Comparison between newer diagnostic approaches against current diagnostic approach in diagnosing pulmonary tuberculosis in Hospital Al-Sultan Abdullah UiTM / Siti Noraisyah Othman

Introduction
A wide spectrum of laboratory techniques has been developed to diagnose tuberculosis (TB). This study compares the performances of light microscopy (Kinyoun stain), fluorescence microscopy (Auramine stain), and molecular (Xpert MTB/RIF Ultra), against the gold standard method of culture (Mycobacteria Growth Indicator Tube, MGIT) in diagnosing pulmonary TB.
Materials and methods
This study is a single-centre, prospective, cross-sectional study conducted at Hospital Al­ Sultan Abdullah (HASA) UiTM in Malaysia, from June 2021 to May 2022. A total of 109 respiratory samples from patients clinically suspected of pulmonary TB which fulfilled inclusion and exclusion criteria were tested with microscopic, molecular and culture methods.
Results
MGIT culture and sensitivity result were used as reference standard. Sensitivity and specificity for AFB detection by Xpert MTB/RIF Ultra, light microscopy and fluorescent microscopy were 93.8% and 92.5%, 56.3% and 98.9% as well as 37.5% and 98.9%, respectively. Sensitivity and specificity ofMTB detection by Xpert MTB/RIF Ultra were 93.8% and 92.5%, whereas those for rifampicin-resistant detection by Xpert MTB/RIF Ultra were 100% and 100%.
Conclusion
For AFB detection, Xpert MTB/RIF Ultra (94%) sensitivity was far superior than both light (56%) and fluorescent (38%) microscopic methods. However, the specificity for all three methods were fairly comparable, at 99% for both microscopic methods but at slightly lower 93% for molecular method. Sensitivity and specificity of Xpert MTB/RIF Ultra for MTB detection and rifampicin-resistant detection, were above 90% and 100%, respectively.