Time point | Contacts | Incident TB cases | Incident TB cases | Other contacts | Sensitivity (95% CI)§ | Specificity (95% CI)§ | PPV (95% CI)§ | NPV (95% CI)§ | ||
Test + | Test - | Test + | Test - | |||||||
Primary analysis# | ||||||||||
TST ≥10 mm | 339 | 9ƒ | 9 | 0 | 279 | 51 | 100 (100–100) | 15 (12–19) | 3.1 (1.3–5.0) | 100 (100–100) |
TST ≥15 mm | 322 | 8ƒ | 7 | 1 | 177 | 137 | 88 (84–91) | 44 (38–49) | 3.8 (1.7–5.9) | 99.3 (98.4–100) |
QFT-GIT | 327 | 8 | 5 | 3 | 173 | 146 | 63 (57–68) | 46 (40–51) | 2.8 (1.0–4.6) | 98.0 (96.5–99.5) |
T-SPOT.TB® | 299 | 8 | 6 | 2 | 175 | 116 | 75 (70–80) | 40 (34–45) | 3.3 (1.3–5.3) | 98.3 (96.8–99.8) |
Secondary analysis¶ | ||||||||||
TST ≥10 mm | 334 | 7 | 7 | 0 | 278 | 49 | 100 (100–100) | 15 (11–19) | 2.5 (0.8–4.1) | 100 (100–100) |
TST ≥15 mm | 317 | 7 | 6 | 1 | 176 | 134 | 86 (82–90) | 43 (38–49) | 3.3 (1.3–5.3) | 99.3 (98.3–100) |
QFT-GIT | 323 | 6## | 3 | 3 | 173 | 144 | 50 (45–55) | 45 (40–51) | 1.7 (0.3–3.1) | 98.0 (96.4–99.5) |
T-SPOT.TB® | 295 | 6## | 4 | 2 | 175 | 114 | 67 (61–72) | 39 (34–45) | 2.2 (0.5–3.9) | 98.3 (96.8–99.8) |
Sensitivity analysis+ | ||||||||||
TST ≥10 mm | 203 | 7 | 7 | 0 | 165 | 31 | 100 (100–100) | 16 (11–21) | 4.1 (1.4–6.8) | 100 (100–100) |
TST ≥15 mm | 191 | 7 | 6 | 1 | 107 | 77 | 86 (81–91) | 42 (35–49) | 5.3 (2.1–8.5) | 98.7 (97.1–100) |
QFT-GIT | 201 | 6## | 3 | 3 | 112 | 83 | 50 (43–57) | 43 (36–49) | 2.6 (0.4–4.8) | 96.5 (94.0–99.1) |
T-SPOT.TB® | 186 | 6## | 4 | 2 | 114 | 66 | 67 (60–73) | 37 (30–44) | 3.4 (0.8–6.0) | 97.1 (94.6–99.5) |
Data are presented as n, unless otherwise stated. +: positive; -: negative; PPV: positive predictive value; NPV: negative predictive value. #: all contacts with TST ≥5 mm; test parameters determined with follow-up until August 1, 2008. ¶: contacts with TST ≥5 mm, who started follow-up ≥12 months before August 1, 2008; test parameters are determined after 12 months follow-up. +: contacts with TST ≥5 mm, who were actively followed for ≥12 months; test parameters determined after 12 months of follow-up. §: sensitivity, specificity, PPV and NPV for development of TB disease are determined in immigrant close contacts with TST ≥5 mm. ƒ: TST was known positive (≥10 mm) in one incident TB case and not determined at recruitment of the study; this case was excluded from the analysis of TST ≥15 mm. ##: interferon-γ release assay was not performed in one incident TB case. QFT-GIT is manufactured by Cellesis, Carnegie, Australia; T-SPOT.TB® is manufactured by Oxford Immunotec, Abingdon, UK.