Gene Xpert Testing of Stool Sample for the Diagnosis of Tb in Children

Globally Tuberculosis (TB) is a major infectious disease. In 2011, there were an estimated 8.7 million new cases with 6% childhood tuberculosis. The majority of the cases occurring in high TB burden countries like Kenya. Accurate pediatric pulmonary tuberculosis (PTB) diagnosis is a challenge. Symptoms are nonspecific, young children are unable to expectorate sputum samples and the procedures for obtaining respiratory samples are invasive. Thus M. tuberculosis cultures and smears are often not performed. This study was done to assess stool samples as an alternative to respiratory samples for the diagnosis of pediatric PTB using stool Xpert MTB/RIF assay test and to determine its sensitivity for detecting the DNA of MTB in stool. Stool for Xpert was processed directly and with prior extraction of DNA using QIAGEN stool DNA extraction kit. Stool Gene Xpert with 100% sensitivity and 89.36% specificity had significant association (P value = 0.000). Thus this study reports that M. tuberculosis DNA can be detected in stool using Xpert. Therefore stool which can easily be obtained are an appropriate alternative sample for the diagnosis of PTB using Xpert assay for children.