Q: Pleural fluid eosinophilia (PFE) is defined as? 

 A) pleural fluid consist of more than 10 percent eosinophils and mostly exudative
 B) pleural fluid consist of more than 10 percent eosinophils and mostly transudative
 C) pleural fluid consist of more than 20 percent eosinophils and mostly exudative
 D) pleural fluid consist of more than 20 percent eosinophils and mostly transudative
 E) pleural fluid consist of more than 25 percent eosinophils and can be either transudative or exudative


Answer: B

 Pleural fluid eosinophilia (PFE) is precisely defined as pleural fluid with a nucleated cell count containing more than 10 percent eosinophils. Only about 10 percent of exudative pleural effusions are eosinophilic.


References:

1. Kalomenidis I, Light RW. Eosinophilic pleural effusions. Curr Opin Pulm Med 2003; 9:254.

2. Martínez-García MA, Cases-Viedma E, Cordero-Rodríguez PJ, et al. Diagnostic utility of eosinophils in the pleural fluid. Eur Respir J 2000; 15:166.