The use of urinary lateral-flow lipoarabinomannan assays for TB diagnosis in children

SUMMARY BACKGROUND Detection of lipoarabinomannan (LAM) in urine is a promising non-sputum-based test for TB. We aimed to evaluate Fujifilm SILVAMP TB-LAM (FujiLAM) for the diagnosis of TB in children, using AlereLAM as a comparator. METHODS Between January 2019 to July 2021, children and young adolescents with presumptive TB disease were enrolled in five countries as part of the RaPaed-TB study. Standardised microbiological, radiologic, and clinical data were used to define TB category following published consensus criteria. FujiLAM and AlereLAM were performed on a single urine sample at enrolment. RESULTS Of 975 children enrolled, 818 (83.9%) had FujiLAM results available. Median age was 5.5 years (interquartile range 2.4–9.4), 83 (10.1%) had severe acute malnutrition, and 138 (16.9%) were living with HIV. Using a microbiological reference standard, overall sensitivity of FujiLAM was 31.0% (95% confidence interval [CI]: 24.7–37.9) and that of AlereLAM 13.3% (95% CI: 9.0–18.8), whereas the overall specificity was 89.8% (95% CI: 86.3–92.7) and 92.7% (95% CI: 89.6–95.1), respectively. Marked differences in FujiLAM accuracy were noted between production lots. CONCLUSION FujiLAM remains a promising non-invasive, urine-based biomarker for childhood TB diagnosis. However, the observed lot-to-lot variability underscores the need for improved assays with rigorous multi-lot evaluations to ensure reliability in future studies.