Value of Adenosine Deaminase in the diagnosis of tuberculous pleurisy at Tikur Anbessa specialized hospital, Addis Ababa, Ethiopia

Abstract

Objectives: Tuberculous (TB) pleurisy is a common form of extrapulmonary tuberculosis in high burden countries including Ethiopia. Adenosine deaminase (ADA) has been used in the early diagnosis of TB pleurisy. This study was designed to evaluate the diagnostic role of ADA in TB pleurisy at Tikur Anbessa Specialized Hospital (TASH). Materials and Methods: A cross-sectional hospital-based study was designed to evaluate the diagnostic value of ADA in consecutive adult patients with unexplained pleural effusions presenting to Chest Clinic at TASH from June 2016 to August 2018. All referred patients underwent thorough clinical and laboratory examinations including assessment of pleural fluid ADA, where a value of ≥40 IU/I was used to suggest TB pleurisy (per manufacturer’s recommendation). A final diagnosis of TB pleurisy was made based on pleural fluid Gene Xpert, AFB smear, pleural biopsy, and cytology results in addition to a clinical and radiologic response to anti-TB therapy. Results: A total of 67 patients were included in the study. The median age was 38.5(±14.5) years; 36 (53.7%) of the participants were males. TB pleurisy was confirmed in 38 (56.7%) subjects. The mean pleural fluid ADA levels was significantly higher in those with TB pleurisy as compared to those without TB pleurisy, 65.8 IU/l versus 28 IU/I (P < 0.05), respectively. Pleural fluid ADA had a sensitivity of 84% and specificity of 79%, resulting in a positive predictive value of 84.2%, a negative predictive value of 79.3%, and an overall test accuracy of 82% in our study population. Conclusion: In our study, pleural fluid ADA played a useful role in the diagnosis of TB pleurisy.