Diagnosis of Tuberculosis by an Enzyme-Linked Immunospot Assay for Interferon-Gamma

Emerg Infect Dis. 2007 Apr;13(4):553-8. doi: 10.3201/eid1304.051195.

Abstract

We evaluated an enzyme-linked immunospot assay for interferon-gamma (T SPOT-TB) for rapid diagnosis of active tuberculosis (TB) in a disease-endemic area. From January to June 2005, patients whose clinical symptoms and radiographic findings were compatible with TB were recruited, and a blood sample was obtained for T SPOT-TB assay within 7 days of microbiologic studies. Sixty-five patients were studied, including 39 (60%) with active TB. Thirty-five (53.8%) patients had underlying medical conditions. Thirty-seven patients had positive cultures for Mycobacterium tuberculosis, and 11 patients had positive cultures for nontuberculous mycobacteria. The sensitivity, specificity, positive predictive value, and negative predictive value of the T SPOT-TB assay were 87.2%, 88.5%, 91.9%, and 82.1%, respectively. The accuracy of this test in diagnosing active TB is >80%, even in an area with a high incidence of nontuberculous mycobacterial disease.

Publication types

  • Evaluation Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Child
  • Child, Preschool
  • Culture Media
  • Enzyme-Linked Immunosorbent Assay / methods*
  • Female
  • Humans
  • Interferon-gamma / biosynthesis*
  • Leukocytes, Mononuclear / immunology
  • Lymphocyte Activation / immunology
  • Male
  • Middle Aged
  • Mycobacterium tuberculosis / immunology*
  • Mycobacterium tuberculosis / isolation & purification
  • Predictive Value of Tests
  • Sensitivity and Specificity
  • Tuberculosis / diagnosis*
  • Tuberculosis / microbiology

Substances

  • Culture Media
  • Interferon-gamma