Comparison of fractional exhaled nitric oxide levels measured by different analyzers produced by different manufacturers

Abstract

Objective: Fractional exhaled nitric oxide (FeNO) is widely used as a biomarker of allergic airway inflammation. At present, both stationary chemiluminescence and portable electrochemical analyzers produced by different manufacturers are available. However, it remains debatable whether those analyzers are comparable to each other. We compare FeNO levels obtained by different analyzers.

Methods: For the first study, 153 subjects were enrolled to compare differences in FeNO levels measured using three analyzers (NA623NP^®, NObreath^®, and NIOX MINO^®) which were produced by different manufacturers. For the second study, 30 subjects were recruited to compare FeNO levels obtained by the two analyzers (NIOX MINO^® and NIOX VERO^®) produced by the same manufacturer. FeNO was measured twice using each analyzer in random order.

Results: FeNO levels obtained using the NIOX MINO^® and NObreath^® were more variable than those measured using the NA623NP^®. There were strong positive correlations in FeNO levels measured by the NA623NP^®, NIOX MINO^®, and NObreath^® (p < 0.001). The NA623NP^® and NIOX MINO^® provided the highest and lowest FeNO levels, respectively; whereas, those obtained by NObreath^® were intermediate. No significant differences were observed in FeNO levels obtained using the NIOX MINO^® and NIOX VERO^®.

Conclusions: FeNO levels measured by the NIOX MINO^® and NIOX VERO^®, both of which were produced by the same manufacturer, have comparability. However, significant differences in FeNO levels exist when measured by analyzers manufactured by different manufacturers. This should be taken into account for FeNO measurement.

Keywords:

• Exhaled nitric oxide
• chemiluminescence analyzer
• electrochemical analyzer
• NIOX MINO^®
• NObreath^®
• NIOX VERO^®
• device difference

Acknowledgments

We would like to thank the Scientific English Editing Section in our university for their linguistic assistance in proofreading the manuscript. We would also like to thank Miss Yasuko Sato for the technical support.

Declaration of interest

All authors declared no conflict of interest.

Additional information

Funding

No financial support was provided for the conduct of the research and/or preparation of this article.

Notes on contributors

Junpei Saito

JS conceived and designed the study; analyzed and interpreted the data; drafted and edited the manuscript; recruited patients and approved the final version of the manuscript. MK and MR recruited patients; analyzed and interpreted the data; reviewed the manuscript critically for important intellectual content. AF, SS, YSu, MU, NF, TKa, TU, RT, YS, TKo, HK, HM, TN, KK, and YT recruited patients and reviewed the manuscript critically for important intellectual content. YSh and MM contributed to interpretation of data and critically revised the manuscript. All authors approved the final version of the manuscript.