Interferon-Gamma Release Assay for the Diagnosis of Latent TB Infection – Analysis of Discordant Results, when Compared to the Tuberculin Skin Test
2008

Interferon-Gamma Release Assay for Latent TB Diagnosis

Sample size: 1033 publication 10 minutes Evidence: moderate

Author Information

Author(s): Nienhaus Albert, Schablon Anja, Diel Roland

Primary Institution: Institution for Statutory Accident Insurance and Prevention in the Health and Welfare Services, Hamburg, Germany

Hypothesis

Is the Interferon-Gamma Release Assay (IGRA) more sensitive to recent infections compared to the Tuberculin Skin Test (TST)?

Conclusion

The IGRA shows excellent agreement with the TST, especially in populations with BCG vaccination or migration backgrounds.

Supporting Evidence

  • Discordant results were observed in 15.4% of participants.
  • BCG vaccination or migration explained 85.1% of TST+/QFT− discordance.
  • Agreement between the two tests was 95.6% in German-born persons younger than 40 years and not BCG-vaccinated.

Takeaway

This study looked at two tests for tuberculosis and found that one test is better for certain groups of people, like those who have had a vaccine or come from other countries.

Methodology

The study combined data from two German studies and used logistic regression to analyze discordant results between IGRA and TST.

Potential Biases

Potential biases include the lack of a gold standard for LTBI diagnosis and the exclusion of indeterminate IGRA results.

Limitations

The study lacked information on the age at vaccination, revaccination, or exposure to non-tuberculous mycobacteria.

Participant Demographics

Participants included 1,033 individuals, with 61.8% female and 25.4% foreign-born.

Statistical Information

P-Value

p<0.05

Confidence Interval

95%CI 3.51–7.33

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.pone.0002665

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