Screening for Latent tuberculosis Infection Among Immigration Facility Employees — Illinois, 2009

Authors: Marie de Perio, T. Niemeier, M. Groenewold

Background: One-third of the world’s population has latent tuberculosis infection (LTBI). Foreign-born persons account for most active tuberculosis (TB) cases in the U.S. TB control in immigration facilities involves routinely screening and treating employees for LTBI.

We assessed LTBI prevalence among employees at two immigration facilities and compared two screening methods.

Methods: We administered questionnaires regarding demographics, work and medical history, and TB risk factors. Participants underwent tuberculin skin test (TST) placement and blood collection for the QuantiFERON-TB Gold in-Tube (QFT-GIT) assay; QFT-GIT requires only one visit and has higher specificity than TST. We compared completion rates for each method and determined predictors for completing TST screening through bivariate analyses.

Results: Seventy-two (60%) of 120 employees participated; 67 (93%) employees reported face-to-face contact with detainees. Fifty-four employees underwent both QFT-GIT and TST placement. All QFT-GIT results were negative. Three (6%) employees tested TST positive and were likely false positives. Forty-seven (92%) employees did not have a TST in the previous year and required 2-step testing; only 23 (49%) underwent second TST placement.

Return rates for first and second TST reading were 76% and 74%. The completion rate for QFT-GIT was higher than TST (100% vs. 39%, P<0.001). Agreement between TST and QFT-GIT results was 94%.

Predictors for completing TST screening included older age (P=0.006), having lived outside of the U.S. (P=0.003), and being a detention removal assistant (P=0.03).

Conclusions: Most immigration employees have face-to-face contact with detainees, placing them at risk for exposure to TB. Employees had low return rates for TST reading and second TST placement. Our evaluation demonstrates the advantages of performing the one visit QFT-GIT for TB screening in this occupational group.

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