Annals of Clinical Microbiology, The official Journal of the Korean Society of Clinical Microbiology
Original article

Clinical Usefulness of Real-time PCR and Amplicor MTB PCR Assays for Diagnosis of Tuberculosis

Chae Lim Jung, Mi Kyung Kim, Dong Chun Seo, Mi Ae Lee

Department of Laboratory Medicine, School of Medicine, Ewha Womans University Mokdong Hospital, Seoul, Korea

Corresponding to Mi Ae Lee, E-mail: miae@ewha.ac.kr

Ann Clin Microbiol 2008;11(1):29-33.
Copyright © Korean Society of Clinical Microbiology.

Abstract

Background: PCR assay has provided a mean of more rapid and sensitive detection of Mycobacterium tuberculosis (MTB) complex than conventional acid- fast bacilli (AFB) smears and MTB cultures. Using the recently developed AdvanSure TB/NTM kit (LG Life Science Diagnostic Division, Korea), which could differentiate nontuberculous mycobacteria (NTM) from MTB, this study compared clinical usefulness of real-time PCR assay and Amplicor MTB PCR assay (Roche Molecular Systems, USA) for diagnosis of tuberculosis. 

Methods: A total of 213 specimens (148 respiratory and 65 nonrespiratory specimens) were tested by using real-time PCR, Amplicor MTB PCR, AFB smear, and MTB culture. The sensitivity and specificity of four methods were evaluated according to clinical diagnosis. 

Results: Of six NTM grown in culture, four (67%) were detected by real-time PCR. The overall agreement of real-time and Amplicor MTB PCR was 92% (191/207). The overall sensitivity and specificity were 91% and 87%, respectively, for real-time PCR, and 86% and 93% for Amplicor MTB PCR. In nonrespiratory specimens, the sensitivities of real-time PCR, Amplicor MTB PCR, AFB smear, and MTB culture were 67%, 60%, 13%, and 40%, respectively, and the specificity of the four methods were all 100%. 

Conclusion: For diagnosis of tuberculosis, the sensitivity and specificity of the real-time PCR assay using AdvanSure TB/NTM kit and Amplicor MTB PCR were similar, and the former could differentiate NTM from MTB. The PCR assay can be considered as a more sensitive technique for the detection of MTB than the conventional AFB smear and culture. (Korean J Clin Microbiol 2008;11:29-33)

Keywords

Mycobacterium tuberculosis, Nontuberculous mycobacteria, nonrespiratory, Real-time PCR