Abstract:

Objective To evaluate the value and significance of Xpert MTB/RIF in the diagnosis of tuberculosis in general hospitals.Methods From June 2016 to August 2017, 376 specimens of patients with suspected tuberculosis in Zhuzhou Central Hospital were collected, including 227 sputum specimens (60.37%), 109 alveolar lavage fluid samples (28.99%), 21 cerebrospinal fluid samples (5.59%), 15 pleural effusion samples (3.99%), and 4 other specimens (1.06%, including drainage fluid, pus, secretions, and urine, 1 case each). GeneXpert MTB/RIF test (referred to as “Xpert method”), sandwich cup liquid-based bacteria acid-fast staining smear microscopy (referred to as “sandwich cup method”) and traditional solid Roche culture method (referred to as “solid culture method”) were conducted for each specimen, and the results were compared. Statistical analysis was performed using SPSS 19.0 software. The count data were compared by χ ² test, and the difference was statistically significant at P<0.05. Results Among the 376 suspected cases, 349 were clinically diagnosed as tuberculosis and 27 were non-tuberculosis. The positive detection rate of Xpert method (37.50%, 141/376) was significantly higher than that of sandwich cup method (22.87%, 86/376) and solid culture method (17.82%, 67/376) (χ ² values were 19.09 and 36.39, respectively; P values <0.05). Taking clinical diagnosis as gold standard, the sensitivity of Xpert method (40.11%, 140/349) was significantly higher than that of sandwich cup method (23.50%, 82/349) and solid culture method (19.20%, 67/349) (χ ² values were 19.86 and 35.98, respectively; P values were <0.05). The diagnostic consistency of Xpert method (K=0.080) was higher than that of sandwich cup method (K=0.016) and solid culture method (K=0.033). Among the 140 positive specimens detected by Xpert method, proportion of resistance to rifampicin was 15.71% (22/140). Among the 63 positive specimens detected by solid culture method, the proportion of resistance to rifampicin was 14.29% (9/63). The difference in proportion of resistance to rifampicin between Xpert and solid culture method was not statistically significant (χ ²=0.07, P>0.05). For the 9 rifampicin-resistant samples detected by solid culture method, consistent results were achieved by Xpert method. Conclusion The Xpert detection method is simple and rapid and shows high sensitive. It has high clinical value for early diagnosis and treatment of tuberculosis in general hospitals.

Key words: Mycobacterium tuberculosis, Nucleic acid amplification technique, Laboratory techniques and procedures, Comparative study