Diagnostic Accuracy of Stool Xpert Mtb/Rif For Pulmonary Tuberculosis In Children Keeping Microbial Culture As Gold Standard

Abstract

Objective: To determine the diagnostic accuracy of stool Xpert MTB/RIF for the detection of pulmonary tuberculosis (PTB) in children, using sputum/gastric aspirate culture as the gold standard.

Methodology: This cross-sectional study was conducted in the Department of Pediatrics, CMH, Gujranwala, after approval from the College of Physicians and Surgeons Pakistan. A total of 181 clinically suspected PTB cases aged 1–12 years were enrolled over six months using non-probability consecutive sampling. Stool and sputum/gastric aspirate samples were obtained according to standard guidelines. Stool samples were tested by Xpert MTB/RIF, while sputum/gastric aspirate samples were subjected to culture as the reference standard. Data were analyzed using SPSS version 22. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were calculated using a 2×2 contingency table.

Results: The mean age of participants was 6.9 ± 3.1 years, and 56.4% were male. Culture-confirmed PTB was detected in 116 (64.1%) children. Stool Xpert MTB/RIF was positive in 108 (59.7%) cases. The sensitivity, specificity, PPV, and NPV of stool Xpert MTB/RIF were 88.8%, 92.3%, 95.4%, and 82.2%, respectively, with an overall diagnostic accuracy of 90.1%. A significant association was observed between PTB and rural residence (p = 0.021) as well as household TB contact (p < 0.001).

Conclusion: Stool Xpert MTB/RIF demonstrated high diagnostic accuracy and can serve as a reliable, non-invasive alternative for diagnosing pediatric pulmonary tuberculosis, particularly in settings where respiratory sample collection is difficult.