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. 2024 May 2;11(5):ofae221.
doi: 10.1093/ofid/ofae221. eCollection 2024 May.

Xpert-Ultra Assay in Stool and Urine Samples to Improve Tuberculosis Diagnosis in Children: The Médecins Sans Frontières Experience in Guinea-Bissau and South Sudan

Laura Moretó-Planas  1   2 , Raman Mahajan  3 , Lazro Fidelle Nyikayo  4 , Yoanis Bedpinj Peter Ajack  4 , Buai Tut Chol  5 , Eltigani Osman  5 , Mitchell Sangma  6 , Apal Tobi  7 , Jonathan Gallo  8 , Evelize Biague  8 , Ramiro Gonçalves  8 , Mercè Rocaspana  1 , Cándida Medina  9 , Miguel Camará  10 , Laurence Flevaud  1 , Lisa C Ruby  11   12 , Sabine Bélard  11   12 , María José Sagrado  1 , Israel Molina  13 , Augusto E Llosa  1
Affiliations

Xpert-Ultra Assay in Stool and Urine Samples to Improve Tuberculosis Diagnosis in Children: The Médecins Sans Frontières Experience in Guinea-Bissau and South Sudan

Laura Moretó-Planas et al. Open Forum Infect Dis. .

Abstract

Background: More than half of childhood tuberculosis cases remain undiagnosed yearly. The World Health Organization recommends the Xpert-Ultra assay as a first pediatric diagnosis test, but microbiological confirmation remains low. We aimed to determine the diagnostic performance of Xpert-Ultra with stool and urine samples in presumptive pediatric tuberculosis cases in 2 high-tuberculosis-burden settings.

Methods: This Médecins Sans Frontières cross-sectional multicentric study took place at Simão Mendes Hospital, Guinea-Bissau (July 2019 to April 2020) and in Malakal Hospital, South Sudan (April 2021 to June 2023). Children aged 6 months to 15 years with presumptive tuberculosis underwent clinical and laboratory assessment, with 1 respiratory and/or extrapulmonary sample (reference standard [RS]), 1 stool, and 1 urine specimen analyzed with Xpert-Ultra.

Results: A total of 563 children were enrolled in the study, 133 from Bissau and 400 from Malakal; 30 were excluded. Confirmation of tuberculosis was achieved in 75 (14.1%), while 248 (46.5%) had unconfirmed tuberculosis. Of 553 with an RS specimen, the overall diagnostic yield was 12.4% (66 of 533). A total of 493 stool and 524 urine samples were used to evaluate the performance of Xpert-Ultra with these samples. Compared with the RS, the sensitivity and specificity of Xpert-Ultra were 62.5% (95% confidence interval, 49.4%-74%) and 98.3% (96.7%-99.2%), respectively, with stool samples, and 13.9% (7.5%-24.3%) and 99.4% (98.1%-99.8%) with urine samples. Nine patients were positive with stool and/or urine samples but negative with the RS.

Conclusions: Xpert-Ultra in stool samples showed moderate to high sensitivity and high specificity compared with the RS and an added diagnostic yield when RS results were negative. Xpert-Ultra in stool samples was useful in extrapulmonary cases. Xpert-Ultra in urine samples showed low test performance.

Clinical trials registration: NCT06239337.

Keywords: LMIC; Xpert-Ultra; pediatric tuberculosis; stool; urine.

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Conflict of interest statement

Potential conflicts of interest. All authors: No reported conflicts.

Figures

Figure 1.
Figure 1.
Flowchart of participants through the study.
See this image and copyright information in PMC

References

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