Pleural effusion Still a Diagnostic Challenge

Objective; Pleural effusion is the most common manifestation of pleural disease. Biochemical examination of this fluid is usually done to try to identify the cause of a pleural effusion. Distinguishing whether the effusion is an exudates or transudates is the first step and is based on Light’s criteria. The aim of this study was comparing this pleural fluid categorization by using this criteria to the ultimate diagnosis of pleural disease. Patients and Methods; In a cross – sectional survey, we selected all patients with pleural fluid analysis, admitted in Alzahra University hospital. Then by light’s criteria we classified pleural fluid to Exudative and Transudate. The aim of this study was to review the help of this Scale and comparing to ultimate diagnosis. Result; In this survey we found 71(74.7%) Exudative pleural effusion and 24(25.3%) transudate pleural effusion. Pleural fluid LDH and protein were the best parameter for this classification. Pleural fluid glucose was a significantly higher in transudate fluids. Cloudy appearance of pleural fluid is also a helpful criteria for differentiating exudates from transudates. Conclusion; Light’s Criteria is still the cornerstone to classify pleural fluid to exudates and Transudates and bounding the different etiologies producing fluid in the pleural space. Additional parameter like PCR, cytology and histology and other new tests are needed to add for pleural fluid analysis to reach the ultimate diagnosis.