Comparison of tuberculin skin test and quantiferon-TB gold in tube test for diagnosis of latent tuberculosis infection in health care workers: A cross sectional study

Abstract

Objective: To compare the diagnostic efficacy and agreement of the traditional tuberculin skin test with QuantiFERON-Tuberculosis Gold In-Tube test for latent tuberculosis infection in healthcare workers.

Methods: The cross-sectional analytical study was conducted between March 1 and 31, 2008, at a specialist tuberculosis hospital in Istanbul, Turkey, and comprised healthcare workers who had been employed for at least one year at the hospital and volunteered to take part. Tuberculin skin test and QuantiFERON-Tuberculosis Gold In-Tube test were both performed simultaneously and their results were compared Using SPSS 12.

Results: Out of 34 subjects, 20(58.8%) had a positive tuberculin skin test, and 7(20.6%) had a positive QuantiFERON-Tuberculosis Gold In-Tube test. The two tests agreed in only 15(44.1%) cases and disagreed in 19(55.9%). In 16(47.1%) subjects, the QuantiFERON-Tuberculosis Gold In-Tube test was negative and tuberculin skin testwas positive, while in 3(8.8%) participants QuantiFERON-Tuberculosis Gold In-Tube test was positive and tuberculin skin test was negative. Kappa test revealed discordance between the two tests (k=-0.13; p=0.92).

Conclusions: Latent tuberculosis infection prevalence was higher based on tuberculin skin test than QuantiFERON-Tuberculosis Gold In-Tube test. The results of the two tests were discordant.

Keywords: Quantiferon, QFT-GIT, Tuberculin skin test, TST, IGRAs, Tuberculosis, Latent tuberculosis infection, LTBI..