Abstract
Background: Tuberculosis is a common cause of pleural effusion, especially in developing countries. ADA and interferon-gamma release assay (IGRA) as diagnostic markers for tuberculosis have been studied but studies with comparative analysis of these markers are scarce especially from developing countries, where burden of tuberculosis is enormous.
Aims and objectives: To compare the efficacy of pleural fluid ADA and IGRA to diagnose tubercular pleural effusion and to differentiate between tubercular and non-tubercular exudative pleural effusion.
Material and methods: Ninety patients, 45 each with tubercular and non-tubercular etiology, with exudative pleural effusion were included in the study, after informed consent. Pleural fluid of all subjects was tested for ADA and IGRA, along with routine pleural fluid analysis. The sensitivity, specificity, negative and positive predictive values (NPV, PPV) of these markers to diagnose tubercular etiology was calculated. The study bears approval from Institutional Ethics Committee.
Results: Sensitivity/specificity/PPV/NPV for ADA (Using a cut off of 40 U/L), IGRA (using a cut off 200 pg/ml) and for combination of these two was 88.89/99.85/86.96/99.87, 97.78/97.78/97.78/97.78 and 99.78/84.78/86.27/97.50 respectively.
Conclusion: Pleural fluid ADA and IGRA have comparable efficacy in diagnosing tubercular pleural effusion. Combining ADA and IGRA improves the sensitivity. Although sensitivity and PPV of IGRA were found to be better than ADA, but considering the cost effectiveness of ADA, in resource poor countries, ADA is more suitable for this purpose.
- Copyright ©ERS 2015
