Role of Real time Polymerase Chain Reaction in the diagnosis of tubercular lymphadenitis

Abstract

Background: Tubercular lymphadenitis (TBL) is the most common form of extra pulmonary tuberculosis. Currently the standard diagnostic tool for TBL is culture, which takes more than several weeks to yield results. Recently the use of nucleic acid amplification tests (NAATs), especially polymerase chain reaction (PCR) has gained acceptance for rapid diagnosis of tubercular lymphadenitis. This study is to evaluate the role of real time PCR in the diagnosis of tubercular lymphadenitis. Methods: This cross-sectional type of descriptive study was conducted in the Department of Pathology, Rajshahi Medical College and Department of Microbiology (BSMMU) over a period of two years from July 2017 to June 2019. Tissue biopsy from the lymph node was fixed with 10% formalin and was processed and stained with haematoxylin and eosin stain and was examined in Pathology Department of Rajshahi Medical College, Rajshahi and Real time PCR was done in Microbiology Department of BSMMU, Dhaka. Out of the 47 cases, 32 cases were histopathologically confirmed as tubercular lymphadenitis and the rest 15 cases were as chronic non-specific lymphadenitis which served as control in the study.  Results: The Real time PCR had (46.87%) sensitivity, (100%) specificity. PPV was (100%) and NPV was (46.87%). The overall diagnostic accuracy of the test was (63.82%). Conclusion:  The study concluded that role of Real time PCR was mildly sensitive and highly specific in the diagnosis of tubercular lymphadenitis.