Evaluation of a new droplet digital PCR for diagnosis of pulmonary tuberculosis and tuberculous pleurisy.

INTRODUCTION

Digital droplet PCR (ddPCR) offers high sensitivity and absolute quantification without standard curves, making it promising for tuberculosis (TB) detection in paucibacillary samples. This study evaluated the diagnostic performance of a ddPCR assay targeting IS6110 and 23S rRNA for pulmonary tuberculosis (PTB) and tuberculous pleurisy (TP).

METHODS

A total of 436 patients (245 suspected PTB, 191 suspected TP) were prospectively enrolled. ddPCR was performed on sputum, bronchoalveolar lavage fluid, and pleural effusion samples. Diagnostic performance was compared with Xpert MTB/RIF and culture.

RESULTS

In suspected PTB, ddPCR showed significantly higher sensitivity than Xpert (49.70% vs. 38.10%, p < 0.001), while Xpert showed higher specificity (98.65% vs. 87.70%). In suspected TP, ddPCR also demonstrated superior sensitivity (17.54% vs. 10.40%, p < 0.001). For NTM detection, ddPCR achieved 60% sensitivity and 99.58% specificity.

DISCUSSION: ddPCR offers improved sensitivity for PTB and TP diagnosis, particularly in paucibacillary cases, though its lower specificity necessitates confirmatory testing. The dual-target design enables simultaneous MTB/NTM differentiation, providing clinical utility for guiding appropriate therapy.