Comparison of exhaled nitric oxide measurements between NIOX MINO® electrochemical and Ecomedics chemiluminescence analyzer

Background: Exhaled nitric oxide (eNO) is an established, noninvasive biomarker of active airway inflammation in (atopic) asthma. Treatment with anti-inflammatory therapy, such as inhaled corticosteroids, effectively decreases eNO levels. The NIOX MINO (R) (MINO) is a hand-held, relatively inexpensive, electrochemical device that has been shown to yield comparable eNO measurements to the NIOX stationary unit. Aim: To compare measurements of MINO with another widely used and validated stationary chemiluminescence analyzer, the Ecomedics (ECO). Methods: We performed subsequent eNO measurements on ECO and MINO in 50 subjects (19 healthy volunteers, 18 healthy smokers and 13 non-smoking, atopic asthmatics, not on controller therapy) on two visits 4-10 days apart. The mean of three acceptable measurements by ECO and the first acceptable measurement with the MINO were used for analysis. Results: Both devices yielded reproducible eNO values for all subjects on both visits, with an overall CV of 22.7% (ECO) and 18.3% (MINO). A significant correlation was found between both devices (r = 0.97, p < 0.0001). Bland-Altman plots showed a high degree of agreement for the entire study population (mean difference MINO vs ECO = -10%; 95% limit of agreement were -36% and +28%) and in the three individual subgroups. Conclusions: Exhaled NO values measured with the MINO are reproducible and in agreement with the ECO. Our results add further evidence to the reliability of the MINO and warrant its applicability in research and clinical practice. (C) 2008 Elsevier Ltd. All rights reserved.