title: Breath analysis as a potential diagnostic tool for tuberculosis.
abstract: METHODS
  Cape Town, South Africa.
  
  
  OBJECTIVE
  We investigated the potential of breath analysis by gas chromatography-mass spectrometry (GC-MS) to discriminate between samples collected prospectively from patients with suspected tuberculosis (TB).
  
  
  METHODS
  Samples were obtained  in a TB-endemic setting in South Africa, where 28% of culture-proven TB patients had Ziehl-Neelsen (ZN) negative sputum smear. A training set of breath samples from 50 sputum culture-proven TB patients and 50 culture-negative non-TB patients was analysed using GC-MS. We used support vector  machine analysis for classification of the patient samples into TB and non-TB.
  
  
  RESULTS
  A classification model with seven compounds had a sensitivity of 72%, a specificity of 86% and an accuracy of 79% compared with culture. The classification model was validated with breath samples from  a different set of 21 TB and 50 non-TB patients from the same area, giving a sensitivity of 62%, a specificity of 84% and an accuracy of 77%.
  
  
  CONCLUSIONS
  This study shows that GC-MS breath analysis is able to differentiate between TB and non-TB breath samples even among patients with a  negative ZN sputum smear but a positive culture for Mycobacterium tuberculosis. We conclude that breath analysis by GC-MS merits further research.
authors.affiliation: KIT Biomedical Research, Royal Tropical Institute, Amsterdam, The Netherlands. arend.kolk@hetnet.nl
authors.forename: A H J
authors.initials: AH
authors.lastname: Kolk
authors.forename: J J B N
authors.initials: JJ
authors.lastname: van Berkel
authors.forename: M M
authors.initials: MM
authors.lastname: Claassens
authors.forename: E
authors.initials: E
authors.lastname: Walters
authors.forename: S
authors.initials: S
authors.lastname: Kuijper
authors.forename: J W
authors.initials: JW
authors.lastname: Dallinga
authors.forename: F J
authors.initials: FJ
authors.lastname: van Schooten
mesh_terms: D000328:Adult; D001944:Breath Tests; D019353:Endemic Diseases; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013019:South Africa / Q000453:epidemiology; D013183:Sputum / Q000382:microbiology; D060388:Support Vector Machine; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology; D055815:Young Adult