Interferon-gamma release assays do not identify more children with active tuberculosis than the tuberculin skin test.
Data are lacking on the performance of interferon-gamma release assays (IGRAs) in children. Although IGRAs are recommended for screening for latent tuberculosis infection (LTBI), many clinicians wish to employ them as a diagnostic test for active tuberculosis (TB). The objective of the present study was to compare the performance of the two commercially available IGRAs and the tuberculin skin test (TST) side-by-side in children with active TB and LTBI. In a prospective study, 209 children were investigated for active (n = 91) or latent TB (n = 118). TST, QuantiFERON-TB Gold In-tube (QFG-IT; Cellestis, Carnegie, Australia) and T-SPOT.TB (Oxford Immunotec, Abingdon, UK) assays were simultaneously used. For culture-confirmed active TB, the sensitivity of the TST was 83%, compared with 80% for QFG-IT and 58% for T-SPOT.TB. IGRAs did not perform significantly better than TST, although QFG-IT was significantly better than T-SPOT.TB. The agreement between QFG-IT and T-SPOT.TB in culture-confirmed TB was poor at 66.7%. In LTBI, the agreement between QFG-IT and T-SPOT.TB was very good (92%) with moderate agreement between TST and T-SPOT.TB (75%) and QFG-IT and TST (77%). A negative interferon-gamma release assay should not dissuade paediatricians from diagnosing and treating presumed active tuberculosis. If used for diagnosis of latent tuberculosis infection, interferon-gamma release assays could significantly reduce the numbers of children receiving chemoprophylaxis. Very good concordance between both tests was found.
Kampmann
B
B
Academic Dept of Paediatrics, 2nd Floor Wright-Fleming Building, Imperial College London, London, UK. b.kampmann@imperial.ac.uk
Whittaker
E
E
Williams
A
A
Walters
S
S
Gordon
A
A
Martinez-Alier
N
N
Williams
B
B
Crook
A M
AM
Hutton
A-M
AM
Anderson
S T
ST
D000293:Adolescent; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007159:Immunologic Tests / Q000379:methods*; D007223:Infant; D007371:Interferon-gamma / Q000097:blood*; D008297:Male; D009169:Mycobacterium tuberculosis; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013997:Time Factors; D014374:Tuberculin Test; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000276:immunology
D007371:Interferon-gamma