Table 2.
Criteria for conversion | Number with repeated tests* | Conversions n | Annual incidence of conversions % | 95%CI |
---|---|---|---|---|
TST | ||||
Baseline TST < 10 mm, repeat TST ≥ 10 mm, plus a 6 mm increase over the baseline | 80 | 11 | 13.8 | 7–23 |
Baseline TST < 10 mm, repeat TST ≥ 10 mm, plus a 10 mm increase over the baseline | 80 | 6 | 7.5 | 3–16 |
QFT | ||||
Baseline IFN-γ < 0.35 IU/ml, repeat IFN-γ ≥ 0.35 IU/ml | 85 | 18 | 21.2 | 13–31 |
Baseline IFN-γ < 0.35 IU/ml, repeat IFN-γ ≥ 0.35 IU/ml, plus a 30% increase over the baseline | 85 | 18 | 21.2 | 13–31 |
Baseline IFN-γ < 0.35 IU/ml, repeat IFN-γ ≥ 0.35, plus an absolute increase of 0.35 IU/ml over the baseline | 85 | 15 | 17.6 | 10–27 |
Baseline IFN-γ < 0.35 IU/ml, repeat IFN-γ ≥ 0.70 IU/ml | 85 | 10 | 11.8 | 6–20 |
Only contacts with baseline concordant negative (QFT-negative/TST-negative) results were included in this analysis.
TST = tuberculin skin test; QFT = QuantiFERON-TB Gold In-Tube®; CI = confidence interval; IFN-γ = interferon-gamma.