Diagnostic and therapeutic algorithm in TMAs. Role of eculizumab in the treatment of secondary aHUS (cancer-, chemotherapy-, solid-organ transplant- or HSCT-, pregnancy-, or autoimmune disorder-associated) have not been established and is out of the scope of this study. *In patients with anti-FH antibody, immunosuppressive reagents (steroid, rituximab, cyclophosphamide, and azathioprine) should be added to eculizumab. ELISA, enzyme-linked immunosorbent assay; LDH, lactate dehydrogenase; PCR, polymerase chain reaction.