Efficacy of a chemiluminescence-based urinary LAM (AIMLAM) assay in the diagnosis of active TB in Chinese children.

UNLABELLED: Child-friendly triage tests that do not rely on sputum for diagnosing active tuberculosis (ATB) in children are urgently required. This study aimed to assess a chemiluminescence-based urinary lipoarabinomannan test (AIMLAM) for diagnosing tuberculosis (TB) in children in China. Among the 579 children enrolled, 331 had TB, 169 had infectious diseases, and 79 were healthy controls. The area under the ROC curve of the AIMLAM test for distinguishing TB from non-TB (children with infectious diseases and healthy controls) was 0.74 (95% confidence interval [CI], 0.70-0.78), with a sensitivity of 52.2% (95% CI, 46.6%-57.6%) and a specificity of 91.9% (95% CI, 87.6%-94.9%). In 288 children with clinically diagnosed TB, the sensitivity of the test was 50.0% (95% CI, 44.1%-55.9%). LAM concentrations in extrapulmonary TB were significantly higher than those in pulmonary TB (= 0.003), which resulted in a higher sensitivity of 63.6% (95% CI, 54.7%-72.1%). The diagnostic sensitivity of AIMLAM was significantly superior to that of Xpert (= 0.004) and Ultra (= 0.002). The sensitivity of AIMLAM is moderate but highest in extrapulmonary TB patients. The test appears to be promising for the rapid diagnosis of TB in children, especially in those with negative bacteriological results.

IMPORTANCE: This study of a large-sample cohort of children in China assessed the diagnostic accuracy of the AIMLAM test kit as an auxiliary tool for childhood TB, and to determine an age-specific reference interval for LAM concentrations in children. Our findings showed that the overall sensitivity of AIMLAM was moderate, whereas a higher sensitivity was observed in patients with bacteriologically confirmed and severe TB. Age-specific cutoff values may be needed to optimize the diagnostic model in children. These results provide preliminary evidence for a method of diagnosing ATB in pediatric patients with samples that are difficult to obtain.