Evaluation of adenosine deaminase activity for the diagnosis of pleural TB in lymphocytic pleural effusions

To evaluate the diagnostic value of pleural adenosine deaminase (P-ADA) as a pleural TB-specific biomarker in lymphocytic pleural effusions. Materials & methods: Pleural effusions were classified on the basis of definitive diagnosis. Results: A total of 218 patients (122 tuberculous and 96 nontuberculous) were included in the study. The optimal cut-off value of P-ADA (receiver operating characteristic curve) for the diagnosis of pleural TB was 40.0 U/I (Giusti method). In lymphocytic pleural effusions P-ADA had a sensitivity of 80.3%, a specificity of 96.0% and an accuracy of 86.2%. The positive predictive value was 97.0% and the negative predictive value was 75.0%. The positive likelihood ratio and negative likelihood ratio were 19.8 and 0.2, respectively (p < 0.0001). Conclusion: P-ADA activity is recommended for the diagnosis of TB in lymphocytic pleural effusions.