Evaluation of TB-LAMP assay for detection of Mycobacterium tuberculosis in children

Background Paediatric tuberculosis remains a major public health problem in developing countries. The diagnosis of tuberculosis in children is challenging because of the paucibacillary nature of the disease, due to which more sensitive nucleic acid amplification tests are needed. In this study, we determined the accuracy of WHO endorsed TB-LAMP assay for detection of Mycobacterium tuberculosis in children. Methods This was a prospective study conducted between March to July, 2018. A total of 177 samples from consecutive suspected TB children were received for microbiological diagnosis of TB. All tests for Mycobacterium tuberculosis detection were performed in parallel (smear microscopy, mycobacterial culture, Xpert MTB/RIF and TB-LAMP). The diagnostic accuracy of index test i.e. TB LAMP were determined using mycobacterial culture as a reference standard. Results Of the 177 samples, 2 (1.1%) were excluded from the study. Among 175 samples, TB-LAMP and Xpert MTB/RIF were positive in 27 (15.4%) and 25 (14.3%) samples, respectively. The sensitivity of both Xpert MTB/RIF and TB-LAMP was same, i.e. 84% (95%CI: 63.9-95.5%), when culture was considered as the reference standard. The specificity, positive predictive value and negative predictive value of TB-LAMP assay was 96% (95%CI: 91.5-98.5%), 77.8% (95%CI: 61.1-88.6%) and 97.3% (95%CI: 93.6-98.9%), respectively. Conclusion For the detection of M. tuberculosis in paediatric samples, TB-LAMP showed a sensitivity and specificity comparable to Xpert MTB/RIF.