The diagnosis of TTP is suggested by Thrombocytopenia and anemia Fragmented red blood cells on the blood smear indicative of microangiopathic hemolysis (schistocytes: helmet cells, triangular RBCs, distorted-appearing RBCs) Evidence of hemolysis (falling hemoglobin level, polychromasia, elevated reticulocyte count, elevated serum LDH and bilirubin, reduced haptoglobin) Negative direct antiglobulin test Normal coagulation profile Testing for ADAMTS13 activity and autoantibody is appropriate in all patients with suspected TTP.