The study by Kitanovski et al. (2006) [11] demonstrated PCT’s robust early performance (Day 1 AUC = 0.832, sensitivity = 93.8%, NPV = 97.3% at >0.55 μg/L) for bacteremia/clinical sepsis, with accuracy improving to AUC = 0.906 by Day 3. The gene discussed is CALCA; the disease is bacterial infectious disease with sepsis.