Stool samples may be an alternative diagnostic sample for detecting pulmonary tuberculosis (TB) in settings where respiratory samples are not available. These findings, from a systematic review and meta-analysis, were published in Open Forum Infectious Diseases.

Study authors from Ethiopia searched publication databases for studies of TB diagnoses among children. In total, 13 studies conducted in low- and middle-income settings among children aged 0 to 16 years (N=2177) were analyzed. Risk for bias was high among 2 studies and unclear among 3. Study authors conducted a systematic review and meta-analysis to assess diagnostic accuracy of Xpert Mycobacterium tuberculosis (MTB)/rifampin(RIF) on stool for pediatric tuberculosis.

In total, 13.6% of study participants had bacteriologically confirmed TB from respiratory specimens. Compared with bacteriologically confirmed specimens, Xpert MTB/RIF stool assessment had a weighted sensitivity of 0.50 (95% CI, 0.44-0.56; I2, 86%) and specificity of 0.99 (95% CI, 0.98-0.99; I2, 0.0%; P =.44).

Heterogeneity was higher among studies in which the median age of children was less than 5 years of age (I2, 88.9%; P <.001) but not among studies with median ages of 5 years or older (I2, 37%; P =.19). The corresponding sensitivities (0.39 vs 0.99, respectively) and specificities (0.45 vs 0.99, respectively) indicated the Xpert MTB/RIF stool assessment was more accurate among older children.


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This study was limited by the variability of protocols among the underlying studies. Some studies did not have access to centrifuge machines and some stored samples for 6 months before processing. Two studies enrolled only children who were positive for HIV and the Xpert test has been established to have altered performance among HIV infected individuals.

These data indicated assessing TB from stool samples of children was relatively robust and should be considered as an alternative in settings in which obtaining a respiratory sample was infeasible. The study authors concluded that by implementing testing for TB from stool at primary health care clinics in regions where risk for TB infection was high, delays in diagnosis may be avoided and treatment initiated more rapidly.

Reference

Gebre M, Cameron L H, Tadesse G, et al. Variable diagnostic performance of stool Xpert in pediatric tuberculosis: a systematic review and meta-analysis. Open Forum Infect Dis. 2020;ofaa627. doi:10.1093/ofid/ofaa627.