Exhaled nitric oxide measurements: correction equation to compare hand-held device to stationary analyzer.
BACKGROUND
Exhaled nitric oxide (FE(NO)) is a reliable non-invasive marker of airway inflammation. In 2003 FE(NO) chemiluminescence analyzer (NIOX; Aerocrine AB, Solna, Sweden) was approved by U.S. Food and Drug Administration for monitoring asthma therapy. Recently, the same company developed a portable device using electrochemical sensors (NIOX-MINO; Aerocrine AB). The aim of our study was to compare NIOX-MINO FE(NO) values to those obtained by NIOX and to calculate a correction equation.


METHODS
Two adequate measurements obtained by NIOX and NIOX-MINO were recorded in 32 subjects (16 females, mean age 41 years).


RESULTS
FE(NO) values measured by NIOX-MINO were systematically higher than those obtained by NIOX (47.1ppb, IC 95% 35.2-59.1 and 36.9ppb, IC 95% 25.0-49.0, respectively). There was a significant correlation (r=0.998, p<0.001) between FE(NO) measured by the two analyzers and the following conversion equation was calculated as: FE(NO(NIOX))=-1.656(SE=0.61)+0.808(SE=0.009)x FE(NO(NIOX-MINO)) DISCUSSION: FE(NO) values measured by the portable nitric oxide analyzer are reliable and strongly correlated with values obtained by the standard stationary device, with a systematic difference observed between the two instruments' values that can be described by the conversion equation we provided. This equation will help clinicians and researchers to compare data obtainable by the two analyzers.
Pizzimenti
Stefano
S
Allergy and Clinical Immunology, University of Torino, Azienda Sanitaria Ospedale Mauriziano "Umberto I", Largo Turati 62, 10128 Torino, Italy.
Bugiani
Massimiliano
M
Piccioni
Pavilio
P
Heffler
Enrico
E
Carosso
Aurelia
A
Guida
Giuseppe
G
Rolla
Giovanni
G
D000328:Adult; D001249:Asthma / Q000175:diagnosis; D001944:Breath Tests / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D045853:Exhalation; D005260:Female; D006801:Humans; D016018:Least-Squares Analysis; D008163:Luminescent Measurements / Q000295:instrumentation; D008297:Male; D009569:Nitric Oxide / Q000032:analysis*; D012680:Sensitivity and Specificity
D009569:Nitric Oxide