Nanogold Assay Improves Accuracy of Conventional TB Diagnostics.

PURPOSE: TB nanodiagnostics have witnessed considerable development. However, most of the published reports did not proceed beyond proof-of-concept. Our objectives are to evaluate the diagnostic accuracy of a novel nanogold assay in detecting patients with active pulmonary TB based on results of BACTEC MGIT (reference test), and to compare its clinical performance to combined use of sputum smear microscopy (SSM) with chest X-ray (CXR).

METHODS: This is a case-control study that involved 20 active TB patients; 20 non-TB chest patients with a previous history of TB infection; 20 non-TB chest patients without a previous history of TB infection.

RESULTS: Sensitivity and specificity of TB nanogold assay were 95% and 100%, respectively, with diagnostic odds ratio (DOR) of 1053.0. ROC curve analysis yielded an area under curve (AUC) of 0.975. TB nanogold assay generated higher performance than combined use of SSM with CXR. The DOR and AUC differences were 996.0 and 0.125, respectively.

CONCLUSIONS: Our study shows that TB nanogold assay is accurate, rapid, and holds the potential for use as an add-on initial test to improve accuracy of SSM and CXR in detecting patients of active pulmonary TB in developing countries. Future studies should involve larger sample size for further assessment of test accuracy.