Comparison of tuberculin skin test and QuantiFERON-TB gold in tube test in patients with chronic inflammatory diseases living in a tuberculosis endemic population.

We aimed to compare tuberculin skin test (TST) and QuantiFERON-TB gold in tube (QFT-IT) in patients with chronic inflammatory diseases living in a population where tuberculosis is endemic and BCG vaccination is routine. Twenty-five patients with rheumatoid arthritis (RA), 16 patients with spondilarthropathy (SpA) and 7 healthy volunteers were recruited in the study. Blood samples were collected for QFT-IT test followed by TST. TST was considered to be positive with an enduration of 5 mm and over in patients with RA and SpA. The cutoff point for TST for the healthy control (HC) was 10 mm. Median TST result of patients who were using immunosuppressive drugs was significantly lower than that of patients who were not [5 (14.5), 13.5 (9.5), respectively, P = 0.04]. Poor agreement between TST and QFT-IT was seen in patients with RA (kappa = 0.141) and in patients with SpA (kappa = 0.190). We found poor concordance between QFT-IT and TST in patients with chronic inflammatory diseases, and TST response was suppressed in patients treated with immunosuppressive drugs.