QuantiFERON–TB Gold In-Tube test performance in Denmark.

Area of Science:

• Immunology
• Infectious Diseases
• Diagnostics

Background:

• Limited data exists on QuantiFERON-TB Gold In-Tube Test (QFT) performance in extreme age groups.
• Previous reports on QFT efficacy in children and the elderly are conflicting.

Purpose of the Study:

• To evaluate the performance of the QuantiFERON-TB Gold In-Tube Test (QFT) in patients diagnosed with Tuberculosis (TB) and those without the disease.
• To assess the impact of age, sex, TB localization, and culture results on QFT outcomes.

Main Methods:

• Retrospective analysis of 18,850 QFT results from Denmark (2005-2010).
• Evaluation of QFT performance, including positive, negative, and indeterminate results, across different age groups and patient cohorts.

Main Results:

• High QFT sensitivity (86.1%) was observed in TB patients, unaffected by sex or TB location, but decreased with age.
• In children aged 1-4 years, QFT sensitivity was 100%.
• Higher indeterminate QFT rates were found in infants (<1 year, 15.6%) and the elderly (>65 years, 8.1%) compared to adults (4.5%), primarily due to low positive control.

Conclusions:

• QFT demonstrates good overall performance in Denmark, a low TB incidence country.
• QFT sensitivity is high in children aged 1 year and older, supporting its use in low endemic regions.
• QFT should be used cautiously in the elderly due to increased indeterminate rates and declining sensitivity with age.