Pulmonary embolism was diagnosed according to current recommendations [26] . Lung cancer was ruled out based on histology and/or cytology specimens. Congestive heart failure was diagnosed according to American Heart Association [27] , and interstitial lung disease according to American Thoracic Society guidelines [28] . All cases were evaluated by two clinicians blinded to TREM-1 and sTREM-1 results. Agreement about the diagnosis was achieved in all cases.