title: Validation study of nasal nitric oxide measurements using a hand-held electrochemical analyser.
abstract: BACKGROUND
  Exhaled nitric oxide (NO) measurement is a simple and non-invasive method for monitoring airway inflammation. Similarly, nasal NO has been proposed as a surrogate marker in inflammatory diseases of the upper airways, e.g. allergic rhinitis. A new portable analyser using an electrochemical sensor has been developed for measurements of exhaled NO, and its reproducibility and comparison with other analysers has been tested recently in healthy subjects and in patients with lower airways disease. The application of this hand-held analyser in nasal NO analysis was tested and compared to the gold standard represented by a chemiluminescence analyser.
  
  
  METHODS
  Thirty subjects including 15 patients with allergic rhinitis (AR) and 15 healthy subjects (HS) were studied. The intraindividual variability, calculated as the difference in nasal NO levels between two measurements from a single nasally exhaled breath manoeuvre, and the comparison between the electrochemical analyser (NIOX MINO, Aerocrine) and a chemiluminescence analyser (NOA, Sievers) were performed.
  
  
  RESULTS
  In AR patients mean nasal NO was 59.0 +/- 16.3 p.p.b. with the MINO and 58.3 +/- 15.6 p.p.b. with the NOA. In HS nasal NO was 49.1 +/- 10.8 p.p.b. with the MINO and 49.8 +/- 8.2 p.p.b. with the NOA. The Bland-Altman analysis showed bias values of 0.005 +/- 3.6 with the 95% limits of agreement from -6.97 to 6.98 p.p.b.
  
  
  CONCLUSIONS
  Measurements of nasal NO levels with a hand-held electrochemical analyser are reproducible and the results are comparable to a stationary chemiluminescence analyser.
authors.affiliation: Section of Respiratory Medicine, Hospital S. Maria della Pietà Casoria Naples, Italy. mauromaniscalco@hotmail.com
authors.forename: M
authors.initials: M
authors.lastname: Maniscalco
authors.forename: G
authors.initials: G
authors.lastname: de Laurentiis
authors.forename: E
authors.initials: E
authors.lastname: Weitzberg
authors.forename: J O
authors.initials: JO
authors.lastname: Lundberg
authors.forename: M
authors.initials: M
authors.lastname: Sofia
mesh_terms: D000328:Adult; D001944:Breath Tests / Q000295:instrumentation* / Q000379:methods; D004563:Electrochemistry / Q000295:instrumentation; D045853:Exhalation; D005260:Female; D006801:Humans; D049449:Luminescence; D008297:Male; D009569:Nitric Oxide / Q000032:analysis*; D015203:Reproducibility of Results; D006255:Rhinitis, Allergic, Seasonal / Q000503:physiopathology*
chemical_list: D009569:Nitric Oxide