Comparison of Quantiferon-TB Gold versus tuberculin skin test for tuberculosis screening in inflammatory bowel disease patients.

BACKGROUND & AIM Screening for latent tuberculosis (LTB) is recommended before starting anti-TNF-alpha therapy. We compared the performance of Quantiferon-TB Gold (QFT-G) with the tuberculin skin test (TST) for the screening of LTB in a population of inflammatory bowel disease (IBD) patients who were candidates for anti-TNF-α therapy. METHODS Ninety-two IBD patients who were candidates for anti-TNF-α therapy were tested with QTF-G and TST. Concomitant therapy and laboratory parameters were recorded. RESULTS One subject was vaccinated with Bacille Calmette Guèrin (BCG), 76% of patients were on immunosuppressive therapy (IST), and all patients had a negative TB history and negative chest X-ray. Agreement between the two tests was observed in 89.2% of patients (79.4% +/+, 9.8% -/-), QFT-G+/TST- was observed in 4.4% (4) patients, and QFT-G-/TST+ was observed in 5.5%, one of which was previously vaccinated. All disagreements were observed in patients on IST (14.3% in this group). The agreement analysis showed moderate strength among the patients (k=0.508), while the agreement was only fair in the subgroup of patients on IST (k=0.388). CONCLUSION Given the high risk of LTB reactivation in patients subjected to anti-TNF-α therapy, our results suggest that in our population, with low TB rate and very low BCG vaccination rate, both tests could be employed.