C3 and Sepsis: The early course, characterized by coagulopathy and bleeding, raised suspicion of disseminated intravascular coagulation [4], whereas marked leukocytosis and a urine culture positive for E. coli initially directed the investigation toward septic shock secondary to urinary tract sepsis [1]. After sepsis was ruled out by persistently negative cultures, and despite the lack of genetic tests to demonstrate complement system dysregulation, the presence of the TMA triad allied with C3 hypocomplementemia strongly supported a diagnosis of complement-mediated TMA [5].