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Chinese Journal of Antituberculosis ›› 2014, Vol. 36 ›› Issue (6): 472-476.doi: 10.3969/j.issn.1000-6621.2014.06.013

Special Issue: GeneXpert MTB/RIF检测技术相关研究

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Evaluation of GeneXpert Mtb/RIF assay for diagnosis of tuberculosis and rifampin-resistant tuberculosis

LI Hui, TAN Yao-ju, LI Hong-min, MA Xiao-guang, XING Jin, HAO Bao-lin, ZHAO Yan-lin   

  1. The Tuberculosis Reference Laboratory, He’nan Provincial Center for Disease Control and Prevention, Zhengzhou 461005, China
  • Received:2014-04-17 Online:2014-06-10 Published:2014-06-28
  • Contact: LI Hui E-mail:lihui2005yan@126.com

Abstract: Objective To evaluate the performance of GeneXpert Mtb/RIF assay for the diagnosis of Mycobacterium tuberculosis (Mtb) and rifampin-resistant tuberculosis (TB) in clinical samples. Methods The sputum samples were collected from all TB suspects who visited the outpatient departments of the 309th Hospital of Chinese People’s Liberation Army and Guangzhou Chest Hospital, as well as the TB clinic of He’nan Provincial Center for Disease Control and Prevention (He’nan Provincial CDC) from January to May 2011. Smear microscopy, culture (golden-standard method), drug susceptibility testing (DST, conventional proportion method) and GeneXpert Mtb/RIF assay were respectively performed on each clinical sample. SPSS software version 11.5 was used for statistical analysis to compare the diagnostic sensitivity and specificity of GeneXpert Mtb/RIF assay and other examination methods, P<0.05 was regarded as a significant difference. Results Sputum samples were collected from 1971 TB suspects. The samples from 3 suspected cases were contaminated and were excluded from the analysis. Thus 1968 suspected cases were involved in the analysis. Compared with the results of smear microscopy and culture, the sensitivity and specificity of GeneXpert Mtb/RIF assay for diagnosis of TB was 93.27%(748/802), 91.93%(797/867) and 91.60%(1068/1166), 95.55%(1052/1101) respectively; compared with the results of clinical diagnosis, the sensitivity and specificity of GeneXpert Mtb/RIF assay for diagnosis of TB was 78.66%(822/1045) and 98.67%(888/900) respectively; compared with the results of conventional DST, the sensitivity and specificity of GeneXpert Mtb/RIF assay for diagnosis of rifampin-resistant TB was 97.92%(188/192) and 100.00%(595/595) respectively. Conclusion GeneXpert Mtb/RIF assay is a rapid, simple and hand-free molecular diagnostic tool with high sensitivity and specificity for the diagnosis of TB and rifampin-resistant TB. It can be used for clinical diagnosis of TB and rifampin-resistant TB.

Key words: Tuberculosis/diagnosis, Rifampin, Drug resistance, bacterial, Nucleic acid amplification techniques, Comparative study