PCR for M. tuberculosis in tissue samples

Background: The presence of granuloma, visualized in histopathology for diagnosing tuberculosis in tissue samples, is not a specific finding. Moreover, histopathological examination of tissue sections needs one to two weeks for final reporting. A rapid and sensitive method is therefore needed for detection of Mycobacterium tuberculosis in these paucibacillary tissue samples. Methodology: A PCR-assay specific for IS6110 was evaluated for 104 different tissue samples in comparison to histopathology that was considered gold standard. Results: PCR showed 74.1% sensitivity and 96.1% specificity. False positive and false negative results were observed in three (2.88%) and seven (6.73%) samples, respectively. Positive agreement between histopathology and PCR was observed as 0.737, indicating substantial good agreement between two tests. Conclusions: PCR can be used for early diagnosis of tuberculosis in tissue samples that can help to initiate timely anti-tubercular treatment and prevent progression to irreversible changes.