Sequential strategy for the LTBI screening of newly-arrived immigrants in vulnerable social situations

Enferm Infecc Microbiol Clin (Engl Ed). 2018 Nov;36(9):550-554. doi: 10.1016/j.eimc.2017.10.010. Epub 2017 Dec 7.
[Article in English, Spanish]


Introduction: Some studies indicate high prevalences of latent tuberculosis infection (LTBI) in the immigrant population, which is relevant because 5-10% of cases will develop active tuberculosis. The objective of this study is to describe the results of a sequential strategy in the newly-arrived immigrant population for the diagnosis of LTBI using the tuberculin skin test (TST) and IGRAs.

Methods: A retrospective descriptive study was carried out with immigrants between 6 and 35years of age from shelters, referred to an international health unit between July 2013 and June 2016. The TST was performed and when it was ≥5mm, IGRAs were conducted. LTBI was defined as an IGRA ≥0.35IU/ml and normal chest X-ray.

Results: Of the 184 cases, 138 (75.0%) were men, 23.0 years of age. The most common geographical areas were: 63 (34.2%) from Asia, 42 (22.8%) from Eastern Europe and 41 (22.3%) from sub-Saharan Africa. The TST was ≥10mm in 79 cases (42.9%). The prevalence of LTBI using the sequential strategy was 33/184 (17.9%). Cohen's Kappa index (between TST≥10mm and IGRAs) was 0.226.

Conclusion: Basing LTBI screening on the TST alone could give rise to an overestimation. Some studies show that sequential screening would be the most cost-effective; this seems most evident in BCG-vaccinated populations.

Keywords: Cribado; Immigrants; Infección tuberculosa latente; Inmigrantes; Interferon Gamma Release Assays; Latent tuberculosis infection; Prueba de tuberculina; Screening; Tuberculosis; Tuberculosis skin test.

MeSH terms

  • Adolescent
  • Adult
  • Africa South of the Sahara / ethnology
  • Asia / ethnology
  • BCG Vaccine
  • Cost-Benefit Analysis
  • Emigrants and Immigrants*
  • Europe, Eastern / ethnology
  • Female
  • Humans
  • Interferon-gamma Release Tests / economics
  • Latent Tuberculosis / diagnosis*
  • Latent Tuberculosis / ethnology
  • Latin America / ethnology
  • Male
  • Mass Screening / economics
  • Mass Screening / methods*
  • Prevalence
  • Retrospective Studies
  • Social Determinants of Health
  • Spain / epidemiology
  • Tuberculin Test / economics
  • Vaccination / statistics & numerical data
  • Vulnerable Populations*
  • Young Adult


  • BCG Vaccine