Performances of loop-mediated isothermal amplification for TB diagnosis in children

Paediatric TB is underdiagnosed in TB-endemic countries. TB-LAMP might improve TB diagnosis in children. This work aimed to assess the performance of TB-LAMP in non-sputum specimens for the detection of paediatric TB in Cameroon.A diagnostic test study was conducted in 2019 using 450 samples retrospectively collected and stored at -20°C within the TB kids study (2016-2018), consisting of gastric aspirations (GA), nasopharyngeal aspirations (NA) and stools from 150 children. Statistical analyses were performed using R and R studio software to compare diagnostic performances of TB-LAMP and Xpert MTB/RIF using culture as the gold standard.The sensitivity and specificity of respectively TB-LAMP were 66.7% and 93.3% for GA, 61.5% and 94.2% for NA, and 64.7% and 94.0% for stool. However, Xpert MTB/RIF showed higher sensitivity and specificity compared to TB-LAMP when using GA (sensitivity: 73.3%, specificity: 99.3%), NA (sensitivity: 92.3%, specificity: 98.5%) and stool (sensitivity: 70.6%, specificity: 98.5%). There was no statistical difference between TB-LAMP and Xpert MTB/RIF.TB-LAMP and Xpert MTB/RIF performed similarly with the three specimen types. These results imply a potential use of TB-LAMP for the diagnosis of paediatric TB. However, similar studies are needed in different contexts..