Predictive values of QuantiFERON-TB Gold testing in screening for tuberculosis disease in asylum seekers

Screening with chest X-ray and the Mantoux test (the tuberculin skin test [TST]) is compulsory for adult asylum seekers who arrive in Norway. In 2005-2006, we included 823 asylum seekers in a study of the QuantiFERON-TB Gold test (QFT-G), and followed them for 23-32 months. Eight subjects with a positive and one with a negative QFT-G test were diagnosed with tuberculosis (TB). The positive (PPV) and negative predictive values (NPV) for TB were respectively 3.3% and 99.8%. The PPV was 2.3% and the NPV 99.1% for TST >or= 15 mm, and the NPV was 99.5% for TST >or= 6 mm in combination with a negative QFT-G.