Evaluation of gene Xpert in detecting suspected pulmonary tuberculosis from stool sample for children

Abstract

Background: Case detection of pulmonary tuberculosis (PTB) is a challenge, even if different diagnostic methods used. Nowadays, it is improved, after the advancement of the detection method such as gene Xpert assay a prodigious change for adults. But in the pediatric PTB is still a challenge, due to the lack of well-developed physiological capacity. Young children are unable to produce enough amount of sputum to be detected by the gene Xpert. So, a substantial number of children are not diagnosed and fail to get treatment. Methods and materials: A cross-sectional study design was used, to evaluate 422 stool and sputum samples were collected from PTB suspected children (<15 years) by consecutive sampling technique. Both stool and sputum specimens were run in the gene Xpert at AHMC and sputum specimens were cultured using LJ culture medium at Oromia Regional Laboratory, Adama, Ethiopia. Specimen processing and testing were done in accordance with the standard mycobacterial safety precautions, procedures, and manufacturer's instruction. Descriptive statistical analysis was done by SPSS version 20, a chi-square test was used to show their association at 95% CI and P-value <0.05 was considered statistically significant, sensitivity, specificity, PPV and NPV of the tests were also calculated. The study was commenced after obtaining ethical approval and permission letter from respective bodies. All data obtained from the participants kept confidential. Results: A total of 422 children were enrolled. About, 70% were living in urban areas. Male to female proportion was 203/219. The mean age was 10.8 years, the majority (71.8%) of the participant age was less than 5years old. From 422 children investigated, 26 had been detected for PTB and 24 of them are confirmed by the sputum culture, with three invalid and four errors. Two of those PTB detected were rifampicin-resistant. Stool gene Xpert had a sensitivity, specificity, PPV and NPV (96%, 99.5%, 92.3%, 99.7%) respectively. Conclusion: The sensitivity of gene Xpert to detected MTB in the stool sample was higher as 96% (P = 0.000). Therefore, the stool can be used as an alternative sample for the diagnosis of PTB using gene Xpert assay for children unable to give respiratory samples.