Utility of PCR targeting IS6110 and MPT64 genes in the diagnosis of extrapulmonary tuberculosis

Introduction Extrapulmonary tuberculosis (EPTB) is one of the major diagnostic challenges in clinical practice. The aim of the study was to compare the utility of Polymerase Chain Reaction (PCR) with conventional techniques in the diagnosis of EPTB. Materials and methods Specimens from 150 patients with a presumptive diagnosis of EPTB were examined by Zeihl-Neelsen staining and mycobacterial culture on Lowenstein Jensen medium. Histopathology was done for lymph node aspirates and endometrial biopsies. DNA from all the samples was amplified by PCR targeting 123 bp and 240 bp fragments of IS6110 and MPT64 genes respectively. Results IS6110 PCR was more sensitive (82.1%) as compared to PCR for MPT64 gene (81%) though the difference was not found to be statistically significant. Four (2.6%) and 2 (1.3%) samples were positive by IS6110-PCR only and MPT64-PCR only respectively.Conclusion: PCR with multiple targets can have potentially important role in improving diagnostic accuracy of EPTB.