RNA Amplification for Direct Detection of Mycobacterium tuberculosis in Respiratory Samples

Abstract

A target amplified test system (AMTDT, Gen-Probe, San Diego, California, USA) was compared with conventional standard methods in the detection of Mycobacterium tuberculosis in sputum and other respiratory specimens from patients with suspected tuberculosis. The highest incidence of positive samples was seen with the AMTDT test. Out of 450 samples from patients with known or suspected tuberculosis, 43 (9.6%) were positive by culture, and 47 (10.4%) with AMTDT. After discrepancy analysis, 7 of the culture-negative but AMTDT-positive samples were judged to be true positive, giving the AMTDT a sensitivity of 92.0% and a specificity of 99.8%. The AMTDT test was rapid, easy to perform, sensitive, and highly specific.