Challenging diagnosis of gastrointestinal tuberculosis made simpler with multi-targeted loop-mediated isothermal amplification assay

Background Prompt and accurate diagnosis of gastrointestinal tuberculosis (GITB) is highly challenging. Current conventional techniques lack sensitivity and are time-consuming. Multi targeted loop-mediated isothermal amplification (LAMP) using two targets (IS6110 and MPB64) is a promising technique for rapid diagnosis of TB. Methods LAMP test using IS6110 and MPB64 targets for M. tuberculosis complex was performed on ileocecal biopsy samples of 35 clinically suspected patients of GITB and 30 ileocecal biopsy samples of non-tuberculosis control subjects. Results of IS6110 LAMP and MPB64 LAMP were compared with IS6110 PCR and culture INFERENCE: Overall LAMP test (using any of the two targets) had a sensitivity and specificity of 100 and 100%, respectively, for confirmed GITB (five culture positive) cases and 85.71 and 100%, respectively, for clinically suspected 30 ileocecal biopsy samples of GITB. Sensitivity of IS6110 LAMP, MPB64 LAMP and IS6110 PCR for clinically suspected cases was 22 (73.33%), 24 (80%) and 21 (70%), respectively. In total 35 GITB patients, the overall sensitivity of microscopy, culture, IS6110 PCR, IS6110 LAMP, MPB64 LAMP and the multi-targeted LAMP assay (if any of the two targets were used) were 5.71, 14.28, 68.57, 74.28, 82.85 and 85.71%, respectively. Specificity of all the tests was 100%. There were three cases which were missed by IS6110 LAMP and two cases by MPB64 LAMP. Conclusion Multi-targeted LAMP is a promising technique for rapid and accurate diagnosis of GITB.