Multicenter evaluation of a real-time loop-mediated isothermal amplification (RealAmp) test for rapid diagnosis of Mycobacterium tuberculosis.

The real-time loop-mediated isothermal amplification (RealAmp) test is a novel technology for rapid diagnosis of Mycobacterium tuberculosis (MTB) from sputum samples. This test has not previously been effectively evaluated. In this study, we assessed the performance of the RealAmp test for tuberculosis (TB) detection among TB suspected patients from three provincial hospitals in China. Each eligible TB suspected patients in Shanghai, Guangzhou, and Shandong provided one sputum specimen each, smear microscopy, liquid culture, and the RealAmp test were performed per patient. A total of 1583 TB suspected patients were enrolled in the study, and 1519 were used for the performance analysis. The sensitivity and specificity of the RealAmp test for MTB detection were calculated using liquid culture as reference method. The sensitivity of RealAmp test in smear-negative and culture-positive patients was 60.08%; the sensitivity in smear-positive and culture-positive patients was 97.09%; and the overall sensitivity in culture-positive patients was 74.88%. The specificity of RealAmp test for MTB detection was 86.50%.