Comparison between the new XpertRifampicin (MTB/RIF) Ultra assay and Xpert MTB/RIF for diagnosis of extra-pulmonary tuberculosis in a tertiary care center.

UNLABELLED: Tuberculosis remains a significant global health challenge, with the re-emergence of(MTB) posing serious concerns, especially in its extra-pulmonary forms. Rapid and accurate diagnosis is crucial for effective management. This study evaluates the performance of the Xpert MTB/RIF Ultra assay compared with the Xpert MTB/RIF and traditional microscopy (Ziehl-Neelsen stain) in diagnosing extra-pulmonary tuberculosis (EPTB) in a tertiary care center in northern India. A total of 100 samples collected from September 2024 to February 2025 underwent testing using these methods. Our findings indicate that the Xpert MTB/RIF Ultra assay demonstrated superior sensitivity and reliability compared with the Xpert MTB/RIF, whereas microscopy was the least effective. This study is the first of its kind in India, highlighting the enhanced diagnostic capabilities of the Xpert MTB/RIF Ultra assay for EPTB.

IMPORTANCE: This is the first study to come out of India where the newly launched Xpert Ultra/RIF test has been used to detect Paucibacillary EPTB cases in comparison to the old Xpert MTB/RIF test.