In the present study, we assessed the diagnostic value of usual biological parameters (schistocytes, LDH, haptoglobin, anemia, and thrombocytopenia) for the diagnostic of TMA in 967 unselected patients who had a TMA from all causes proven by renal biopsy and biological results at the time of biopsy from 25 French hospital centers. The gene discussed is HP; the disease is anemia (phenotype).