Table 4.
Median quantitative test values of converters* among 406 contacts with triple negative baseline results enrolled in a multi-center study in the United States.
| TST | QFT-GIT | T-SPOT | |||||||
|---|---|---|---|---|---|---|---|---|---|
| (Median (IQR), mm) | (Median (IQR), IU/ml) | (Median (IQR), spots) | |||||||
| n | Baseline | Retest | n | Baseline | Retest | n | Baseline | Retest | |
| TB case characteristics | |||||||||
| Chest radiograph | |||||||||
| Cavitary | 30 | 0 (0–0) | 12 (9–15) | 20 | 0 (0–0.1) | 2.3 (0.7–3.4) | 13 | 0 (0–2) | 32 (19–50) |
| Noncavitary | 11 | 0 (0–0) | 10 (6–15) | 3 | 0.1 (0–0.1) | 1.1 (0.4–1.2) | 1 | 1 (1–1) | 27 (27–27) |
| Contact characteristics | |||||||||
| Nativity | |||||||||
| Non-U.S.–born | 31 | 0 (0–0) | 12 (8–15) | 17 | 0 (0.01–0.1) | 2.4 (0.8–3.7) | 13 | 1 (0–2) | 32 (20–50) |
| U.S.-born | 10 | 0 (0–0) | 10 (7–12) | 6 | 0 (-0.01–0.1) | 1.2 (0.4–2.3) | 1 | 0 (0–0) | 17 (17–17) |
| Sex | |||||||||
| Female | 20 | 0 (0–0) | 14 (8–17) | 14 | 0 (0.01–0.1) | 1.8 (0.8–2.8) | 8 | 1 (0–2) | 26 (20–35) |
| Male | 21 | 0 (0–0) | 11 (10–13) | 9 | 0.1 (0–0.1) | 2.3 (0.6–3.7) | 6 | 0 (0–2) | 45 (17–50) |
| Age (years) | |||||||||
| ≤14 | 6 | 0 (0–0) | 7 (6–11) | 3 | 0 (0.0–0.1) | 2.8 (0.4–10) | 1 | 0 (0–0) | 50 (50–50) |
| 15–24 | 9 | 0 (0–0) | 11 (9–14) | 5 | 0 (0.0–0.1) | 1.1 (0.4–1.2) | 1 | 0 (0–0) | 17 (17–17) |
| 25–44 | 18 | 0 (0–0) | 13 (10–19) | 10 | 0.1 (0–0.3) | 2.5 (0.8–3.7) | 9 | 1 (0–3) | 32 (20–50) |
| 45–64 | 6 | 0 (0–0) | 15 (11–17) | 4 | 0 (0–0.1) | 1.2 (0.6–5.7) | 2 | 0 (0–0) | 28 (19–37) |
| ≥65 | 2 | 0 (0–0) | 11 (10–12) | 1 | 0 (0–0) | 3.1 (3.1–3.1) | 1 | 1 (1–1) | 24 (24–24) |
| Race/ethnicity | |||||||||
| Asian | 15 | 0 (0–0) | 11 (8–19) | 10 | 0.1 (0–0.1) | 1.2 (0.78–2.5) | 6 | 0 (0–2) | 38 (19–50) |
| African American/Black | 7 | 0 (0–0) | 13 (6–15) | 4 | 0.1 (0–0.2) | 5.0 (0.4–9.8) | 3 | 3 (0–4) | 32 (9–50) |
| White | 4 | 0 (0–0) | 11 (10–15) | 1 | 0 (0–0) | 2.3 (2.3–2.3) | 1 | 0 (0–0) | 17 (17–17) |
| Hispanic | 13 | 0 (0–0) | 12 (1–14) | 5 | 0 (0–0) | 2.8 (1.7–2.8) | 3 | 1 (0–1) | 27 (20–50) |
| Other** | 2 | 0 (0–0) | 11 (10–12) | 3 | 0.1 (0–0.4) | 1.9 (0.4–3.1) | 1 | 1 (1–1) | 24 (24–24) |
*Contacts with negative results at baseline who converted to positive results at retest and having all information for TB cases and contact demographics are included here. ** ‘Other’ race also includes Alaska Native/American Indian, and Native Hawaiian/Pacific Islander groups. All listed races are non-Hispanic. AFB = acid-fast bacillus; TST = tuberculin skin test; QFT-GIT = QuantiFERON-TB Gold In-Tube; T-SPOT = T-SPOT.TB; IQR = Interquartile range, mm = millimeter, IU/mL = international units per milliliter.