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

Table 3 Characteristics of the 5 T-SPOT.TB-positive HCWs

Characteristics	HCW 1	HCW 2	HCW 3	HCW 4	HCW 5
Mantoux (mm) median pre/post exposure	Previously TST positive	12 mm and vesicular	16 mm and vesicular	Previous tuberculosis	15 mm and vesicular
TST positive	Not tested	Yes	Yes	Not tested	Yes
Exposure time (≤ 8 h/> 8 h)	≤ 8 h	≤ 8 h	≤ 8 h	≤ 8 h	> 8 h

Table 3 depicts the characteristics of the 5 HCWs with a positive T-SPOT.TB. Results in absolute numbers 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 tuberculin skin test (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).

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