Utility of clinicoradiological, microbiological, histopathological, and molecular methods in the diagnosis of spinal tuberculosis

Purpose The diagnosis of STB is mainly based on clinicoradiological observations substantiated by bacterial culture, staining, Gene Xpert, and histopathology. The purpose of the study was to correlate these methods to evaluate the effectiveness in the diagnosis of STB. Methods A total of 178 clinicoradiologically suspected cases of STB were included in the study. The specimens for diagnostic workup were collected either during surgery or by CT-guided biopsy. All these specimens were tested for tuberculosis through ZN staining, solid culture, histopathology, and PCR. The sensitivity, specificity, PPV, and NPV of each test were calculated using histopathology as a gold standard. Results Out of the 178 cases, a total of 15 cases were excluded from this study. Among the remaining 163 cases, TB was diagnosed in 143 [87.73%] on histopathology, 130 [79.75%] on Gene Xpert, 40 [24.53%] on culture, and 23 [14.11%] on ZN stain. The sensitivity, specificity, PPV, and NPV of Gene Xpert were 86.71, 70, 95.38, and 42.42%, respectively. The sensitivity, specificity, PPV, and NPV of AFB culture were 27.97, 100, 100, and 16.26%, respectively. The sensitivity, specificity, PPV, and NPV of AFB stain were 16.08, 100, 100, and 14.29%, respectively. Gene Xpert showed a moderate agreement [Ƙc = 0.4432] with histopathology. Conclusion No single diagnostic modality can ascertain the diagnosis, and it is desirable to have a combination of diagnostic batteries for better results. A combination of Gene Xpert and histopathology aids in early and reliable diagnosis of STB.