The recommendation is for diagnostic fluid sampling via thoracentesis in all patients with pleural effusions with greater than 2 cm depth on lateral decubitus film or computed tomography, associated with a pneumonic illness, recent chest trauma, surgery or features of ongoing sepsis.[12][13] Frank pus in the pleural space invariably necessitates surgical drainage. However, if there is uncertainty whether a turbid fluid is infected, a pH less than 7.2 measured via a blood gas analyzer warrants an invasive procedure for drainage.[14] Polymorphonucleocyte predominance, low glucose, and LDH over 1000 on biochemical analysis of pleural fluid support the diagnosis of empyema. Furthermore, fluid culture data should be used to guide appropriate antimicrobial therapy. Research shows that culture yield can be increased significantly if the pleural fluid gets injected into blood culture bottles immediately after aspiration