Comparative repeatability of two handheld fractional exhaled nitric oxide monitors.
BACKGROUND
The use of portable fractional exhaled nitric oxide (FENO) devices is increasingly common in the diagnosis and management of allergic airways inflammation.


METHODS
We tested two handheld FENO devices, to determine (a) if there was adequate intradevice repeatability to allow the use of single breath testing, and (b) if the devices could be used interchangeably. In a mixed pediatric population, including normal, asthmatic, and children with peanut allergies, 858 paired values were collected from the NIOX-MINO® and/or the NObreath® devices.


RESULTS
The NIOX-MINO® showed excellent repeatability (mean difference of 0.1 with 95% limits of agreement between -7.93 to 7.72 ppb), while the NObreath® showed good repeatability (mean difference of -1.61 with 95% limits of agreement between -14.1 and 10.8 ppb). Intradevice repeatability was good but not adequate and the NIOX-MINO® systematically produced higher results than the NObreath® [mean difference of 7.8 ppb with 95% limits of agreement from -11.55 to 27.52 ppb (-33% to 290%)].


CONCLUSIONS
Our results support the manufacturer's advice that single breath testing is appropriate for the NIOX-MINO®. NObreath® results indicate that the mean of more than one breath should be utilized. The devices cannot be used interchangeably.
Centre for Infection & Immunity, Health Sciences Building, Queen's University Belfast, Belfast, UK.
Kirsty M
KM
Kapande
Laura A
LA
McConaghy
Isabella
I
Douglas
Sonia
S
McKenna
Jenny L
JL
Hughes
David R
DR
McCance
Madeline
M
Ennis
Michael D
MD
Shields
D000293:Adolescent; D001249:Asthma / Q000175:diagnosis* / Q000628:therapy; D001944:Breath Tests / Q000295:instrumentation; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D019468:Disease Management; D006801:Humans; D007249:Inflammation / Q000175:diagnosis* / Q000628:therapy; D009569:Nitric Oxide / Q000032:analysis*; D021183:Peanut Hypersensitivity / Q000175:diagnosis* / Q000628:therapy; D015203:Reproducibility of Results
D009569:Nitric Oxide