Table 2.
Distribution of retest results by nativity among 406 close contacts enrolled in a multi-center study in the United States.
| Test combination | Retest results n = 406 |
Non-U.S.–born n = 209 |
U.S.-born n = 197 |
|||
|---|---|---|---|---|---|---|
| n | (%) | n | (%) | n | (%) | |
| Triple positive (+++) | 12 | (3) | 11 | (5) | 1 | (1) |
| Triple negative ( − − −) | 358 | (88) | 173 | (83) | 185 | (94) |
| Isolated TST+ (+−−) | 24 | (6) | 18 | (9) | 6 | (3) |
| Isolated QFT-GIT+ (−+−) | 5 | (1) | 3 | (1) | 2 | (1) |
| Isolated T-SPOT+ (−−+) | 1 | (0.2) | 1 | (0.5) | 0 | (0) |
| Isolated TST− (−++) | 1 | (0.2) | 1 | (0.5) | 0 | (0) |
| Isolated QFT-GIT− (+−+) | 0 | (0) | 0 | (0) | 0 | (0) |
| Isolated T-SPOT− (++−) | 5 | (1) | 2 | (1) | 3 | (2) |
The 406 contacts had negative results for all three tests at baseline, valid results (positive or negative, i.e., no missing, indeterminate, invalid or borderline results) for all three tests at retest, and all information on TB cases and contact characteristics. TST = Tuberculin skin test; QFT-GIT = QuantiFERON-TB Gold In-Tube; T-SPOT = T-SPOT.TB. The order of test results (TST, QFT-GIT, T-SPOT); + = positive, − = negative.