At its best cut-off value of 7.9 pg/ml, IL-1β performance for VAP diagnosis resulted in 81.5% sensitivity (95% CI 61.9–93.7), 50.0% specificity (95% CI 27.2–72.8), 68.8% positive predictive value (95% CI 50.0–83.9), and 66.7% negative predictive value (95% CI 38.4–88.2). This evidence concerns the gene IL1B and ventilator-associated pneumonia.