Evaluation of the Xpert MTB/RIF assay for diagnosis of tuberculosis and rifampin resistance in county-level laboratories in Hunan province, China.

Peilei HU; Liqiong Bai; Fengping Liu; Xichao OU; Zhiying Zhang; Songlin YI; Zhongnan Chen; Daofang Gong; Binbin Liu; Jingwei Guo; Yunhong Tan

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Evaluation of the Xpert MTB/RIF assay for diagnosis of tuberculosis and rifampin resistance in county-level laboratories in Hunan province, China.

Author: Peilei HU ¹ ; Liqiong BAI ¹ ; Fengping LIU ¹ ; Xichao OU ² ; Zhiying ZHANG ³ ; Songlin YI ¹ ; Zhongnan CHEN ¹ ; Daofang GONG ¹ ; Binbin LIU ¹ ; Jingwei GUO ¹ ; Yunhong TAN ⁴
Author Information

1. Hunan Provincial Tuberculosis Reference Laboratory, Hunan Provincial Institute for Tuberculosis Control and Prevention, Changsha, Hunan 410013, China.
2. National Tuberculosis Reference Laboratory, Chinese Center for Disease Control and Prevention, Beijing 102206, China.
3. Tuberculosis Program Office, Program for Appropriate Technology in Health, Beijing 100022, China.
4. Hunan Provincial Tuberculosis Reference Laboratory, Hunan Provincial Institute for Tuberculosis Control and Prevention, Changsha, Hunan 410013, China. Email: tanyunhong@163.com.
Publication Type:Journal Article
MeSH: Adult; Antibiotics, Antitubercular; therapeutic use; China; Female; Humans; Male; Middle Aged; Rifampin; therapeutic use; Tuberculosis; diagnosis; drug therapy; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pulmonary; diagnosis; drug therapy; Young Adult
From: Chinese Medical Journal 2014;127(21):3744-3750
CountryChina
Language:English
Abstract:
BACKGROUNDThe Xpert MTB/RIF showed high sensitivity and specificity in previous studies carried out in different epidemiological and geographical settings and patient populations in high-burden tuberculosis (TB) countries. However, there were little data obtained by validation or demonstration study of the assay in China. In this study, the performance of Xpert MTB/RIF was investigated in two county-level laboratories in Hunan Province, China.
METHODSConsecutive patients with suspected pulmonary tuberculosis (PTB) and suspicion for multidrug-resistant tuberculosis (MDR-TB) were enrolled. For each patient suspected to have PTB, three sputum specimens (one spot sputum, one night sputum, and one morning sputum) were collected and each sputum was tested with smear microscopy, Löwenstein-Jensen (LJ) culture, and Xpert MTB/RIF test. For comparison across subgroups and testing methods, 95% confidence intervals were calculated. All analyses were done with SPSS 16.0, and P < 0.05 was regarded as significant.
RESULTSFor case detection, the sensitivity of Xpert MTB/RIF was 100% for smear- and culture-positive TB and 88.6% for smear-negative and culture-positive TB; the overall sensitivity was 94.5% for all culture-positive patients. The specificity was 99.8%. The sensitivity of Xpert MTB/RIF assay was 22.0% in clinical TB patients and the specificity reached 100.0% in the group of patients who are infected with nontuberculous mycobacteria. For the detection of rifampin resistance, the sensitivity of MTB/RIF RIF-resistance detection was 92.9%, and the specificity was 98.7%. Of the 26 Xpert MTB/RIF-positive and RIF-resistant patients confirmed by LJ proportion tests, 20 (76.9%) patients were infected by MDR-TB.
CONCLUSIONSThe Xpert MTB/RIF assay is a highly sensitive and specific method for diagnosis of TB and RIF resistance, which will enable it to have the potential to be used in county-level laboratories and lead to the reduction of the infectious pool and improvements in TB control in China. Further evaluations in county-level laboratories for implementing the assay are still required.