Abstract: Objective To evaluate the application value of Xpert Mtb/RIF detection assay in the diagnoses of tuberculosis (TB) and Rifampin resistance. Methods Clinicians continuously recruited 2142 TB suspects in four counties (districts) level TB dispensary (Xiangtan, Yueyang, Beilin, Lanxi). Three sputum specimens each patient provided were performed smear, solid culture and Xpert Mtb/RIF test. The TB patients with definite diagnoses were followed up for two months. The staff in provincial laboratory completed rifampin susceptibility test in 555 culture-positive strains using proportional method. The staff in national reference laboratory sequenced the rifampin-resistant determinant region of rpoB genes in the strains with the inconsistent results between Xpert Mtb/RIF and traditional drug susceptibility test. Using clinical diagnosis as gold standard, the performance of smear, solid culture and Mtb/RIF test were evaluated. The performance of Xpert Mtb/RIF for rifampin resistance detection was compared with traditional drug susceptibility test.   Results Using clinical diagnosis result as the gold standard, the sensitivities of smear, solid culture and Xpert Mtb/RIF were 25.68%（284/1106）, 51.44%（555/1079） and 58.82%（650/1105）, respectively. The sensitivity of Xpert Mtb/RIF was higher than smear (χ²=360.10, P<0.05) and the solid culture(χ²=50.13, P<0.05). Compared with traditional drug susceptibility test, the sensitivity and the specificity of Xpert Mtb/RIF for rifampin resistance detection were 87.10% (27/31) and 97.95% (477/487), respectively. Conclusion Xpert Mtb/RIF test is simple, the sensitivity of Xpert Mtb/RIF is higher than smear microscopy and solid culture，it can also diagnose patients of rifampin resistance, so it has very good application prospects in our county (district) level laboratories.

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