Tuberculosis diagnostic accuracy of stool Xpert MTB/RIF and urine AlereLAM in vulnerable children.

Authors: Orikiriza P Smith J Ssekyanzi B Nyehangane D Mugisha Taremwa I Turyashemererwa E Byamukama O Tusabe T Ardizzoni E Marais BJ Wobudeya E Kemigisha E Mwanga-Amumpaire J Nampijja D Bonnet M
Journal Reference: The European respiratory journal 2021 Jun 17; (); Array. doi: 10.1183/13993003.01116-2021. Epub 2021 06 17
eng

Abstract

BACKGROUND: Non-sputum based diagnostic approaches are crucial in children at high risk of disseminated tuberculosis [TB] who cannot expectorate sputum. We evaluated the diagnostic accuracy of Xpert MTB/RIF from stool and urine AlereLipoarabinomannan [LAM] test in this group of children.

METHODS: Hospitalised children with presumptive TB and either age

RESULTS: The study enrolled 219 children; median age 16.4 months, 72 (32.9%) HIV-positive and 184 (84.4%) severely malnourished. Twelve (5.5%) and 58 (28.5%) children had confirmed and unconfirmed TB respectively. Stool and urine were collected in 219 (100%) and 216 (98.6%) children. Against the microbiological reference standard the sensitivity and specificity (n/N, 95% confidence intervals) of stool Xpert MTB/RIF was 50.0% (6/12, 21.1-78.9) and 99.1% (198/200 96.4-99.9), while that of urine AlereLAM was 50.0% (6/12, 21.1-78.9) and 74.6% (147/197, 67.9-80.5) respectively. Against the composite reference standard sensitivity was reduced to 11.4% (8/70) for stool and 26.2% (17/68) for urine, with no major difference by age group (

CONCLUSION: The Xpert MTB/RIF assay has excellent specificity on stool, but sensitivity is suboptimal. Urine AlereLAM is compromised by poor sensitivity and specificity in children.

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