Performance of Commercial Blood Tests for the Diagnosis of Latent Tuberculosis Infection in Children and Adolescents

• Published in: Pediatrics (Evanston) 2009-03, Vol.123 (3), p.e419-e424
• Main Authors: Bergamini, Barbara Maria, Losi, Monica, Vaienti, Francesca, D'Amico, Roberto, Meccugni, Barbara, Meacci, Marisa, De Giovanni, Donatella, Rumpianesi, Fabio, Fabbri, Leonardo M, Balli, Fiorella, Richeldi, Luca
• Format: Article
• Language: English
• Subjects: Adolescent; Age Factors; Child; Child, Preschool; Children & youth; Disease Progression; Enzyme-Linked Immunosorbent Assay - methods; Female; Hematologic Tests - methods; Humans; Immunoassay; Infant; Interferon; Interferon-gamma - blood; Italy; Male; Mass Screening; Medical diagnosis; Mycobacterium tuberculosis - immunology; Pediatrics; Predictive Value of Tests; Reagent Kits, Diagnostic; Retrospective Studies; Risk; Studies; Tuberculin Test - statistics & numerical data; Tuberculosis; Tuberculosis, Lymph Node - diagnosis; Tuberculosis, Lymph Node - epidemiology; Tuberculosis, Pulmonary - diagnosis; Tuberculosis, Pulmonary - epidemiology
• ISSN: 0031-4005; 1098-4275
• DOI: 10.1542/peds.2008-1722

The accurate diagnosis of latent tuberculosis infection reduces the risk of progression to severe disseminated disease. However, in young children, a major limitation of the standard tuberculin skin test is that false-negative results cannot be detected. The new interferon-gamma release assays QuantiFERON-TB Gold (Cellestis Carnegie Victoria, Australia), QuantiFERON-TB In-Tube (Cellestis), and T-SPOT.TB (Oxford Immunotec, Abingdon, United Kingdom) show promise of greater accuracy, but they may also be affected by impaired cellular immunity, resulting in indeterminate results (ie, insufficient response in positive-control wells). To evaluate the impact of age on the performance of interferon-gamma release assays when used in a routine hospital setting among children tested for suspected active or latent TB infection. We retrospectively studied 496 children 0 to 19 years of age who had been tested with the tuberculin skin test and at least 1 interferon-gamma release assay: 181 with QuantiFERON-TB Gold and 315 with QuantiFERON-TB In-Tube. In 154 of the children, paired interferon-gamma release assay testing was available: 87 with QuantiFERON-TB Gold/T-SPOT.TB and 67 with QuantiFERON-TB In-Tube/T-SPOT.TB. Compared with T-SPOT.TB, the rates of indeterminate results were significantly higher for both QuantiFERON-TB Gold and QuantiFERON-TB In-Tube. QuantiFERON-TB Gold and QuantiFERON-TB In-Tube also gave indeterminate results more frequently in children /=4 years of age. Indeterminate results were associated with younger age for both QuantiFERON-TB Gold and QuantiFERON-TB In-Tube but not for T-SPOT.TB. Considering age as a binary variable (/=4 years of age), a significantly higher concentration of phytohaemagglutinin-produced interferon-gamma was observed in older children with both QuantiFERON-TB Gold and QuantiFERON-TB In-Tube. Different blood tests for the diagnosis of latent tuberculosis infection in children seem to perform differently, because both QuantiFERON-TB tests were more likely than T-SPOT.TB to give indeterminate results in children