Predictors of discordant tuberculin skin test and QuantiFERON®-TB Gold In-Tube results in various high-risk groups

Int J Tuberc Lung Dis. 2011 Aug;15(8):1056-61. doi: 10.5588/ijtld.10.0650.

Abstract

Setting: Persons in whom targeted testing for latent tuberculosis infection (LTBI) is recommended in Seattle, Washington; Atlanta, Georgia; and central North Carolina, United States.

Objective: To compare the performance of an interferon-gamma release assay (QuantiFERON®-TB Gold In-Tube [QFT-GIT]) with the tuberculin skin test (TST) among foreign-born, homeless, human immunodeficiency virus (HIV) infected and substance abuse persons tested for LTBI.

Design: A cross-sectional study requiring participants to have a blood test, a TST and data collected.

Results: Of 1653 persons, 19.5% were TST-positive and 14.0% were QFT-GIT-positive. Overall concordance was moderate (kappa 0.53; 95%CI 0.47-0.58). Compared to concordant positive results, TST+/QFT-GIT- discordance was associated with HIV infection and sex, while TST-/QFT-GIT+ discordance was associated with HIV and inversely associated with foreign birth. Compared to concordant negative results, TST-/QFT-GIT+ discordance was associated with foreign birth and age ≥50 years, while TST+/QFT-GIT-discordance was associated with foreign birth, age 30-49 years, being Black and inversely associated with HIV. HIV infection was significantly associated with indeterminate QFT-GIT results.

Conclusion: QFT-GIT may be an improvement over the TST for diagnosing LTBI in foreign-born and older persons, and may be as useful as the TST in HIV-infected persons. The sensitivity of both tests may be low in HIV-infected persons.

Publication types

  • Comparative Study
  • Multicenter Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • African Americans / statistics & numerical data
  • Age Factors
  • BCG Vaccine / administration & dosage
  • Cross-Sectional Studies
  • Drug Users / statistics & numerical data
  • Ethnic Groups / statistics & numerical data
  • Female
  • HIV Infections / ethnology
  • Homeless Persons / statistics & numerical data
  • Humans
  • Immunoassay / statistics & numerical data*
  • Interferon-gamma / metabolism*
  • Latent Tuberculosis / diagnosis*
  • Latent Tuberculosis / ethnology
  • Latent Tuberculosis / microbiology
  • Male
  • Middle Aged
  • Mycobacterium tuberculosis / immunology*
  • Odds Ratio
  • Predictive Value of Tests
  • Refugees / statistics & numerical data
  • Reproducibility of Results
  • Risk Assessment
  • Risk Factors
  • T-Lymphocytes / immunology
  • T-Lymphocytes / microbiology*
  • Tuberculin Test / statistics & numerical data*
  • United States / epidemiology
  • Vulnerable Populations / statistics & numerical data*

Substances

  • BCG Vaccine
  • Interferon-gamma