Comparative diagnostic value of Genexpert MTB/RIF, PCR targeting IS6110 and culture for the diagnosis of spinal tuberculosis

Introduction Spinal tuberculosis is an extra-pulmonary tuberculosis infection caused by Mycobacterium tuberculosis (MTB) which affects the vertebrae. Culture test is the «gold standard» diagnostic method, but it takes a long time. PCR is a method of a shorter time than the culture test, so it can be an alternative diagnostic method for MTB. Materials and Methods This study is a cross-sectional study. The data were analyzed with diagnostic tests on patients with suspected spinal tuberculosis who performed surgery in Hasan Sadikin Hospital in Bandung. Clinical examinations and diagnostic examinations were done in 40 patients and surgery was performed to obtain samples from the spinal cord and the infected tissue. GeneXpert, PCR targeting IS6110 and culture tests were performed. The research was conducted at the Department of Orthopaedics and Traumatology and the Clinical Pathology Laboratory of FK UNPAD/RSHS from September 2019 to September 2020. Results GeneXpert assay compared with culture tests as the standard diagnostic method showed sensitivity of 96.67 %; specificity of 90.00 %; positive predictive value 96.67 %; and a negative predictive value of 90.00 %, with an accuracy of 95.00 %. The PCR targeting IS6110 against culture showed that the sensitivity of MTB bacterial infection was 93.33 %, the specificity was 80.00 %, the positive predictive value was 93.33 %, the negative predictive value was 80.00 %, and the accuracy was 90.00 %. Conclusion This study concluded that the GeneXpert MTB/RIF RT-PCR assay has a high sensitivity, specificity, and accuracy compared to PCR targeting IS6110 in examining tissue samples in patients with spinal TB.