Adenosine deaminase activity in serum and pleural fluid of patients with tuberculosis and those without tuberculosis

Background Adenosine deaminase (ADA) has been considered as a marker for cell-mediated immunity. The purpose of this study is to evaluate the usefulness of ADA as a biomarker in diagnosis of pleural effusion in tuberculosis (TB). Patients and methods Forty patients from Abbasia Chest Hospital who were suspected to have exudative pleural effusion and prepared for pleural biopsy were enrolled in the study. ADA in pleural fluid and serum was measured for all of them, and then data were reported and analyzed. Results Of the 40 patients included in the study, most of the 20 patients with TB pleurisy were diagnosed mainly by thoracoscope (16/20), whereas the rest four cases were diagnosed by sonar-guided biopsy. The other 20 patients, diagnosed as non-TB pleural effusion (6/20), mesothelioma (8/20), pneumonia, and adenocarcinoma (6/ 20). There were significant statistical difference between both groups regarding age, total leukocyte count, erythrocyte sedimentation rate, and tuberculin skin test, whereas no significant association regarding sex, clinical presentation, and radiological finding within any groups. ADA in effusion, serum, and index had a significant statistical difference between the two groups, with cutoff point value in effusion and serum of similar to 31.4 and 29.5 U/l, respectively, and 1.1 for the index, with sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of similar to 100, 90, 90, 100, and 95%, respectively, for ADA in effusion and serum, whereas for the index of similar to 80, 65, 69, 76, and 73%, respectively. Conclusion Serum and pleural fluid ADA level significantly increases in patients with TB pleural effusion than non-TB pleural effusion with higher sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in prediction.