title: Asthma diagnosis and severity monitoring in primary school children: essential role of sequential testing of exhaled nitric oxide.
abstract: BACKGROUND
  Chronic eosinophilic airway inflammation, airflow limitation, and airway hyper-responsiveness are the mainstays of asthma diagnosis. The increased levels of exhaled nitric oxide (FeNO) in asthma are closely related to the extent of airway inflammation. Sequential measurement of FeNO concentrations may accurately predict asthma severity and guide therapeutic decisions.
  
  
  METHODS
  A total of 22,083 grade 1 students in Taipei city primary schools were screened for wheezing episodes using the International Study of Asthma and Allergies in Childhood questionnaire (ISAAC) questionnaires while their sero-atopic conditions were confirmed by Fluorescent Enzyme Immune Assay (FEIA). All students with allergies were tested by FeNO electrochemical test. 100 age-matched healthy students were used as control group (FeNO levels<25ppb).
  
  
  RESULTS
  From the 2650 students (12%) initially included via the wheezing criteria, 2065 (78.0%) were confirmed to have allergy by FEIA (sensitisation to at least two common aero-allergens in Taiwan) and diagnosed by a paediatric allergologist. Among them, 1852 (89.6%) had elevated FeNO values (>25ppb) and 266 (10%) had FeNO values<25ppb. Using the GINA guidelines, 140 mild-to-moderate asthma students who had received inhaled corticosteroids (ICS) with or without Singulair treatment completed serial FeNO testing every three months for one year. The FeNO levels decreased in 121 students (86.4%) and increased in 19 students (13.6%), which was compatible to changing childhood asthma control score and response to step-down treatment, respectively.
  
  
  CONCLUSIONS
  FeNO is an easy, used non-invasive tool for the diagnosis of allergic asthma. Sequential FeNO testing can accurately reflect asthma severity and provide for successful stepwise therapy for asthmatic children.
authors.affiliation: Department of Pediatrics, Taipei City Hospital, Renai Branch, Taiwan; Colleges of Medicine, National Yang-Ming University, Taipei, Taiwan. Electronic address: DXD40@tpech.gov.tw.
authors.forename: K-S
authors.initials: KS
authors.lastname: Wan
authors.affiliation: Colleges of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: W-H
authors.initials: WH
authors.lastname: Chiu
authors.affiliation: Colleges of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Pediatrics, Taipei City Hospital, Yangming Branch, Taiwan.
authors.forename: W
authors.initials: W
authors.lastname: Yang
mesh_terms: D001249:Asthma / Q000175:diagnosis*; D001944:Breath Tests; D002648:Child; D045853:Exhalation; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D009569:Nitric Oxide / Q000032:analysis*
chemical_list: D009569:Nitric Oxide
keywords: Asthma; Exhaled nitric oxide; Monitor; Treatment