DIAGNOSTIC YIELD OF ADA IN TUBERCULAR PLEURAL EFFUSION

Abstract

Objective: Tuberculosis (TB) is one of the most common causes of pleural effusion in developing countries like India encountered by medical professionals globally. The present study was carried out to evaluate the diagnostic yield of pleural fluid adenosine deaminase (ADA) in tubercular pleural effusion. Methods: This descriptive study was conducted in the Department of Medicine and Pulmonary Medicine, Saheed Laxman Naik Medical College and Hospital from January 1, 2019, to March 31, 2020. All patients >15 years of age with lymphocytic exudative pleural effusion and pleural effusion associated with smear/CBNAAT-positive pulmonary TB patients, who attended the department during the study period, were included in the study. A case was taken as tuberculous employing defined criteria. Patients with transudative effusions, post-traumatic effusions, pregnant and lactating women, and persons on drugs that affect ADA activity like interferon alpha, deoxycoformycin, ribavirin, and viramidine were excluded from the study. Results: The mean ADA value was 93.93±44.63 IU/L among the cases with tuberculous effusion and 56.36±62.81 IU/L in the non-tuberculous effusion group. At a cutoff value of 50.7 IU/L, pleural fluid ADA showed a sensitivity of 87% and a specificity of 74% in diagnosing TB etiology. Conclusion: The mean ADA values were significantly higher in tuberculous pleural effusions when compared to the non-tuberculous group. When this was combined with pleural fluid lymphocyte dominancy, the specificity increased to 96%. Pleural fluid ADA values have a strong association with age. ADA estimation is a simple, cost-efficient, and diagnostically helpful investigation with high reliability.