Evaluation of the enhanced amplified Mycobacterium tuberculosis direct test for direct detection of Mycobacterium tuberculosis complex in respiratory specimens.
OBJECTIVE
To evaluate the performance of the enhanced Mycobacterium Tuberculosis Direct Test (E-MTD), for the direct detection of M tuberculosis complex (MTBC) in respiratory specimens.


METHODS
Two hundred seventy-four respiratory specimens from 151 patients in respiratory isolation were tested with the E-MTD, and the results were compared with the results of mycobacterial smear, culture, and the earlier form of the test, MTD-1.


RESULTS
Forty-one specimens were culture positive for mycobacteria (20 MTBC and 21 nontuberculous mycobacteria), 23 of which were smear positive (16 MTBC, 7 nontuberculous mycobacteria). Twenty-four specimens were positive by E-MTD, and 21 were positive by MTD-1. Of the 20 MTBC culture-positive specimens, 19 were positive by the E-MTD and 19 were positive by the MTD-1. The remaining specimens were MTBC negative by all methods. After resolution of discrepancies, the sensitivity, specificity, and positive and negative predictive values were 95.2%, 100%, 100%, 99.6% for the MTD-1 and 95.2%, 98.8%, 87.0%, and 99.6%, for the E-MTD. For the E-MTD smear-positive and smear-negative specimens, these same values were 93.8%, 100%, 100%, and 87.5% and 100%, 98.8%, 62.5%, and 100%, respectively.


CONCLUSIONS
The results suggest that the E-MTD is a reliable method for the direct detection of MTBC in smear-positive respiratory specimens.
Smith
M B
MB
Division of Microbiology, Department of Pathology, University of Texas Medical Branch, Galveston 77555, USA.
Bergmann
J S
JS
Onoroto
M
M
Mathews
G
G
Woods
G L
GL
D001431:Bacteriological Techniques / Q000706:statistics & numerical data; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology; D003951:Diagnostic Errors; D005069:Evaluation Studies as Topic; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000302:isolation & purification*; D021141:Nucleic Acid Amplification Techniques; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000382:microbiology*