Diagnostically useful pleural fluid characteristics
| Fluid | Suspected disease |
| Putrid odour | Anaerobic empyema |
| Food particles | Oesophageal rupture |
| Bile stained | Cholothorax (biliary fistula) |
| Milky | Chylothorax/pseudochylothorax |
| ‘Anchovy sauce’ like fluid | Ruptured amoebic abscess |