Detection of Spinal TB Infection: A Retrospective Study Evaluating Comparative Diagnostic Efficacy of AFB Smear, Gene Expert, Histopathology, Culture Sensitivity and LPA Tests From a Biopsy Sample

Background: Spinal Tuberculosis (TB) is one of the significant health dangers that affect the general wellbeing of an individual. It is one of the most common form of extra pulmonary tuberculosis that affects the general population. Diagnosis of tuberculosis is done using an array of techniques. The present study has compared the efficacy of these tests used for detecting the spinal TB in biopsy samples. Material and Methods: The study was conducted on patients who suffered from spondylodiscitis and with biopsy proven spinal TB by one of the following tests and were treated in the study center. The study included a total of 150 patients with spinal TB who visited the department for further treatment. The biopsy samples of these patients were then processed for Line probe assay (LPA), Gene Xpert, liquid culture (bactec MGIT) followed by gram staining and fungal staining, and histopathological examination. Result: In this study total of 150 patients were included who had ages ranging from 16-77 years with 93male and 57 female patients. When the study results were compared Gene Experts showed a 100% sensitivity and 80% of specificity. When we compared the histopathology results with gene expert, we get a sensitivity of 16.7% and specificity of 50%. Gram stain with the sensitive gene expert, the sensitivity is 45.5% and specificity is 25%. Similar analysis was done with sensitive gene and now with the resistant gene to identify their sensitivity was 0% and the specificity was at 42.9%. Gram stain when correlated with gene, the sensitivity came out to be 9.1% and specificity at 25%. Fungal stain with resistant gene, when correlated, sensitivity comes to 9.1% and specificity is at 0%. Conclusion: This study showed that for detection of tuberculosis rather than relying on only single technique it should be done with a combination of techniques. Keywords: Gene Xpert, LPA, Histopathological examination, Tuberculosis, Gram staining