Table 5.
Baseline IFN-γ response, IU/ml | Retested n | TST-positive at baseline n (%) | Frequency of QFT reversions | Annual incidence of QFT reversions % | P value for trend in QFT reversion rates* |
---|---|---|---|---|---|
0.35–0.69 | 10 | 5 (50) | 2 | 20.0 | 0.001 |
0.70–1.0 | 5 | 2 (40) | 1 | 20.0 | |
1.01–3.0 | 23 | 15 (65) | 4 | 17.4 | |
3.01–6.0 | 17 | 14 (82) | 0 | 0 | |
6.01–10.0 | 54 | 49 (91) | 0 | 0 | |
Total | 109 | 85 (78) | 7 | 6.4 |
Cochrane-Armitage test for trend: χ2 = 11.66 (df 1); P = 0.001.
IFN-γ = interferon-gamma; QFT = QuantiFERON-TB Gold In-Tube®; IU = international units; TST = tuberculin skin test; df = degrees of freedom.