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

[摘要] BACKGROUND. 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-γ 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).OBJECTIVE. To evaluate the impact of age on the performance of interferon-γ release assays when used in a routine hospital setting among children tested for suspected active or latent TB infection.METHODS. 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-γ release assay: 181 with QuantiFERON-TB Gold and 315 with QuantiFERON-TB In-Tube. In 154 of the children, paired interferon-γ release assay testing was available: 87 with QuantiFERON-TB Gold/T-SPOT. TB and 67 with QuantiFERON-TB In-Tube/T-SPOT. TB .RESULTS. 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 than in those ≥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 and ≥4 years of age), a significantly higher concentration of phytohaemagglutinin-produced interferon-γ was observed in older children with both QuantiFERON-TB Gold and QuantiFERON-TB In-Tube.CONCLUSIONS. 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 <4 years of age.

[学科分类] 儿科学