Abstract:

Objective: To evaluate the application value of GeneXpert MTB/RIF assay in the diagnosis of tuberculous pleurisy and the detection of rifampicin resistance. Methods: A retrospective study was conducted. Pleural effusion samples were collected from 547 patients with pleurisy admitted to Lanzhou Pulmonary Hospital between January 2023 and June 2025. All samples were subjected to GeneXpert MTB/RIF assay, acid-fast bacilli smear microscopy, rapid liquid culture of mycobacterium, PCR-TB-DNA, and PCR-TB-RNA. Using the final clinical diagnosis as reference standard, the diagnostic performances of the five assays for tuberculous pleurisy was assessed. With phenotypic drug susceptibility testing as reference, the efficacy of GeneXpert MTB/RIF in detecting rifampicin resistance was analyzed. Results: Among the 547 patients with pleurisy, 300 were clinically diagnosed with tuberculous pleurisy and 247 with non-tuberculous pleurisy. Taking clinical diagnosis as reference, the sensitivities of GeneXpert MTB/RIF, acid-fast bacilli smear, rapid liquid culture, PCR-TB-DNA, and PCR-TB-RNA were 28.67% (86/300), 2.67% (8/300), 11.00% (33/300), 9.00% (27/300), and 7.33% (22/300), respectively; the specificities were all 100.00% (247/247); the positive predictive values were 100.00% (86/86), 100.00% (8/8), 100.00% (33/33), 100.00% (27/27), and 100.00% (22/22), respectively; the negative predictive values were 53.58% (247/461), 45.83% (247/539), 48.05% (247/514), 47.50% (247/520), and 47.05% (247/525), respectively; the accuracies were 60.88% (333/547), 46.62% (255/547), 51.19% (280/547), 50.09% (274/547), and 49.18% (269/547), respectively; and the areas under curve (AUCs) of receiver operating characteristic (ROC) were 0.64, 0.51, 0.56, 0.46, and 0.45, respectively. GeneXpert MTB/RIF showed higher sensitivity, negative predictive value, accuracy, and AUC than the other four assays. Compared with phenotypic drug susceptibility testing, 22 cases showed consistent rifampicin resistance results by GeneXpert MTB/RIF, while 1 case was identified as rifampicin-sensitive by GeneXpert MTB/RIF but resistant by phenotypic testing. Kappa test revealed high consistency between the two methods(Kappa=0.881). Conclusion: GeneXpert MTB/RIF assay demonstrates low sensitivity but high specificity in the early diagnosis of tuberculous pleurisy. Meanwhile, it shows strong consistency with phenotypic drug susceptibility testing in detecting rifampicin resistance, and can serve as a rapid and effective tool for the detection of rifampicin resistance in tuberculous pleurisy.

Key words: Tuberculosis,pleural, Molecular diagnostic techniques, Diagnosis, differential