Abstract:

Objective: To explore the efficacy of multiple combination detection methods, including sputum smear staining microscopy (referred to as “smear”), solid culture of mycobacteria (referred to as “culture”), GeneXpert MTB/RIF (referred to as “Xpert”) detection, and RNA real-time fluorescent constant temperature amplification (referred to as “SAT”), in the diagnosis of pulmonary tuberculosis in grassroots laboratories. Methods: A total of 2161 suspected pulmonary tuberculosis patients with qualified sputum samples were selected from Binxian County, Shangzhi County and Yanshou County, Heilongjiang Province from July 2019 to June 2021. Each patient’s sputum sample was subjected to smear, culture, SAT, and Xpert testing. Using clinical diagnostic results as reference standards, calculate the sensitivity and specificity of single item and multiple combination tests for diagnosing pulmonary tuberculosis, and evaluate their diagnostic efficacy for pulmonary tuberculosis. Results: Among the 2161 initially diagnosed suspected tuberculosis patients, 515 were clinically diagnosed as tuberculosis and 1646 were non tuberculosis. Based on clinical diagnostic results, the sensitivity of smear, culture, and smear+culture for diagnosing pulmonary tuberculosis were 38.83% (200/515), 52.62% (271/515), and 55.92% (288/515), respectively, and the specificity were 99.88% (1644/1646), 99.76% (1642/1646), and 99.76% (1642/1646), respectively. The sensitivity of SAT, smear+SAT and smear+culture+SAT in diagnosing pulmonary tuberculosis were 53.98% (278/515), 61.17% (315/515), and 68.54% (353/515), respectively; and the specificity was 98.78% (1626/1642), 98.66% (1624/1646), and 98.54% (1622/1646), respectively. The sensitivity of smear+culture+SAT diagnosis was higher than that of smear+SAT, and the difference was statistically significant (χ²=6.15, P<0.05). The sensitivity of smear+SAT diagnosis was higher than SAT, and the difference was statistically significant (χ²=5.44, P<0.05). The sensitivity of Xpert, smear+Xpert and smear+culture+Xpert in diagnosing pulmonary tuberculosis were 69.71% (359/515), 70.49% (363/515), and 73.01% (376/515), respectively; and the specificity was 100.00% (1646/1646), 99.88% (1644/1646), and 99.76% (1642/1646), respectively. There was no statistically significant difference in diagnostic sensitivity between smear+culture+Xpert and smear+Xpert (χ²=0.81, P>0.05); and there was no statistically significant difference in sensitivity between smear+Xpert and Xpert (χ²=0.07, P>0.05). Conclusion: The combination of Xpert/SAT, smear, and culture can improve the diagnostic efficiency of pulmonary tuberculosis. When promoting molecular biology methods for the initial diagnosis of suspected pulmonary tuberculosis, the use of traditional bacteriological methods should not be abolished. A reasonable combination of the two methods is more effective in diagnosing pulmonary tuberculosis.

Key words: Tuberculosis, pulmonary, Diagnosis, differential, Diagnostic techniques and procedures, Evaluation studies