A Comprehensive Evaluation of a Loop-Mediated Isothermal Amplification Assay for the Diagnosis of Pulmonary Tuberculosis in Children Using Bronchoalveolar Lavage Fluid

Lichao Fan,1,* Bo Guan,2,* Moxin Cheng,1,* Chang Liu,3 Yao Tian,1 Ran Li,1 Yu Chen1 1Department of Tuberculosis, Shenyang Tenth People’s Hospital, Shenyang Chest Hospital, Shenyang, Liaoning Province, 110044, People’s Republic of China; 2Geriatric Cardiology Department of the Second Medical Center & National Clinical Research Center for Geriatric Diseases, Chinese PLA General Hospital, Beijing, People’s Republic of China; 3Department of Thoracic Surgery, Shenyang Tenth People’s Hospital, Shenyang Chest Hospital, Shenyang, 110044, Liaoning, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yu Chen, Email yuchensyxk@163.comObjective: Using TB-LAMP for diagnosing pediatric PTB, however, still requires systematic evaluation. Here, we evaluated TB-LAMP performance alone and in combination with conventional assays for diagnosing PTB in Chinese children, using mycobacterial culture or CCRS (the composite clinical reference standard) as references.Design or Methods: BALF samples were collected at Shenyang Tenth People’s Hospital from 251 children susceptible to TB infection with indications for fiberoptic bronchoscopy.Results: When mycobacterial culture was the reference, TB-LAMP used alongside smear microscopy doubled sensitivity for detecting pediatric PTB compared with smear microscopy alone (82.5% vs 40.0%). When CCRS was the reference, AFB microscopy, MTB culture, and TB-LAMP had sensitivities of 16.5%, 30.1%, and 51.1%, respectively, and specificities of 98.2%, 100.0%, and 99.1%. Combining MTB culture with TB-LAMP gave a sensitivity of 61.1% and specificity of 96.6%. TB-LAMP identified 39.3% and 43.2% of cases with negative MTB culture or AFB microscopy results.Conclusion: TB-LAMP using BALF samples provided faster results, allowing early and accurate PTB diagnosis. Our findings provide insights for optimizing diagnostic algorithms for pediatric PTB.Keywords: child, pulmonary tuberculosis, diagnosis, loop-mediated isothermal amplification assay, bronchoalveolar lavage fluid