Abstract: Objective To investigate the value of rifampicin resistant real-time fluorescent quantitative nucleic acid amplification technology (GeneXpert MTB / RIF) combined with the gene chip technology in the diagnosis of smear-negative Mycobacterium tuberculosis (MTB) and the clinical significance of serum soluble triggering receptor-1 (sTREM-1) and procalcitonin (PCT) levels in pulmonary tuberculosis. Methods A total of 130 cases of suspected smear-negative pulmonary tuberculosis patients in Liaocheng People’s Hospital from January 2019 to January 2021 were selected. Alveolar lavage fluid were collected, GeneXpert MTB / RIF were performed, gene chip method were applied, and the serum levels of sTREM-1 and PCT were detected. The alveolar lavage fluid tuberculosis culture method and the drug sensitivity test were used as the gold standard to evaluate the diagnostic value of GeneXpert MTB / RIF combined with gene chip technology for the smear-negative pulmonary tuberculosis. ROC analysis was used to evaluate the diagnostic value of serum sTREM-1 and PCT in smear-negative pulmonary tuberculosis. Results A total of 58 patients with non-smear-negative pulmonary tuberculosis and 72 patients with smear-negative pulmonary tuberculosis were diagnosed by using the alveolar lavage fluid tuberculosis culture method. The sensitivity of GeneXpert MTB / RIF combined with gene chip technology for the diagnosis of pulmonary tuberculosis was 68. 06 % , which was higher than that of gene chip method alone (P< 0. 05). The specificity, accuracy, positive predictive value and negative predictive value of GeneXpert MTB / RIF combined with gene chip method for the diagnosis of pulmonary tuberculosis were 91. 38 % , 78. 46 % , 90. 74 % and 69. 74 % , respectively, despite that the differences were not statistically significant when compared with the GeneXpert MTB / RIF or gene chip method alone (P> 0. 05). The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of GeneXpert MTB / RIF combined with gene chip method for the diagnosis of MDR-TB were 94. 12 % , 85. 45 % , 87. 50 % , 66. 67 % and 97. 92 % , respectively, compared with GeneXpert MTB / RIF and gene chip method alone, the differences were not statistically significant (P> 0. 05). The levels of serum sTREM-1 and PCT in patients with severe pulmonary tuberculosis were (18. 04 ± 2. 07) ng / mL and (2. 09 ± 0. 19) ng / mL respectively, which were significantly higher than those in patients with mild pulmonary tuberculosis ( P < 0. 05 ). The areas under the ROC curve of serum sTREM-1 and PCT for the prediction of severe pulmonary tuberculosis were 0. 811 and 0. 844. The cut-off values were 16. 32 ng / mL and 2. 00 ng / mL, the sensitivities were 89. 30 % and 82. 00 % , the specificities were 61. 40 % and 79. 60 % , respectively. Conclusion The GeneXpert combined with gene chip technology can improve the diagnostic sensitivity of smear-negative MTB, and both methods have good diagnostic values for MDR-TB. The levels of sTREM-1 and PCT in patients with severe pulmonary tuberculosis were significantly higher than those in patients with mild pulmonary tuberculosis. Serum sTREM-1 and PCT have high sensitivities and specificitise in the diagnosis of severe pulmonary tuberculosis, which can be applied for the early diagnosis of pulmonary tuberculosis.

Key words: rifampicin resistant real-time fluorescent quantitative nucleic acid amplification technology, gene chip method, smear-negative Mycobacterium tuberculosis, diagnostic value, soluble triggering receptor-1 of myeloid cells, procalcitonin