DIAGNOSTIC ACCURACY OF STOOL XPERT MTB/ RIF FOR THE DIAGNOSIS OF PULMONARY TUBERCULOSIS IN CHILDREN'S LESS THAN 15 YEARS OF AGE KEEPING GASTRIC ASPIRATE/SPUTUM XPERT MTB/RIF AS GOLD STANDARD

Background: Childhood tuberculosis (TB) is poorly diagnosed because of the challenges in getting sputum samples and the paucibacillary nature of the disease. Xpert MTB/RIF based on stool has developed as an alternative non-invasive method of diagnosis. Objective: To determine diagnostic accuracy of stool xpert MTB/ RIF for the diagnosis of tuberculosis in children's less than 15 years of age keeping gastric Aspirate/Sputum Xpert MTB/RIF as reference standard. Methodology: This is a cross-sectional study, which was done in the Department of Pediatric Medicine, Children Hospital Lahore from November 2025 to February 2026. The sample size was 185 children (<15 years) suspected of pulmonary TB who were recruited using non-probability consecutive sampling. Samples of stool and respiratory were collected and tested with Xpert MTB/RIF assay. The measures of diagnostic accuracy such as sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy were determined using a 2x2 contingency table. Result: The average age of the sample was 7.2 +/- 3.8 years and 56.2 percent of the sample was males. The prevalence of TB was 23.2% according to the reference standard. Stool Xpert MTB/RIF showed a sensitivity of 90.7, specificity of 94.4, PPV of 85.9 and NPV of 96.8. The total diagnostic accuracy was 93.0%. Conclusion: Stool Xpert MTB/RIF is a non-invasive, high sensitivity and specificity diagnostic tool to identify pulmonary TB in children. It may be of special benefit in a resource-constrained environment in which sputum samples are difficult to obtain.