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Table 2 Concordance between TST and T-SPOT.TB Results

From: Use of interferon gamma-based assay to diagnose tuberculosis infection in health care workers after short term exposure

Characteristics New TST positives Previously defined as TST positives Total
TST positives among exposed (%) 27/155 (17%) 15/155 (10%) 42/155 (27%)
T-SPOT.TB -positives among exposed (%) 3/155 (2%) 2/155 (1%) 5/155 (3%)
T-SPOT.TB -positives among TST positives (%) 3/27 (11%) 2/15 (13%) 5/42 (12%)
  1. Table 2 depicts concordance between tuberculin skin test (TST) and T-SPOT.TB results. Results in absolute numbers (percentages in brackets) from post-exposure screening of 155 health care workers (HCWs) and 48 healthy controls, 2005–2007. During childhood all participants were either BCG-immunized or had a naturally positive TST. The definition of a positive TST (Mantoux) was an increase of ≥ 10 mm, or of ≥ 15 mm if previous TST status was unknown (in concordance with the national guidelines). The exposed HCWs were also tested with T-SPOT.TB, an interferon-gamma release assay (IGRA). Some HCWs had been defined as TST positives during previous post-exposure screenings (15) while others were defined as TST positives during the current study (27).