Impact of nucleic acid amplification test on pulmonary tuberculosis notifications and treatments in Taiwan: a 7-year single-center cohort study

BACKGROUND: Nucleic acid amplification tests (NAAT) have been used as a diagnostic tool for pulmonary tuberculosis (PTB) in Taiwan for many years. In accordance with Taiwanese legislation, health care personnel are required to notify the Centers for Disease Control and Prevention (CDC) in case of suspected PTB. This study aimed to investigate the impact of NAAT(Gen-Probe) on the notification system for PTB and anti-tuberculosis treatments in Taiwan. METHODS: A retrospective study on the impact of NAAT (Enhanced Amplified Mycobacterium tuberculosis Direct Test [E-MTD], Gen-Probe, San Diego, CA, USA) [NAAT(Gen-Probe)] was carried out at Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation from March 2011 to December 2017. During the study period, microscopic acid-fast-bacilli smears and mycobacterial cultures were available for PTB diagnosis. NAAT(Gen-Probe) was first introduced at the hospital in January 2014 for use as a diagnostic method for PTB. Positive sputum culture was considered as the gold standard for PTB diagnosis. We excluded clinically-diagnosed PTB cases. RESULTS: When NAAT(Gen-Probe) was applied, the rate of error notification to CDC decreased from 64.3 to 7.0% (P < 0.001), and unnecessary anti-TB treatments administered to suspected cases decreased from 14.9 to 6.5% (P = 0.005). In the non-PTB group, the mean duration of unnecessary anti-TB treatments changed from 38.9 ± 38.3 days to 37.0 ± 37.9 days (P = 0.874). In the PTB group, the mean time from notifying CDC to initiating treatment decreased from 3.05 ± 6.95 days to 1.48 ± 1.99 days (P = 0.004). The sensitivity, specificity, positive predictive value, and negative predictive value of NAAT(Gen-Probe) were 99.0, 92.3, 99.0, and 92.3%, respectively. CONCLUSIONS: Use of NAAT(Gen-Probe) led to decrease in the rate of error notification of suspected PTB cases to the CDC, avoidance of unnecessary use of anti-TB treatments, and accelerated initiation of appropriate treatments.