenia, including disseminated intravascular coagulation, sepsis, occult cancer with hypercoagulability and migratory thrombophlebitis (Trousseau syndrome), preeclampsia, systemic sclerosis, systemic lupus erythematosus, accelerated hypertension, and acute renal allograft rejection.