Conversion rates of an interferon-γ release assay and the tuberculin skin test in the serial monitoring of healthcare workers

Publié le 28 janvier 2014 • Catégorie(s) : Risques biologiques • Mot(s) clef(s) : tuberculose

Auteur S Y Kim
Auteur M S Park
Auteur Y S Kim
Auteur S K Kim
Auteur J Chang
Auteur Y A Kang
Volume 41
Numéro 2
Pages 511-516
Publication Infection
Date Apr 2013
Résumé PURPOSE: Regular monitoring of latent tuberculosis (TB) infection in healthcare workers (HCWs) is recommended, but the view about the effective method and performance of serial monitoring is controversial. The aim of this study was to determine differences in conversion rates according to TB exposure risk using the tuberculin skin test (TST) and the QuantiFERON-TB Gold In-Tube (QFT-GIT), and to evaluate the reproducibility and within-subject variability of the QFT-GIT in South Korea. METHODS: Fifty-three HCWs were grouped according to their risk for TB exposure: group 1, high risk (n = 21); group 2, low risk (n = 32). Baseline and follow-up TSTs and QFT-GITs were performed from June 2009 to July 2011. Enzyme-linked immunosorbent assays (ELISAs) were repeated for the second QFT-GIT and a third QFT-GIT was performed after 8 weeks when discordant results of the second TST and QFT-GIT or a conversion or reversion were observed. RESULTS: No difference in the QFT-GIT conversion rate was evident between the two groups (15.4 vs. 6.5 %, p = 0.57), and no TST conversion was observed. The rate of QFT-GIT positivity was higher in the high-risk group (first QFT-GIT: 38.1 vs. 3.1 %, p = 0.002; second QFT-GIT: 33.3 vs. 9.4 %, p = 0.039). The re-test reproducibility of QFT-GIT results was high (100 %), and the within-subject results of repetitive QFT-GITs were variable. CONCLUSIONS: Stricter prevention strategies remain necessary in HCWs at high risk of TB exposure, and serial interferon-γ release assays (IGRAs) should be interpreted with caution in HCWs.