Interferon-gamma release assays and TB screening in high-income countries: a cost-effectiveness analysis

Int J Tuberc Lung Dis. 2007 Jan;11(1):16-26.


Objective: Interferon-gamma release assays (IGRA) are now available alternatives to tuberculin skin testing (TST) for detection of latent tuberculosis infection (LTBI). We compared the cost-effectiveness of TST and IGRA in different populations and clinical situations, and with variation of a number of parameters.

Methods: Markov modelling was used to compare expected TB cases and costs over 20 years following screening for TB with different strategies among hypothetical cohorts of foreign-born entrants to Canada, or contacts of TB cases. The less expensive commercial IGRA, Quanti-FERON-TB Gold (QFT), was examined. Model inputs were derived from published literature.

Results: For entering immigrants, screening with chest radiograph (CXR) would be the most and QFT the least cost-effective. Sequential screening with TST then QFT was more cost-effective than QFT alone in all scenarios, and more cost-effective than TST alone in selected subgroups. Among close and casual contacts, screening with TST or QFT would be cost saving; savings with TST would be greater than with QFT, except in contacts who were bacille Calmette-Guérin (BCG) vaccinated after infancy.

Conclusions: Screening for LTBI, with TST or QFT, is cost-effective only if the risk of disease is high. The most cost-effective use of QFT is to test TST-positive persons.

Publication types

  • Comparative Study

MeSH terms

  • Biomarkers / blood
  • Canada / epidemiology
  • Cost-Benefit Analysis
  • Developed Countries
  • Emigration and Immigration
  • Humans
  • Incidence
  • Income
  • Interferon-gamma / blood*
  • Markov Chains
  • Mass Screening / economics*
  • Mass Screening / methods*
  • Radiography, Thoracic / economics
  • Sensitivity and Specificity
  • Tuberculin Test
  • Tuberculosis / blood
  • Tuberculosis / diagnosis*
  • Tuberculosis / economics
  • Tuberculosis / epidemiology


  • Biomarkers
  • Interferon-gamma