Performance and correlation of QuantiFERON-TB Gold, T-SPOT.TB and tuberculin skin test in young children with tuberculosis exposure or tuberculosis disease

ABSTRACT

To evaluate the performance of interferon gamma release assays and tuberculin skin test in Bacillus Calmette-Guerin vaccinated young children. Methods: A cross-sectional study was conducted in healthy children younger than 5 years who were recently diagnosed with tuberculosis or had recent exposure to active tuberculosis. QuantiFERON-TB Gold, T-SPOT.TB and tuberculin skin test were performed in each patient. Results: Of the 60 children, median age 3.3 years, 17 had tuberculosis and 43 had recent tuberculosis exposure. Overall, 15 (25.0%) children had tuberculin skin test reaction =10 mm; 8 (13.3%) were positive by QuantiFERON-TB Gold In-Tube test, and 12 (20.0%) by T-SPOT.TB. Nineteen (31.7%) children had at least one positive test. There was a moderate agreement between interferon gamma release assays and tuberculin skin test. Conclusions: The positive rates of interferon gamma release assays and tuberculin skin test were low in young children who were infected with tuberculosis, supporting the management strategy of not testing children younger than 5 years. (IGRA) do not react to BCG and most NTM[2], are preferred to TST in older children and adults[3], but may be less reactive in young children with immature T-cell function. Due to the limited knowledge of IGRA in BCG-vaccinated young children, we evaluated the performance and correlation of IGRA tests and TST in young children in a high TB burden setting who received BCG vaccination at birth and recently diagnosed with LTBI, or with active TB.