Evaluation of rapid identification method for Mycobacterium tuberculosis complex using the immunochromatographic slide test kit

Capilia TB, a lateral flow immunochromatographic slide test kit for directly identifying Mycobacterium tuberculosis complex (MTC), was evaluated by using culture-positive specimens from Mycobacteria Growth Indicator Tubes (MGIT). Sputum specimens from patients suspected of having tuberculosis were treated with NALC-NaOH and cultivated in MGIT960. Liquid specimens were collected from the positive tubes and directly inoculated with Capilia TB. Liquid specimens were also directly tested with AccuProbe. Of the organisms isolated from the 100 MGIT positive tubes, M. tuberculosis complex was identified in 49 (49%) tubes with Capilia TB and not identified in 51 (51%) with Capilia TB. Mycobacterium avium-intracellulare complex (MAC) was identified in 46 (46%) with AccuProbe MAC and other acid-fast bacteria were identified in 5 (5%) by DNA-DNA hybridization method. There were one tube in which M. tuberculosis complex was detected with Capilia TB and M. tuberculosis complex was not detected with AccuProbe MTC, but no tubes in which M. tuberculosis complex was detected with AccuProbe MTC and M. tuberculosis complex was not detected with Capilia TB. Capilia TB is excellent in sensitivity and specificity and very suitable for rapid diagnosis of tuberculosis and is considered to contribute to public health intervention measures taken for the tuberculosis control in Japan.