ABSTRACT
@#Abstract: Objective To investigate the diagnostic value of joint detection of Mycobacterium tuberculosis rifampicin resistance gene (Xpert MTB/RIF), Mycobacterium tuberculosis ribonucleic acid (TB-RNA) and Mycobacterium tuberculosis deoxyribonucleic acid (TB-DNA) in bronchoalveolar lavage fluid for smear-negative pulmonary tuberculosis. Methods A total of 806 patients with suspected smear-negative pulmonary tuberculosis admitted to our hospital from May 2020 to July 2022 were selected, 506 patients diagnosed as bacterial negative pulmonary tuberculosis by clinical, X-ray and sputum samples were classified as bacterial negative pulmonary tuberculosis group, and the other 300 patients with non-tuberculous pulmonary disease were classified as non-tuberculous pulmonary disease group. XpertMTB/RIF, TB-RNA and TB-DNA in bronchoalveolar lavage fluid of all patients were detected. With clinical, X-ray and sputum specimen examination of mycobacterium tuberculosis as the gold standard, the diagnostic efficacy of alveolar lavage solution Xpert MTB/RIF, TB-RNA and TB-DNA alone and in combination was analyzed. Results The positive detection rates of Xpert MTB/RIF, TB-RNA and TB-DNA in bronchoalveolar lavage fluid of the smear-negative pulmonary tuberculosis group and the non-tuberculosis pulmonary disease group were 69.96% (354/506) and 2.67% (8/300), 61.46% (311/506) and 5.00% (15/300), and 63.64% (322/506) and 8.00% (24/300), respectively. The rates in the smear-negative pulmonary tuberculosis group were higher than those in the non-tuberculosis lung disease group, and the differences were statistically significant (χ2=342.005, 246.930, 235.687, P<0.01). Compared with the gold standard, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value of Xpert MTB/RIF in the diagnosis of smear-negative pulmonary tuberculosis were 69.96%, 97.33%, 80.15%, 97.79% and 65.77%, respectively; those values of TB-RNA were 61.46%, 95.00%, 73.95%, 95.40% and 59.38%, respectively; those values of TB-DNA were 63.64%, 92.00%, 74.19%, 93.06% and 60.00%, respectively; those values of combined diagnosis with Xpert MTB/RIF, TB-RNA and TB-DNA were 61.26%, 100.00%, 75.68%, 100.00% and 60.48%, respectively; the specificity and positive predictive value of combined detection were higher than those of single detection (P<0.05). Conclusions The joint detection of Xpert MTB/RIF, TB-RNA and TB-DNA in bronchoalveolar lavage fluid can improve the diagnostic efficacy of smear-negative pulmonary tuberculosis and is worthy of clinical promotion and application.