Interferon-gamma release assay improves the diagnosis of tuberculosis in children.
BACKGROUND
Interferon-gamma release assays (IGRAs) have been recently developed for the diagnosis of tuberculosis (TB) infection. The aim of the present study was to evaluate the performance of an enzyme-linked immunosorbent assay (ELISA)-based IGRA for detecting TB in children.


METHODS
A prospective study in 336 children at risk for TB infection was carried out. All children were tested with tuberculin skin test (TST) and a commercial ELISA-based IGRA [QuantiFERON-TB Gold In-Tube (Cellestis)].


RESULTS
TST were positive in 58 of 336 (17.3%) and IGRA in 60 of 336 (17.9%) children. Two (0.6%) IGRA results were indeterminate. The overall agreement between the 2 tests was intermediate (86.2%, kappa= 0.533). IGRA was positive in 15 of 16 (93.8%) children with active pulmonary TB. The discordant pattern IGRA-/TST+ was significantly associated with Bacille Calmette-Guérin (BCG) vaccination. Among IGRA+ children (excluding cases of TB disease), TST- were significantly younger than TST+ children.


CONCLUSIONS
The good agreement between positive IGRA and active TB disease suggests a good sensitivity of IGRA. Discrepancies between IGRA and TST can be a result of higher specificity of IGRA that is not influenced by previous BCG vaccination. IGRA may be more sensitive in children younger than 48 months.
Bianchi
Leila
L
Department of Pediatrics, University of Florence, Florence, Italy.
Galli
Luisa
L
Moriondo
Maria
M
Veneruso
Giuseppina
G
Becciolini
Laura
L
Azzari
Chiara
C
Chiappini
Elena
E
de Martino
Maurizio
M
D001500:BCG Vaccine; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism*; D008297:Male; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology
D001500:BCG Vaccine; D007371:Interferon-gamma