Table 2.

Tests indicated based on the appearance of the pleural effusion [1]

Appearance of fluid	Test indicated	Interpretation
Cloudy or turbid Turbid supernatant	Centrifugation Triglyceride levels	Turbid supernatant → high lipid levels >110 mg/dL → chylothorax >50 mg/dL but ≤110 mg/dL → obtain lipoprotein analysis Presence of chylomicrons → chylothorax ≤50 mg/dL and cholesterol >250 mg/dL → pseudochylothorax
Bloody	Hematocrit	<1% → non-significant 1–20% → cancer, pulmonary embolism, trauma >50% of peripheral hematocrit: hemothorax
Putrid odor	Stain and culture	Infection