Comparison of the tuberculin skin test and the quantiferon test for latent Mycobacterium tuberculosis infections in health care workers in Turkey.

The aim of this study was to compare the efficacy of the tuberculin skin test (TST) and the quantiferon test (QFT) for detecting latent tuberculosis infection (LTBI) in health care workers (HCWs). Seventy-six participants who were working in Duzce University Hospital, where tuberculosis patients were being treated, were included in the study. TST was performed according to the Mantoux technique. QFT was performed in accordance with the manufacturer's instructions. A positive TST result was defined as an induration diameter of > or = 15 mm. TSTs were positive in 41 of 76 participants (53.9%) and QFT was positive in 65 of 76 participants (85.5%). There was a significant difference between the numbers of QFT-positive and TST-positive cases (P=0.02). When the induration diameter of TST was > or = 20 mm, QFT positivity was 100%. Multivariate analysis revealed that there was a significant correlation between the percentage of patients with QFT positivity and the induration diameter of TST (P=0.009). QFT thus seems to be more effective for LTBI diagnosis than TST. However, large-scale trials including quantitative measurement of QFT in subgroups taking into account the division where HCWs are employed and the different results of TST might clarify the usefulness of QFT in LTBI diagnosis.