No added value of interferon-γ release to a prediction model for childhood tuberculosis.

The predictive value of a combination of clinical and radiological features with interferon-γ release assay (IGRA) for diagnosis of active tuberculosis (TB) disease among TB-exposed children is unknown. 150 symptomatic HIV-negative children (aged 3 months to 14 years), prospectively recruited through active contact tracing, were included. Backward stepwise logistic regression and bootstrapping techniques were used for the development and internal validation of a clinical prediction model for active TB disease. Model discrimination and incremental value of a positive IGRA test were assessed by area under the receiver operating characteristic curve (AUC). 35 (23%) children were diagnosed with active TB disease and started on treatment and 115 (77%) had other respiratory tract infections. A final parsimonious clinical model, comprising age versus 0.70; p=0.644). A clinical algorithm, including age