SESSION TITLE: Chest Infections Posters: Tuberculosis
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 28, 2015 at 01:30 PM - 02:30 PM
PURPOSE: The Xpert MTB/RIF assay, an automated nucleic acid amplification test (NAAT), was introduced for detecting tuberculosis (TB). The performance of the Xpert assay has been evaluated in various clinical settings. However, there are no data comparing the Xpert assay to other NAAT for pulmonary TB (PTB) especially in lower respiratory tract specimen (LRTS).
METHODS: We conducted this study to evaluate the practical diagnostic performance of the Xpert assay in detecting PTB as compared with the AdvanSure TB/NTM RT-PCR kit, using LRTS obtained thorough bronchoscopy on one session. The Xpert assay was performed with direct LRTS, while the AdvanSure TB/NTM RT-PCR was done with decontaminated and concentrated LRTS according to manufacturer’s protocol.
RESULTS: In total, 249 patients were included. Of these, 105 had culture-confirmed PTB. Based on the culture as a reference method, the overall sensitivities of the Xpert assay and the AdvanSure TB/NTM RT-PCR were 92.4% and 83.8%, respectively. When AFB smear results were taken into consideration, the sensitivities of the Xpert assay for smear-positive and smear-negative LRTS were 100% and 88.9%, while those of the AdvanSure TB/NTM RT-PCR were 100% and 76.4%, respectively. The Xpert assay showed better results than the AdvanSure TB/NTM RT-PCR for overall sensitivity and sensitivity in smear-negative LRTS (P=0.012), while no differences in smear-positive LRTS.
CONCLUSIONS: The Xpert assay may be advantageous role in detect PTB using LRTS, especially in low microbiologic burden setting, considering no requirement of decontamination and concentration steps.
CLINICAL IMPLICATIONS: The Xpert assay may be advantageous role using LRTS, especially in the situation of low microbiologic burden such as stain-negative PTB, because the Xpert assay do not require both decontamination and concentration steps, resulted in a loss of micro-organism. In conclusion, the Xpert MTB assay showed the better practical diagnostic performance in comparison with the AdvanSure TB/NTM RT-PCR in LRTS obtained by bronchoscopy.
DISCLOSURE: The following authors have nothing to disclose: Yousang Ko, Boksoon Chang
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