Usefulness of exhaled nitric oxide for diagnosing asthma.
J Asthma
; 47(7): 817-21, 2010 Sep.
Article
in En
| MEDLINE
| ID: mdl-20718633
ABSTRACT
RATIONALE A standard asthma diagnosis is made based on clinical history, reversibility of airway obstruction, and bronchial hyperresponsiveness. Fractional exhaled nitric oxide (FeNO) is a noninvasive airway inflammatory marker that has been suggested as a diagnostic tool for asthma. The aim of this study was to establish a FeNO cut-off value for asthma diagnosis. METHODS:
One hundred and fourteen consecutive adult patients (mean age 34 ± 13 years) reporting symptoms consistent with asthma, with normal spirometric parameters and a negative bronchodilator test, were included in the study. All underwent a methacholine challenge test following the five-breath dosimeter protocol. FeNO was measured with a portable device (NioxMino, Aerocrine AB, Sweden) just before the methacholine challenge. The sensitivity, specificity, and diagnostic performance of FeNO measurement were calculated.RESULTS:
Thirty-five out of the 114 patients (30.7%) were diagnosed with asthma. A positive methacholine challenge was associated with higher FeNO levels and with lower forced expiratory volume in one second (FEV(1)) at baseline. No correlation was found between methacholine provocative concentration causing a decrease of 20% in FEV(1) (PC(20)) and FeNO levels. A receiver-operating characteristic curve was constructed for FeNO levels (area under the curve [AUC] 0.762; 95% confidence interval [CI] 0.667-0.857; p < .001). The FeNO cut-off point with maximal specificity and sensitivity for asthma diagnosis was 40 ppb.CONCLUSIONS:
Patients with confirmed asthma showed higher FeNO levels. A cut-off value of 40 ppb was calculated as the most efficient for asthma diagnosis in our population. The use of FeNO measurement may be a helpful tool to rule out a diagnosis of asthma, especially in patients in whom a methacholine challenge is not feasible or available.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Asthma
/
Breath Tests
/
Nitric Oxide
Type of study:
Diagnostic_studies
/
Guideline
/
Prognostic_studies
Limits:
Adolescent
/
Adult
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Aged
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Journal:
J Asthma
Year:
2010
Document type:
Article
Affiliation country:
Publication country:
ENGLAND
/
ESCOCIA
/
GB
/
GREAT BRITAIN
/
INGLATERRA
/
REINO UNIDO
/
SCOTLAND
/
UK
/
UNITED KINGDOM