Objectives:To evaluate the value of pleural fluid aspartate transaminaseand pleural fluid/serum aspartate transaminaseratio for the purpose of differentiating exudate from transudate pleural effusion.

Materials and Methods:A total of 100 indoor patients, admitted to our hospital, having pleural effusion and suffering from varying etiologies, were included in this study. According to the final diagnosis, these 100 patients were divided into two groups: exudate (60) and transudate (40) pleural effusion.

Results:The mean serum AST level in exudates and transudates are 34.25 ± 2.55 IU/L and 43.92 ± 4.86 IU/Lrespectively and they are statistically insignificant (p = 0.083). The mean pleural AST level in exudates and transudates are 28.98 ± 2.37 IU/L and 28.80 ± 1.93 IU/Lrespectively and they are statistically insignificant (p=0.952)

Conclusion:From this study it is concluded that aspartate transaminaseactivityhaving no significant value for differentiation of exudate from transudate pleural effusion.