title: Evaluation of a bovine antibody test for diagnosing Mycobacterium avium complex in patients with cystic fibrosis.
abstract: The aim of this study was to test a commercial bovine enzyme-linked immunosorbent assay for investigating antibody activity against Mycobacterium avium complex.
  
  
  
  All patients at the Copenhagen Cystic Fibrosis (CF) Center who had culture for nontuberculous mycobacteria performed were included. A commercially available antibody test used in veterinary medicine, was adjusted for human use, and applied to patient sera in a cross sectional test. The test positivity threshold was determined using a receiver operating curve (ROC). A longitudinal analysis of antibody kinetics before and after culture conversion was performed in case patients.
  
  
  
  Out of 286 included subjects, six had clinical M. avium complex pulmonary disease at the time of sera sampling. These patients presented with higher antibody test values (P-value <0.01). A test cut point of 0.78 was chosen, corresponding to a sensitivity of 100% (54-100), specificity of 66% (60-72), a positive predictive value of 6% (2-13), and negative predictive value of 100% (98-100).
  
  
  
  While not suited for direct diagnosis of M. avium complex due to a high number of false positive subjects, the assay proved useful at ruling out pulmonary disease. Screening sera from patients with CF could guide clinicians to focus attention on patients at higher risk of M. avium complex pulmonary disease. Pediatr Pulmonol. 2017;52:34-40. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Infectious Diseases, CF Center Copenhagen, University Hospital Rigshospitalet, Copenhagen, Denmark.
authors.forename: Tavs
authors.initials: T
authors.lastname: Qvist
authors.affiliation: Department of Infectious Diseases, CF Center Copenhagen, University Hospital Rigshospitalet, Copenhagen, Denmark.
authors.forename: Tacjana
authors.initials: T
authors.lastname: Pressler
authors.affiliation: Department of Infectious Diseases, CF Center Copenhagen, University Hospital Rigshospitalet, Copenhagen, Denmark.
authors.forename: Terese L
authors.initials: TL
authors.lastname: Katzenstein
authors.affiliation: Department of Clinical Microbiology, CF Center Copenhagen, University Hospital Rigshospitalet, Copenhagen, Denmark.|Institute for Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Niels
authors.initials: N
authors.lastname: Høiby
authors.affiliation: Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Wisconsin, Madison.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Collins
mesh_terms: D000328:Adult; D000818:Animals; D002417:Cattle; D003430:Cross-Sectional Studies; D003550:Cystic Fibrosis / Q000382:microbiology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D015269:Mycobacterium avium Complex / Q000276:immunology*; D012680:Sensitivity and Specificity
keywords: NTM; diagnostic accuracy; nontuberculous; serology