QuantiFERON-TB Gold In-Tube Test in the Diagnosis of Latent Tuberculosis Infection in Arthritis Patients Treated with Tumor Necrosis Factor Antagonists

The aim of this study was to investigate the role of the QuantiFERON-TB Gold In-Tube test (QFT-GIT) in detecting latent tuberculosis in immunocompromised patients before introducing tumor necrosis factor (TNF-α) antagonists. The study included 300 subjects of similar age. The study group comprised of 150 QuantiFERON (QFT) positive subjects with rheumatoid arthritis, Crohn’s disease, ulcerative colitis, ankylosing spondylitis and psoriatic arthritis, while control group comprised of 150 QFT negative respondents with the same diseases. Exhaustive medical history was documented for all patients. Screening tests were performed including QFT-GIT, tuberculin skin test (TST), chest radiography and detection of Mycobacterium tuberculosisin sputum culture 2 times. A positive QFT-GIT test result, regardless of TST result, was considered as an indication for latent tuberculosis infection (LTBI) treatment. Results of this study showed good correlation between the conclusive results of QFT-GIT and TST. All study group patients had normal clinical findings, normal radiologic findings and negative results of sputum microbiological analysis during the course of prophylaxis and after its completion and during the course of biological therapy. Conversion of positive QFT-GIT test to negative was observed in 4% of study group patients, while QFT negative respondents remained negative. There was a statistically significant positive correlation between QFTGIT, TST results and patient age, smoking habit and contact with tuberculosis. Study results showed that along with good clinical evaluation and detailed medical history, it is important to conduct testing in order to avoid disease progression or unnecessary isoniazid prophylaxis