Table 2.
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%) |
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).