Rapid detection of Mycobacterium tuberculosis using a novel ultrafast chip-type real-time polymerase chain reaction system

BACKGROUND: NBS LabChip G2-3 is a novel, ultrafast, chip-type portable real-time polymerase chain reaction (PCR) system. We evaluated the clinical usefulness of this system in detecting pulmonary TB and assessed its diagnostic performance compared witha conventional tube-type PCR system. METHODS: A total of 247 sputum samples were collected from patients suspected of having pulmonary TB. After the decontamination process, these samples were examined by fluorescence staining for acid-fast bacilli, cultures with both solid and liquid media, and real-time PCR with the NBS LabChip and a conventional tube-type system. The diagnostic accuracy of the NBS LabChip system and the agreement between the two assays were evaluated. RESULTS: Considering mycobacterial culture results as a gold standard, the overall sensitivity and specificity of the NBS LabChip was 83.8% (95% CI, 73.8%-91.1%) and 94.0% (95% CI, 89.3%-97.1%), respectively. For the detection of TB from the smear-positive samples, the sensitivity and specificity of the NBS LabChip was 96.0% (95% CI, 86.3%-99.5%) and 83.3% (95% CI, 72.3%-95.7%), respectively. For the smear-negative samples, the sensitivity and specificity of the NBS LabChip was 63.3% (95% CI, 43.9%-80.1%) and 95.0% (95% CI, 90.4%-97.8%), respectively. There were no significant differences in the sensitivity and specificity between the NBS LabChip and a conventional tube-type system, although the NBS LabChip shortened the PCR time (27 min for 45 cycles). CONCLUSIONS: The NBS LabChip G2-3 system has potential as an ultrafast, cost-effective diagnostic tool for pulmonary TB with high sensitivity and specificity.