SHOULD PLEURAL FLUID CBNAAT BE DONE TO ALL SUSPECTED CASES OF TUBERCULOUS PLEURITIS……?

Abstract

Introduction: Molecular tests are rapid and specific for mycobacteria but expansive and have lower sensitivity in pleural fluid because of paucibacillary nature of diseases. We did this study to analyse whether a molecular test should be done in all suspected cases of tubercular pleural effusion or the use of these tests should be restricted to the patients with diagnostic dilemma only.

Methods: Total 116 patients were enrolled for the study out of which thoracocentesis were performed in 104 patients and 63 patients were started on Anti-tubercular therapy on the basis of disease defining criteria. A total of 61 patients who showed either complete clinic radiological resolution at the end of therapy and/or microbiologically confirmed tuberculous effusions, were finally analysed.

Results: Out of these 61 patients, biochemical and cytological analysis of 31 (50.8%) effusions were conclusive while the remaining 30 (49.2%) had inconclusive analysis for tuberculosis. Among inconclusive effusion (30), seven were microbiologically confirmed for tuberculosis including four CBNAAT positive pleural fluids. In these four patients, one patient had sputum CBNAAT positive. That means only three patients were additionally added to tubercular pleural diffusion by exclusively pleural fluid CBNAAT. The sensitivity of CBNAAT was 15.25% in our study.

Conclusion: Pleural fluid CBNAAT should be done only in case of diagnostic dilemma, not as ‘always to do test’ for the diagnosis of tubercular pleural effusion.