A significantly positive correlation was found between PCT levels and community versus nosocomial acquired CDI (8.9 and 1.1 ng/ml, respectively, p = 0.0345) and with mortality at 30 days compared with patients who remained alive (11.2 and 0.6 ng/ml, respectively, p = 0.0002). The gene discussed is CALCA; the disease is clostridium difficile infection.