[Evaluation of the isothermal RNA amplification assay for Mycobacterium tuberculosis in sputum samples].

OBJECTIVE: To evaluate the use of isothermal RNA amplification assay for detection of Mycobacterium tuberculosis (SAT-TB) in sputum samples. METHODS: A total of 244 sputum samples from patients with pulmonary tuberculosis and those with other lung diseases were detected by SAT-TB and Lowenstein-Jensen (L-J) culture. The samples with different results between SAT-TB and L-J culture were tested by Mycobacterium tuberculosis PCR fluorescence diagnostic kits. The sensitivity and specificity of SAT-TB were calculated according to the results of L-J culture. The detection rates of SAT-TB and L-J culture were analyzed according to the clinical diagnosis and the difference of the 2 methods were analyzed by chi-square test. RESULTS: With the result of L-J culture as the reference, the sensitivity and the specificity of SAT-TB were 92% (71/77) and 86% (143/167), respectively. The accordance rate of SAT-TB and L-J culture was 88% (214/244). For tuberculosis patients, the detection rate of L-J culture and SAT-TB was 42% (75/177) and 54% (95/177) respectively. The difference between the detection rates of SAT-TB and L-J was significant by chi-square test (χ² = 4.527, P < 0.05). CONCLUSIONS: SAT-TB is a rapid, sensitive and specific method for detection of Mycobacterium tuberculosis in clinical sputum samples.