Pre-employment screening of latent tuberculosis infection among healthcare workers using tuberculin skin test and QuantiFERON-TB Gold test at a tertiary care hospital in Saudi Arabia

ABSTRACT

To assess the agreement between the tuberculin skin test [TST] and the QuantiFERON-TB Gold test [QFT-G] as pre-employment screening tests for latent tuberculosis infection [LTBI] among healthcare workers. A retrospective cross-sectional study was conducted among 1412 healthcare workers who were screened for LTBI during the period from August 2009 to May 2011 at a tertiary-care hospital in the Kingdom of Saudi Arabia [KSA]. The studied population was screened for LTBI using both TST and QFT-G simultaneously. The agreement between both tests was quantified using the Kappa coefficient [k]. Comparing the results of QFT-G with TST, the tests had a significant overall agreement of 73.7% [1040/1412; k = 0.33; p < 0.01]. Negative concordance comprised 60.1% of the results, and positive concordance comprised 13.5%. However, positive TST but negative QFT comprised 16.3% of the results, and negative TST but positive QFT-G comprised 10.1%. Concordance was significantly associated with young age, female gender, Saudi-born nationals, and early career but not job type [clinical versus non-clinical] nor status of Bacillus Calmette-Guerin [BCG] vaccination. This study demonstrated 73.7% overall agreement between TST and QFT-G results among healthcare workers during pre-employment screening for LTBI. The results need to be confirmed in future studies before recommending QFT-G as a pre-employment screening test for LTBI