The Performance of Quantiferon TB Gold In-Tube as a Screening Tool in Paediatric Rheumatology prior to Initiation of Infliximab: A Single Centre's Experience.

Background. Patients with autoimmune diseases and latent tuberculosis infection (LTBI) are at risk of developing catastrophic tuberculosis disease following infliximab treatment. Quantiferon-TB gold in-Tube (QTB) has proven a more accurate screening tool than tuberculin skin test (TST) in adult populations. Objectives. To assess the utility and validity of QTB in children, prior to treatment with infliximab. Methods. Retrospective cohort of patients started on infliximab following endorsement of QTB as a screening tool by the NICE guidelines in 2006. Results. Twenty three patients (12 females and 11 males) were included in the study. A chest radiograph (CXR) and QTB was performed prior to starting infliximab. Fourteen patients had a recorded negative TST result. One patient had a positive QTB while two had indeterminate results. Their CXRs were not suggestive of TB and TSTs were negative. The patients with indeterminate results were started on infliximab and had regular clinical assessment for TB disease. Repeat QTB was negative in one while remained indeterminate in the other. None of our 23 patients developed TB. Conclusion. QTB is a useful screen tool for LTBI. Indeterminate results warrant careful assessment and re-evaluation, but should not preclude from initiation of anti TNF treatment.