Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Meta-Analysis
. 2023 May 24:11:1117709.
doi: 10.3389/fpubh.2023.1117709. eCollection 2023.

Stool Xpert MTB/RIF as a possible diagnostic alternative to sputum in Africa: a systematic review and meta-analysis

Francesco Vladimiro Segala  1   2 , Roberta Papagni  1 , Sergio Cotugno  1 , Elda De Vita  1 , Maria Chiara Susini  3 , Valeria Filippi  3 , Ottavia Tulone  4 , Enzo Facci  3 , Rossana Lattanzio  1 , Claudia Marotta  2 , Fabio Manenti  3 , Davide Fiore Bavaro  1 , Giuseppina De Iaco  1 , Giovanni Putoto  2 , Nicola Veronese  4 , Mario Barbagallo  4 , Annalisa Saracino  1 , Francesco Di Gennaro  1   2
Affiliations
Meta-Analysis

Stool Xpert MTB/RIF as a possible diagnostic alternative to sputum in Africa: a systematic review and meta-analysis

Francesco Vladimiro Segala et al. Front Public Health. .

Abstract

Introduction: Worldwide, COVID-19 pandemic lead to a large fall in the number of newly reported TB cases. In sub-Saharan Africa, microbiological diagnosis of TB is generally based on smear microscopy and Xpert MTB/RIF on sputum samples, but good quality sputum samples are often difficult to obtain, leading clinicians to rely on more invasive procedures for diagnosis. Aim of this study was to investigate pooled sensitivity and specificity of Xpert MTB/RIF on stool samples compared to respiratory microbiological reference standards in African countries.

Methods: Four investigators independently searched PubMed, SCOPUS, and Web of Science until 12th October 2022, then screened titles and abstracts of all potentially eligible articles. The authors applied the eligibility criteria, considered the full texts. All the studies reported the data regarding true positive (TP), true negative (TN), false positive (FP) and false negative (FN). Risk of bias and applicability concerns were assessed with the Quadas-2 tool.

Results: overall, among 130 papers initially screened, we evaluated 47 works, finally including 13 papers for a total of 2,352 participants, mainly children. The mean percentage of females was 49.6%, whilst the mean percentage of patients reporting HIV was 27.7%. Pooled sensitivity for Xpert MTB/RIF assay for detecting pulmonary tuberculosis was 68.2% (95%CI: 61.1-74.7%) even if characterized by a high heterogeneity (I2=53.7%). Specificity was almost 100% (99%, 95%CI: 97-100%; I2 = 45.7%). When divided for reference standard, in the six studies using sputum and nasogastric aspirate the accuracy was optimal (AUC = 0.99, SE = 0.02), whilst in the studies using only sputum for tuberculosis detection the AUC was 0.85 (with a SE = 0.16). The most common source of bias was exclusion of enrolled patients in the analysis.

Conclusions: Our study confirms that, in Africa, stool Xpert MTB/RIF may be a useful rule-in test for children above and below 5 years of age under evaluation for pulmonary tuberculosis. Sensitivity increased substantially when using both sputum and nasogastric aspirate as reference samples.

Keywords: diagnostic microbiology; meta-analysis; pulmonary tuberculosis; stool Xpert MTB/RIF; systematic review.

PubMed Disclaimer

Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
PRISMA flow-chart.
Figure 2
Figure 2
Forest plots of sensitivity and specificity of the Xpert MTB/RIF Ultra assay for tuberculosis detection. Power of the single studies is indicated by dot size, while horizontal lines indicate emerging from the box indicate the magnitude of the confidence interval. Dot size is proportional to the studies' sample size. and that the lozenge and box represents the pooled numbers with 95% CI error margins.
Figure 3
Figure 3
Summary receiver operating characteristic (SROC) curve of the diagnostic accuracy of Xpert MTB/RIF Ultra assay for tuberculosis detection. In this figure, the blue lines represent the AUC (central line) with its 95% CI (external lines) calculated with a meta-analytic approach, while red dots represent the sensitivity and specificity data for each study.
Figure 4
Figure 4
QUADAS-2 risk of bias and applicability concerns graph.
See this image and copyright information in PMC

References

    1. World Health Organization. Global tuberculosis report 2022. Geneva: World Health Organization (2022). https://apps.who.int/iris/handle/10665/363752 (accessed November 23, 2022).
    1. The End TB Strategy . https://www.who.int/teams/global-tuberculosis-programme/the-end-tb-strategy (accessed November 25, 2022).
    1. Tiemersma EW, van der Werf MJ, Borgdorff MW, Williams BG, Nagelkerke NJD. Natural history of tuberculosis: duration and fatality of untreated pulmonary tuberculosis in HIV negative patients: a systematic review. PLoS ONE. (2011) 6:e17601. 10.1371/journal.pone.0017601 - DOI - PMC - PubMed
    1. Use of Xpert MTB/RIF and Xpert MTB/RIF Ultra on GeneXpert 10-colour instruments – WHO Policy Statement . Available online at: https://www.who.int/news/item/03-12-2021-use-of-xpert-mtb-rif-and-xpert-... (accessed December 9, 2022).
    1. Bates M, O'Grady J, Maeurer M, Tembo J, Chilukutu L, Chabala C, et al. . Assessment of the Xpert MTB/RIF assay for diagnosis of tuberculosis with gastric lavage aspirates in children in sub-Saharan Africa: a prospective descriptive study. Lancet Infect Dis. (2013) 13:36–42. 10.1016/S1473-3099(12)70245-1 - DOI - PubMed