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In vitro interferon-γ (IFN-γ) assays have emerged as novel alternatives to the tuberculin skin test (TST) for the diagnosis of latent tuberculosis (TB) infection. These assays have been evaluated in low incidence countries, mainly in adults, and have been shown to be more specific than TST. Because few studies have been done in high incidence countries, and because paediatric data are limited, we compared a whole-blood IFN-γ assay with TST among hospitalized Indian children.

Between July 2004 and June 2005, a total of 105 consecutively admitted children (median age 6years; 82% had BCG scars) in whom TB was suspected or had history of contact with an index case were recruited at a rural hospital in India. All children underwent TST, and the QuantiFERON-TB-Gold In Tube (QFT) assay.

The overall prevalence of TB infection was similar with both tests. With a TST cut-off …