GeneXpert versus histopathological examination and culture as a diagnostic tool for spinal tuberculosis: a comparative analysis

Background: Spinal tuberculosis, a common type of osteoarticular tuberculosis accounts for a significant proportion of extrapulmonary tuberculosis cases. This study compares the sensitivity, specificity of GeneXpert with histopathology and acid-fast bacilli (AFB) culture. Methods: This study conducted at a tertiary health care and teaching institution from October 2018 to October 2023 included 60 patients with suspected spinal tuberculosis. Samples including vertebral tissue and pus, obtained by open biopsy, fluoroscopy or computed tomography (CT) guided percutaneous vertebral body biopsy were collected in sterile containers with 2-3 ml of saline and immediately sent for testing with GeneXpert and AFB culture. Histopathological samples were placed in 10% formalin prior to examination. Results: When comparing GeneXpert with AFB culture, Sensitivity was found to be 82.2%, specificity 40.0%, positive predictive value (PPV) 80.4%, negative predictive value (NPV) 42.9% and accuracy was 71.7%. When comparing GeneXpert with histopathological examination (HPE), sensitivity was found to be 84.8%, specificity 50.0%, PPV 84.8%, NPV 50.0% and accuracy was 76.7%. Conclusions: Despite longer diagnostic time as compared to GeneXpert, AFB culture is still the gold standard diagnostic modality.