[Basic characteristics of a novel diagnostic method (QuantiFERON TB-2G) for latent tuberculosis infection with the use of Mycobacterium tuberculosis-specific antigens, ESAT-6 and CFP-10]

Kekkaku. 2004 Dec;79(12):725-35.
[Article in Japanese]


Purposes: To determine the optimum cut-off level of a newly developed method for diagnosing tuberculosis infection based on whole-blood interferon-gamma measurement, and to study the basic characteristics of the method.

Study subjects: 1) A total of 220 young, healthy individuals having no apparent exposure to tuberculosis infection, most of whom have had a vaccination with BCG vaccine. 2) One hundred eighteen tuberculosis patients who were diagnosed by positive Mycobacterium tuberculosis on culture. 3) A group of 75 youngsters exposed to an infectious tuberculosis patient and who showed a strong tuberculin reaction (with erythema diameter of 30 mm or more).

Method: Whole-blood specimens of donors were stimulated with antigens, i.e., ESAT-6 and CFP-10, and then cultured. Plasma concentrations of interferon-gamma discharged were then determined with QuantiFERON-CMI. Correlation between interferon-gamma concentrations in response to ESAT-6 and CFP-10, and their correlation with Mantoux test results were analyzed for various categories of donors. The Receiver Operating Characteristics analysis was performed considering the loss due to misclassification. [

Results and discussion: The optimum cut-off level was determined as 0.35 IU/ml for both ESAT-6 and CFP-10. This gave the test a sensitivity of 89.0% and specificity of 98.1% in detecting tuberculosis infection. The correlation of interferon-gamma response with tuberculin tests among BCG-vaccinated individuals was low, which suggested that the test was not influenced by previous BCG vaccination. The low correlation between ESAT-6 and CFP-10 tests suggested that the simultaneous use of the two tests was beneficial. As in the case of clinical tests in general, the cut-off should be set at a lower level when the test is applied to high prevalence situation and vice versa.

Publication types

  • English Abstract

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Antigens, Bacterial*
  • Bacterial Proteins*
  • Biomarkers / blood
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Humans
  • Immunologic Tests / methods*
  • Interferon-gamma / blood*
  • Male
  • Middle Aged
  • Mycobacterium tuberculosis / immunology
  • Reagent Kits, Diagnostic / standards*
  • Tuberculosis / diagnosis*


  • Antigens, Bacterial
  • Bacterial Proteins
  • Biomarkers
  • CFP-10 protein, Mycobacterium tuberculosis
  • ESAT-6 protein, Mycobacterium tuberculosis
  • Reagent Kits, Diagnostic
  • Interferon-gamma