Relying on schistocyte presence as the single diagnostic criterion would lead to missed diagnosis in 23.8% (STEC-HUS) to 86.4% (BMT) of patients (for anemia: 8.2%–22.3%; thrombocytopenia: 31.8%–67.9%; high LDH: 10.0%–40.7%, low haptoglobin: 0%–70.4%, according to the causes of TMA). The gene discussed is HP; the disease is hemolytic-uremic syndrome.