Acute effect of low-flux hemodialysis process on the results of the interferon-gamma-based QuantiFERON-TB Gold In-Tube test in end-stage renal disease patients.

BACKGROUND: Screening for latent tuberculosis infection before solid organ transplantation is mandatory, but this is not so easy in uremic patients on hemodialysis (HD) treatment. The newly developed interferon-gamma (IFN-gamma)-based QuantiFERON((R))-TB Gold In-Tube test (QFT-G) seems to be superior to the other available tests. Objective. To investigate the acute effect of the low-flux HD process on the results of the QFT-G assay.
METHODS: A total of 56 HD patients participated in this prospective study. They were dialyzed under low-flux HD for at least 1 month before blood sampling for QFT-G assay. This assay was performed before and after the 4-h low-flux HD session.
RESULTS: Compared with the pre-dialysis level, there was an obvious reduction in the IFN-gamma production level (in response to the TB-antigen cocktails) after the HD process (P=0.00). The pre-dialysis test result was negative in 21 (37.5%), positive in 33 (58.9%), and indeterminate in 2 (3.6%) patients. One pre-dialysis negative result changed to positive after the HD process. On the other hand, 7 pre-dialysis positive and 2 indeterminate results become negative after HD (P=0.012).
CONCLUSION: In order to maintain the sensitivity of QFT-G assay in chronic renal failure patients on low-flux HD treatment, it is better to perform the test immediately before (not after) the HD process.