CALCA and ventilator-associated pneumonia: Among the studies that evaluated patients with VAP, Bloos et al. (2011) conducteda multicenter study and determined PCT levels in 175 critically ill patients onmechanical ventilation, of whom 57 presented CAP, 57 presented nosocomialpneumonia, and 61 presented VAP.(41) Notably, the initial PCT levels were higher in patientswith CAP than in those with VAP, with a median of 2.4 (0.95 - 15.8) versus 0.7(0.30-2.15) ng/mL (p < 0.001).