Evaluation of the simultaneous amplification and testing for diagnosis of Mycobacterium tuberculosis / 中华检验医学杂志

ABSTRACT

Objective To evaluate the clinical value of the isothermal RNA amplification assay (SAT) for detection of Mycobacterium tuberculosis in sputum samples.Methods Sputum specimens from 230 patients with diagnosed tuberculosis and 78 cases of other respiratory diseases during September to December 2011 were detected using SAT,BD960 culture,LowenStein-Jensen( L-J ) culture and concentrated smear simultaneously.The samples with different results between SAT and BD960 culture were tested by Mycobacterium tuberculosis PCR fluorescence diagnosis kits.Strains were identified by amplification and sequencing the BD960 culture-positive isolates and SAT amplification products.Positive detection rate of SAT and other three methods for patients with tuberculosis were compared by chi-square test.Results Using the results of BD960 culture as the golden standard (7 cases of pollution bacteria in BD960 culture was rejected ),the sensitivity,specificity,positive predictive value,and negative predictive value of SAT was 90.5％ (95/105),84.2％ (165/196),75.4％ (95/126),94.3％ (165/175),respectively.The agreement rate of SAT and BD960 culture was 86.4％ (260/301).For 223 tuberculosis patients,the positive detection rate of SAT,BD960 culture,L-J culture and concentrated smear was 56.5％ ( 126/223 ),45.7％ ( 102/223 ),41.7％ ( 93/223 ) and 37.2％ ( 83/223 ) respectively.The positive detection rate of SAT is significantly higher than the other three methods (x2 =4.087,P ＜ 0.05 ).Conclusion SAT,as a new technology for laboratory diagnosis of TB,has high specificity and sensitivity.The operation is fast and simple,and the pollution rate is low.It is a promising laboratory diagnosis method.