Head-to-Head Comparison between Xpert MTB/RIF Assay and Real-Time Polymerase Chain Reaction Assay Using Bronchial Washing Specimens for Tuberculosis Diagnosis.
Eunjeong Son, Jinook Jang, Taehwa Kim, Jin Ho Jang, Jae Heun Chung, Hee Yun Seol, Hye Ju Yeo, Seong Hoon Yoon, Seung Eun Lee, Woo Hyun Cho, Yun Seong Kim, Doosoo Jeon
Author Information
Eunjeong Son: Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.
Jinook Jang: Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.
Taehwa Kim: Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.
Jin Ho Jang: Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.
Jae Heun Chung: Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.
Hee Yun Seol: Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.
Hye Ju Yeo: Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.
Seong Hoon Yoon: Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.
Seung Eun Lee: Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.
Woo Hyun Cho: Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.
Yun Seong Kim: Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.
Doosoo Jeon: Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.
BACKGROUND: With the introduction of Xpert MTB/RIF assay (Xpert), its incorporation into tuberculosis (TB) diagnostic algorithm has become an important issue. The aim of this study was to evaluate the performance of the Xpert assay in comparison with a commercial polymerase chain reaction (PCR) assay. METHODS: Medical records of patients having results of both Xpert and AdvanSure TB/NTM real-time PCR (AdvanSure) assays using the same bronchial washing specimens were retrospectively reviewed. RESULTS: Of the 1,297 patients included in this study, 205 (15.8%) were diagnosed with pulmonary TB. Using mycobacterial culture as the reference method, sensitivity of the Xpert assay using smear-positive specimens was 97.5%, which was comparable to that of the AdvanSure assay (96.3%, p=0.193). However, the sensitivity of the Xpert assay using smear-negative specimens was 70.6%, which was significantly higher than that of the AdvanSure assay (52.9%, p=0.018). Usng phenotypic drug susceptibility testing as the reference method, sensitivity and specificity for detecting rifampicin resistance were 100% and 99.1%, respectively. Moreover, a median turnaround time of the Xpert assay was 1 day, which was significantly shorter than 3 days of the AdvanSure assay (p<0.001). CONCLUSION: In comparison with the AdvanSure assay, the Xpert assay had a higher sensitivity using smear-negative specimens, a shorter turnaround time, and could reliably predict rifampin resistance. Therefore, the Xpert assay might be preferentially recommended over TB-PCR in Korean TB diagnostic algorithm.
