Tuberculosis infection in drug users: Interferon-gamma release assay performance

C. Z. Grimes, L. Y. Hwang, M. L. Williams, C. M. Austin, Edward A. Graviss

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


SETTING: An inner city neighborhood in Houston, Texas, known for a high rate of drug use. OBJECTIVE: To determine the prevalence of latent tuberculosis infection (LTBI) using the QuantiFERON®-TB Gold (QFT-G) test, the TSPOT.TB® test and the tuberculin skin test (TST) in drug users and to evaluate the performance of the QFT-G and TSPOT.TB tests vs. the TST. DESIGN: Cross-sectional study. Bivariate and multivariate logistic regression analyses were used to determine risks associated with each test outcome. RESULTS: The prevalence of LTBI in 119 drug users studied was 28% by TST and 34% by QFT-G and TSPOT.TB. Kappa statistics indicated fair to moderate concordance between QFT-G and TSPOT.TB vs. TST. About one-fifth of the population that tested negative with TST was positive with either QFT-G or T-SPOT.TB. On multivariate analysis, the likelihood of testing QFT-positive or T-SPOT.TB-positive increased by 8% and 6%, respectively, for every year of age; TST positivity was associated with smoking crack at home; being Caucasian or having a history of alcohol use was positively associated with a positive T-SPOT.TB test. CONCLUSION: Interferon-gamma release assays (IGRAs) are superior to the TST in drug users with a higher prevalence of LTBI. Future studies need to assess the predictive value of IGRAs on the progression from LTBI to active TB in high-risk populations.

Original languageEnglish (US)
Pages (from-to)1183-1189
Number of pages7
JournalInternational Journal of Tuberculosis and Lung Disease
Issue number11
StatePublished - Nov 2007


  • Crack cocaine
  • Interferon-gamma release assay
  • Tuberculin skin test
  • Tuberculosis

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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