Abbreviations APACHE II: Acute Physiology and Chronic Health Evaluation II; AUC: area under the curve; BAL: bronchoalveolar lavage; CAP: community acquired pneumonia; CI: confidence interval; GCP: Good Clinical Practice; GCS: Glasgow Coma Scale; HAP: hospital acquired pneumonia; ICU: intensive care unit; IQR: interquartile range; PCT: procalcitonin; PSI: pneumonia severity index; SD: standard deviation; SOFA: Sequential Organ Failure Assessment; ROC: receiver operating characteristic; VAP: ventilator associated pneumonia; WBC: white blood cell count.