Table 3 Qualitative and quantitative analysis of tuberculin skin test (TST) and interferon gamma release assay (IGRA) results in household contacts with TST conversion according to contact age
Variable | Total | Household Contact Age Group (years) | ||||
|---|---|---|---|---|---|---|
0–5 | 6–10 | 11–20 | 21–40 | >40 | ||
Number of contacts | 838 | 91 | 126 | 203 | 224 | 194 |
TST <5 mm at baseline (at risk of conversion) | 262 | 42 | 52 | 68 | 53 | 47 |
TST conversion (Criterion 1 OR Criterion 2) | ||||||
N converters/ total contacts (%) | 62 (7.4) | 5 (5.5) | 12 (9.5) | 17 (8.3) | 14 (6.3) | 14 (7.2) |
TST size in converters (mm) | ||||||
Median [IQR] | 16 [13–20] | 11 [10–20] | 18 [15–20] | 15 [14–18] | 18 [10–19] | 15 [12–16] |
Mean [SD] | 16 {4.2} | 14 {5.3} | 17 {3.7} | 16 {3.3} | 16 {5.0} | 17 {4.6} |
Range | [10–25} | [10–20] | [10–23] | [10–24} | [10–24] | [11–25] |
IGRA in TST converters (IU/mL) | ||||||
Positive (%) | 40/58 (69) | 2/3 (67) | 8/12 (67) | 12/16 (75) | 8/13 (62) | 10/14 (71) |
Median [IQR] | 4.7 [0.07–10] | 6.4 [0–10] | 10.3 [0.07–10] | 10 [0.08–10] | 2.6 [0.04–9.1] | 2.7 [0.2–10] |
Mean [SD] | 5.1 {4.6} | 5.5 {5.1} | 5.1 {4.7} | 6.2 {4.7} | 4.2 [4.8] | 4.5 {4.5} |
Range | [0–10] | [0–10] | [0–10] | [0–10] | [0–10] | [0–10] |