Measurement of Fractional Exhaled Nitric Oxide: Comparison of Three Different Analysers

Respiration. 2020;99(1):1-8. doi: 10.1159/000500727. Epub 2019 Jul 9.


Background: Fractional exhaled nitric oxide (FeNO) is a surrogate marker for airway inflammation, supporting the diagnostic pathway and treatment decisions for asthma patients.

Objectives: Aim of this study was to compare the new analyser Vivatmo pro (Bosch, BV) with NIOX VERO (Circassia, CN) and CLD (Ecomedics, EC).

Methods: In 100 asthmatics (median 53 years [range 20-87], 62% female, 86% on inhaled corticosteroids [mean 1,300 μg beclomethasone dipropionate or equivalent], 35% treated with biologics) 2 FeNO measurements per device were performed. Additionally, the success rate to achieve a valid NO value was evaluated.

Results: Sixty-eight percent of the patients had FeNO values below 50 ppb. Median NO concentrations were 31 ppb (range 6-194) for BV, 33 ppb (9-164) for CN and 31ppb (7-353) for EC. Bland-Altman plots suggested an agreement within the predefined limits of ±5 ppb for all analysers within the therapeutically relevant range (0-70 ppb). The highest agreement in FeNO levels were between BV and EC with mean differences of -0.26 (95% CI -1.48 to 0.95) vs. 1.52 (95% CI 0.4-2.6) ppb for CN and EC. The results indicate an equivalence of the methods (two-one sided t test-equivalence test: p < 0.0001, ±5 ppb margins). Acceptance of the measurements was high for all devices (97%). The highest success rate to obtain 2 valid NO values without failed attempts was achieved with the BV analyser (73 vs. 62% for the CN analyser and 46% for the EC analyser).

Conclusions: For the range between 0 and 70 ppb, FeNO concentrations measured with all 3 devices were statistically equivalent within predefined acceptance criteria and did not differ in a clinically relevant way.

Keywords: Airway markers; Asthma; Inflammation; Nitric oxide.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Anti-Asthmatic Agents / therapeutic use
  • Asthma / drug therapy
  • Asthma / metabolism*
  • Asthma / physiopathology
  • Breath Tests / instrumentation*
  • Female
  • Forced Expiratory Volume
  • Humans
  • Male
  • Middle Aged
  • Nitric Oxide / analysis*
  • Vital Capacity
  • Young Adult


  • Anti-Asthmatic Agents
  • Nitric Oxide