Table 1.
LTBI test results among older people and young adults, by exposure history
| Community + Recent contacts |
Community |
Recent contacts |
|||||||
|---|---|---|---|---|---|---|---|---|---|
| Young adults n (%) |
Elderly n (%) |
P value | Young adults n (%) |
Elderly n (%) |
P value | Young adults n (%) |
Elderly n (%) |
P value | |
| Conclusive (T-SPOT.TB and QFT complement) a | 0.075 | <0.001 | 0.641 | ||||||
| Negative | 219 (45.6) | 65 (37.8) | 92 (77.3) | 33 (44.6) | 127 (35.2) | 32 (32.7) | |||
| Positive | 261 (54.4) | 107 (62.2) | 27 (22.7) | 41 (55.4) | 234 (64.8) | 66 (67.4) | |||
| T-SPOT.TB | 0.264 | 0.002 | 0.124 | ||||||
| Negative | 230 (48.0) | 72 (42.9) | 92 (77.3) | 37 (52.9) | 138 (38.3) | 35 (35.7) | |||
| Positive | 230 (48.0) | 85 (50.6) | 25 (21.0) | 32 (45.7) | 205 (56.9) | 53 (54.1) | |||
| Borderline | 19 (4.0) | 11 (6.6) | 2 (1.7) | 1 (1.4) | 17 (4.7) | 10 (10.2) | |||
| QFT (QFT-Gold In-tube or QFT-Plus) | 0.117 | <0.001 | 0.177 | ||||||
| Negative | 173 (46.0) | 58 (39.5) | 58 (85.3) | 30 (53.6) | 115 (37.3) | 28 (30.8) | |||
| Positive | 194 (51.6) | 81 (55.1) | 10 (14.7) | 24 (42.9) | 184 (59.7) | 57 (62.6) | |||
| Indeterminate | 9 (2.4) | 8 (5.4) | 0 (0.0) | 2 (3.6) | 9 (2.9) | 6 (6.6) | |||
| Inconclusive (borderline or indeterminate) vs conclusive (positive and negative combined) b | |||||||||
| Borderline or indeterminate | 28 (5.8) | 20 (11.6) | 0.012 | 2 (1.7) | 3 (4.0) | 0.313 | 26 (7.2) | 17 (17.3) | 0.002 |
| Borderline | 19 (4.0) | 11 (6.6) | 0.171 | 2 (1.7) | 1 (1.4) | 0.893 | 17 (4.7) | 10 (10.2) | 0.041 |
| Indeterminate | 9 (2.4) | 8 (5.4) | 0.077 | 0 (0.0) | 2 (3.6) | 0.116 | 9 (2.9) | 6 (6.6) | 0.106 |
a
LTBI was positive when the T-SPOT.TB or QuantiFERON (QFT) assays (Gold In-tube or QuantiFERON-Plus) were positive. Borderline or indeterminate results were complemented with the positive or negative finding from the other IGRA.
b
Comparisons of negative and positive values combined (conclusive) vs borderline or indeterminate or both types of inconclusive results combined. Differences between groups established by Chi-square test. Significant or borderline significant differences are shown in bold text.