title: Clinical efficacy of the amplified Mycobacterium tuberculosis direct test for the diagnosis of pulmonary tuberculosis.
abstract: The amplified Mycobacterium tuberculosis direct test (MTD) is a rapid diagnostic test based on a nucleic acid amplification technique, which can be used directly on processed clinical specimens. We evaluated the clinical utility of the MTD for diagnosing pulmonary tuberculosis by comparing the sensitivity and specificity of the test with acid-fast smear, mycobacterial culture, and clinical evaluation. The study included 844 respiratory tract specimens from 421 patients, which were submitted to the microbiology laboratory of our urban teaching hospital over a 6-mo period. Compared with culture, MTD had a sensitivity of 93.6% and specificity of 97.8%. MTD was more sensitive in detecting pulmonary tuberculosis in patients with previously undiagnosed disease (74.7%) than in those with established disease receiving chemotherapy (29.2%), and in smear-positive (95.5%) than in smear-negative (70.0%) disease. There were two false positive MTD results in patients with nontuberculous mycobacteria, for a specificity in this population of 97.3%. We conclude that MTD, when used in conjunction with routine smear and culture, is a useful rapid diagnostic test for suspected pulmonary tuberculosis.
authors.affiliation: Department of Medicine, University of California San Diego 92103-8374, USA.
authors.forename: S P
authors.initials: SP
authors.lastname: Bradley
authors.forename: S L
authors.initials: SL
authors.lastname: Reed
authors.forename: A
authors.initials: A
authors.lastname: Catanzaro
mesh_terms: D000995:Antitubercular Agents / Q000627:therapeutic use; D001431:Bacteriological Techniques; D015342:DNA Probes; D004269:DNA, Bacterial / Q000032:analysis; D005189:False Positive Reactions; D005260:Female; D006784:Hospitals, Teaching; D006786:Hospitals, Urban; D006801:Humans; D007755:Laboratories, Hospital; D008297:Male; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000302:isolation & purification; D009170:Nontuberculous Mycobacteria / Q000145:classification / Q000302:isolation & purification; D021141:Nucleic Acid Amplification Techniques; D012329:RNA, Bacterial / Q000032:analysis*; D012335:RNA, Ribosomal / Q000032:analysis; D012137:Respiratory System / Q000382:microbiology; D012680:Sensitivity and Specificity; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D015342:DNA Probes; D004269:DNA, Bacterial; D012329:RNA, Bacterial; D012335:RNA, Ribosomal