title: Accuracy of exhaled nitric oxide measurements for the diagnosis of bronchiolitis obliterans syndrome after lung transplantation.
abstract: BACKGROUND
  Exhaled nitric oxide (eNO) is increased in patients with bronchiolitis obliterans syndrome (BOS) after lung transplantation. However, the accuracy of eNO measurements in diagnosing BOS is unknown.
  
  
  METHODS
  Thirty-two lung-transplant patients were included. Their immunosuppressive regimen consisted of cyclosporin A (tacrolimus), azathioprine (mycophenolate mofetil), and oral but no inhaled steroids. eNO levels and spirometry were prospectively followed until 2 years after transplantation or until the patient developed BOS.
  
  
  RESULTS
  Thirteen patients (group A) developed BOS (607 +/- 158 days after transplantation). Their mean eNO level at that time was 24.3 +/- 13.2 parts per billion (ppb), whereas the eNO value in the stable patients at 2 years (group B) was 11.4 +/- 4.9 ppb, P=0.0054. All group A patients had an eNO of 15 or greater ppb. Seven patients of group B also had an eNO of 15 or greater ppb, resulting in a test accuracy for the diagnosis of BOS of 0.78. However, considering only those patients who had two consecutive measurements (3-6 weeks apart) of eNO 15 or greater ppb during the months preceding the diagnosis of BOS or in the whole 2-year evaluation period, only 3 of 19 patients in group B (false-positives) but 12 of 13 in group A (1 false-negative) now fulfilled that criteria, which became positive at a mean of 263 +/- 169 days before the diagnosis of BOS was met, based on the forced expiratory volume in 1 second criteria. This increased the accuracy to 0.88.
  
  
  CONCLUSIONS
  Measurements of eNO appear to be an accurate test for the early diagnosis of BOS.
authors.affiliation: Department of Respiratory Diseases, University Hospital Gasthuisberg, 49 Herestraat, B-3000 Leuven. geert.verleden@uz.kuleuven.ac.be
authors.forename: Geert M
authors.initials: GM
authors.lastname: Verleden
authors.forename: Lieven J
authors.initials: LJ
authors.lastname: Dupont
authors.forename: Dirk E
authors.initials: DE
authors.lastname: Van Raemdonck
authors.forename: Johan
authors.initials: J
authors.lastname: Vanhaecke
mesh_terms: D000328:Adult; D001944:Breath Tests; D001989:Bronchiolitis Obliterans / Q000175:diagnosis*; D005260:Female; D006801:Humans; D016040:Lung Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis*; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D009569:Nitric Oxide