QuantiFERON-TB Gold test for screening latent tuberculosis infection in hemodialysis patients

Abstract

Hemodialysis patients are at increased risk of latent tuberculosis infection (LTBI) compared with the general population. QuantiFERON-TB Gold (QFT-G) for LTBI detection is more promising than tuberculin skin test (TST) in hemodialysis patients. The aim of this study is to determine whether the QFT-G is more sensitive than the TST in hemodialysis patients in LTBI. Eighty nine hemodialysis patients were evaluated for latent tuberculosis infection with the TST and QFT-G. Blood was obtained for QFT-G, and then TST was administered to all patients. Demographic information, laboratory tests, chest radiography results and BCG vaccination status were collected on standardized patient medical files. Forty patients had positive QFT-G results. 56 patients had TST induration above 5 mm, 28 patients above 10 mm. 61 patients had BCG vaccination scar. Statistically significant correlation was detected between TST and QFT-G (p< 0.05). In the BCG non-vaccinated subgroup, TST was positive in 8 (29%) patients and the QFT-G was positive in 11 (39%). Among the 21 non vaccinated patients with results for both tests, the concordance between the TST and QFT-G was 82%, k= 0.61, p= 0.001. We found good agreement between the TST and QFT-G test for LTBI in non vaccinated hemodialysis patients, whereas we found poor agreement in vaccinated patients. Because BCG vaccination is widely used in our country, the QFT-G test might be more useful for the diagnosis of LTBI than TST in hemodialysis patients who are suspected to have LTBI.