Objective:To evaluate the value of applying targeted next-generation sequencing on bronchoalveolar lavage fluid specimens in screening pulmonary tuberculosis in older adults with lung infectious diseases.Methods:In this cross-sectional study, the clinical data of 370 patients with infectious lung diseases who received treatment at Shanghai Deji Hospital between January 2021 and July 2023 were analyzed. Bronchoscopy was performed to obtain 370 bronchoalveolar lavage fluid specimens, and targeted next-generation sequencing confirmed the diagnosis of pulmonary tuberculosis in 28 patients. The clinical data of these 28 patients were retrieved from the electronic medical record system. Patient age, clinical characteristics, comorbidities, methods of diagnosis, imaging findings, and results of pathogen testing were analyzed.Results:The patients' ages ranged from 70 to 93 years. Among the 28 patients included, 16 patients were in the medium-age (> 70-80 years) group and 12 patients were in the advanced age (> 80 years) group. Clinical findings revealed that 9 patients (32.1%) exhibited fatigue, 8 patients (29.6%) presented with cough and sputum, 4 patients (14.3%) experienced chest tightness, 4 patients (14.3%) had loss of appetite, and 3 patients (10.7%) showed a reduction in body mass. Furthermore, 12 patients had diabetes mellitus, 10 patients had infectious lung diseases, 4 patients had lung cancer, and 2 patients had liver and kidney insufficiency. Tuberculosis was passively confirmed by the targeted next-generation sequencing test. Imaging findings indicated the presence of two or more lesions in the lungs of 24 patients (85.7%), while 4 patients (14.3%) showed only one lesion in the lung. There was a significant difference between the number of patients with two or more lesions compared with those with only one lung lesion ( χ2 = 25.79, P < 0.001). The positive rate of the conventional pathogen test among the 28 patients was 14.3%, which was significantly different from that obtained by targeted next-generation sequencing on bronchoalveolar lavage fluid specimens ( χ2 = 68.55, P < 0.001). Conclusion:The onset of pulmonary tuberculosis in older adults is subtle, and its complications can result in clinical symptoms and imaging findings that lack specificity. Conventional methods of positive etiology detection often yield low accuracy rates. However, the application of targeted next-generation sequencing on bronchial bronchoalveolar lavage fluid specimens collected from older adult patients with respiratory infectious diseases at non-tuberculosis-designated hospitals can enhance the positive detection rate. This approach can facilitate earlier diagnosis and treatment of pulmonary tuberculosis in older adults, ultimately contributing to the prevention of its transmission.