Optimising Pulmonary Tuberculosis Detection: A Comparative Study of Modern and Traditional Diagnostic Methods In A Tertiary Healthcare Centre of Telangana

Abstract

Background: Tuberculosis (TB) has afflicted humanity for millennia. In 1882, Robert Koch identified Mycobacterium tuberculosis as the causative agent. Despite this early discovery, TB remains a major global health challenge, largely due to inadequate case detection. Early and accurate diagnosis is critical for timely treatment and effective TB control.

Methods: This study compared the diagnostic performance of smear microscopy, Cartridge-Based Nucleic Acid Amplification Test (CBNAAT/GeneXpert), and Truenat in detecting pulmonary TB. A total of 2,875 patients were screened over two years (2022–2024). Of these, 196 were clinically and radiologically suspected of TB, and CBNAAT microbiologically confirmed 123.

Results: Among the 123 CBNAAT-positive cases, 71 were men and 52 were women. The highest prevalence (21%) was seen in the 21–30 and 51–60-year age groups, followed by 19% in the 31–40-year group. Of the 82 Truenat-negative samples, nine were CBNAAT-positive, while CBNAAT confirmed all 114 Truenat-positive cases. Among 93 AFB smear-negative samples, 21 were CBNAAT-positive, and 102 AFB smear-positive samples were also CBNAAT-positive. Using CBNAAT as the gold standard, Ziehl-Neelsen (ZN) staining demonstrated 82.93% sensitivity, 98.63% specificity, 99.03% positive predictive value (PPV), 77.42% negative predictive value (NPV), and 88.78% accuracy. In contrast, Truenat exhibited 92.68% sensitivity, 100% specificity, 100% PPV, 89.02% NPV, and 95.41% accuracy.

Conclusion: Truenat outperformed ZN staining in diagnostic accuracy and reliability for pulmonary TB detection. Integrating molecular diagnostics such as Truenat and CBNAAT with conventional microscopy within a unified diagnostic algorithm can enhance TB case detection and improve differentiation of Mycobacterium tuberculosis from non-tuberculous mycobacteria. Such an approach will be vital in strengthening TB control strategies and advancing toward the goal of ending TB by 2035.