Abstract
BACKGROUND: Diagnosing childhood TB is challenging due to nonspecific symptoms and difficulty obtaining sputum samples. This study evaluated the urine-based Alere Determine™ TB-LAM Ag test (AlereLAM) in a high-burden TB, HIV, and malnutrition setting. METHODS: Médecins Sans Frontières conducted a cross-sectional study in Malakal, South Sudan (October 2021-November 2023). Children (6 months-15 years) with presumptive TB received clinical and laboratory tests, including Xpert-Ultra and AlereLAM, regardless of HIV status. TB was classified as confirmed (Xpert-Ultra positive), unconfirmed (clinical), or unlikely. RESULTS: Of the 276 children (median age: 44 months), 53.3% (147/276) were female, 64.9% (179/276) were severely malnourished, and 9.4% (26/276) were children living with HIV. TB was confirmed in 10.5% (29/276), unconfirmed in 50.7% (140/276), and unlikely in 38.8% (169/276). Overall, AlereLAM positivity was 17.8% (49/276), with higher positivity in confirmed TB (27.6%; 8/29) than unconfirmed (20.0%; 28/140) and unlikely TB (12.1%; 13/107). Using confirmed plus unconfirmed TB as positive and unlikely TB as negative reference standard, sensitivity was 21.3% (95% confidence interval [CI]: 15.4-28.3), specificity 87.9% (95% CI: 80.1-93.4), positive predictive value (PPV) 73.5% (95% CI: 58.9-85.1), and negative predictive value 41.4% (95% CI: 34.9-48.1). CONCLUSION: AlereLAM's high specificity and PPV support ruling in TB in resource-limited settings, but low sensitivity highlights the need for additional diagnostic tests.