Evaluation of a New Interferon Gamma Release Assay, in Comparison to Tuberculin Skin Tests and Quantiferon Tuberculosis Goldplus for the Detection of Latent Tuberculosis Infection in Children from a High Tuberculosis Burden Setting

Background: : Detection of latent tuberculosis infection (LTBI) in children, exposed to tuberculosis (TB) infections, followed by appropriate treatment, could be instrumental in reducing TB burden. Interferon Gamma release assays (IGRA) have higher specificity than tuberculin skin tests (TST), hence are more effective option for diagnosis. Hence, the present study was aimed to diagnose the presence of latent TB in children with the help of a new Standard E TB-Feron Enzyme-Linked Immunosorbent Assay (TBF) and evaluating its efficiency as compared to TST and Quantiferon TB Gold plus (QFT Plus). Methods: Diagnosis of LTBI in participants, <18 years old, who were the close household contacts of patients with active TB was carried out employing techniques such as TST, QFT Plus, and TBF. Results: Higher positive results were obtained with IGRA assays QFT Plus and TBF than TST. The perfect agreement was observed between QFT Plus and TBF assays with a Kappa value of 0.9176 whereas TST and TBF assay showed moderate agreement with a Kappa value of 0.42365. The level of cytokines secreted as a result of stimulation by the antigens from QFT Plus tubes was lower in comparison to antigens from TBF tubes. Conclusion: Hence, TBF, which showed similar efficiency as the widely used QFT Plus, can be a useful detection technique for LTBI in children. Moreover, it could prove to be an efficient alternative to expensive IGRAs like QFT Plus.