Value of GeneXpert MTB/RIF in the detection of Mycobacterium tuberculosis in sputum and fiberbronchoscopy specimens

Abstract

Objective To evaluate the application value of GeneXpert MTB/RIF(Xpert)technique in the laboratory diagnosis of tuberculosis.

Methods Totally 566 suspected tuberculosis patients and clinical specimens in Suzhou Fifth People’s Hospital from January to December 2018 were collected retrospectively, including 421 sputum specimens and 145 fiberbronchoscopy specimens, GeneXpert MTB / RIF, fluorescence quantitative PCR , Ziehl–Neelsen staining and culture methods were respectively used for detection. Sensitivity and specificity of GeneXpert MTB/RIF technology were analyzed in the detection of Mycobacterium tuberculosis, and the detection efficacy of GeneXpert MTB/RIF was evaluated.

Results In the detection of the sputum specimens,the positive rates of GeneXpert MTB/RIF, fluorescence quantitative PCR, Ziehl–Neelsen staining and tuberculosis culture were 36.8%, 24.0%, 19.0% and 32.1% respectively; in the fiberbronchoscopy specimens, the positive rates of the four methods were 54.5%, 33.1%, 12.4% and 41.4% respectively. We can see that the positive detection rate of Gene Xpert MTB/RIF technique is significantly higher than the other three detection methods. Take culture as gold standard, the sensitivity and specificity of the GeneXpert MTB/RIF were 77.0% and 82.2% respectively; positive predictive value and negative predictive value were 67.1% and 88.3%, respectively, with a coincidence rate of 80.5% and a Kappa value of 0.57. The sensitivity and specificity of the GeneXpert MTB/RIF method were 93.3% and 72.9%, respectively, the positive predictive value and negative predictive value were 70.9% and 93.9%, the coincidence rate was 81.4%, and the Kappa value was 0.633.

Conclusion GeneXpert MTB /RIF has a higher sensitivity and specificity in the detection of Mycobacterium tuberculosis, which can significantly improve the diagnostic efficiency of tuberculosis, and has a higher clinical application value in the early diagnosis and treatment of tuberculosis.

Abstract

摘要： 目的 评价GeneXpert MTB/RIF (Xpert) 技术在肺结核病实验室诊断中的应用价值。 方法 收集2018年1月—12月苏州市第五人民医院收治的疑似肺结核患者标本566份, 其中痰标本421份, 纤支镜洗液145份, 分别采用Xpert法、荧光定量PCR法、痰涂片抗酸染色法、结核培养法进行检测, 收集数据, 分析比较Xpert 技术在检测结核分枝杆菌时的敏感度和特异度, 并与结核培养结果做比较, 评价Xpert技术的检测效能。 结果 对痰标本的检测, Xpert 技术、荧光定量PCR法、痰涂片法、结核培养法检测的阳性率分别为36.8%、24.0%、19.0%、32.1%; 对纤支镜洗液标本的检测, 四种检测方法的阳性率分别为54.5%、33.1%、12.4%、41.4%, 可见Xpert 技术的阳性检出率明显高于其他三种检测方法。以培养法作为金标准, Xpert 方法检测痰标本的敏感性和特异性分别为77.0%和82.2%, 阳性预测值和阴性预测值分别为67.1%和88.3%, 符合率为80.5%, Kappa 值为0.57。Xpert 方法检测纤支镜洗液标本的敏感性和特异性分别为93.3%和72.9%, 阳性预测值和阴性预测值分别为70.9%和93.9%, 符合率为81.4%, Kappa 值为0.633。 结论 Xpert 技术在检测结核分枝杆菌时具有较高的敏感性和特异性, 能显著提高结核病的诊断效率, 在肺结核的早期诊断、早期治疗等方面具有较高的临床应用价值。