Abstract:
SETTING: Six health facilities in Dar es Salaam, Tanzania.
OBJECTIVE: To evaluate the use of stool specimens in the
diagnostic workup of paediatric TB using the Xpert®
MTB/RIF assay.
DESIGN: Between December 2018 and May 2019, we
performed a cross-sectional diagnostic study of children
aged between 1 month and 14 years with presumptive
TB. A single stool specimen was tested using Xpert. The
result was compared with the reference microbiological
standard for respiratory or gastric specimens tested using
Xpert and/or solid culture. The sensitivity, specificity and
predictive values of stool Xpert assay were assessed.
RESULTS: A total of 225 children with a median age of
2.17 years (IQR 1.16–5.19) were enrolled; 165/225
(73.3%) were aged 5 years. Of 225 children, 8 (3.6%)
were diagnosed with TB as they were culture- or
Xpert-positive on sputum/gastric aspirate. The stool
Xpert assay showed a sensitivity of 62.5% (95% CI 25–
92) and specificity of 100% (95% CI 98–100) against the
reference standard.
CONCLUSION: Use of the Xpert assay on stool specimens
had a moderate sensitivity and high specificity in
the diagnosis of pulmonary TB in children. Our data adds
to the body of evidence for the use of Xpert assay on
stool as a non-respiratory specimen to complement conventional
methods used to diagnose the disease.
