Differentiating features of chylothorax and pseudochylothorax
| Parameter | Chylothorax | Pseudochylothorax |
| Pleural fluid triglyceride level, mg·dL–1 | >110 | <50 |
| Pleural fluid cholesterol, mg·dL–1 | <200 | >200 |
| Chylomicrons in the pleural fluid | Present | Absent |
| Cholesterol crystals in the pleural fluid | Not seen | Often seen |
| Ratio of pleural fluid triglyceride to serum triglyceride | >1 | <1 |
| Ratio of pleural fluid cholesterol to serum cholesterol | <1 | >1 |
| Ratio of pleural fluid cholesterol to pleural fluid triglyceride | <1 | >1 |
| Persistence of turbidity on addition of ethyl ether | Yes | No |