The diagnostic value of cholesterol in the differentiation of exudative and transudative pleural effusion

Background and Pleural effusion is a common finding in many pulmonary or extrapulmonary diseases and its analysis is essential for differentiating transudates from exudates. Light's criteria is questioned by some researchers and measuring of cholesterol in pleural effusion is proposed due to its simplicity and low cost. This study evaluates the diagnostic value of pleural fluid cholesterol for differentiating transudates from exudates. In this prospective study, 70 cases of pleural effusion with definite diagnosis according to clinical gold standards were included and cholestrol, LDH and protein in pleural effusion and simultaneous in blood serum were measured. Pleural cholesterol alone, and its ratio with serum cholesterol, pleural-LDH and its ratio with, serum-LDH, pleural protein and its ratio with serum protein, combination of pleural Cholestrol + LDH were compared with Light,s criteria. Sensitivity and specificity of pleural cholesterol was 85% and 100%, respectively with 90% efficiency, pleural/serum cholesterol showed a sensitivity of 87%, specificity of 95%, with 90% efficiency. Lights,s criteria gave a sensitivity of 87%, specificity 79%, with 91% efficiency. Combination of Pleural + pleural/serum cholesterol showed sensitivity of 87%, specificity of 100%, with 90% efficiency and for Pleural-LDH + pleural-cholesterol sensitivity, specificity and efficiency were 97%, 83% and 92% respectively. The use of pleural fluid cholesterol is useful as Light,s criteria for distinguishing pleural transudates from exudates but not superior. Combination of pleural fluid cholesterol and LDH slightly improves the specifity and efficiency of differentiation. The advantage of cholesterol measuring is its simplicity, low price and that it can be used along with routine diagnostic pleural effusion tests.