Comparison of the automated cobas amplicor mycobacterium tuberculosis assay with the conventional methods for direct detection of mycobacterium tuberculosis complex in respiratory and extrapulmonary specimens

ABSTRACT

To evaluate the recently available Cobas Amplicor polymerase chain reaction [PCR] system for the detection of Mycobacterium tuberculosis complex [MTBC] in well-characterized clinical specimens and to compare the results with clinical classification, conventional culture and staining techniques. Three hundred and forty-four clinical specimens consecutively received for culture of acid-fast bacilli by the laboratory of Zayed Military Hospital, Abu Dhabi, United Arab Emirates, from 2004 to 2005, were used in this study. Acid-fast bacilli and culture for tuberculosis were compared with Cobas Amplicor PCR. The final diagnostic evaluation of the Cobas Amplicor MTB showed the followings sensitivity 73.3%, specificity 99.4%, positive predictive value 84.6%, negative predictive value 98.8% and with accuracy of 98.2% for the Cobas Amplicor MTB assay. The automated Cobas Amplicor MTB assay is suitable for routine use in clinical laboratories