A comparative study of the RuiBreath and NIOX VERO analyzers for detecting fractional exhaled nitric oxide

BACKGROUND: Fractional exhaled nitric oxide (FeNO) measurement is a reliable, noninvasive marker of airway inflammation. Portable FeNO analyzers facilitate the assessment of airway inflammation in primary care. Differences between analyzers from different manufacturers are not comparable. Here, we aimed to compare the FeNO values obtained by a new portable device (RuiBreath, Guangzhou Ruipu Medical Technology Co., Ltd, Guangzhou, China) to those obtained by the widely used NIOX VERO portable analyzer (Aerocrine AB, Solna, Sweden) in patients with asthma. METHODS: This prospective validation study enrolled patients (≥14 years old) with asthma over a 2-month period (July and August 2019) at the Beijing Chao-Yang Hospital. At least one valid FeNO measurement was obtained using each analyzer for all the participants. RESULTS: There were 197 participants in this study. The FeNONIOX and FeNORuiBreath values significantly differed (P=0.016). After log-transformation, a difference was found only when the FeNONIOX was <25 ppb (P<0.001). The FeNONIOX and FeNORuiBreath values had a significant correlation (r=0.938, P<0.001), which was confirmed by the Altman-Bland plot. Using a receiver-operating characteristic curve analysis, when using 49 ppb as the cut-off point for the two devices in identifying patients with symptomatic asthma symptoms, the sensitivity and specificity were 0.42 and 0.88, respectively, by NIOX, and 0.40 and 0.89, respectively, by RuiBreath. CONCLUSIONS: This is the first report of FeNO values obtained by the new portable RuiBreath FeNO analyzer. The FeNORuiBreath values are reliable and directly comparable with the FeNONIOX values.