Detection of Mycobacteria in Clinical Samples by the Newly Developed PaxView TB/NTM MPCR-ULFA Kit

Aims: To evaluate sensitivity and specificity of the newly developed PaxView TB/NTM MPCR-ULFA Kit.  Study Design: Compared with the licensed AdvanSure TB/NTM real-time PCR. Place and Duration of Study: SCL and PaxGenBio in Gyeonggi-do, Korea, between August 2018 and May 2019. Methodology: In this study, 350 specimens including sputum, bronchial washing, body fluid, tissue, urine, and cerebrospinal fluid were examined to evaluate the performance of the PaxView TB/NTM MPCR-ULFA Kit compared to results of the currently licensed AdvanSure TB/NTM real-time PCR (LG Chem, Korea). Results: Compared to the AdvanSure TB/NTM real-time PCR, the PaxView TB/NTM MPCR-ULFA Kit test was found to possess a 100% sensitivity. In other words, all 140 MTB and 61 non-tuberculous mycobacteria (NTM) specimens that tested positive with the AdvanSure TB/NTM real-time PCR also tested positive with the PaxView TB/NTM MPCR-ULFA Kit. However, the specificity of the later kit found to be 97.9% (146/149; 95% CI 95.6–100.0), meaning that out of 149 MTB/NTM specimens that tested negative with the AdvanSure TB/NTM real-time PCR, 146 were identified as MTB/NTM-negative according to the PaxView TB/NTM MPCR-ULFA Kit. Nonetheless, the overall agreement between the two diagnostic tools was 99.1% (347/350; 95% CI 98.1– 100.0) and the kappa value was 0.982 (350; 95% CI 0.968 – 0.995), meaning that the two diagnostic tools rendered almost identical results. Conclusion: The PaxView TB/NTM MPCR-ULFA Kit could be useful to identify MTB and NTM in resource-limited countries, as this procedure is far more cost-effective than real-time PCR and convenient than conventional gel electrophoresis approaches.