Alkaline phosphatase: Distinguishing between tuberculous and nontuberculous pleural effusion.

OBJECTIVES: To evaluate the value of pleural fluid alkaline phosphatase and pleural fluid/serum alkaline phosphatase ratio for the purpose of differentiating tuberculous from nontuberculous pleural effusion. MATERIALS AND METHODS: A total of 60 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 60 patients were divided into two groups: Tuberculous (30) and nontuberculous (30) pleural effusion. RESULTS: The mean pleural alkaline phosphatase and pleural fluid/serum alkaline phosphatase ratio was significantly higher in tuberculous compared to nontuberculous pleural effusion. (P < 0.0001). In receiver operating characteristic curve analysis, sensitivity and specificity values were 90% and 80% for a cut-off value of 71 IU/L for pleural alkaline phosphatase activity; and were 90% and 86.66% for a cut-off value of 0.51 for pleural fluid/serum alkaline phosphatase ratio. CONCLUSION: From this study it is concluded that alkaline phosphatase activity remains a useful test in differentiation of tuberculous from nontuberculous pleural effusion.

Diagnostic value of adenosine deaminase to differentiate exudates and transudates.

The differentiation of pleural effusions as exudates or transudates is the first step in the diagnosis of pleural effusions. The aim of this study was to evaluate the value of adenosine deaminase (ADA) concentration in the pleural effusions for differentiating exudates from transudates. Sixty indoor patients, admitted to our hospital, having pleural effusions and suffering from varying etiologies were included in this study. According to the final diagnosis, these 60 patients were divided into two groups: exudates (50) and transudates (10). The mean pleural ADA, serum ADA and pleural fluid/serum ADA ratio were significantly (P < 0.0001) higher in exudates as compared to transudates. Using a cut-off point of 22 IU/L, the sensitivity and specificity of pleural ADA in the diagnosis of exudates was computed to be 90% and 90% respectively. At a cut-off point 1.28, pleural fluid/serum ADA ratio was found to have sensitivity 84% and specificity 90%, respectively. From this study it is concluded that, ADA is a useful biochemical marker to suggest exudative effusions.