title: Measurement of exhaled nitric oxide as a potential screening tool for pulmonary tuberculosis.
abstract: BACKGROUND
  There is a need for low-technology, inexpensive screening tools for active tuberculosis (TB) case finding.
  
  
  OBJECTIVE
  to assess the potential usefulness of measuring exhaled nitric oxide (eNO).
  
  
  METHODS
  Cross-sectional comparison in Hanoi, Viet Nam, comparing 90 consecutive smear-positive, culture-confirmed TB patients presenting at a referral hospital with office workers (no X-ray confirming TB) at this hospital (n = 52) and at a construction firm (n = 84). eNO levels were analysed using a validated handheld analyser.
  
  
  RESULTS
  eNO levels among TB patients (median 15 parts per billion [ppb], interquartile range [IQR] 10-20) were equal to those among construction firm workers (15 ppb, IQR 12-19, P = 0.517) but higher than those among hospital workers (8.5 ppb, IQR 5-12.5, P < 0.001). Taking the hospital workers as the comparison group, best performance as a diagnostic tool was at a cut-off of 10 ppb, with sensitivity 78% (95%CI 68-86) and specificity 62% (95%CI 47-75). Test characteristics could be optimised to 84% vs. 67% by excluding individuals who had recently smoked or consumed alcohol.
  
  
  CONCLUSIONS
  While eNO measurement has limited value in the direct diagnosis of pulmonary TB, it may be worth developing and evaluating as a cost-effective replacement of chest X-ray in screening algorithms of pulmonary TB where X-ray is not available.
authors.affiliation: Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: S C
authors.initials: SC
authors.lastname: Van Beek
authors.forename: N V
authors.initials: NV
authors.lastname: Nhung
authors.forename: D N
authors.initials: DN
authors.lastname: Sy
authors.forename: P J
authors.initials: PJ
authors.lastname: Sterk
authors.forename: E W
authors.initials: EW
authors.lastname: Tiemersma
authors.forename: F G J
authors.initials: FG
authors.lastname: Cobelens
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000032:analysis; D001944:Breath Tests; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification; D009426:Netherlands; D009569:Nitric Oxide / Q000032:analysis*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000378:metabolism / Q000382:microbiology / Q000503:physiopathology; D014744:Vietnam; D055815:Young Adult
chemical_list: D015415:Biomarkers; D009569:Nitric Oxide