ORIGINAL PAPER

Comparison of Quantiferon-TB Gold versus Tuberculin Skin Test for Tuberculosis Screening in Inflammatory Bowel Disease Patients

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Gianluca Andrisani, Alessandro Armuzzi, Alfredo Papa, Manuela Marzo, Carla Felice, Daniela Pugliese, Italo De Vitis, Gian Lodovico Rapaccini, Luisa Guidi

Department of Gastroenterology CIC, Catholic University, Rome, Italy


Abstract


Background & Aim: Screening for latent tuberculosis (LTB) is recommended before starting anti-TNF-α
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 Guerin (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+/TSTwas 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.

Key words: inflammatory bowel disease - latent tuberculosis - Quantiferon test - tuberculin skin test - anti- TNF-α.

Abbrevations: INHA: isoniazide; AZA: azathioprine; BCG: Bacille Calmette Guerin; CFP-10: culture filtrate protein-10; ESAT-6: early secretory antigen target-6; IBD: inflammatory bowel disease; IFN: interferon; IGRA: interferon-gamma release assay; IST: immunosuppressive therapy; LTB: latent tuberculosis; QFT-G: Quantiferon-TB gold; TB: tuberculosis; TNF-α: tumor necrosis factor-alpha; TST: tuberculin skin test.