RT Journal Article SR Electronic T1 Diagnosing TB infection in children: analysis of discordances using in vitro tests and tuberculin skin test JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP erj00227-2010 DO 10.1183/09031936.00022710 A1 N. Altet-Gómez A1 M. De Souza-Galvao A1 I. Latorre A1 C. Milá A1 M.Á. Jiménez A1 J. Solsona A1 A. Cantos A1 J.J. Zamora A1 J. Ruiz-Manzano A1 V. Ausina A1 J. Domínguez YR 2010 UL http://erj.ersjournals.com/content/early/2010/08/19/09031936.00022710.abstract AB To study the performance of the IFN-γ tests (QuantiFERON-TB-Gold In Tube [QFN-G-IT] and T-SPOT.TB) and the tuberculin skin test (TST) in diagnosing tuberculosis infection in children, and to analyse discordant results.A prospective study including 98 children from contact-tracing studies; and 68 children with TST≥5mm recruited during public health screenings.Positive IFN-γ tests results were associated with risk of exposure (p<0.0001). T-SPOT.TB was positive in 11/14 cases with active TB (78.6%) and QFN-G-IT in 9/14 (64.3%). In 6 of 12 children non-BCG-vaccinated, with a TST induration between 5 and 9 mm and both IFN-γ tests negatives, the detection of sensitised T cells against Mycobacterium avium was positive. In concordant IFN-γ tests results, a positive correlation was found (p=0.0001) between the number of responding cells and the amount of IFN-γ released; however, in discordant IFN-γ tests results this correlation was negative (p=0.371): an increase in the number of spot forming cells correlated with a decrease in the amount of IFN-γ released.The use of IFN-γ tests is helpful for the diagnosis of TB infection, avoiding cross-reactions with BCG immunisation and NTM infections. The analysis of highly discordant results requires further investigation to elucidate possible clinical implications.