title: Comparison of two nucleic acid amplification assays, the Xpert MTB/RIF assay and the amplified Mycobacterium Tuberculosis Direct assay, for detection of Mycobacterium tuberculosis in respiratory and nonrespiratory specimens.
abstract: We compared the performance of the Xpert MTB/RIF assay, a new real-time tuberculosis (TB) PCR test, with that of the Amplified Mycobacterium Tuberculosis Direct (MTD) assay using 162 respiratory and nonrespiratory specimens. Based on culture as the gold standard, the overall sensitivity and specificity for all sample types for the Xpert MTB/RIF assay were 90.9 and 89%, respectively, while for the MTD assay, the overall sensitivity and specificity were 97.3 and 87.1%, respectively. A higher proportion of total equivocal results were obtained for the MTD assay, at 10.5% (17/162), while the Xpert MTB/RIF assay generated 5.5% (9/162) of invalid reads.
authors.affiliation: National University Hospital, Main Building Level I, Department of Laboratory Medicine, Microbiology Unit, Singapore 119074, Singapore. Jeanette_Teo@nuhs.edu.sg
authors.forename: Jeanette
authors.initials: J
authors.lastname: Teo
authors.forename: Roland
authors.initials: R
authors.lastname: Jureen
authors.forename: Donald
authors.initials: D
authors.lastname: Chiang
authors.forename: Douglas
authors.initials: D
authors.lastname: Chan
authors.forename: Raymond
authors.initials: R
authors.lastname: Lin
mesh_terms: D001431:Bacteriological Techniques / Q000379:methods*; D006801:Humans; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000175:diagnosis* / Q000382:microbiology*