Abstract
Background: Pulmonary tuberculosis (PTB) remains one of the most pressing issues of the population in high-burden areas and requires accurate and timely diagnosis which is the key to proper disease control. Mycobacterial culture is considered the diagnostic gold standard.
Materials and Methods: This cross-sectional study of diagnostic accuracy was done in, Tertiary Hospital, Punjab, Pakistan from 2025 to 2026. Adults between age 18 and 75 years with clinical suspicion of PTB were consecutively recruited through a non-probability method. Each of the enrolled subjects gave three early-morning sputum samples, which were analyzed using the auramine-O fluorescent smear microscopy, GeneXpert MTB/RIF assay, and Lowenstein-Jensen mycobacterial culture, which was used as a control.
Results: Among 208 participants, 2 (1.1%) were culture-positive for Mycobacterium tuberculosis. The GeneXpert MTB/RIF assay detected both culture-positive cases and has a sensitivity of 100% and a specificity of 100 %. Fluorescent smear microscopy did not show any culture-positive people, which gives the zero sensitivity and 100% specificity. The GeneXpert assay resulted in the area of the ROC curve of 0.515, which is slightly higher than the one of fluorescent smear microscopy (0.473), which suggests a slightly better discriminative ability.
Conclusion: The GeneXpert MTB/RIF assay has a high sensitivity compared to fluorescent smear microscopy, even though the culture-confirmed PTB is not very prevalent, and it still has a high specificity. These findings support the use of GeneXpert MTB/RIF as a more plausible diagnostic modality in high-burden environments.