Screening of respiratory tract specimens for the presence of Mycobacterium tuberculosis by using the Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test.
A prospective 2-month trial involving 617 respiratory tract specimens was conducted to compare sensitivity, specificity, and predictive values of the newly developed Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test kit (AMTDT; Gen-Probe, Inc., San Diego, Calif.) for the rapid detection of Mycobacterium tuberculosis and of fluorescent acid-fast staining versus combined BACTEC 12B and solid-medium cultures as the "gold standard." A total of 590 specimens were culture and AMTDT negative. Twenty-one (3.4%) cultures yielded M. tuberculosis. Of these, 15 (71.4%) were detected by AMTDT, whereas 6 (28.6%) were missed. M. tuberculosis did not grow in six (28.6%) of AMTDT-positive specimens derived from three patients under treatment for tuberculosis. AMTDT exhibited a sensitivity, a specificity, a negative predictive value, and a positive predictive value of 71.4, 99, 99, and 71.4%, respectively. In comparison, the same values for fluorescent microscopy were 66.7, 98.3, 98.8, and 58.3%, respectively. AMTDT was easy to perform and highly specific. However, a screening test would require an improved sensitivity and, when feasible, the implementation of an internal amplification control.
Bodmer
T
T
Institute for Medical Microbiology, University of Berne, Switzerland.
Gurtner
A
A
Schopfer
K
K
Matter
L
L
D001431:Bacteriological Techniques; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology; D003470:Culture Media; D015342:DNA Probes; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D008856:Microscopy, Fluorescence; D009169:Mycobacterium tuberculosis / Q000276:immunology / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012329:RNA, Bacterial / Q000032:analysis*; D012335:RNA, Ribosomal / Q000032:analysis*; D011933:Reagent Kits, Diagnostic; D012137:Respiratory System / Q000382:microbiology*; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D013194:Staining and Labeling; D013997:Time Factors; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology
D003470:Culture Media; D015342:DNA Probes; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012329:RNA, Bacterial; D012335:RNA, Ribosomal; D011933:Reagent Kits, Diagnostic