title: Early diagnosis of subclinical multidrug-resistant tuberculosis.
abstract: BACKGROUND
  Tuberculosis control hinges on prompt diagnosis of active cases and screening of contacts by tuberculin skin testing. Rapid blood tests for Mycobacterium tuberculosis infection are a new alternative to the tuberculin skin test, but whether they improve clinical outcomes is unknown.
  
  
  OBJECTIVE
  To describe how a novel T-cell-based test for M. tuberculosis infection helped diagnose tuberculosis in an asymptomatic, immunosuppressed adult with a negative result on a tuberculin skin test.
  
  
  METHODS
  Case report.
  
  
  METHODS
  Household contact.
  
  
  METHODS
  Asymptomatic man receiving maintenance azathioprine therapy for Crohn disease whose wife had multidrug-resistant pulmonary tuberculosis.
  
  
  METHODS
  Enzyme-linked immunospot (ELISPOT) assay, computed tomography, and bronchoalveolar lavage cultures.
  
  
  RESULTS
  The man had a negative tuberculin skin test result and a positive ELISPOT assay result. High-resolution computed tomography of the chest showed consolidation with early cavitation. Bronchoalveolar lavage and culture confirmed multidrug-resistant tuberculosis.
  
  
  CONCLUSIONS
  This single case report is a proof of concept and is not a formal evaluation of clinical utility.
  
  
  CONCLUSIONS
  A positive ELISPOT assay result helped diagnose subclinical active tuberculosis in an immunosuppressed patient with a false-negative tuberculin skin test result. Large prospective studies that compare benefits and costs of this alternative to tuberculin skin testing are needed.
authors.affiliation: University of Modena and Reggio Emilia and Azienda Ospedaliera Policlinico di Modena, Modena, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Richeldi
authors.forename: Katie
authors.initials: K
authors.lastname: Ewer
authors.forename: Monica
authors.initials: M
authors.lastname: Losi
authors.forename: David M
authors.initials: DM
authors.lastname: Hansell
authors.forename: Pietro
authors.initials: P
authors.lastname: Roversi
authors.forename: Leonardo M
authors.initials: LM
authors.lastname: Fabbri
authors.forename: Ajit
authors.initials: A
authors.lastname: Lalvani
mesh_terms: D000328:Adult; D000942:Antigens, Bacterial / Q000032:analysis; D001379:Azathioprine / Q000627:therapeutic use; D018893:Bronchoalveolar Lavage; D003424:Crohn Disease / Q000188:drug therapy; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D016867:Immunocompromised Host; D007124:Immunoenzyme Techniques; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D009169:Mycobacterium tuberculosis / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D014057:Tomography, X-Ray Computed; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis* / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D007166:Immunosuppressive Agents; D001379:Azathioprine